Publications

Governments in countries in Sub-Saharan Africa (SSA) are keen to expand irrigation to improve food security and are placing particular emphasis on adoption and use of smallholder private groundwater irrigation. Yet private irrigation is a multi-stage technology, the adoption of which is affected by fiscal support and extension services offered on different investment stages but also by uncertainties around actions that need to be undertaken in these stages. Groundwater-based irrigation in Ethiopia presents a case where policy has focused on fiscally easing the purchase of pumps while considerable ambiguity (unquantifiable uncertainty) exists around the outcomes of drilling boreholes (reaching water). In this paper, we examine farmers’ willingness to adopt smallholder private irrigation packages in response to lower pump prices following tax breaks, loan availability, and reduction in ambiguities related to borehole drilling, using a discrete choice experiment (DCE) in two districts of Ethiopia. The results indicate that the provision of loans and reduction in ambiguities related to well drilling have the greatest effect on the probability of farmers adopting irrigation packages. Lowering pump prices has the smallest effect. Pump-type has a small effect, with energized pumps preferred over manual ones. In exploring heterogeneity in preferences, we find that farmers without irrigated plots and those with greater market access have a greater preference for the provision of loans, while those with greater market access also have greater preferences for reductions in well drilling ambiguities. The results of this choice experiment suggest that reducing ambiguities around well drilling (initial investments) is an essential and cost-effective step toward expanding groundwater-based irrigation in Ethiopia.

The increasing use of Solar Irrigation Pumps (SIPs) has raised concerns about the overexploitation of groundwater. So, this study aims to evaluate the impact of SIPs on pumping behaviour of farmers and its subsequent effect on overall groundwater resources in Bangladesh and India. In Bangladesh, the study is being carried out in the intensively irrigated North-West region, where the government is promoting the feefor- service model for solar irrigation. This model creates a solar irrigation command area by setting up centralized sponsored SIPs. In India, the study is being conducted in the state of Gujarat, where the grid-connected solar irrigation pump model has been implemented under the Suryashakti Kisan Yojana (SKY) scheme.

The Tana-Beles sub-basin, a strategic economic growth corridor in Ethiopia, relies on water storage to provide a suite of key services to agriculture, drinking water supply, energy, and ecosystems. While there are a range of storage options (e.g., from large dams to subsurface aquifers) that can be utilized to provide these services, a systematic stock-take of literature on water storage in the Tana-Beles has not been undertaken. This knowledge gap constrains the identification of the relative contribution of different storage types in the Tana-Beles. Accordingly, in this study, we conducted a systematic review of literature on the surface and sub-surface storages to examine key issues of the different storage types and their linkages in the Tana-Beles sub-basin. Peer-reviewed and grey publications from various databases were considered for the systematic review. The results indicate that literature in the Tana-Beles sub-basin is more focused on natural storage like wetlands and Lake Tana than built storage types like human-made reservoirs. Overall, the analysis revealed three key points. First, storage volume and water quality in those storages are declining. Second, the causal factors for storage loss and water quality deterioration are agricultural expansion, land degradation, sedimentation, and increasing water withdrawals. Third, the storage gap will increase because of climate change, population, and economic growth while current management options are fragmented. Therefore, the need for more integrated nexus approaches is paramount to optimize storage resources in water, food, energy, and ecosystems in light of population-driven growth in demand and the ongoing global climate crisis.

This chapter presents an overview of the groundwater resources of the upper Indus basin’s three major transboundary river basins, with particular attention to the Kabul river basin, where information is more readily available. It examines the state of knowledge and information, challenges, and gaps in and barriers to sustainable groundwater resource management. Afghanistan and Pakistan are highly water-scarce countries that have traditionally not given adequate priority to managing their groundwater resources. This has resulted in a situation of inadequate scientific knowledge, technical capacity, policies and regulatory frameworks in relation to groundwater. Recommendations to address these gaps are provided.

As groundwater levels steadily decline in India, authorities are concerned about reducing extraction for irrigation purposes without jeopardizing food security. Very low or zero prices for electricity and water in agriculture is partly responsible for overextraction, but charging higher prices is politically not feasible. In this study, we describe the results of a pilot scheme implemented in Punjab, India, where farmers who enrolled were allocated a monthly entitlement of electricity units and compensated for unused electricity. Eight hours of uninterrupted daytime electricity supply were also provided under the scheme instead of the usual mix of daytime and night-time supply. Analyzing data from a cross-sectional farm household survey and instrumenting for enrollment, we find that self-reported hours of irrigation for enrolled farmers were significantly lower than for non-enrolled ones, with no impact on rice yields. We also find a reduction in monthly electricity consumption at electricity-feeder level due to the pilot scheme using the synthetic control method. Our results suggest that the combination of daytime electricity provision and cash incentives for unused electricity has the potential to incentivize farmers to reduce electricity consumption and irrigation hours by at least 7.5% and up to 30% without impacting paddy yields.

Soil aquifer treatment (SAT) is an emerging, nature-based, economically viable wastewater treatment solution. Currently, most SAT experiments are done at the laboratory scale, which cannot generate the same conditions as natural field sites and limits the understanding of treatment efficiency. The current study carried out in situ SAT experiments in the Musi River basin in India, where wastewater irrigation is a common practice. SAT efficiency was determined using an integrated approach, including electrical resistivity tomography (ERT) surveys, soil investigations (grain size, permeability, and moisture measurements), and biochemical characterization of raw and SAT treated wastewater. The ERT scans of SAT column show lower order electrical resistivity 10-30 O-m with enhanced chargeability gt;5–6 mV/V attributed to the vadose zone, characterized by clay-rich soil and sandy soil up to 5–6 m depth. The increase in sand percentage (gt;70%) below 140–160 cm depth corroborates with the high moisture content (23.5%). The vadose zone permeability (K) 1.58 m/day and discharge (Q) 38.19 m3/day is used to determine the pollutants reduction efficiency of SAT column. Hydrogeological and biogeochemical observations reveal that the improved dissolved oxygen from lt;1.0 to 5–6 mg/L in the vadose zone catalyzes the oxidation of organic matter resulting in the reduction of BOD and COD up to 92% and 97%, respectively, and denitrification reducing NO3-- (0.55 kg/day). In addition, the precipitation and adsorption by kaolinite clay prompted the reduction of PO42- (0.26 kg/day). Furthermore, the oxic-vadose zone could not support the growth of coliforms and faecal coliforms, and the reduction observed was up to 99.99% in the SAT production well. Overall, the results indicated a positive outcome with SAT efficiency and framed the SAT sitting criteria for different geological environments.

International water conventions—e.g., the 1997 United Nations Convention on the Non-Navigational Uses of International Watercourses—include positive but insufficient focus on groundwater and its interaction with surface water. As such, a growing body of literature has proposed modifications to existing frameworks to enable consideration to surface and groundwater and their interactions. While this literature places considerable focus on coupling and amending existing legal frameworks, elaboration and evaluation of a new protocol on conjunctive water management comprises a key gap. To fill this gap, this paper seeks to answer the following question: does formulation and adoption of a new “conjunctive” protocol provide more value than existing proposals centered around modifications to existing law? This paper seeks to compare benefits associated with current proposals to strengthen the international legal framework for management of surface–groundwater interaction, vis-a-vis adoption of a new protocol on conjunctive management of transboundary freshwaters. To do so, the authors use doctrinal legal methods to analyze the existing main instruments globally assessing the degree to which they consider key interlinkages between surface water and groundwater. Then, the paper examines the concept of conjunctive water management and deduces tenets that should be pursued in shared waters to achieve this objective. To identify the preferred option to support conjunctive water management in international water law, the paper explores the degree to which existing proposals vs a new protocol enable an embrace of these tenets of conjunctive water management. The paper finds that while a new protocol may add greater value in advancing conjunctive water management, multiple options can and should be concurrently pursued. In particular, the authors argue that new protocols to the existing treaties must be adopted in combination with the amendment of the Draft Articles on the Law of Transboundary Aquifers. Benefits of doing so include more effective management of transboundary freshwater resources that are interconnected hydrologically, a less fragmented and more consistent international water regime, and ultimately more benefits accruing to the populations and environmental goods dependent on shared water resources.

Nitrate is globally the most widespread and widely studied groundwater contaminant. However, few studies have been conducted in sub-Saharan Africa, where the leaching potential is enhanced during the rainy monsoon phase. The few monitoring studies found concentrations over drinking water standards of 10 mg N-NO3 - L -1 in the groundwater, the primary water supply in rural communities. Studies on nitrate movement are limited to the volcanic Ethiopian highlands. Therefore, this study aimed to evaluate the transport and fate of nitrate in groundwater and identify processes that control the concentrations. Water table height, nitrate, chloride, ammonium, reduced iron, and three other groundwater constituents were determined monthly in the groundwater in over 30 wells in two contrasting volcanic watersheds over two years in the Ethiopian highlands. The first watershed was Dangishta, with lava intrusion dikes that blocked the subsurface flow in the valley bottom. The water table remained within 3 m of the surface. The second watershed without volcanic barriers was Robit Bata. The water table dropped rapidly within three months of the end of the rain phase and disappeared except near faults. The average nitrate concentration in both watersheds was between 4 and 5 mg N-NO3 - L -1 . Hydrogeology influenced the transport and fate of nitrogen. In Dangishta, water was blocked by volcanic lava intrusion dikes, and residence time in the aquifer was larger than in Robit Bata. Consequently, nitrate remained high (in several wells, 10 mg N-NO3 - L -1 ) and decreased slowly due to denitrification. In Robit Bata, the water residence time was lower, and peak concentrations were only observed in the month after fertilizer application; otherwise, it was near an average of 4 mg N-NO3 - L -1 . Nitrate concentrations were predicted using a multiple linear regression model. Hydrology explained the nitrate concentrations in Robit Bata. In Dangishta, biogeochemistry was also significant.

Study region: Lake Tana sub-basin of the Upper Blue Nile River Basin, Ethiopia. Study focus: Groundwater use for small-scale irrigation is increasing in the Lake Tana sub-basin. However, the abstraction amount and its impact are not well understood. In this study, a new methodological approach was utilized to estimate the irrigation water abstraction amount, which is based on groundwater level monitoring before, during, and at the end of the irrigation season (2021/2022). The monitoring was conducted on 361 hand-dug wells distributed throughout the sub-basin, which is subdivided into East, Southwest, and North zones. New hydrological insights for the region: Groundwater abstraction for irrigation and associated groundwater level decline estimates are 10.6 × 106 m3 and 2.43 m in the East, 4.2 × 106 m3 and 3.23 m in the Southwest, and 0.6 × 106 m3 and 1.32 m in the North. These abstractions account for 103%, 97%, and 62% of the mean annual groundwater recharge in the East, Southwest, and North zones, respectively. Groundwater is overexploited in the East and Southwest zones although, at the sub-basin scale, the amount of groundwater used for irrigation is small compared to the renewable groundwater resource. However, if groundwater-based irrigation continues to expand especially in the East and Southwest zones, groundwater scarcity at the local scales will worsen. Adaptive management strategies are required to minimize the potential adverse effects on groundwater resources.

The Central Dry Zone (CDZ) of Myanmar is the heartland of the Burmese culture, and in many ways, it is socially and culturally coherent with the other rice-centred cultures of mainland Southeast Asia. In climatic terms, it is a semi-arid outlier in a mostly wet-tropical region. Climate change is exacerbating weather variability and water insecurity, and the CDZ thus epitomises the challenges posed by climate change for much of the region. This chapter describes two examples of interventions aimed at addressing water insecurity in the CDZ: pumped irrigation at Pyawt Ywar; and artesian groundwater in the Pale Subbasin. Both address the interconnections between social and physical drivers of vulnerability. They demonstrate the challenges and importance of working across institutional scales. These examples demonstrate that progress is possible at local levels despite a lack of (or inappropriate) national policy and regulations, which limit the scale, and possibly the long-term sustainability of such gains.

Reliance on groundwater in Sub-Saharan Africa is growing and expected to rise as surface water resource variability increases under climate change. Major questions remain about how groundwater will be used, and who informs these decisions. We represent different visions of groundwater use by ‘pathways’: politically and environmentally embedded socio-technological regimes for governing and managing groundwater systems. We presented policy actors (9 sets), development and research stakeholders (4 sets), and water users (6 sets) in three river basins in Ethiopia, Niger and Tanzania with information on the social and environmental impacts of six ‘Groundwater Development Pathways’, before gathering their opinions on each, through Multicriteria Mapping (MCM). Participants preferred pathways of low-intensity use, incorporating multiple agricultural, pastoral and domestic purposes, to high-intensity single-use pathways. Water availability and environmental sustainability, including water quality, were central concerns. Participants recognised that all groundwater uses potentially impinge upon one another affecting both the quantity and quality of abstracted water. Across participant groups there was ambiguity about what the most important water use was; each expressed demands for more detailed, certain modelling data. Water users preferred community or municipal-scale management regimes, perceiving that water quality was more likely to be safeguarded by institutions at these levels, whereas policy and development actors preferred individual-scale management, viewed as more efficient in terms of operation and maintenance. We conclude that MCM, combined with more detailed modelling, can provide an effective framework for policy actors to understand other stakeholders’ perspectives on groundwater development futures, enabling equitable, inclusive decision-making and governance.

Groundwater (GW) is a key source of drinking water and irrigation to combat growing food insecurity and for improved water access in rural sub-Saharan Africa. However, there are limited studies due to data scarcity in the region. New modeling techniques such as Machine learning (ML) are found robust and promising tools to assess GW recharge with less expensive data. The study utilized ML technique in GW recharge prediction for selected locations to assess sustainability of GW resources in Ghana. Two artificial neural networks (ANN) models namely Feedforward Neural Network with Multilayer Perceptron (FNN-MLP) and Extreme Learning Machine (FNN-ELM) were used for the prediction of GW using 58 years (1960–2018) of GW data. Model evaluation between FNN-MLP and FNN-ELM showed that the former approach was better in predicting GW with R2 ranging from 0.97 to 0.99 while the latter has an R2 between 0.42 to 0.68. The overall performance of both models was acceptable and suggests that ANN is a useful forecasting tool for GW assessment. The outcomes from this study will add value to the current methods of GW assessment and development, which is one of the pillars of the sustainable development goals (SDG 6).

Study region: Dak Lak province in the Central Highlands of Vietnam Study focus: Intensification of agriculture has resulted in unsustainably high levels of groundwater use in the Central Highlands. High monsoonal rainfall provides opportunities to boost groundwater storage through managed aquifer recharge (MAR), yet experience with MAR in the region is absent. In response, five farm-scale pilots were implemented in collaboration with local farmers whereby runoff from roofs and fields was recharged into shallow dug wells. The pilots were closely monitored over three years. New hydrological insights for the region: MAR pilots exhibited large contrasts in performance, with volumes recharged ranging from 5 to 530 m3 per year. Pilot sites with cleaner roof runoff water performed best, whilst those using more turbid water from unpaved roads performed worst. Water quality analyses did not identify parameters of major concern for irrigation. Field data and modelling indicate that the size of the recharge water plumes are small relative to the high groundwater velocities making the recharge water difficult to recover from the recharge well in this setting. Water is however contained locally, providing potential for improved water availability within the local area. Farmer attitudes towards MAR vary in response to the technical performance and a range of socioeconomic factors. These findings may provide insights for researchers or practitioners from other regions where groundwater dependence is high but experience in MAR is lacking.

Closing the yield gap and enhancing efficiency in rainfed maize production systems in Ethiopia requires urgent action in increasing the productivity of degraded agricultural land. The degradation of land through continuous compaction and decline in the organic matter has resulted in a wide-spread formation of a hardpan that restricts deep percolation, prevents plant root development, and, ultimately can lead to increased erosion. Studies exploring practical low-cost solutions to break the hardpan are limited in Ethiopia. The main objective was to evaluate soil mechanical (i.e. modified plow or Berken plow) or biological intervention (i.e. intercropping with pigeon pea) effectiveness to enhance soil water management and crop yield of rainfed maize systems whilst reducing soil erosion and runoff. Five farm fields, each including four plots with different tillage treatments, were monitored during two rainy seasons in 2016 and 2017. The treatments were: (i) farmers practice under conventional (CT) tillage; plots tilled three times using an oxen driven local plow Maresha, (ii) no-till (NT), (iii) Berken tillage (BT), plots tilled three times using an oxen pulled Berken plow, and (iv) biological (CT + Bio), taprooted pigeon pea intercropped with maize on plots conventionally tilled. Results showed that mean tillage depth was significantly deeper in the BT (28 cm) treatment compared to CT and CT + Bio (18 cm) treatments. Measured soil penetration resistance significantly decreased up to 40 cm depth under BT and maize roots reached 1.5 times deeper compared to roots measured in the CT treatment. Under BT, the estimated water storage in the root zone was estimated at 556 mm, 1.86 times higher compared to CT, 3.11 times higher compared to NT and 0.89 times higher compared to CT + Bio. The positive effects on increased water storage and root development resulted in an average increase in maize grain (i.e. 15%, 0.95 t ha- 1 ) and residual above ground biomass (0.3%, 6.4 t ha- 1 ) leading to a positive net benefit of 138 USD ha- 1 for the BT treatment compared to the CT treatment. The negative net benefit obtained under CT and CT+Bio was mainly related to the high labor cost related to plowing, weeding, planting, and fertilizer application whilst in the NT this was related to the significantly lower maize yields. The positive effects in the BT treatment, and to some extent the CT+Bio treatment show great potential for smallholder rainfed maize systems where degraded soils with hardpans and high variability in rainfall prevail.

Study region: The study region is the Kamadhiya catchment (1150 km2 ), located in the Saurashtra region of the western state of Gujarat, India. The region has seen intensive development of check dams (CDs) for groundwater recharge with an estimated 27,000 CDs constructed up until 2018. Study focus: The impact of CDs on groundwater storage, food production and resilience are assessed for Kamadhiya catchment by estimating and comparing changes, across periods of low and high CD development, in potential recharge from CDs, rainfall trends, and irrigation demand. The analysis is carried out for the period from 1983 to 2015. New hydrological insights for the region: Groundwater storage gains observed following CD development can partly be attributed to an increase in high rainfall years after several drought years. Groundwater demand for irrigation has increased substantially, outweighing increase in groundwater recharge from CDs. This deficit in supply relative to demand is greatest in dry years, and when considered together with the low inter-annual carry-over storage of the region’s hardrock aquifers, means that CDs capacity to enhance groundwater storage and mitigate the negative impacts of drought remains limited. Findings suggest that a standalone focus on MAR, unless complemented by greater emphasis on management of water demand and groundwater resources more broadly, may not be sufficient to achieve the long-term goals of sustainable groundwater and concurrently expanding agricultural crop production.

For decades, millions of farmers in Bangladesh have been capturing more water than even the world’s largest dams. They did so simply by irrigating intensively in the summer dry season using water from shallow wells. The ability to use groundwater to irrigate rice paddies during the dry seasons (January to May) helped Bangladesh become food self-sufficient by the 1990s, which was no small feat for one of the most densely populated countries in the world. Researchers proposed that lowering of the groundwater table as a result of intensive irrigation practices in the dry season created conditions for recharge from monsoon rains (June to September), which then replenishes the groundwater (1). On page 1315 of this issue, Shamsudduha et al. (2) present a quantitative analysis of this depletion-replenish process and show that this recharge has indeed been happening at a large scale, in a process they call the Bengal Water Machine (BWM).

Across several coastal areas in Morocco, groundwater is the strategic source of irrigation. In this work, a database of thirteen Moroccan coastal aquifers was used to assess groundwater for agriculture purposes, as well as to highlight the process responsible of the degradation of groundwater resource quality in Moroccan coastal areas. According to electrical conductivity parameter, the results show that 92% of the collected samples were not suitable for irrigation uses. This situation is due to seawater intrusion and water–rock interaction processes, in addition to intensive agriculture activities and the introduction of domestic and industrial wastewater without any treatment. In order to control the impact of groundwater salinity on agriculture, management plans are proposed.

In India, artificial recharge (AR) of aquifers is considered a primary supply-side measure to combat the widespread over-exploitation of groundwater. As a major collateral benefit of rainwater harvesting (RWH) is aquifer rejuvenation, both rainwater harvesting and AR are planned and executed as a set of coherent interventions. The Central and state governments have brought in several schemes involving AR and RWH. Moreover, a number of researches are being conducted on how to select the sites for structure construction, the types of structure and their designs depending upon the local hydrogeology, groundwater flow regime, terrain condition and demand of water, and how they impact on resource rejuvenation and improvement in water quality. Various researches are also available on how such endeavors are translating into socio-economic benefits. The paper reviews the researches that have been done in India on these issues and related government policies and schemes under execution. The critical issues like source water availability for recharge, upstream-downstream conflicts, and the rising awareness of different demand-side interventions for sustainable management of groundwater resources have also been discussed.

Groundwater for Sustainable Livelihoods and Equitable Growth explores how groundwater, often invisibly, improves peoples’ lives and livelihoods. This unique collection of 19 studies captures experiences of groundwater making a difference in 16 countries in Africa, South America and Asia. Such studies are rarely documented and this book provides a rich new collection of interdisciplinary analysis. The book is published in colour and includes many original diagrams and photographs. Spring water, wells or boreholes have provided safe drinking water and reliable water for irrigation or industry for millennia. However, the hidden nature of groundwater often means that it’s important role both historically and in the present is overlooked. This collection helps fill this knowledge gap, providing a diverse set of new studies encompassing different perspectives and geographies. Different interdisciplinary methodologies are described that can help understand linkages between groundwater, livelihoods and growth, and how these links can be threatened by over-use, contamination, and ignorance. Written for a worldwide audience of practitioners, academics and students with backgrounds in geology, engineering or environmental sciences; Groundwater for Sustainable Livelihoods and Equitable Growth is essential reading for those involved in groundwater and international development.

Groundwater is a significant resource that supports almost one-fifth population globally, but has been is diminishing at an alarming rate in recent years. To delve into this objective more thoroughly, we calculated interannual (2002–2020) GWS (per grid) distribution using GRACE amp; GRACE-FO (CSR-M, JPL-M and SH) Level 3 RL06 datasets in seven Indian river basins and found comparatively higher negative trends (-20.10 1.81 to -8.60 1.52 mm/yr) in Basin 1–4 than in Basin 5–7 (-7.11 0.64 to -0.76 0.47 mm/yr). After comparing the Groundwater Storage (GWS) results with the CHIRPS (Climate Hazards Group Infrared Precipitation with Stations) derived SPI (Standardized Precipitation Index) drought index, we found that GWS exhausts analogously in the same period (2005–2020) when SPI values show improvement (~ 1.89–2), indicating towards wet condition. Subsequently, the GWSA time series is decomposed using the STL (Seasonal Trend Decomposition) (LOESS Regression) approach to monitor long-term groundwater fluctuation. The long term GWS rate (mm/yr) derived from three GRACE amp; GRACE-FO solutions vary from -20.3 5.52 to -13.19 3.28 and the GWS mass rate (km3 /yr) lie in range of -15.17 4.18 to -1.67 0.49 for basins 1–3. Simultaneously, in basin 4–7 the GWS rate observed is -8.56 8.03 to -0.58 7.04 mm/yr, and the GWS mass rate differs by -1.71 0.64 to -0.26 3.19 km3 /yr. The deseasonalized GWS estimation (2002–2020) states that Himalayan River basins 1,2,3 exhibit high GWS mass loss (-260 to -35.12 km3 ), with Basin 2 being the highest (-260 km3 ). Whereas the Peninsular River basin 4,6,7 gives moderate mass loss value from -26.72 to -23.58 km3 . And in River basin 5, the GWS mass loss observed is the lowest, with a value of -8 km3 . Accordingly, GPS (Global Positioning System) and SAR (Synthetic Aperture Radar) data are considered to examine the land deformation as an effect due to GWS mass loss. The GPS data acquired from two IGS stations, IISC Bengaluru and LCK3 Lucknow, negatively correlates with GWS change, and the values are ~ -0.90 to ~-0.21 and ~-0.7 to -0.4, respectively. Consequently, correlation between GWS mass rate (km3 /yr) and the SAR (Sentinel-1A, SBAS) data procured from Chandigarh, Delhi, Mehsana, Lucknow, Kolkata and Bengaluru shows ~ 72 – 48% positively correlated area (PCA). The vertical velocity ranges within ~ -94 to -25 mm/yr estimated from PCA. There is an increase in population (estimated 2008–2014) in Basin 1 amp; 2. Likewise, the correlation coefficient ( ) between GWS change and the irrigational area is positive in all seven basins indicating significant depletion in GWS due to an uncalled hike in population or irrigational land use. Similarly, the positive linear regression (R 2 ) in Basins 1–3 also indicates high depletion in GWS. But basins 4–7 observe negative linear regression even after increasing population, which implies a control on the irrigational land use, unable to determine the GWS change at local scale a

Freshwater in both natural and man-made stores is critical for socioeconomic development. Globally, cumulative reduction in terrestrial water storage from 1971 to 2020 is estimated to be of the order of 27,079 Bm3. Although insignificant in comparison to the total volume stored, the decrease in ‘operational’ water stored (i.e., the proportion of water storage that is sustainably utilizable by people) is estimated to be of the order of 3% to 5% since 1971. In many places, both natural and man-made water storage are declining simultaneously, exacerbating water stress. Conjunctive use of different water stores is a prerequisite for water security and it is vital that natural water stores are fully integrated, alongside man-made water infrastructure, in future water resources planning and management.

This paper illustrates an approach to measuring economic benefits and ecological and social impacts of various configurations of reservoir systems for basin-wide planning. It suggests indicators and examines their behavior under several reservoir arrangement scenarios using two river basins in Sri Lanka as examples. A river regulation index is modified to take into account the volume of flow captured by reservoirs and their placement and type. Indices of connectivity illustrate that the lowest river connectivity in a basin results from a single new reservoir placed on the main stem of a previously unregulated river between the two locations that command 50% and 75% of the basin area. The ratio of the total affected population to the total number of beneficiaries is shown to increase as the cumulative reservoir capacity in a river basin increases. An integrated index comparing the performance of different reservoir system configurations shows that while results differ from basin to basin, the cumulative effects of a large number of small reservoirs may be comparable to those with a few large reservoirs, especially at higher storage capacities.

This brief provides a summary of research and findings on the impacts of rapid rural electrification in Bangladesh on the informal water markets during the last decade and how these markets in turn have affected irrigation access among smallholder farmers. The note emphasizes the importance of energy sources in determining the nature of groundwater access in Bangladesh, where groundwater remains central to irrigated agriculture and food production.

The Gravity Recovery and Climate Experiment (GRACE) has recently been identified as a useful tool for monitoring changes in groundwater storage (GWS), especially in areas with sparse groundwater monitoring networks. However, GRACE’s performance has not been evaluated in the highly heterogeneous Indus Basin (IB) to date. The objective of this study was thus (i) to evaluate GRACE’s performance in two distinctively different agroecological zones of the IB, and (ii) to quantify the trend of groundwater abstraction over 15 years (i.e., from 2002 to 2017). To capture this heterogeneity at the IB, the two different agro-ecological zones were selected: i) the Kabul River Basin (KRB), Afghanistan, and ii) the Lower Bari Doab Canal (LBDC) command area in Pakistan. The groundwater storage anomalies (GWSA) for both regions were extracted from random pixels. The results show a correlation (R2 ) of 0.46 for LBDC and 0.32 for the KRB, between the GWSA and in-situ measurements. The results further reveal a mean annual depletion in GWSA of - 304.2 749 and - 301 527 mm at the LBDC and the KRB, respectively. Overall, a net GWS depletion during 2002–2017 at the LBDC and KRB was 4.87 and 4.82 m, respectively. The GWSA’s response to precipitation analyzed through cross-correlation shows a lag of 4 and 3 months at the KRB and the LBDC, respectively. The GWSA’s poor correlation with the in-situ measurements particularly in the mountainous region of the KRB is driven by the 4 months lag time unlike in the LBDC (i.e. 3 months); besides, the observations wells are sparse and limited. The complex geomorphology and slope of the landscape also cause discrepancies in the correlation of the in-situ measurements and the GRACE-derived changes in GWS at the two different agroecological zones of the IB. The spatially averaged GWSA in monthly time steps is another reason for the lower correlation between GRACE-based GWSA estimates and point-based in-situ measurements. Therefore, care must be taken while using GRACE’s output in regions with heterogeneous geomorphologic features.

There is a scarcity of long-term groundwater hydrographs from sub-Saharan Africa to investigate groundwater sustainability, processes and controls. This paper presents an analysis of 21 hydrographs from semi-arid South Africa. Hydrographs from 1980 to 2000 were converted to standardised groundwater level indices and rationalised into four types (C1–C4) using hierarchical cluster analysis. Mean hydrographs for each type were cross-correlated with standardised precipitation and streamflow indices. Relationships with the El Nino– Southern Oscillation (ENSO) were also investigated. The four hydrograph types show a transition of autocorrelation over increasing timescales and increasingly subdued responses to rainfall. Type C1 strongly relates to rainfall, responding in most years, whereas C4 notably responds to only a single extreme event in 2000 and has limited relationship with rainfall. Types C2, C3 and C4 have stronger statistical relationships with standardised streamflow than standardised rainfall. C3 and C4 changes are significantly (p lt; 0.05) correlated to the mean wet season ENSO anomaly, indicating a tendency for substantial or minimal recharge to occur during extreme negative and positive ENSO years, respectively. The range of different hydrograph types, sometimes within only a few kilometres of each other, appears to be a result of abstraction interference and cannot be confidently attributed to variations in climate or hydrogeological setting. It is possible that high groundwater abstraction near C3/C4 sites masks frequent small-scale recharge events observed at C1/C2 sites, resulting in extreme events associated with negative ENSO years being more visible in the time series.

Study region: Robit-Bata watershed, Upper Blue Nile basin, Ethiopia. Study focus: Stable isotopes of water (Oxygen-18 and Deuterium) were used as tracers to estimate the contribution of groundwater in shallow hillslope aquifers to streamflow in the Robit-Bata watershed. To assess the spatiotemporal variability of shallow groundwater and develop a hydrograph separation technique, we collected rainfall, shallow groundwater, and streamflow samples and analyzed their d18O and d2 H isotopic compositions. The local meteoric water line (LMWL) and local evaporative line (LEL) of the study area were determined and compared with the global meteoric water line (GMWL). A standard unweighted two-component isotope-based hydrograph separation model was used to determine the percentage contribution of shallow groundwater to streamflow. New hydrological insights for the region: The LMWL (d2 H = 8.63d18O + 18.2) mostly showed heavy isotopic enrichment relative to GMWL, and the LEL (d2 H = 5.45d18O + 6.96) indicated isotopic enrichment compared to Ethiopian lakes. Shallow groundwater responded rapidly to rainfall, with good spatial correlation depending on topographic positions of wells. Pre-event water contributed 90% when the watershed reached maximum storage. This finding gives insight towards the predominant runoff generation process and has significant implications for sustainable dry season irrigation expansion in the area as the sub-surface flow drains out of the watershed from October onwards reducing water tables in the shallow wells.

The century old irrigation tanks mostly found in south India account for about 1/3 of rice irrigated areas and largely benefit the small and marginal farmers. The current performance of these tanks is below the 50 percent level. Major factors contributing to their declining performance are: erratic rainfall pattern and reduced inflows (hydrology side); poor management of the tanks (tank side); ineffective water control amp; poor groundwater development (farmers’ side). Given the future impacts of climate change on water resources, sustaining tank irrigation is considered important. Evidence shows that developing an interface between tank ecosystems and wells is expected to augment water supplies, improve tank management and boost tank irrigation. This paper outlines a five-pronged strategy to achieve this: a) partial rehabilitation (partial desilting); b) full scale tank rehabilitation; c) converting tanks into percolation ponds; d) converting non-system tanks into system tanks; e) full scale groundwater development (tapping the full groundwater potential). Financial viability of the strategy also varies according to the scale and size of the investments and the expected benefits. There is an important need for policy reforms converging ongoing as well as proposed programs (by national and international funding agencies) on tank rehabilitation; these can be planned in a phased manner by prioritizing the investment scenarios.

This chapter highlights the key dependences, linkages and challenges of water resources management. (Many of these issues discussed are revisited and illustrated in the following chapters.) The first part introduces surface and groundwater management in the terrestrial part of the water cycle. Comprehensive presentations of key hydrological phenomena and processes, monitoring, assessment and control are followed by overviews of dependences, linkages and challenges. The manifold facets of intensive human/resource interaction and inherent threats to the resources base are exposed. Both sections present examples illustrating differing contexts and options for solution. The second part summarizes the main drivers and challenges of contemporary water resources management and governance. It provides a critical overview of different water discourses in recent decades. The role of benchmark and recurring water events, their declarations and intergovernmental resolutions are analyzed, and the key concepts and methods of implementation are discussed.

This report assesses the potential of solar photovoltaic (PV) irrigation for smallholder agriculture in Ghana, using elements of business planning and business models with a suitability mapping approach. These approaches take into account the economic as well as environmental sustainability of expanding such technology. Using data from existing solar PV irrigation systems and interviews with key industry actors, the report discusses the regulatory and institutional context for investment in solar PV technology and outlines the technology supply chain, mapping the key actors and their roles. The financial viability of two empirical business cases – directly funding an agribusiness and subsidizing a cooperative model – is analyzed to assess the feasibility of expanding access to the technology. Furthermore, three solar PV irrigation business model scenarios are presented based on insights gained from the two empirical cases as well as from analyzing the existing policy and regulatory framework, the technology supply chain and environmental suitability. The potential for solar PV irrigation pumps is substantial, especially in northern Ghana, although care must be taken to avoid overpumping some aquifers. Achieving this potential will require strengthening the policy framework and making finance available at a reasonable cost. The report identifies alternative financing mechanisms and business models that have been tried elsewhere and can be adapted to Ghana, and makes recommendations to enhance the sustainable uptake of solar PV irrigation.

In semi-arid India, managed aquifer recharge (MAR) is often used to enhance aquifer storage, and by implication, water security, and climate resilience, by capturing surface runoff, mainly through check dams implemented at the community level. Despite their extensive use, the design of these structures typically does not follow a systematic method to maximize performance. To aid in the improvement of check dam design parameters and location siting, we develop a dynamic tool, which integrates the daily water balance of a check dam with analytical infiltration equations to assess check dam performance measured as temporal dynamics of storage, infiltration, and evaporation. The tool is implemented in R environment and requires meteorological and hydrogeological data, as well as check dam geometry and nearby well-abstractions, if any. The tool is applied to a case study in Saurashtra in Gujarat, where field visits were conducted. Simulations show that typical check dams in the area are able to store a volume between three and seven times their storage capacity annually. Infiltration volumes highly depend on hydroclimatic and hydrogeological conditions, as well as the formation of a clogging layer, highlighting the importance of site selection and periodic maintenance. The tool is validated with data from a previous study in Rajasthan, where daily water balance parameters were monitored. Validation results show an average R 2 of 0.93 between the simulated and measured water levels. The results are adequate to suggest that the tool is able to assist in check dam planning in semi-arid environments.

We have one Earth and one water resource defining our living space. We are the key custodians for safeguarding these resources, which underpin the healthy and peaceful environment in which we all want to live. We cannot expand the physical boundaries, but we can stretch our perspectives to achieve water sustainability through global solidarity and considering water inside Earth’s crust: groundwater.

This paper addresses the questions of acceptable upper limits for storage development and how best to deploy storage capacity in the long-term planning of built surface water storage in river basins. Storage-yield curves are used to establish sustainable storage development pathways and limits for a basin under a range of environmental flow release scenarios. Optimal storage distribution at a sub-basin level, which complies with an identified storage development pathway, can also be estimated. Two new indices are introduced—Water Supply Sustainability and Environmental Flow Sustainability—to help decide which pathways and management strategies are the most appropriate for a basin. Average pathways and conservative and maximum storage limits are illustrated for two example basins. Conservative and maximum withdrawal limits from storage are in the range of 45–50% and 60–65% of the mean annual runoff. The approach can compare the current level of basin storage with an identified pathway and indicate which parts of a basin are over- or under-exploited. A global storage–yield–reliability relationship may also be developed using statistics of annual basin precipitation to facilitate water resource planning in ungauged basins.

While determining the water balance for large irrigation schemes, coping with complexities and uncertainties in estimation of groundwater (GW) abstraction is still a challenge. On other hand, estimating GW abstraction is of paramount importance to ensure the proper management of surface and GW resources. Although, there are number of well-known methods exist to map GW abstraction, utilization-factor (Uf) is considered as a reliable method. However, at large scales, tubewells utilization time required for Uf method is difficult to retrieve as large and small tubewells are governed under different rules. Geo-informatics is another emerging approach being used to estimate GW abstraction, however, there are several complexities and uncertainties involved in characterizing GW abstraction using satellite remote sensing imagery that leads to inaccurate end results. In current study, in-situ GW measurements were performed to calibrate and validate the GW abstraction estimated from geo-informatics approach at Lower Bari Doab Canal (LBDC) command area of the Indus basin of Pakistan. For in-situ measurements, an intensive tubewell survey was conducted at a grid size of 1 km at 30 locations situated at head, middle and tail end reaches of the LBDC. For the geo-informatics approach used in this study, GW abstraction is considered as a difference of actual evapotranspiration (ETa) from net canal water use and effective rainfall after satisfying soil moisture storage changes. Results of calibration of geo-informatics approach compared with the in-situ measurements showed R2 of 0.89, 0.81 and 0.79 at head, middle and tail end reaches, respectively. Intra-grid annual comparison of in-situ measurements showed that tubewells were being governed by different rules and thus yielded different abstraction within a grid ranging from 854 mm (105) at head, 742 mm (220) at middle and 649 mm (244) at tail grids. Statistical analysis showed that annual GW abstraction by in-situ measurements at head 814 mm (52), middle 769 mm (44) and tail 688 mm (56) end reaches varied significantly at a confidence interval of 95%. The spatial mapping by geo-informatics showed that farmers’ fields situated at proximity of head end reaches utilize 4% and 9% extra water than from those placed at middle and tail end reaches, respectively. The inequity of GW abstraction in LBDC command area highlighted in this study requires immediate intervention of policy makers for sustainable GW management.

Arid areas in East Africa are characterized by physical water scarcity. The physical water scarcity is further exacerbated by poor water quality (mainly salinity and fluoride) of mainly groundwater sources. Combined physical water scarcity and poor water quality makes the region a hydrogeologically difficult environment. Nevertheless, some viable high-yielding aquifers exist in East Africa. Difficult hydrogeology means that the best practices of reaching rural dwellers, towns, and urban centers require specialized financial, technical, and engineering approaches. The chapter describes the hydrogeology difficulty and the ongoing management strategies and its implications for the Water, Sanitation and Hygiene sector in East Africa arid regions.

This paper outlines a new and integrated water storage agenda for resilient development in a world increasingly characterised by water stress and climate uncertainty and variability.; Storing water has long been a cornerstone of socio-economic development, particularly for societies exposed to large climatic variability. Nature has always supplied the bulk of water storage on earth, but built storage has increased significantly, particularly over the twentieth century. Today, numerous countries suffer from water storage gaps and increasingly variable precipitation, threatening sustainable development and even societal stability. There is a growing need to develop more storage types and manage existing storage better. At the same time, the policy, engineering, and scientific communities may not fully recognise the extent of these storage gaps and how best to manage them. There are large and uncertain costs and benefits of different types of storage, and developing storage can be risky and controversial. Although there is consensus that built and natural storage are fundamentally complementary, there is still no pragmatic agenda to guide future integrated water storage development.; This paper argues that water storage should be recognised as a service rather than only a facility. More than volumes of water stored behind a dam or in a watershed, what ultimately matters is the ability to provide different services at a particular time and place with a given level of assurance. Integrated storage systems should be developed and managed to deliver a targeted service standard. This will reduce the costs of new storage development and make the benefits more sustainable.; As this paper demonstrates, there are numerous data gaps pertaining to water storage, as well as a need for greater clarity on some key concepts. This paper does not introduce new data or research but rather provides a review of some of the current knowledge and issues around water storage, and outlines a new, integrated and constructive water storage agenda for the decades to come.

South Asiaapos;s heavy reliance on groundwater for irrigated agricultural production supports the livelihoods of tens of millions of smallholder farmers but is being undermined by rampant overexploitation of groundwater. Without major intervention, this is expected to be further exacerbated by growing demand and climate change. Groundwater management, scientific and evidence-based, can make an important contribution to managing unsustainable groundwater use and strengthening the climate resilience of farmers due to groundwaterapos;s unique storage characteristics. This study brings together a set of strategies and solutions to better manage groundwater that cover the augmentation of groundwater recharge through managed aquifer recharge, management of groundwater demand through participatory groundwater management and other methods, and the harnessing synergies of co-dependent sectors. The opportunities, constraints and available evidence for each are analysed and the boundaries, barriers and specificities identified to establish entry points for positive change through policies and implementation programmes.

Groundwater (GW) depletion and recurring floods have become a major concern among researchers and planners across the world. To rejuvenate stressed aquifer and moderate flood impacts, a modified version of managed aquifer recharge (MAR) consisting of a cluster of ten recharge wells (RWs) embedded in a community pond with an area of 2625 m2 and utilizing diverted floodwater was tested on a pilot scale in Ramganga sub basin, India. The approach could recharge a maximum of 72426 m3 of floodwater in 78 days during the wet season. The pond intervention minimized clogging of RWs by retaining maximum silt load of 68.01%. Hydro-geochemically, majority of water samples were of Mg-HCO3 and Ca-HCO3type. Ion exchange processes and weathering of carbonate and silicates were the controlling factors, determining water quality of the area. Total dissolved solids, fluoride, iron, zinc, manganese, chromium, cobalt, nickel, mercury, phosphate, nitrate, and ammonical nitrogen were found within the permissible limits as laid down by World Health Organization except arsenic and lead, which seems to be the inherent problem in the area, as evidenced by water quality analysis of farmers tube wells located upstream and down streams of the recharge site. The coliform presence in the 88.23% of sampled GW may thwart from direct use for drinking whereas it was fit for irrigation. Looking the benefits of modified MAR as a proactive GW quality improvement with good aquifer recharge, it is recommended for scaling up of the intervention across the GW stressed parts of the whole Ram Ganga basin and similar hydro-geological regions elsewhere.

This GRIPP Case Profile assesses whether the proactive involvement of rural communities in the management of groundwater positively contributes towards sustainable resource use. The assessment uses the long-term (2003-2013) Andhra Pradesh Farmer-Managed Groundwater Systems (APFAMGS) project in India as a case study. Implemented across seven districts, the assessment is based on a critical review and synthesis of existing literature and complementary field visits conducted five years after project closure. APFAMGS worked towards creating awareness and bringing about behavioral change to achieve sustainable groundwater use, primarily for irrigation. The approach focused on knowledge transfer and capacity building to set up participatory processes conducive to informal management measures, and technologies supporting participatory hydrological monitoring and crop water budgeting. In addition, awareness creation in relation to demand as well as supply side management options was critical. The analysis suggests that APFAMGS has helped in filling the knowledge and information gaps on groundwater resources among local farming communities. Some degree of long-term reduction in groundwater pumping was observed, but the attribution to the project is not clear, and effects on reducing groundwater level declines may be limited and localized. The APFAMGS approach of participatory groundwater management (PGM) fell short in terms of equity considerations, with implications for the institutional sustainability of the approach. The study provides policy guidance for adopting more inclusive PGM-based institutions on a wider scale.

Governments in sub-Saharan Africa promote the expansion of irrigation to improve food security, primarily through the adoption and use of groundwater-based smallholder private irrigation. Using the case of Ethiopia, we examine farmers’ willingness to adopt smallholder private irrigation packages in response to subsidies on pump prices, loan availability and reduction in ambiguities related to borehole drilling. The results of the research highlight that subsidizing pump prices may not be the best use of public funds to expand irrigation. Instead, decreasing ambiguities around borehole drilling is likely to play a significant role and is a cost-effective step toward expanding groundwater-based irrigation and increasing the adoption of pumps by small-scale farmers. The policy implication is that the government should help farmers minimize the uncertainties and cost of unsuccessful drilling. This will require the government to study groundwater hydrogeology, use information on groundwater depth, seasonality and recharge to drill boreholes, and absorb the costs of unsuccessful drilling.

Lao People’s Democratic Republic is a poorly developed, surface water-rich country that has traditionally given limited priority to its groundwater resources, which has resulted in a situation of inadequate scientific knowledge, technical capacity, and policies within the sector. This is slowly changing as the role of groundwater in socioeconomic development is better recognized. This chapter presents an overview of the country’s groundwater resources. It examines the state of knowledge, challenges, gaps, and barriers for effective groundwater resource development. It also reviews the scope and degree of success of recent efforts to enhance groundwater governance. Finally, it presents a concise outlook for groundwater governance, including policy, capacity development, and research perspectives.

This paper assesses how the Huruluwewa tank (HWT) irrigation system in the North Central Province of Sri Lanka adapts to climate variability. The lessons learned in the HWT will be helpful for many water-scarce irrigation systems in the country, which bear high climate risks. Recurrent droughts are the bane of agriculture in the Dry Zone, comprising three-fourths of the land area spread over the Northern, North Central and Eastern provinces. In the HWT, the fifteenth largest canal irrigation system in the country, adaptation to climate variability happens on several fronts: changes made by the irrigation management to the water release regime; changes in the cropping patterns practiced by farmers in the command area; and the use of groundwater, which is recharged from rainfall, reservoir storage and canal irrigation, as supplemental irrigation. Such adaptation measures ensure that the available water supply in the reservoir is adequate for 100% cropping intensity over two cropping seasons, even in drought years, and enhances economic water productivity in terms of value per unit of consumptive water use. Moreover, irrigation management should consider groundwater recharge through canal irrigation as a resource, which brings substantial agricultural and economic benefits not only for the command area but also outside the command area. The adaptation patterns implemented in HWT demonstrate how water-scarce irrigation systems can achieve higher economic water productivity, i.e., generate ‘more income per drop’ to enhance climate resilience for people in and outside the canal command areas.

The frequency and intensity of extreme climate events such as heavy rainfall and droughts are expected to increase with climate change and are predicted to severely affect the agriculture sector. However, drought vulnerability of rural communities in sub-Saharan Africa is not well documented, despite these communities being composed of mainly smallholder farmers whose livelihoods depend on rainfed agriculture. In this study, we evaluated the vulnerability of a rural community in Ethiopia to drought using both primary and secondary data. The primary data was generated from a household survey, whereas the secondary data was obtained from the National Meteorology Agency of Ethiopia and Climate Hazards Group Infrared Precipitation (CHIRP) product. We decomposed vulnerability in to three components which are exposure, sensitivity, and adaptive capacity to drought based on indices derived from the primary and secondary data. Results show that the average score for exposure, sensitivity, and adaptive capacity is nearly equal. High seasonal water variability coupled with severe, frequent, and long drought status increases exposure to drought in the study area. The main factor which affects sensitivity to drought in this community is the land cover. For adaptive capacity, the social capital of the community is low while their physical capital is high. The overall estimated drought vulnerability shows that the community is moderately vulnerable. The community’s exposure and sensitivity analyses show the need to increase the amount of moisture stored within the soil with the adoption of appropriate soil and water conservation techniques. Results also show that the head of the household’s educational level, the number of livestock owned, and annual income affect the community’s adaptive capacity.

Pragmatic, cost-effective, socially inclusive and scalable solutions that reduce risks from recurrent cycles of floods and droughts would greatly benefit emerging economies. One promising approach known as Underground Transfer of Floods for Irrigation (UTFI) involves recharging depleted aquifers with seasonal high flows to provide additional groundwater for irrigated agriculture during dry periods, while also mitigating floods. It has been identified that there is potential for implementing the UTFI approach across large parts of South Asia. The first pilot-scale implementation of UTFI was carried out in a rural community of the Indo-Gangetic Plain in India, and performance of the approach was assessed over three years from a technical, environmental, socioeconomic and institutional perspective. The results are promising and show that UTFI has the potential to enhance groundwater storage and control flooding, if replicated across larger scales. The challenges and opportunities for more wide-scale implementation of UTFI are identified and discussed in this report. In areas with high potential for implementation, policy makers should consider UTFI as an option when making decisions associated with relevant water-related development challenges.

In many parts of the world, wastewater irrigation has become a common practice because of freshwater scarcity and to increase resource reuse efficiency. Wastewater irrigation has positive impacts on livelihoods and at the same time, it has adverse impacts related to environmental pollution. Hydrochemical processes and groundwater behaviour need to be analyzed for a thorough understanding of the geochemical evolution in the wastewater irrigated systems. The current study focuses on a micro-watershed in the peri-urban Hyderabad of India, where farmers practice intensive wastewater irrigation. To evaluate the major factors that control groundwater geochemical processes, we analyzed the chemical composition of the wastewater used for irrigation and groundwater samples on a monthly basis for one hydrological year. The groundwater samples were collected in three settings of the watershed: wastewater irrigated area, groundwater irrigated area and upstream peri-urban area. The collected groundwater and wastewater samples were analyzed for major anions, cations and nutrients. We systematically investigated the anthropogenic influences and hydrogeochemical processes such as cation exchange, precipitation and dissolution of minerals using saturated indices, and freshwater-wastewater mixtures at the aquifer interface. Saturation indices of halite, gypsum and fluorite are exhibiting mineral dissolution and calcite and dolomite display mineral precipitation. Overall, the results suggest that the groundwater geochemistry of the watershed is largely controlled by long-term wastewater irrigation, local rainfall patterns and water-rock interactions. The study results can provide the basis for local decision-makers to develop sustainable groundwater management strategies and to control the aquifer pollution influenced by wastewater irrigation.

This report presents a spatial analysis conducted at global scale to identify areas of high suitability for implementing the Underground Transfer of Floods for Irrigation (UTFI) approach. The study used multiple global spatial datasets, and the related data were arranged under three categories – water supply, water demand and water storage – to assess global UTFI suitability. Among the river basins with high suitability, the Awash in Ethiopia, Ramganga in India (one of the major tributaries of the Ganges River Basin) and Chao Phraya in Thailand were selected for the economic analysis in this study. The results from this study are intended to provide a first step towards identifying the broad areas (at the river basin or country scale) where more detailed investigation would be worthwhile to ascertain the technical and economic feasibility of UTFI, with greater confidence.

Built water infrastructure impacts the balance of services provided by a river and its flow regime. Impacts on both commercial and subsistence activities should be considered in water management decision-making. Various methods used to define mandatory minimum environmental releases do not account for the inherent and often complex trade-offs and synergies which must be considered in selecting a balance of ecosystem and engineered services. This paper demonstrates the value and use of optimised many-objective trade-off analysis for managing resource-systems providing diverse and sometimes competing services. Using Kenya’s Tana River basin as a demonstration it shows controlled releases from multi-reservoir systems can be optimised using multiple performance metrics, representing individual provisioning ecosystem and engineered services at different locations and relating to different time periods. This enables better understanding the interactions between natural and built assets, and selecting river basin interventions that appropriately trade-off their services. Our demonstration shows prioritising Kenya’s statutory minimum environmental ‘reserve’ flows degrades flood-related provisioning services. Low overall flow regime alteration correlates negatively with consistency of hydropower generation, but positively with other provisioning services.

Groundwater governance has become an intractable policy issue, which has many implications for the living standards and well-being of millions of rural poor in South Asia. Groundwater governance is complex as it is influenced by various hydrogeological, sociopolitical and socioeconomic factors. Unregulated groundwater extraction rates in South Asia have depleted the aquifers causing a raft of socioeconomic, environmental and human health problems. This paper analyzes de facto rights in groundwater markets and other emerging ‘groundwater-sharing institutional arrangements’ in India. Using a multi-dimensional property rights model, the paper decomposes de facto groundwater rights while drawing insights and broad policy lessons. The findings indicate that there is much scope for enhancing the ‘small group groundwater sharing’ governed by social regulatory measures. Moreover, distortionary subsidies for agriculture in general and groundwater development, in particular, have had an adverse impact of the resource use and merit further attention.

A key question in sustainable development is how much alteration in natural systems, such as river basins, is acceptable? One of the ways by which humans alter a river basin is by building water storage infrastructure. While storage reservoirs deliver numerous benefits, they can also induce social and environmental costs by displacing people, fragmenting river networks and altering downstream flow regimes. In such a context, merely capping total water withdrawal from rivers for human consumption is not sufficient. River basin plans should also identify optimal (acceptable) limits to surface storage capacities, and optimal numbers, degrees of distribution and locations of storage infrastructure. It remains largely unclear, however, whether it is possible to define a hydrologically, ecologically and socially justified ‘surface water storage boundary’ for a river basin. An associated question is what would be the ‘best’ arrangement of this bounding storage capacity in the basins river network (in terms of numbers, sizes and locations of reservoirs) to maximize water storage benefits and minimize environmental and social costs. The main objective of this review is to examine contemporary knowledge on surface water storage development with a focus on tools and approaches that may help to answer the above questions of a ‘surface water storage boundary’ and its ‘optimum arrangement’ for a river basin. In order to achieve this objective, our review introduces two novel concepts: the ‘storage scale’ and the ‘sustainable storage development framework.’ The ‘storage scale’ has four elements – capacity, number, distribution and location – individual scales that help visualize a ‘surface water storage boundary’ and its ‘optimum arrangement’ for a typical river basin. The ‘sustainable storage development framework’ consists of three dimensions – economic benefits, ecosystems and society- and a set of indicators quantifying each dimension. This review shows that optimal levels of the elements of the ‘storage scale’ may be identified using the ‘sustainable storage development framework’.

Twelve actual evaporation datasets are evaluated for their ability to improve the performance of the fully distributed mesoscale Hydrologic Model (mHM). The datasets consist of satellite-based diagnostic models (MOD16A2, SSEBop, ALEXI, CMRSET, SEBS), satellite-based prognostic models (GLEAM v3.2a, GLEAM v3.3a, GLEAM v3.2b, GLEAM v3.3b), and reanalysis (ERA5, MERRA-2, JRA-55). Four distinct multivariate calibration strategies (basin-average, pixel-wise, spatial bias-accounting and spatial bias-insensitive) using actual evaporation and streamflow are implemented, resulting in 48 scenarios whose results are compared with a benchmark model calibrated solely with streamflow data. A process-diagnostic approach is adopted to evaluate the model responses with in-situ data of streamflow and independent remotely sensed data of soil moisture from ESA-CCI and terrestrial water storage from GRACE. The method is implemented in the Volta River basin, which is a data scarce region in West Africa, for the period from 2003 to 2012. Results show that the evaporation datasets have a good potential for improving model calibration, but this is dependent on the calibration strategy. All the multivariate calibration strategies outperform the streamflow-only calibration. The highest improvement in the overall model performance is obtained with the spatial bias-accounting strategy (+29%), followed by the spatial bias-insensitive strategy (+26%) and the pixel-wise strategy (+24%), while the basin-average strategy (+20%) gives the lowest improvement. On average, using evaporation data in addition to streamflow for model calibration decreases the model performance for streamflow (-7%), which is counterbalance by the increase in the performance of the terrestrial water storage (+11%), temporal dynamics of soil moisture (+6%) and spatial patterns of soil moisture (+89%). In general, the top three best performing evaporation datasets are MERRA-2, GLEAM v3.3a and SSEBop, while the bottom three datasets are MOD16A2, SEBS and ERA5. However, performances of the evaporation products diverge according to model responses and across climatic zones. These findings open up avenues for improving process representation of hydrological models and advancing the spatiotemporal prediction of floods and droughts under climate and land use changes.

Many regions in Africa and the Middle East are vulnerable to drought and to water and food insecurity, motivating agency efforts such as the U.S. Agency for International Development’s (USAID) Famine Early Warning Systems Network (FEWS NET) to provide early warning of drought events in the region. Each year these warnings guide life-saving assistance that reaches millions of people. A new NASA multimodel, remote sensing–based hydrological forecasting and analysis system, NHyFAS, has been developed to support such efforts by improving the FEWS NET’s current early warning capabilities. NHyFAS derives its skill from two sources: (i) accurate initial conditions, as produced by an offline land modeling system through the application and/or assimilation of various satellite data (precipitation, soil moisture, and terrestrial water storage), and (ii) meteorological forcing data during the forecast period as produced by a state-of-the-art ocean–land–atmosphere forecast system. The land modeling framework used is the Land Information System (LIS), which employs a suite of land surface models, allowing multimodel ensembles and multiple data assimilation strategies to better estimate land surface conditions. An evaluation of NHyFAS shows that its 1–5-month hindcasts successfully capture known historic drought events, and it has improved skill over benchmark-type hindcasts. The system also benefits from strong collaboration with end-user partners in Africa and the Middle East, who provide insights on strategies to formulate and communicate early warning indicators to water and food security communities. The additional lead time provided by this system will increase the speed, accuracy, and efficacy of humanitarian disaster relief, helping to save lives and livelihoods.

Climatic variability and change result in unreliable and uncertain water availability and contribute to water insecurity in Africa, particularly in arid and semi-arid areas and where water storage infrastructure is limited. Managed aquifer recharge (MAR), which comprises purposeful recharge and storage of surface runoff and treated wastewater in aquifers, serves various purposes, of which a prominent one is to provide a means to mitigate adverse impact of climate variability. Despite clear scope for this technology in Africa, the prevalence and range of MAR experiences in Africa have not been extensively examined. The objective of this article is provide an overview of MAR progress in Africa and to inform the potential for future use of this approach in the continent. Information on MAR from 52 cases in Africa listed in the Global MAR Portal and collated from relevant literature was analyzed. Cases were classified according to 13 key characteristics including objective of the MAR project, technology applied, biophysical conditions, and technical and management challenges. Results of the review indicate that: (i) the extent of MAR practice in Africa is relatively limited, (ii) the main objective of MAR in Africa is to secure and augment water supply and balance variability in supply and demand, (iii) the surface spreading/infiltration method is the most common MAR method, (iv) surface water is the main water source for MAR, and (v) the total annual recharge volume is about 158 Mm3 /year. MAR schemes exist in both urban and rural Africa, which exemplify the advancement of MAR implementation as well as its out scaling potential. Further, MAR schemes are most commonly found in areas of high inter-annual variability in water availability. If properly planned, implemented, managed, maintained and adapted to local conditions, MAR has large potential in securing water and increasing resilience in Africa. Ultimately, realizing the full potential of MAR in Africa will require undertaking hydrogeological and hydrological studies to determine feasibility of MAR, especially in geographic regions of high inter-annual climate variability and growing water demand. This, supported by increased research to gauge success of existing MAR projects and to address challenges, would help with future siting, design and implementation of MAR in Africa.

Understanding recharge processes is fundamental to improve sustainable groundwater resource management. Shallow groundwater (SGW) is being developed for multiple purposes in Ethiopia without consideration of monitoring. We established a citizen science-based hydro-meteorological monitoring network, with a focus on SGW recharge estimation, in Eshito micro-watershed, Ethiopia. Citizen scientists collected rainfall, groundwater-level and stream water-level data. We characterized the shallow aquifer using pumping tests. The data were used to estimate SGW recharge using three methods: chloride mass balance, water-level fluctuation (WLF) and baseflow separation. Approximately 20% and 35% of annual rainfall amount contributes to recharge based on the chloride mass balance and WLF results, respectively. Baseflow separation showed recharge values for the watershed vary from 38% to 28% of annual rainfall at the upstream and downstream gauging stations, respectively. This study shows that the recharge in previously unmonitored micro-watersheds can be studied if citizens are involved in data generation.

Integration of remote sensing data sets from multiple satellites is tested to simulate water storage variation of Lake Ziway, Ethiopia for the period 2009-2018. Sixty Landsat ETM+/OLI images served to trace temporal variation of lake surface area using a water extraction index. Time series of lake levels were acquired from two altimetry databases that were validated by in-situ lake level measurements. Coinciding pairs of optical satellite based lake surface area and radar altimetry based lake levels were related through regression and served for simulating lake storage variation. Indices for extracting lake surface area from images showed 91–99 % overall accuracy. Lake water levels from the altimetry products well agreed to in-situ lake level measurements with R2 = 0.92 and root mean square error of 11.9 cm. Based on this study we conclude that integrating satellite imagery and radar altimetry is a viable approach for frequent and accurate monitoring of lake water volume variation and for long-term change detection. Findings indicate water level reduction (4 cm/annum), surface area shrinkage (0.08km2 /annum) and water storage loss (20.4Mm3 /annum) of Lake Ziway (2009–2018).

We present an evidence-based approach to identify how best to support development of groundwater for smallscale irrigation in sub-Saharan Africa (SSA). We argue that it is important to focus this effort on shallow groundwater resources. We demonstrate and test this proposal at a case study site: Dangila woreda in the northwestern highlands of Ethiopia. This site was selected to allow exploration of a shallow weathered volcanic regolith type aquifer formation which is found to the South of Lake Tana and also exists more extensively across Ethiopia. We believe lessons from this case study are transferable and there is a case for arguing that shallow groundwater represents a neglected opportunity for promoting sustainable small-scale irrigated agriculture in SSA. In comparison with other global regions, the groundwater resources of SSA are among the least understood; borehole records and hydrogeological studies are lacking. Assessments of groundwater resources do exist, but they rely on remotely sensed data combined with modelling at national or regional scale, and they focus on deeper aquifers. There is a need for these broad evaluations to be supplemented by localised and detailed assessments. The case study here presents such an assessment in order to support analysis of strengths, weaknesses, opportunities and threats associated with developing small-scale irrigation utilising shallow groundwater. A multimethod groundwater recharge assessment was conducted utilising formal and community-based monitoring, field investigation and existing published data. Water table recovery tests at existing hand dug wells confirm that well yields of 1 l/s are achievable at the end of the wet season when water would be available to support an additional irrigated crop. Hydraulic conductivity estimates ranged from 0.2 to 6.4 m/d in the dry season and from 2.8 to 22.3 m/day in the wet season. Specific yield estimations have a wider range though the mean value of 0.09 is as would be expected. Records of groundwater levels and rainfall monitored by the local community for the period April 2014 to April 2018 show that all the wells maintained useable water levels beyond the end of the rainy season. An assessment of the hydrology of the Kilti catchment provided insights into groundwater availability within the wider area. The catchment receives about 1600 mm/year of rainfall, of which about 350 mm/year enters the groundwater as recharge, discharging to the river as baseflow with a similar amount of rapid runoff contributing to a total river flow of about 400 mm/year. The lowest value of baseflow is 82% of the mean baseflow, which suggests a degree of buffering and indicates that groundwater is available even in a very dry year. We conclude that arguments previously put forward against the promotion of shallow groundwater use for agriculture in SSA appear exaggerated. Our analysis challenges the view that shallow aquifers are unproductive and that irrigation will have u

This study attempted to conceptualize the hydrogeological setting of the Hout River Catchment, located in the Limpopo River Basin, using multiple methods that include groundwater flow patterns, structural analysis, stable (18O, 2H and 13C) and radiogenic (14C) isotopes of water and Water Table Fluctuation methods. The hydrogeological system of the catchment is represented by fractured crystalline basement aquifer as the main host for groundwater and is overlain by weathered rocks that act as a vadose zone and shallow aquifer in various places. Groundwater from the fractured basement rocks is the main source of water for large-scale irrigation and domestic use. Potential aquifers in the area are evident within the Hout River granitic gneiss and the Goudplaats granitic gneiss besides the younger granites as a result of fracturing and weathering. Groundwater flow map shows a flow pattern from the southern part of the catchment towards the north-eastern part of the catchment dictated by dolerite dykes and tectonic lineaments that trend in the ENE and E direction (088 and 075) with the dip angle of 50 to 55. The deeper aquifer in the southern and central part of the catchment contain old groundwater with high salinity due to long residence time. The stable isotopes further confirmed the limited possibility of local recharge, with rather dominance of regional groundwater circulation into the catchment. The northern part of the catchment seems to be receiving recent recharge with the groundwater of high 14C content derived from the mountains that border the catchment.

Urbanisation will be one of the 21st centuryapos;s most transformative trends. By 2050, it will increase from 55% to 68%, more than doubling the urban population in South Asia and Sub-Saharan Africa. Urbanisation has multifarious (positive as well as negative) impacts on the wellbeing of humans and the environment. The 17 UN Sustainable Development Goals (SDGs) form the blueprint to achieve a sustainable future for all. Clean Water and Sanitation is a specific goal (SDG 6) within the suite of 17 interconnected goals. Here we provide an overview of some of the challenges that urbanisation poses in relation to SDG 6, especially in developing economies. Worldwide, several cities are on the verge of water crisis. Water distribution to informal settlements or slums in megacities (e.g. N50% population in the megacities of India) is essentially non-existent and limits access to adequate safe water supply. Besides due to poor sewer connectivity in the emerging economies, there is a heavy reliance on septic tanks, and other on-site sanitation (OSS) system and by 2030, 4.9 billion people are expected to rely on OSS. About 62–93% of the urban population in Vietnam, Sri Lanka, the Philippines and Indonesia rely on septic tanks, where septage treatment is rare. Globally, over 80% of wastewater is released to the environment without adequate treatment. About 11% of all irrigated croplands is irrigated with such untreated or poorly treated wastewater. In addition to acute and chronic health effects, this also results in significant pollution of often-limited surface and groundwater resources in Sub-Saharan Africa and Asia. Direct and indirect water reuse plays a key role in global water and food security. Here we offer several suggestions to mitigate water and food insecurity in emerging economies.

Streamflow alteration and subsequent change in long-term average, seasonality, and extremes (e.g., floods and droughts) may affect water security, which is a major concern in many watersheds across the globe. Both climatic and anthropogenic activities may contribute to such changes. Therefore, this study assesses: (i) Streamflow and precipitation trends to identify streamflow alterations in the Extended East Rapti (EER) watershed in central-southern Nepal; (ii) relationship of the alterations to climatic and anthropogenic sources; and (iii) implications of streamflow changes to the socio-environmental system. The trends in streamflow were analyzed for pre-and post-1990 periods considering the abrupt shift in temperature trend in 1990. Results showed a general decreasing trends in discharge post-1990 in the EER watershed. Human activities have significantly contributed in altering streamflow in the EER. Human-induced streamflow alterations have affected the water availability, food security, river health, aquatic biodiversity, and groundwater abstraction in the EER watershed.

Study Region: Semi-Arid Regions of Marathawada, Vidarbha and Saurashtra in India Study Focus: To understand and evaluate the impact of Managed Aquifer Recharge (MAR) efforts. New Hydrological Insights for the Region: Since 1990, the Saurashtra region of Gujarat, India witnessed a massive community-based distributed groundwater recharge movement, initially catalyzed by NGOs and later supported by the government. The region has witnessed visible improvement in groundwater resources during recent years, which was attributed by some researchers to the recharge movement. A competing hypothesis holds that improvement in groundwater levels in Saurashtra are a result more due to a succession of good rainfall years during 2001–2014, aided by transfer of surface water from a big dam on Narmada River, rather than the distributed recharge movement. We develop and implement a 2-way test of these competing hypotheses: First, we compare groundwater recharge patterns in Saurashtra during a recent period of high rainfall years with a similar period before the onset of the recharge movement; second, for both these high rainfall periods, we also compare groundwater recharge patterns in two other comparable aquifer and terrain regions, viz., Vidarbha and Marathawada in Maharastra, which did not experience recharge movement on the same scale as Saurashtra did. Our results support the hypothesis that the community supported distributed recharge movement is the key to improved groundwater recharge in Saurashtra during 2004-09.

Understanding the complex relationship between water, agriculture and poverty (WAP) is essential for informed policy-making in light of increasing demand for scarce water resources and greater climatic variability. Yet, our understanding of the WAP nexus remains surprisingly undeveloped and dispersed across multiple disciplines due to conceptual (biophysical and economic) and measurement issues. We argue that water for agriculture will need to be better managed for it to contribute to reductions in poverty and vulnerabilities. Moreover, this management will need to consider not just quantities of water, but the quality of the water and the multiple agricultural and non-agricultural uses. For this reason, expanding research in WAP needs to involve interdisciplinary efforts. We identify three key knowledge gaps in WAP that are particularly pressing in light of greater climatic variability. These are climate change adaptation, over-abstraction of groundwater, and water quality.

The managed aquifer recharge (MAR) of excess monsoonal runoff to mitigate downstream flooding and enhance groundwater storage has received limited attention across the Indo-Gangetic Plain of the Indian subcontinent. Here, we assess the performance of a pilot MAR trial carried out in the Ramganga basin in India. The pilot consisted of a battery of 10 recharge wells, each 24 to 30 m deep, installed in a formerly unused village pond situated adjacent to an irrigation canal that provided river water during the monsoon season. Over three years of pilot testing, volumes ranging from 26,000 to 62,000 m3 were recharged each year over durations ranging from 62 to 85 days. These volumes are equivalent to 1.3–3.6% of the total recharge in the village, and would be sufficient to irrigate 8 to 18 hectares of rabi season crop. High inter-year variation in performance was observed, with yearly average recharge rates ranging from 430 to 775 m3 day-1 (164–295 mm day-1 ) and overall average recharge rates of 580 m3 day-1 (221 mm day-1 ). High intra-year variation was also observed, with recharge rates at the end of recharge period reducing by 72%, 88% and 96% in 2016, 2017 and 2018 respectively, relative to the initial recharge rates. The observed inter- and intra-year variability is due to the groundwater levels that strongly influence gravity recharge heads and lateral groundwater flows, as well as the source water quality, which leads to clogging. The increase in groundwater levels in response to MAR was found to be limited due to the high specific yield and transmissivity of the alluvial aquifer, and, in all but one year, was difficult to distinguish from the overall groundwater level rise due to a range of confounding factors. The results from this study provide the first systematic, multi-year assessment of the performance of pilot-scale MAR harnessing village ponds in the intensively groundwater irrigated, flood prone, alluvial aquifers of the Indo-Gangetic Plain.

This chapter establishes linkages between climate change and various aspects of water management. Adaptation and resilience-building options are presented with respect to water storage – including groundwater – and water supply and sanitation infrastructure, and unconventional water supply options are described. Mitigation options for water management systems are also presented.

Solar-powered irrigation pumps (SPIPs) have been promoted in the Eastern Gangetic Plains (EGP) in recent decades, but rates of adoption are low. This case study assesses the evidence from several solar pump business models being adopted in parts of the EGP, particularly eastern Nepal and northern India, and explores how different models perform in various contexts. It documents lessons for increasing farmers’ resilience to droughts through better groundwater use by promotion of SPIPs. Groundwater access for agriculture in the past was dependent on diesel and electric pumps, respectively constrained by costs and reliability of energy. Both government and nongovernment agencies have promoted SPIPs in the Ganges basin for irrigation and drinking purposes. SPIPs receive different levels of subsidies across countries and states in the region to facilitate adoption and ensure continuous and timely irrigation, which particularly benefits small and marginal farmers. Because the EGP faces variability in water availability, the SPIPs could help in building drought resilience. However, because low operating costs for SPIPs does little to incentivize farmers to use water efficiently, one critical question is how to balance equitable access to SPIPs while ensuring groundwater overdraft is not perpetuated. Farmers’ awareness of efficient water management options is crucial to avoid overextraction of groundwater.

Interventions that are robust, cost effective, and scalable are in critical demand throughout South Asia to offset growing water scarcity and avert increasingly frequent water-related disasters. This case study presents two complementary forms of intervention that transform water hazards (floodwater) into a resource (groundwater) to boost agricultural productivity and enhance livelihoods. The first intervention, holiya, is simple and operated by individual farmers at the plot/farm scale to control local flooding in semiarid climates. The second is the underground transfer of floods for irrigation (UTFI) and operates at the village scale to offset seasonal floods from upstream in humid climates. Rapid assessments indicate that holiyas have been established at more than 300 sites across two districts in North Gujarat since the 1990s, extending the crop growing season and improving water quality. UTFI knowledge and experience has grown rapidly since implementation of a pilot trial in western Uttar Pradesh in 2015 and is now embedded within government programs with commitments for modest scaling up. Both approaches can help farmers redress the multiple impacts associated with floods, droughts, and groundwater overexploitation at a range of scales from farm plot to the river basin. The potential for wider uptake across South Asia depends on setting up demonstration sites beyond India and overcoming gaps in technical knowledge and institutional capacity.

Groundwater resources of Kathmandu Valley in Nepal are under immense pressure from multiple stresses, including climate change. Due to over-extraction, groundwater resources are depleting, leading to social, environmental and economic problems. Climate change might add additional pressure by altering groundwater recharge rates and availability of groundwater. Mapping groundwater resilience to climate change can aid in understanding the dynamics of groundwater systems, facilitating the development of strategies for sustainable groundwater management. Therefore, this study aims to analyse the impact of climate change on groundwater resources and mapping the groundwater resiliency of Kathmandu Valley under different climate change scenarios. The future climate projected using the climate data of RCMapos;s namely ACCESS-CSIRO-CCAM, CNRM-CM5- CSIRO-CCAM and MPI-ESM-LR-CSIRO-CCAM for three future periods: near future (2010–2039), mid future (2040–2069) and far future (2070–2099) under RCP 4.5 and RCP 8.5 scenarios were bias corrected and fed into the Soil and Water Assessment Tool (SWAT), a hydrological model, to estimate future groundwater recharge. The results showed a decrease in groundwater recharge in future ranging from 3.3 to 50.7 mm/yr under RCP 4.5 and 19–102.1 mm/yr under RCP 8.5 scenario. The GMS-MODFLOW model was employed to estimate the future groundwater level of Kathmandu Valley. The model revealed that the groundwater level is expected to decrease in future. Based on the results, a groundwater resiliency map of Kathmandu Valley was developed. The results suggest that groundwater in the northern and southern area of the valley are highly resilient to climate change compared to the central area. The results will be very useful in the formulation and implementation of adaptation strategies to offset the negative impacts of climate change on the groundwater resources of Kathmandu Valley.

Protecting flood prone locations through floodwater recharge of the depleted aquifers and using it for protecting dry season irrigated agriculture is the rationale for a form of intervention termed as ‘underground transfer of floods for irrigation’ (UTFI). This helps reduce the intensity of seasonal floods by tapping and storing excess floodwater in aquifers for productive agricultural use. This paper presents a case study of managing the recharge interventions in the context of the Ramganga basin, India. Using a case study approach, this study determines the socio-economic and institutional context of the study area, proposes three potential routes to institutionalize UTFI, and provides insights for scaling up the interventions in the Ganges and other river basins that face seasonal floods and dry season water shortages. Managing the interventions involves community participation in regular operations and maintenance tasks. Given the limited scale of the pilot UTFI intervention implemented to date, and the socio-economic and institutional context of the case study region, the benefits are not conspicuous, though the piloting helped in identifying potential ways forward for the long-term management of the pilot site, and for scaling up the interventions. Initially pilot site management was handled by the project team working closely with the community leaders and villagers. As the intervention was demonstrated to perform effectively, management was handed over to the district authorities after providing appropriate training to the government personnel to manage the system and liaise with the local community to ensure the site is operated and managed appropriately. The district administration is willing to support UTFI by pooling money from different sources and routing them through the sub-district administration. While this is working in the short term, the paper outlines a programmatic longer term approach for wider replication.

Feeding 9 billion people in 2050 will require sustainable development of all water resources, both surface and subsurface. Yet, little is known about the irrigation potential of hillside shallow aquifers in many highland settings in sub-Saharan Africa that are being considered for providing irrigation water during the dry monsoon phase for smallholder farmers. Information on the shallow groundwater being available in space and time on sloping lands might aid in increasing food production in the dry monsoon phase. Therefore, the research objective of this work is to estimate potential groundwater storage as a potential source of irrigation water for hillside aquifers where lateral subsurface flow is dominant. The research was carried out in the Robit Bata experimental watershed in the Lake Tana basin which is typical of many undulating watersheds in the Ethiopian highlands. Farmers have excavated more than 300 hand dug wells for irrigation. We used 42 of these wells to monitor water table fluctuation from April 16, 2014 to December 2015. Precipitation and runoff data were recorded for the same period. The temporal groundwater storage was estimated using two methods: one based on the water balance with rainfall as input and baseflow and evaporative losses leaving the watershed as outputs; the second based on the observed rise and fall of water levels in wells. We found that maximum groundwater storage was at the end of the rain phase in September after which it decreased linearly until the middle of December due to short groundwater retention times. In the remaining part of the dry season period, only wells located close to faults contained water. Thus, without additional water sources, sloping lands can only be used for significant irrigation inputs during the first 3 months out of the 8 months long dry season.

The African Water Facility, together with the Water Research Commission, South Africa, as its implementing agent, supported the demonstration project Operationalizing community-led Multiple Use water Services (MUS) in South Africa. As knowledge broker and research partner in this project, the International Water Management Institute (IWMI) analyzed processes and impacts at the local level, where the nongovernmental organization Tsogang Water and Sanitation demonstrated community-led MUS in six diverse rural communities in two of the poorest districts of South Africa, Sekhukhune and Vhembe districts - Ga Mokgotho, Ga Moela and Phiring in the Sekhukhune District Municipality, and Tshakhuma, Khalavha and Ha Gumbu in Vhembe District Municipality. In conventional water infrastructure projects, external state or non-state agencies plan, diagnose, design and prioritize solutions, mobilize funding, and implement the procurement of materials, recruitment of workers and construction. However, this MUS project facilitated decision-making by communities, and provided technical and institutional advice and capacity development. Based on IWMI’s evidence, tools and manuals, the project team organized learning alliances and policy dialogues from municipal to national level on the replication of community-led MUS by water services authorities; government departments of water, agriculture, and others; employment generation programs; climate and disaster management; and corporate social responsibility initiatives. This working paper synthesizes the lessons learned about the six steps of the community-led MUS process in all six communities. The step-wise process appeared to be welcome and effective across the board. The duration of the process and the costs of facilitation, technical and institutional capacity development, and engineering advice and quality control were comparable to conventional approaches. However, the respective responsibilities of the government and communities, also in longer-term co-management arrangements, depended on the type of infrastructure. Some communities were supported to improve their communal self supply systems. In other communities, the process enabled an extension of the reticulation of borehole systems owned, operated and maintained by municipalities. Almost all households used water supplies at homesteads for multiple purposes, underscoring synergies in cross-sectoral collaboration between the water, sanitation and hygiene (WASH) and irrigation sectors.

The African Water Facility, together with the Water Research Commission, South Africa, as its implementing agent, supported the demonstration project Operationalizing community-led Multiple Use water Services (MUS) in South Africa. As knowledge broker and research partner in this project, the International Water Management Institute (IWMI) analyzed processes and impacts at the local level, where the nongovernmental organization Tsogang Water and Sanitation demonstrated community-led MUS in six diverse rural communities in two of the poorest districts of South Africa, Sekhukhune and Vhembe districts - Ga Mokgotho, Ga Moela and Phiring in the Sekhukhune District Municipality, and Tshakhuma, Khalavha and Ha Gumbu in Vhembe District Municipality. In conventional water infrastructure projects, external state and non-state agencies plan, diagnose, design and prioritize solutions, mobilize funding, and implement the procurement of materials, recruitment of workers and construction. However, this MUS project facilitated decision-making by communities, and provided technical and institutional advice and capacity development. Based on IWMI’s evidence, tools and manuals, the project team organized learning alliances and policy dialogues from municipal to national level on the replication of community-led MUS by water services authorities; government departments of water, agriculture, and others; employment generation programs; climate and disaster management; and corporate social responsibility initiatives. This working paper reports on the local findings of Ga Mokgotho and Ga Moela villages, which had completed construction works. The paper presents an in-depth analysis from the preproject situation to each of the steps of the participatory process, and highlights the resulting benefits of more water, more reliable and sustainable supplies, and multiple benefits, including a 60% and 76% increase in the value of irrigated produce in Ga Mokgotho and Ga Moela, respectively. Women were the sole irrigation manager in 68% and 60% of the households in Ga Mokgotho and Ga Moela, respectively. The user satisfaction survey highlighted communities’ unanimous preference of the participatory process, capacity development and ownership compared to conventional approaches.

The Ganga is an international transboundary river that flows across three major riparian countries: India, Nepal, and Bangladesh, where India shares a significant proportion of the total basin area. The river system is highly dynamic and regularly floods in all three countries due to abundant rainfall in a short period of only four months each year that causes tremendous loss of both property and human life. In this study, we have done a synoptic review to synthesize the hydrology, hydrogeology, and modeling studies that have analyzed hydrological changes and their impacts in the Ganga basin. This review also identifies some of the knowledge gaps and discusses possible options for enhancing the understanding of sustainable water development and management. This review indicated that transparent data sharing, use of satellite-based observations along with in-situ data, integrated hydro-economic modeling linked to reliable coupled surface–groundwater models, a central shared decision support center for early warning systems to deal with hydrological extremes, joint river commissions and monitoring teams, and multilateral water sharing treaties (agreements) are required to promote sustainable and equitable distribution of water resources and to avoid water sharing conflicts in the Ganga basin.

Faced with severe groundwater depletion, many governments have opted to increase the power of the state. Despite calls for more inclusive governance and a role for groundwater users, modes of governance have tended to continue to rely on a diversity of policy tools and state-run strategies in the attempt to control groundwater (over)abstraction. Yet, around the world, the performance of state-centered governance has remained dismal. Beyond common difficulties in terms of data and financial or human resources, this article analyzes in greater depth the limited effectiveness of state groundwater policies that has been observed, emphasizing its political ramifications. The various aspects of weak monitoring and enforcement, as well as of the infamous “lack of political will,” are considered from the perspective of the political economy of groundwater economies. Cases of relative success are then used to identify favorable drivers and contexts for effective state-centered groundwater governance.

Chunnakam aquifer is the main limestone aquifer of Jaffna Peninsula. The population of the Jaffna Peninsula depends entirely on groundwater resources to meet all of their water requirements. Thus for protecting groundwater quality in Chunnakam aquifer, data on spatial and temporal distribution are important. Geostatistics methods are one of the most advanced techniques for interpolation of groundwater quality. In this study, Ordinary Kriging and IDW methods were used for predicting spatial distribution of some groundwater characteristics such as: Electrical Conductivity (EC), pH, nitrate as nitrogen, chloride, calcium, carbonate, bicarbonate, sulfate and sodium concentration. Forty four wells were selected to represent the entire Chunnakam aquifer during January, March, April, July and October 2011 to represent wet and dry season within a year. After normalization of data, variogram was computed. Suitable model for fitness on experimental variogram was selected based on less Root Mean Square Error (RMSE) value. Then the best method for interpolation was selected, using cross validation and RMSE. Results showed that for all groundwater quality, Ordinary Kriging performed better than IDW method to simulate groundwater quality. Finally, using Ordinary Kriging method, maps of groundwater quality were prepared for studied groundwater quality in Chunnakam aquifer. The result of Ordinary Kriging interpolation showed that higher EC, chloride, sulphate and sodium concentrations are clearly shown to be more common closer to the coast, and decreasing inland due to intrusion of seawater into the Chunnakam aquifer. Also higher NO3 - - N are observed in intensified agricultural areas of Chunnakam aquifer in Jaffna Peninsula.

The last 60 years has seen unprecedented groundwater extraction and overdraft as well as development of new technologies for water treatment that together drive the advance in intentional groundwater replenishment known as managed aquifer recharge (MAR). This paper is the first known attempt to quantify the volume of MAR at global scale, and to illustrate the advancement of all the major types of MAR and relate these to research and regulatory advancements. Faced with changing climate and rising intensity of climate extremes, MAR is an increasingly important water management strategy, alongside demand management, to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. During this time, scientific research—on hydraulic design of facilities, tracer studies, managing clogging, recovery efficiency and water quality changes in aquifers—has underpinned practical improvements in MAR and has had broader benefits in hydrogeology. Recharge wells have greatly accelerated recharge, particularly in urban areas and for mine water management. In recent years, research into governance, operating practices, reliability, economics, risk assessment and public acceptance of MAR has been undertaken. Since the 1960s, implementation of MAR has accelerated at a rate of 5%/year, but is not keeping pace with increasing groundwater extraction. Currently, MAR has reached an estimated 10 km3/year, ~2.4% of groundwater extraction in countries reporting MAR (or ~1.0% of global groundwater extraction). MAR is likely to exceed 10% of global extraction, based on experience where MAR is more advanced, to sustain quantity, reliability and quality of water supplies.

Small reservoirs are a critical coping mechanism in water-stressed rural areas in Africa, providing immense livelihood benefits that include improved food and water security, entrepreneurial activities and climate resilience. Challenges associated with the implementation of investments in small reservoirs include appropriate site selection, weak institutions, insufficient maintenance and sedimentation. The findings from this study suggest that the benefits of small reservoirs may be tapped more efficiently by rehabilitating old sites rather than building new infrastructure. However, the findings also point to broader lessons on the need to change the way of doing business, i.e., to adopt a long-term, more holistic approach (or model) to the construction and maintenance of small reservoirs that matches the degree of the challenge associated with sustainably tapping the benefits of the water that they store.

An integrated hydrogeological modelling approach applicable to hard-rock aquifers in semi-arid data-scarce Africa was developed using remote sensing, rainfall-runoff modelling, and a three-dimensional (3D) dynamic model. The integrated modelling approach was applied to the Hout catchment, Limpopo Province, South Africa, an important agricultural region where groundwater abstraction for irrigation doubled during 1968–1986. Since the 1960s, groundwater levels in irrigated areas have displayed extended periods of decline with partial or full recovery in response to major decadal rainfall events or periods. The integrated dynamic 3D hydrogeological flow model, based on the One-Water Hydrologic Flow Model (MODFLOW-OWHM), helped to understand recharge and flow processes and inform water use and management. Irrigation abstraction was estimated based on irrigated crop area delineated using the Landsat Normalized Difference Vegetation Index (NDVI) and crop water requirements. Using groundwater level data, the model was calibrated (2008–2012) and validated (2013–2015). Estimated mean diffuse recharge (3.3 2.5% of annual rainfall) compared well with estimates from the Precipitation Runoff Modelling System model. Recharge and groundwater storage showed significant inter-annual variability. The ephemeral river was found to be losing, with mean net flux to the aquifer (focused recharge) of ~1.1% of annual rainfall. The results indicate a delicate human-natural system reliant on the small but highly variable recharge, propagating through variable pumping to an even more variable storage, making the combined system vulnerable to climate and anthropogenic changes. The integrated modelling is fundamental for understanding spatio-temporal variability in key parameters required for managing the groundwater resource sustainably.

Easy access, round the year availability even in the draught years and lack of regulations coupled with advanced and cheap technology to create extraction structure have been major factors responsible for indiscriminate extraction of groundwater. With a rise in population leading to increasing water requirement, the untapped groundwater resource has been the biggest bone of contention amongst multiple stakeholders with a threat of serious depletion in many parts of the world especially regions without perennial surface water availability and arid or semi-arid climate. India is the largest extractor of groundwater and the alarming situation has already tapped in. Semi-arid region of Saurashtra has the most extreme case with just 500 mm of rainfall and almost 40 percent of coefficient of variation leading to frequent drought-like condition. Saurashtraapos;s almost 83 per cent of the total irrigated area is through groundwater. High extraction of groundwater of Saurashtra caused major groundwater depletion in the region. The condition even intensified during consecutive drought years of 1985-87 when Saurashtra received just 93 mm of total rainfall during 1987 on top of 60 per cent rainfall in 2 consecutive drought years of 1985 (299 mm) and 1986 (298 mm). Severity of the condition led to a mass movement for rainwater harvesting as well as a decentralized groundwater recharge at an unprecedented scale. The community-led movement with the support of local leaders, merchants and religious gurus in the early 90s got support from the state government. The movement was formalized as Sardar Patel Sahkari Jal Sanchay Yojana (SPSJSY) soon after Narendra Modi assumed office as Chief Minister of Gujarat. Under this pan-Gujarat scheme, 5 lakh structures created (113738 check dams, 55917 bori bandhs, 240199 farm ponds, besides 62532 large and small check dams) making way for 808 MCM (Million Cubic Meter) of storage capacity. The scheme performed best in Saurashtra as almost 60 per cent of this storage capacity (482 MCM) confined in 7 districts of Saurashtra. The success of the program was much lauded by state and central governments making it exemplary for other semiarid regions like Marathawada and Vidarbha those that have comparable terrain, soil and aquifer characteristics. The comparative analysis of the movementapos;s success with pre-post analysis by considering monsoonal groundwater recharge during good rainfall spell of 1975-84 (pre) and 2004-09 (post) show almost a two-fold increase in the groundwater recharge during the similar monsoon years in Saurashtra. This temporal analysis enables to establish the impact of the collective efforts by people as well as the government for groundwater rejuvenation in Saurashtra. With availability of dependable irrigation, Saurashtra has also emerged as a major contributor to Gujarat stateapos;s agriculture growth which has normally been shadowed by other regions of the state making the state agriculture growth reachi

The impact of climate variability on groundwater storage has received limited attention despite widespread dependence on groundwater as a resource for drinking water, agriculture and industry. Here, we assess the climate anomalies that occurred over Southern Africa (SA) and East Africa, south of the Equator (EASE), during the major El Nio event of 2015–2016, and their associated impacts on groundwater storage, across scales, through analysis of in situ groundwater piezometry and Gravity Recovery and Climate Experiment (GRACE) satellite data. At the continental scale, the El Nio of 2015–2016 was associated with a pronounced dipole of opposing rainfall anomalies over EASE and Southern Africa, north–south of ~12 S, a characteristic pattern of the El Nio–Southern Oscillation (ENSO). Over Southern Africa the most intense drought event in the historical record occurred, based on an analysis of the cross-scale areal intensity of surface water balance anomalies (as represented by the standardised precipitation evapotranspiration index – SPEI), with an estimated return period of at least 200 years and a best estimate of 260 years. Climate risks are changing, and we estimate that anthropogenic warming only (ignoring changes to other climate variables, e.g. precipitation) has approximately doubled the risk of such an extreme SPEI drought event. These surface water balance deficits suppressed groundwater recharge, leading to a substantial groundwater storage decline indicated by both GRACE satellite and piezometric data in the Limpopo basin. Conversely, over EASE during the 2015–2016 El Nio event, anomalously wet conditions were observed with an estimated return period of ~10 years, likely moderated by the absence of a strongly positive Indian Ocean zonal mode phase. The strong but not extreme rainy season increased groundwater storage, as shown by satellite GRACE data and rising groundwater levels observed at a site in central Tanzania. We note substantial uncertainties in separating groundwater from total water storage in GRACE data and show that consistency between GRACE and piezometric estimates of groundwater storage is apparent when spatial averaging scales are comparable. These results have implications for sustainable and climate-resilient groundwater resource management, including the potential for adaptive strategies, such as managed aquifer recharge during episodic recharge events.

A reliable supply of water is critical for agricultural intensification and yield improvement. Technological devices that lift, transport and apply water contribute to increased yield from improved crop varieties and high input cultivation. The increasing use of motor pumps is a significant contribution to the development of small-scale irrigation. The objective of this study was to identify and analyze the trajectories of technological innovations and uptake for agricultural water management in farming systems in Sri Lanka, with a special focus on identifying impacts, emerging issues and potential responses to the rapid proliferation of motor pumps in the intensification of agriculture in the country. The Government of Sri Lanka promoted the rapid adoption of water pumps through interventions such as the development of groundwater wells for agriculture; provision of subsidies and credit facilities for purchasing micro-irrigation equipment; and government policies on tax, tariffs and extension support. At the same time, the high profit margin realized from cash crop cultivation motivated farmers to invest in water lifting and related technologies. Finally, water scarcity and restrictions on the use of surface water, i.e., canals, prompted a shift to using water-lifting technologies to pump groundwater. The use of water pumps in agriculture has expanded the area under cultivation; increased cropping intensity, especially during the dry seasons; changed the cropping pattern from low-return rice cultivation to high-return cash crop cultivation; and enhanced household incomes. Expanded and intensified cultivation has provided more opportunities for women to participate in agriculture, generating additional income, and enhancing their purchasing power and decision-making at the household level. Some farmers do not have groundwater wells and water pumps because they lack the necessary capital to make the initial investment. Smallholder farmers, in particular, are reluctant to risk their limited income on new technologies. This may lead to the further marginalization of poor farmers. Inclusive intensification will require helping farmers to access irrigation technology, for example, through carefully targeted subsidies and access to credit. Using water pumps can provide benefits to both users and non-users, but uncontrolled groundwater extraction may also create new problems by putting enormous pressure on common property resources. The government will need to take on a dual role to both promote the inclusive growth of small-scale irrigation, and to prevent and mitigate its negative environmental impacts. This second role may include establishing a regulatory system, setting standards for well construction, and monitoring and enforcing standards on extraction and water quality. There is an urgent need for institutional measures and governance arrangements to guide and regulate groundwater irrigation, especially in the context of intensive cultivation us

Indian agricultural communities are facing a crisis driven by, among other things, skewed terms of trade and farmers’ inability to deal with increasingly adverse climatic conditions. Because agriculture continues to be the primary source of livelihood for most of India’s population, governments at all levels are under pressure to find ways to help farmers. In western and peninsular India, where droughts are common, several state governments have vowed to make farming “drought-proof” through ambitious flagship programs. This case study reviews the experience of four such programs in Gujarat, Maharashtra, Telangana, and Rajasthan. Although the programs differ in approach, implementation style, and duration, all of them aim to shield farmers, particularly smallholders, from the misery imposed by droughts. Among these states, efforts in Gujarat appear to be the most mature; however, concerns regarding sustaining momentum, capacity building of communities, demand management, and establishing functional local governance remain. We use evidence gathered through field studies to draw lessons for designing effective drought-mitigation strategies through improved management of groundwater resources.

Water availability for agriculture will become a growing constraint in areas already under environmental and social stress due to population growth, development, and climatic variability. This limits the potential for expanding irrigated areas and for sustainable intensification, and compromises the ability of smallholder farmers to cater to the increased demand for food. This chapter assesses the key global challenges to water availability and how increasing scarcity and competition for water resources are affecting agricultural productivity, especially that of smallholder producers in Asia and Africa. It further analyzes emerging water management practices that can be sustainably adapted to the needs of smallholder farmers. We provide evidence of the economic viability and potential to improve farmers’ income from such solutions. The opportunity for scaling up high-impact solutions is also assessed against available empirical evidence.

To meet the demand deficit in Kathmandu Valley, the Government of Nepal has planned to supply an additional 510 million liters per day (mld) of water by implementing the Melamchi Water Supply Project (MWSP) in the near future. In this study, we aim to assess the spatial distribution of groundwater availability and pumping under five scenarios for before and after the implementation of the MWSP using a numerical groundwater flow model. The data on water demand, supply infrastructure, changes in hydraulic head, groundwater pumping rates, and aquifer characteristics were analyzed. Results showed that groundwater pumping from individual wells ranges from 0.0018 to 2.8 mld and the average hydraulic head declined from 2.57 m below ground level (bgl) (0.23 m/year) to 21.58 m bgl (1.96 m/year). Model simulations showed that changes in average hydraulic head ranged from þ2.83 m to þ5.48 m at various stages of the MWSP implementation, and 2.97 m for increased pumping rates with no implementation of the MWSP. Regulation in pumping such as monetary instruments (groundwater pricing) on the use of groundwater along with appropriate metering and monitoring of pumping amounts depending on the availability of new and existing public water supply could be interventions in the near future.

The purpose of the module is to demonstrate how scientific information can make a big difference in proper understanding of the differences in WS impacts across projects and sites. The module presents scientific information in an easy-to-understand format. Concepts are explained and applied and implications discussed making the module highly practice oriented. Rich scientific information on case study sites is presented in detail to help visualize the case study characteristics clearly so that the learners can relate the information to sites they are familiar with. Toward the end of the module, learners will be exposed to a decision support tool that can be run on Microsoft Excel, which is designed to assist in water resource planning for watershed at the mesoscale. It can also be used for assessing changing land use and climate regimes within the watershed. The tools help in exploring recharge interventions, changes in cropping patterns, and irrigation practices.

Kathmandu Upatyaka Khanepani Limited (KUKL) currently uses 35 surface and 57 groundwater sources to supply water for Nepal’s capital, Kathmandu. It is necessary to understand if the Melamchi Water Supply Project (MWSP) can assist lean period water supply by indirectly increasing groundwater storage, through diverting excess water supply to groundwater recharge zones. The current study analyzed long-term groundwater depletion to assess available groundwater storage, followed by assessment of groundwater balance for the Kathmandu Valley. Results show that total groundwater extraction for Kathmandu was 69.44 million cubic meters (MCM) and drawdown of the groundwater surface was 15–20 m since the construction of wells in 1984/85, indicating substantial overexploitation. Results indicate that the ongoing unmet demand of 170 MCM/year can be easily satisfied if groundwater storage is recharged effectively, as underground water storage potential is 246 MCM/year due to a groundwater depletion rate of 2–10 m. From results, it is evident that that the timely implementation of the MWSP can help ease ongoing water stress and aid in reversing the damage caused to groundwater storage. In the long run, MWSP can supply water and recharge groundwater during monsoon periods, thus improving the quality of life and socio-economic status in Kathmandu.

Rural communities in sub-Saharan Africa commonly rely on shallow hand-dug wells and springs; consequently, shallow aquifers are an extremely important water source. Increased utilisation of shallow groundwater could help towards achieving multiple sustainable development goals (SDGs) by positively impacting poverty, hunger, and health. However, these shallow aquifers are little studied and poorly understood, partly due to a paucity of existing hydrogeological information in many regions of sub-Saharan Africa. This study develops a hydrogeological conceptual model for Dangila woreda (district) in Northwest Ethiopia, based on extensive field investigations and implementation of a citizen science programme. Geological and water point surveys revealed a thin (3–18 m) weathered volcanic regolith aquifer overlying very low permeability basalt. Hydrochemistry suggested that deep groundwater within fractured and scoriaceous zones of the basalt is not (or is poorly) connected to shallow groundwater. Isotope analysis and well monitoring indicated shallow groundwater flow paths that are not necessarily coincident with surface water flow paths. Characteristics of the prevalent seasonal floodplains are akin to “dambos” that are well-described in literature for Southern Africa. Pumping tests, recharge assessments, and hydrometeorological analysis indicated the regolith aquifer shows potential for increased utilisation. This research is transferrable to the shallow volcanic regolith aquifers that overlie a substantial proportion of Ethiopia and are prevalent throughout the East African Rift and in several areas elsewhere on the continent.

Hydropower production is altering the Mekong River basin’s riverine ecosystems, which contain the world’s largest inland fishery and provide food security and livelihoods to millions of people. The basin’s hydropower reservoir storage, which may rise from ~2% of its mean annual flow in 2008 to ~20% in 2025, is attenuating seasonal flow variability downstream of many dams with integral powerhouses and large storage reservoirs. In addition, tributary diversions for off-stream energy production are reducing downstream flows and augmenting them in recipient tributaries. To help manage tradeoffs between dam benefits (hydropower, irrigation, flood control, domestic water supply, and navigation) and their consequences for livelihoods and ecosystems, we review observed and projected impacts on river flows along both the Mekong mainstream and its tributaries. We include the effects of diversions and inter-basin transfers, which prior reviews of flow alteration in the Mekong basin have largely neglected. We also discuss the extent to which concurrent changes in climate, water demand, and land use, may offset or exacerbate hydropower-induced flow alteration. Our major recommendations for assessing hydrological impacts in the Mekong and other basins undergoing rapid hydropower development include synchronizing and integrating observational and modeling studies, improving the accuracy of reservoir water balances, evaluating multi-objective reservoir operating rules, examining hydropeaking-induced flow alteration, conducting multi-dam safety assessments, evaluating flow indicators relevant to local ecosystems and livelihoods, and considering alternative energy sources and reservoir sedimentation in long-term projections. Finally, we strongly recommend that dam impact studies consider hydrological alteration in conjunction with fish passage barriers, geomorphic changes and other contemporaneous stressors.

Although most recharge estimation studies apply multiple methods to identify the possible range in recharge values, many do not distinguish clearly enough between inherent uncertainty of the methods and other factors affecting the results. We investigated the additional value that can be gained from multi-method recharge studies through insights into hydrogeological understanding, in addition to characterizing uncertainty. Nine separate groundwater recharge estimation methods, with a total of 17 variations, were applied at a shallow aquifer in northwest Ethiopia in the context of the potential for shallow groundwater resource development. These gave a wide range of recharge values from 45 to 814 mm/a. Critical assessment indicated that the results depended on what the recharge represents (actual, potential, minimum recharge or change in aquifer storage), and spatial and temporal scales, as well as uncertainties from application of each method. Important insights into the hydrogeological system were gained from this detailed analysis, which also confirmed that the range of values for actual recharge was reduced to around 280-430 mm/a. This study demonstrates that even when assumptions behind methods are violated, as they often are to some degree especially when data are limited, valuable insights into the hydrogeological system can be gained from application of multiple methods.

Globally, many populations face structural and environmental barriers to access safe water, sanitation and hygiene (WASH) services. Among these populations are many of the 200 million pastoralists whose livelihood patterns and extreme environmental settings challenge conventional WASH programming approaches. In this paper, we studied the Afar pastoralists in Ethiopia to identify WASH interventions that can mostly alleviate public health risks, within the populationapos;s structural and environmental living constraints. Surveys were carried out with 148 individuals and observational assessments made in 12 households as part of a Pastoralist Community WASH Risk Assessment. The results show that low levels of access to infrastructure are further compounded by risky behaviours related to water containment, storage and transportation. Additional behavioural risk factors were identified related to sanitation, hygiene and animal husbandry. The Pastoralist Community WASH Risk Assessment visually interprets the seriousness of the risks against the difficulty of addressing the problem. The assessment recommends interventions on household behaviours, environmental cleanliness, water storage, treatment and hand hygiene via small-scale educational interventions. The framework provides an approach for assessing risks in other marginal populations that are poorly understood and served through conventional approaches.

While hydrological science has made great strides forward during the last 50 years with the advance of computing power and availability of satellite images, much is unknown about the sustainable development of water for irrigation, domestic use, and livestock consumption for millions of households in the developing world. Specifically, quantification of shallow underground water resources for irrigation in highland regions remains challenging. The objective is to better understand the hydrology of highland watersheds with sloping hillside aquifers. Therefore, we present a subsurface flow model for hillside aquifers with recharge that varied from day to day. Recharge to the aquifer was estimated by the Thornthwaite Mather procedure. A characteristic time was identified for travel time of water flowing from the upper part of the hillside to the river or well. Using the method of characteristics, we found that the height of shallow groundwater level can be predicted by determining the total recharge over the characteristic time divided by drainable porosity. We apply the model to farmer-dug wells in the Ethiopian highlands using observed rainfall, potential evaporation, and a fitted travel time. We find that the model performs well with maximum water table heights being determined by the soil surface and minimum heights by the presence or absence of volcanic dikes downhill. Our application shows that unless the water is ponded behind a natural or artificial barrier, hillslope aquifers are unable to provide a continuous source of water during the long, dry season. This clearly limits any irrigation development in the highlands from shallow sloping groundwater.

Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled human and natural system (CHANS) linking climate, sanitation, and groundwater quality in Ramotswa, a rapidly growing peri-urban area in the semi-arid southeastern Botswana, which relies on the transboundary Ramotswa aquifer for water supply. Analysis of long-term rainfall records indicated that droughts like the one in 2013–2016 are increasing in likelihood in the area due to climate change. Key informant interviews showed that due to the drought, people increasingly used pit latrines rather than flush toilets. Nitrate, fecal coliforms, and caffeine analyses of Ramotswa groundwater revealed that human waste leaching from pit latrines is the likely source of nitrate pollution. The results in conjunction indicate critical indirect linkages between climate change, sanitation, groundwater quality, and water security in the area. Improved sanitation, groundwater protection and remediation, and local water treatment would enhance reliable access to water, de-couple the community from reliance on surface water and associated water shortage risks, and help prevent transboundary tension over the shared aquifer.

In the Ganges basin, 8268.6 km2 of irrigation command area is waterlogged following monsoon rains. In this study, vertical drain (VD) (L × D, 7 × 1 m) filled with drainage gravel (6.5 m) and coarse sand (0.5 m) is installed in farmer’s agricultural field to minimize the duration of seasonal waterlogging and tested in Mukundpur village, Vaishalli District, Bihar, India. At the experimental site, inundation of rainfall and runoff from surrounding areas along with the seepage from an earthen canal start in September and remain till February, every year which prevents timely planting of wheat in November-end/December. Drainage due to percolation and recharge to groundwater is constrained by 6.4-m thick clay layer, below 0.5-m root-zone, and the groundwater level, which rises to the surface level. VDs were installed to provide a path and allow inundated water to recharge the aquifer, as groundwater level recedes. Groundwater level drop, floodwater infiltration rate, groundwater discharge, and VD capability were estimated through field data. Results show that VDs connected the floodwater to groundwater and transferred the floodwater to the aquifer when groundwater level started to recede. The site was fully drained by the end of December, permitting farmers to plant wheat in January providing cool nights at germination, thus increasing yields.

Participatory groundwater management is increasingly being recognised for its ability to address the challenges of equity, efficiency and sustainability. It can particularly help with effective engagement at the grassroots level for monitoring, recharging and managing the groundwater as a common pool resource. The main aim of this article is to discuss the training and management process used and the lessons learnt from a participatory groundwater management project, titled Managing Aquifer Recharge and Sustainable Groundwater Use through Village-level Intervention (MARVI). In this project, researchers, rural development facilitators and local villagers worked together to initiate participatory groundwater monitoring in 11 villages from the Dharta and Meghraj watersheds in Rajasthan and Gujarat, India. The study involved educating villagers through an intensive program of capacity building, wherein the villagers who participated in the program were called Bhujal Jaankars (BJs), a Hindi word meaning ‘groundwater informed’. The BJs were trained in their local settings through relevant theory and practical exercises, so that they could perform a geo-hydrological evaluation of their area, monitor groundwater and share their findings and experiences with their village community. The study has highlighted that with a well-designed program of capacity building and on-going support through training and nurturing, BJs can play an important role in monitoring watertable depth and other data for estimating groundwater recharge, leading to a sharing of the groundwater information with the local village community to influence the sustainable use of groundwater. Overall they can act as local champions for groundwater futures. Further, this study has demonstrated that BJ capacity building can help to provide a scientific basis for village level groundwater dialogue and assist village communities and other stakeholders to improve their decision making regarding groundwater use, crop selection, agronomy, recharge strategies and other aspects of sustainable groundwater management. Although the BJ program has been successful and BJs can act as a valuable interface between local communities and other stakeholders managed aquifer recharge activities, there still exists some challenges to the BJ programme, such as the need for mechanisms and funding sources that will sustain the BJs over the longer term; wider acceptance of BJs among scientific communities and policy makers; and the acceptance of the role and involvements of BJs in natural resources management programs of the State and Central governments in India.

Target 6.4 of the recently adopted Sustainable Development Goals (SDGs) deals with the reduction of water scarcity. To monitor progress towards this target, two indicators are used: Indicator 6.4.1 measuring water use efficiency and 6.4.2 measuring the level of water stress (WS). This paper aims to identify whether the currently proposed indicator 6.4.2 considers the different elements that need to be accounted for in a WS indicator. WS indicators compare water use with water availability. We identify seven essential elements: 1) both gross and net water abstraction (or withdrawal) provide important information to understand WS; 2) WS indicators need to incorporate environmental flow requirements (EFR); 3) temporal and 4) spatial disaggregation is required in a WS assessment; 5) both renewable surface water and groundwater resources, including their interaction, need to be accounted for as renewable water availability; 6) alternative available water resources need to be accounted for as well, like fossil groundwater and desalinated water; 7) WS indicators need to account for water storage in reservoirs, water recycling and managed aquifer recharge. Indicator 6.4.2 considers many of these elements, but there is need for improvement. It is recommended that WS is measured based on net abstraction as well, in addition to currently only measuring WS based on gross abstraction. It does incorporate EFR. Temporal and spatial disaggregation is indeed defined as a goal in more advanced monitoring levels, in which it is also called for a differentiation between surface and groundwater resources. However, regarding element 6 and 7 there are some shortcomings for which we provide recommendations. In addition, indicator 6.4.2 is only one indicator, which monitors blue WS, but does not give information on green or green-blue water scarcity or on water quality. Within the SDG indicator framework, some of these topics are covered with other indicators.

Groundwater use in India, and many developing countries, is linked to livelihood and well-being of village communities. It is, therefore, important to characterise groundwater behaviour and resilience and identify strategies that will help to improve the sustainability of groundwater supplies. The concept of Standardised Precipitation Index (SPI) has been widely used for analysing rainfall drought. In this study, we adapt SPI to understand watertable fluctuations and assess resilience of groundwater supplies vis--vis rainfall variability from one year to the next. The modified SPI, called Groundwater Resilience Index (GRI), represents a normalized continuous watertable elevation variability function. The index is applied to two districts, viz., Udaipur and Aravalli in Rajasthan and Gujarat, India, respectively, to assess its usefulness. To evaluate the association of rainfall variability with groundwater depth fluctuation, SPI was also calculated. The study showed that GRI varies less than SPI, indicating that groundwater availability is less variable than the rainfall in both districts. This means that groundwater increases reliability of water supply for irrigation in both districts. The estimated SPI and GRI at 6-month intervals for the study period show that even though the groundwater is not stressed (normal condition in 75% of the months observed), there is variation in resilience of the aquifer system to drought and extreme events. Overall, the study indicated that the proposed GRI can be a useful tool for understanding watertable fluctuations and assessing groundwater resilience, especially to prioritise areas for groundwater recharge when funds for recharge works are limited.

Storage of surface water is widely regarded as a form of insurance against rainfall variability. However, creation of surface storage often endanger the functions of natural ecosystems, and, in turn, ecosystem services that bene t humans. The issues of optimal size, placement and the number of reservoirs in a river basin – which maximizes sustainable bene ts from storage – remain subjects for debate. This study examines the above issues through the analysis of a range of reservoir con gurations in the Malwatu Oya river basin in the dry zone of Sri Lanka. The study produced multiple surface storage development pathways for the basin under different scenarios of environmental ow (EF) releases and reservoir network con gurations. The EF scenarios ranged from “zero” to “very healthy” releases. It is shown that if the “middle ground” between the two extreme EF scenarios is considered, the theoretical maximum “safe” yield from surface storage is about 65–70% of the mean annual runoff (MAR) of the basin. It is also identi ed that although distribution of reservoirs in the river network reduces the cumulative yield from the basin, this cumulative yield is maximized if the ratio among the storage capacities placed in each sub drainage basin is equivalent to the ratio among their MAR. The study suggests a framework to identify drainage regions having higher surface storage potential, to plan for the right distribution of storage capacity within a river basin, as well as to plan for EF allocations.

Groundwater resources are vital for the well-being and livelihoods of most of the ten million people living in the Dry Zone of central Myanmar. Despite this importance, there is remarkably little known or documented on the nature, extent and use of these resources. This contribution has attempted to address this gap by reviewing the literature, gathering data and stakeholder consultations. The study reveals that utilizable groundwater is present across most of the Dry Zone, most notably in the unconsolidated sedimentary aquifers that are present across large portions of the region. However, rates of replenishment appear to be relatively modest, and use is limited by high levels of salinity and arsenic that are naturally present in some areas. The scope to access groundwater is generally good, and development has steadily increased to provide water supply for domestic, agriculture and industry. In broad terms, is would appear that prospects to expand groundwater use for irrigation and other purposes are good in almost all districts. In more hydrogeologically complex settings in particular, a lack of information creates more risk that may add to drilling costs. More detailed assessments and databases are required to support effective resource management.

Study region : Transboundary aquifers (TBAs) of Africa.; Study focus: Review of work on TBAs in Africa, including an overview of assessments and management efforts that have taken place over the last half century.; New hydrological insights : Seventy-two TBAs have been mapped in Africa. They underlie 40% of the continent, where 33% of the population lives, often in arid or semi-arid regions. TBA inventories have progressed since 2000 and remain work in progress. Despite their importance only eleven TBAs have been subjected to more detailed studies. Cooperation has been formalised for seven TBAs. Most of these TBAs are in North Africa and the Sahel. The recent global Transboundary Waters Assessment Programme compiled information at the national level to describe TBAs in terms of key indicators related to the water resource, socio-economic, and legal and institutional conditions. Availability of data at national level is low, hampering regional assessment. Comparing indicators, from questionnaire surveys, with those from a global water-use model showed variable levels of agreement, calling for further research. Reports on agreements scoping TBA management, indicate that this may be dealt with within international river/lake agreements, but reported inconsistencies between TBA sharing countries also indicate that implementation is limited. Increasing awareness and support to joint TBA management is noticeable amongst international organisations. However, such cooperation requires long-term commitment to produce impacts at the local level.

Overall high annual precipitation in Sri Lanka belies significant spatial and temporal variation in surface water availability. The ‘dry zone’ comprising two-third of Sri Lanka’s land area receives significantly less rainfall and has high precipitation rates and a five-month dry season. Nevertheless, these regions account for the majority of rice production, the staple crop, thanks largely to the ancient hydraulic civilization based on networks of rainwater harvesting (irrigation) tanks. This manipulation of surface water resources including modern surface irrigation schemes continues to form the backbone of dry zone farming. Groundwater irrigation has remained in the shadows except in the North where surface flows are absent. This scenario is now changing as population growth; poorly maintained infrastructure; commercial agriculture; sectoral competition for water and climate change combine to exert severe pressure on surface water resources. Since the dry zone is also home to a large number of Sri Lanka’s poor households, and a close association exists between high poverty clusters and access to irrigation, the implications of water insecurity for a range of poverty indicators are clear. Not surprisingly, these pressures have prompted an increasing recourse to groundwater in several parts of the dry zone, as governments and farmers recognize the imperative to increase agriculture output, promote crop diversification, and improve agrarian incomes. Yet, with limited groundwater potential, limited detailed knowledge of this resource, and under-developed groundwater-oriented institutions, it is far from certain whether future groundwater exploitation can steer away from anarchy.

The study is being carried out to investigate the potential for applying SAT in Xaysetha district, Lao PDR and investigation the most suitable site for SAT in Xaysetha district. The methodology was used MCDA, GIS, RRA and semistructured interview to rank SAT site and investigate the physical, social and economic factor at the most suitable site (Nonvay site). The results of SAT ranking indicated that Xaysetha district has a potential to construct up to 3 high suitable site, 8 moderate suitable sites, and 6 low suitable sites. On the other hand, the results of physical, social and economic assessment at Nonvay site represented that DO was exceeded the Lao National Environmental Standard, and the soil infiltration rate is about 24 mm/hour (0.58 m/day). The households around Nonvay site have their own land and they access to water use and have a relationship with 9 organizations. They product wastewater was estimate 150 liter/person/day. And the land available for SAT is worth to US$ 39 million.

Managed aquifer recharge (MAR) is the umbrella term for a range of technologies that enable the integrated use and management of surface water and groundwater to achieve a wide and growing range of social, economic and environmental benefits. The extent and variety of its applications and benefits have mushroomed in recent years as demonstrated in the suite of papers contained within this Special Issue of Sustainable Water Resources Management. This paper introduces the Special Issue and draws together some insights arising from the findings of these papers. Managed aquifer recharge projects normally evolve through a development cycle that covers planning, investigations, pilot scale trials and then implementation of fullscale projects. This Special Issue starts with four papers that synthesize information from a large number of MAR sites, to demonstrate the scope and geographic distribution of international efforts in MAR, factors affecting the economics of MAR projects, and efforts to find metrics to compare their performance among sites and over time. Then there are four papers describing some significant and widely contrasting completed MAR projects in four continents covering their development, what has been learned and some operational issues. Given this context, the next five papers explore the implementation and evaluation of pilot projects in three countries. These papers address issues ranging from hydrogeological characterization, evaluating impacts on groundwater-dependent ecosystems to community participation. All papers to this point give context to the final five papers that show the planning and preliminary studies performed to select MAR sites, to design pilot projects or to explore the feasibility of large-scale MAR programs. Arranging the sequence of papers in this way is intended to yield an understanding of the need for the investigations and modelling to produce viable projects, and to help readers to consider some important practical questions. What steps are needed for any given project to: define objectives; build partnerships; engage with communities; assemble evidence of technical viability, sustainability and safety; secure funding; design and construct efficiently; streamline operations; and finally to monitor the extent to which a completed project met its goals? These papers were developed out of a broader selection of papers presented at the 9th International Symposium on Managed Aquifer Recharge (ISMAR9), Mexico City, June 2016. They are a companion to another Special Issue arising from ISMAR9, published in the journal Water on the complementary theme “Water Quali ty Consi derat ions for Manag ed Aquif er Recharge Systems” edited by Prof. Dr. Pieter Stuyfzand and Dr. Niels Hartog (2017). These Issues are a contribution of the International Association of Hydrogeologists Commission on Managing Aquifer Recharge (IAH-MAR) to the advancement and dissemination of knowledge for wise application of MAR.

Small-scale irrigation continues to cushion the food security gap in sub-Saharan Africa. Irrigation is largely governed by water availability, soil type and crop water requirements, among other factors. Thus, a study was conducted to assess the suitability of various water sources for irrigation in northern Ghana. Specifically, the study sought to assess quality of water sources in the Savelugu, Kasena-Nankana East, and Nabdam districts for small-scale irrigation development. The water quality parameters used were: pH, electrical conductivity (ECw), sodium adsorption ratio (SAR), sodium percent (Na%), soluble sodium percentage (SSP), magnesium adsorption ratio (MAR), Kelleyapos;s ratio (KR), total hardness (TH), Chloride (Cl), E. coli, and Faecal coliforms. While we found most of the irrigation water sources, including small reservoirs, dams, wells and rivers suitable, few unsuitable irrigation water sources were also identified. Overall, the study found that opportunities for scaling small-scale irrigation exist in all the sites. The knowledge generated from this study will guide irrigation water use, and agricultural policy for sustainable smallholder irrigation development in the region.

Wastewater irrigation is a common livelihood practice in many parts of the developing world. With the continuous irrigation supply, groundwater systems in these regions perceive adverse impacts due to inadequate infrastructure to treat the wastewater. The current study area, Musi River irrigation system, is one such case study located in the peri-urban Hyderabad of South India. The Musi River water, which is used for irrigation, is composed of untreated and secondary treated wastewater from Hyderabad city. Kachiwani Singaram micro-watershed in the peri-urban Hyderabad is practicing wastewater irrigation for the last 40 years. The current quality of (untreated) wastewater used for irrigation is expected to have adverse impacts on the local aquifers, but detailed investigations are lacking. To elucidate the groundwater quality dynamics and seasonality of the wastewater irrigation impacts on the peri-urban agricultural system, we analyzed the groundwater quality on a monthly basis for one hydrological year in the wastewater and groundwater irrigated areas, which exist next to each other. The spatio-temporal variability of groundwater quality in the watershed was analyzed with respect to wastewater irrigation and seasonality using multivariate statistical analysis, multi-way modeling and self-organizing maps. This study indicates the significance of combining various statistical techniques for detailed evaluation of the groundwater processes in a wastewater irrigated agricultural system. The results suggest that concentrations of the major ionic substances increase after the monsoon season, especially in wastewater irrigated areas. Multi-way modeling identified the major polluted groundwaters to come from the wastewater irrigated parts of the watershed. Clusters of chemical variables identified by using self-organizing maps indicate that groundwater pollution is highly impacted by mineral interactions and long-term wastewater irrigation. The study recommends regular monitoring of water resources and development of sustainable management strategies to mitigate the aquifer pollution in wastewater irrigation systems.

As solar panels become more a ordable, solar photovoltaic (PV) pumps have been identi ed as a high potential water lifting technology to meet the growing irrigation demand in sub-Saharan Africa (SSA). However, little is known aboutthegeo-spatial potentialofsolarbasedPVpumpingforirrigationtakinginto accountnotonlysolar radiation but also the availability of water resources and linkage to markets. This study developed a suitability framework using multi-criteria analysis in an open source GIS environment and tested it in the case of Ethiopia. Theaccessibilityofwaterresourceswasthedrivingfactorfordi erentscenarios.Suitabilityresultsfollowingthe groundwater scenarios showed good agreement with the available referenced well depth data. Comparing the suitability maps with available land use data showed that on average 9% (96103ha) of Ethiopian irrigated and 18% (3739103ha) of rainfed land would be suitable for solar PV pump irrigation. Furthermore, small solar PV pumps could be an alternative water lifting technology for 11% of the current and future small motorized fuel hydro-carbon pumps on smallholder farms (2166103ha). Depending on the technical pump capacity, between 155103ha and 204103ha of land would be suitable for solar PV pumps and provide smallholder farmers with the option to either pump from small reservoirs or shallow groundwater. With the ongoing interest in development for smallholder irrigation, the application of this model will help to upscale solar PV pumps for smallholder farmers in SSA as a climate smart technology in an integrated manner.

Cooperative management of transboundary river basins is widely recognized as important. Emphasis on joint management of shared aquifers has also grown in recent years. Perhaps surprisingly, despite abundant focus on transboundary surface water and growing focus on shared groundwater, there is scant focus on their intersection. To address this knowledge limitation, this article reviews experiences in transboundary water treaties oriented toward different water sources, in order to: i) understand how transboundary water institutions vary according to the water source to which they are oriented, ii) gauge the nature and strength of conjunctive transboundary water management treaties, and iii) identify ways to enhance conjunctive water management in transboundary contexts. The results reveal the existence of more than 50 treaties that make mention of both water sources. Nonetheless, only eight treaties devote ‘substantive’ focus to both surface and groundwater. Review of treaty contents reveals that their focus is on ‘softer’ issues related to institutional development. Moving forward, the reality that the evolution of conjunctive treaties is relatively nascent, and that scope of such treaties is still limited to institutional issues, may indicate large untapped potential – it may be time to outline pathways toward practical implementation of conjunctive water management in transboundary contexts.

Assessment of specific yields is important for effective groundwater management in semi-arid hardrock aquifers, especially in India with its unsustainable groundwater usage rates. The Dharta watershed in the Udaipur district of Rajasthan is one such hardrock area in India where the groundwater extraction rate is a concern. In this study, we use groundwater balance analysis to estimate the specific yield (Sy) based on crop irrigation water use and changes in water table depths, during the irrigation season, to develop an understanding of the volume of groundwater recharge from pre and post monsoon water table depths and an understanding of the spatial and temporal changes in estimates of specific yield in the study area. The analysis used here estimates values at village scale (average area 3.65 km2) and is a technique compatible with the farmers monitoring of groundwater levels to facilitate local cooperative groundwater management. Five villages in the Dharta watershed in Rajasthan were selected and 50 wells per village were monitored for water table depth, at weekly intervals, over a two-year period. This resulted in a total of 250 wells in the study area and the monitoring was carried out by local farmer volunteers - called Bhujal Jankaars (BJs), a Hindi word meaning ‘groundwater informed.’ Crop area coverage (with a total of 40 crops) was examined for two years in the study area. Estimates of Sy in the five villages were between 1.4 and 8%, resulting in values comparable with previous studies. The watershed area-weighted average Sy was 3.8%. The method used in this study enabled estimates of recharge without needing a calibrated groundwater model in an area with sparse information on aquifer hydraulic characteristics and unreliable digital elevation maps.

This paper explores ways to increase public investments in agricultural water management and irrigation for improved agricultural productivity in Southern Africa, with a specific focus on Malawi, Mozambique and Zambia. The analysis was based on a critical review of literature and assessment of the national agricultural investment plans and agricultural/water policies in the study countries. Despite the potential to improve agricultural productivity, irrigation does not currently play a significant role in Southern African agriculture. There have been efforts and formal commitments at the continental, regional and country levels to promote investments in agricultural water management and irrigation to improve and sustain agricultural productivity. However, despite these commitments, actual implementation has been a challenge and the first 5 years of national agricultural investment plans have passed or are now coming to an end without much progress having been made regarding actual investments. Lack of adequate resources and institutional capacity have been some of the challenges affecting implementation of the investment plans to meet commitments in sustainable land and water management. Overall, as countries plan for the second phase of the CAADP programme, there are opportunities to ensure that investments in agricultural water management and irrigation and complementary technologies are prioritised and allocated adequate resources for implementation.

The Nile Delta and its 2.27 million ha of irrigated land makes up two thirds of Egypt’s agricultural land. It is also the terminal part of a river basin that spans and feeds 11 countries. Increases in dam and irrigation development in upstream parts of the basin is poised to conflict with agricultural expansion and population growth in Egypt. Understanding where and how waters comes into and leaves the delta is therefore a crucial question for the future of the country. This paper revisits the surface and groundwater balances of the delta, emphasizes the additional relevance of drainage water reuse and of the salt balance, and evidences a relative stability of the outflow to the sea over the past 30 years. Various reasons for such a phenomenon and the scope for saving water are explored and discussed. The confusion between plot-level and delta-level efficiency and the relatively limited gains possible are emphasized. Beyond the overall water balance and quantitative issues, water management in the delta remains a complex task of spatially distributing the resource over a complex ramified network. Finally, limitations in the analysis related to data availability and accuracy are emphasized.

Climate induced extreme events such as floods and droughts are often disastrous in incidences and affects Indian economy often. Low per capita surface water storage (225 m3/capita1), few sites for additional storages facilities and depleting groundwater aquifers reduce the resilience of the communities to alleviate the day-to-day short age and larger seasonal shocks. India has a long history of storing and recharging runoff waters through community participation. Ongoing such programs are focused on drought-prone or socio-economically weak areas and exclude the flood prone zones. The present study aims to improve the groundwater resources availability through diverting flows from rivers or canals at times when these flows pose flood risk and recharging the groundwater through suitable artificial recharge structures. This method addresses the issue of groundwater depletion as well as reducing the flood risks. A geo-hydrological analysis in spatial platform using data available in public domain and detailed ground survey, a site was identified in Jiwai Jadid village of Milk Block of Rampur district of Uttar Pradesh, India. A community owned pond was retrofitted with recharge wells and associated infrastructure to draw excess monsoon water from a nearby flood-prone river. The preliminary results show a positive impact on groundwater table and water quality. However, to achieve the full benefit of the method it is required to implement it in larger scale. Ongoing government programs that are focused on livelihood improvement and natural resources management are the best options to scale up such effect in regional scale.

Underground taming of floods for irrigation (UTFI) is a new approach for mitigating flood impacts through targeted floodwater storage in depleted aquifers for irrigating crops in the dry season. UTFI not only fosters the much desired conjunctive use and management of water resources but also provides the environmental services that are of high socioeconomic value. UTFI interventions are individually established at the local scale (e.g. village pond, check dam) but to achieve more substantial positive benefits at the scale of meso watersheds (10 s of km2) or sub-basins (100–1,000 s of km2) in the flood-prone river basins requires area-based implementation. Given the nature and scale required, UTFI needs to be managed at the community level with the help of appropriate institutional arrangements taking into account both the upstream and downstream locations. This paper reviews the existing institutional approaches and proposes an institutional framework that can help to mainstream UTFI management in the context of South Asia. The proposed model is centred on the existing formal institutions and also integrates non-market (participatory) and market (payment for ecosystem services) instruments that can provide win–win strategies for water resource management to downstream and upstream communities.

Capturing inundation extent by floods is indispensable for decision making for mitigating hazard. Satellite images have commonly been used for flood mapping, but there are limitations such as unavailability due to satellite’s orbital period or cloud cover. Additionally, it would also be beneficial for policy makers to figure out the impact of water management measures such as water storage options on flood mitigation and irrigation water strengthening. Utilization of flood inundation models would support providing information for these demands. In this study, the rainfall–runoff inundation (RRI) model was applied in a flood-prone basin in eastern Sri Lanka, and its applicability was discussed. The RRI model was capable of simulating discharge and inundation extent during flood events, although it should be noted that the model had been calibrated targeting only the flooding period. Satellite-observed rainfall data corrected with a scale factor were able to be used as the model input to simulate long-term trends in runoff just as well as when gauged rainfall data were applied. The calibrated model was also capable of evaluating flood mitigation effects of existing and proposed water storage options by simulating discharge with and without flood capture operations. By reproducing long-term inflow to the storage facilities using satellite rainfall data, it was possible to determine that water would reach the maximum level of the proposed storage facilities even during low-rainfall years.

The karst dolomite aquifers of the North West Province in South Africa are among the most important in the nation. They serve as key water sources for municipal water supply and irrigation, and are also ecologically important in supplying springs that feed important rivers. Over-abstraction and consequent falling groundwater levels jeopardize water supply security, with increasing costs and risks to sustainable development. Better aquifer and conjunctive water management would improve water supply security and lower costs, with wider benefits to many sectors. This GRIPP Case Profile discusses these challenges and management experiences through the examples of two representative North West dolomite aquifers - the Grootfontein and Steenkoppies aquifers. These aquifers are relatively well understood hydrogeologically, and modern South African water law mandates sustainable use. Yet, underperforming collaboration between stakeholders using and managing the aquifers at various levels, and poor support from the national authority have led to an entrenched suboptimal equilibrium where stakeholders are reluctant to change behavior, despite awareness of the negative outcomes. Neither prescriptive local nor top-down organization has been effective. The synthesis argues for prioritized input from a legally mandated and capacitated convening authority (the national Department of Water and Sanitation) to catalyze and support effective local stakeholder groups and other governance initiatives. It calls for a renewed effort by this convening authority and other stakeholders, emphasizing mutually beneficial or “win-win” outcomes.

Private investments in groundwater have emerged as the main pathway through which smallholder farmers in India access irrigation. This paper discusses the role of groundwater in agrarian growth in West Bengal, India. It finds that agricultural growth in the state has stagnated since mid-1990s, after an initial period of growth in the 1980s and early 1990s. We hypothesize that this stagnation was a direct result of slowdown in growth in groundwater irrigation. The reason for this slowdown was, in turn, government policies related to groundwater and electricity. The paper then goes on to discuss the Groundwater Act of 2005 as well as electrification policies of the government of West Bengal and locates these policies within the broader backdrop of groundwater resource endowments in the state. By juxtaposing groundwater policies and resource realities, the paper questions the relevance of current regulations and suggests some policy alternatives - alternatives that are likely to propel the state and its smallholder farmers on a path of higher agricultural growth.

Impacts of climate change on water resources, especially groundwater, can no longer be hidden. These impacts are further exacerbated under the integrated influence of climate variability, climate change and anthropogenic activities. The degree of impact varies according to geographical location and other factors leading systems and regions towards different levels of vulnerability. In the recent past, several attempts have been made in various regions across the globe to quantify the impacts and consequences of climate and non-climate factors in terms of vulnerability to groundwater resources. Firstly, this paper provides a structured review of the available literature, aiming to critically analyse and highlight the limitations and knowledge gaps involved in vulnerability (of groundwater to climate change) assessment methodologies. The effects of indicator choice and the importance of including composite indicators are then emphasised. A new integrated approach for the assessment of groundwater vulnerability to climate change is proposed to successfully address those limitations. This review concludes that the choice of indicator has a significant role in defining the reliability of computed results. The effect of an individual indicator is also apparent but the consideration of a combination (variety) of indicators may give more realistic results. Therefore, in future, depending upon the local conditions and scale of the study, indicators from various groups should be chosen. Furthermore, there are various assumptions involved in previous methodologies, which limit their scope by introducing uncertainty in the calculated results. These limitations can be overcome by implementing the proposed approach.

This paper assesses a case of co-management of groundwater between the state of Texas, pushing for the rationalisation of groundwater management, and local (mainly farming) communities organised in Groundwater Conservation Districts (GCDs), which are protective of their private groundwater rights. We first describe the main legal and policy steps that have shaped this relationship. The article focuses on the Texan portion of the Ogallala Aquifer in the High Plains aquifer system – an almost non-renewable system covering 90,000 km2 and providing 95% of the irrigation needs in northern Texas. With this example, we further highlight the strategies of both parties, the different political, administrative, legal and regulatory complexities of the struggle around the definition of GCD-level aquifer management rules (the so-called apos;Desired Future Conditionsapos;). We end by reflecting on the power balance that has resulted from successive adjustments to a co-management form of governance, the advantages and disadvantages of a multi-layered state water governance system, and whether the de facto apos;managed depletionapos; of the Ogallala Aquifer in Texas should be seen as an achievement or a failure.

The Ganges basin faces considerable spatial and temporal imbalance between water demand and availability. Lack of water storage infrastructure has led to this mismatch, wherein there are limited options to store flood water during the wet season and limited groundwater and surface water resources during the dry season. In this current study, a semi-coupled hydrological modeling framework is used to test scenarios that can help bridge this imbalance. A hydrological model (SWAT), groundwater model (MODFLOW) and flood inundation model (HEC-RAS) were applied to the Ramganga basin in India (*19,000 km2) to understand the baseline hydrologic regime and to test scenarios with distributed managed aquifer recharge (MAR) interventions, which when applied to at the basin scale to co-address flooding and groundwater depletion has come to be known as Underground Taming of Floods for Irrigation. The scenarios with MAR, which used available basin runoff to recharge groundwater, yielded favorable results in flood reduction and groundwater level improvement throughout the sub-basin. Groundwater levels improved within 5 years of introducing MAR, resulting in a groundwater elevation increase of up to 7 mwhen compared to baseline conditions. The HEC-RAS model indicated that a 20% reduction in basin outflow converted a 15-year flood peak to an 8-year flood peak, a 5-year peak to 3 years and a 2-year peak to 1 year. In addition, this resulted in a 10% reduction in the inundated area in all return periods tested. Therefore, distributed MAR practices can be effective in reducing the negative impacts from larger return period floods and increasing the groundwater levels.

This study focuses on Laos, a landlocked nation located in South-East Asia with sub-tropical climate and highly seasonal rainfall distribution. Laos is one of the world’s least developed countries, and currently witnesses an unprecedented level of development that is highly reliant on its natural resources, including groundwater. There is currently very limited data and no nationwide assessment of shallow (lt;30 m) groundwater resources to support sustainable management. This study provides a first step towards addressing this issue by (i) identifying the major aquifer units of the country; (ii) integrating localized data and regional maps into an assessment of the groundwater potential; and (iii) producing quantitative maps of key hydrogeological indicators. Eight aquifer units have been described and evaluated: (i) Basement aquifers, (ii) Volcanic aquifers, (iii) Schists, (iv) Paleozoic sedimentary, (v) Karsts, (vi) Limestones, (vii) Mesozoic sedimentary and (viii) Alluvial sediments. The Mesozoic sandstones and the Alluvial aquifers are the most extensive and productive hydrogeological systems in the country. The Volcanic and Karstic aquifers, although poorly known, might also have important potential. This assessment, along with the maps of quantitative aquifer indicators, provide a significant improvement in both spatial resolution and accuracy compared to previously available information. It will likely support improved management plans and the identification of areas with higher potential for groundwater development.

Groundwater has been noted as a major resource for irrigation water in Nepal Terai. The development of different methods of groundwater withdrawal has been promoted in Rupandehi District. Open dug wells were a major source for domestic water use in the 1980s due to cost and ease of construction. But in later years, the promotion of tube wells, access to diesel pump sets, low yield and the deterioration of water quality from the open dug wells have caused a decline in usage and their abandonment in favor of shallow tube wells. This study was conducted in Mahuwari Village, Rupandehi District to assess the feasibility for the rehabilitation of abandoned open dug wells by reassessing access to irrigation water during the dry season, in areas with limited conductivity of aquifer hydrogeology. The yields of the wells were observed to be too low for large-scale irrigation, especially with the rice paddy cropping system. An assessment of well storage and recharge patterns offer an opportunity for off-season supplementary irrigation of home gardens for establishing vegetables and seedlings, with good water management practices. The potential yield of the open dug wells at the peak of the dry season was 4 m3 day-1 (0.44 mm-ha), suficient to irrigate 0.12 ha of a tomato ield, satisfying 25% of a currently fallowed field for home gardening.

Denmark is making continuous efforts to attain sustainable groundwater management. With groundwater constituting virtually the only resource for all water uses, groundwater management was addressed early on and has progressed over the last century. This article gives an overview of the advances, along with past and present challenges in securing sustainable groundwater utilization. The objective is to document comprehensively the Danish case and to highlight some of the unique conditions and principles that have shaped and facilitated groundwater management in the country.

The Bhungroo Irrigation Technology (BIT) is a system designed to infiltrate excess ‘standing’ floodwater to be stored underground and abstracted for irrigation during the dry season. The system was developed in India and piloted in three sites in northern Ghana. This paper documents the implementation of BIT, the operating principles and criteria for selecting appropriate sites for the installation of such systems, as well as the potential benefits complementing existing irrigation systems in Ghana. Essential requirements for the installation of BIT include biophysical features such as land-use type, soil type, surface hydrology and slope of the terrain. The hydrogeological characteristics of the subsoil are also vital, and must exhibit high storage capacity and potential for groundwater accessibility. To be profitable and generate benefits for farmers, the technology needs to be situated in close proximity to markets and must have public acceptance.

The control of groundwater over abstraction is a vexing problem worldwide. Jordan is one of the countries facing severe water scarcity which has implemented a wide range of measures and policies over the past 20 years. While the gap between formal legal and policy frameworks and local practices on the ground is widely acknowledged, few studies investigate how local users react to state regulations and document their tactics to circumvent them. This paper examines the major tools implemented by the Jordanian government to control well expansion and water abstraction and how farmers in the Azraq basin have responded to these measures. It then documents how, in response, the Ministry of Water and Irrigation has recently enacted a series of creative counter-measures, both direct and indirect, in an attempt to toughen law enforcement and raise pressure over groundwater users. The lessons learned are highly relevant for countries with similar situations, both in the region and elsewhere.

Increasing climate variability and challenge in access to water pose major impediments to rainfed agricultural productivity. Extensive flooding of agricultural lands during the rainy season and lack of water during the 8-month long dry season affect the livelihood of the people in the northern Ghana, a situation that calls for better water management practices. The use of aquifer storage and recharge (ASR) based technique, helps to reduce flooding and improve access to water during the dry season; however such technology has specific requirements for successful implementation. This study assesses suitable areas for the technology in the northern Ghana terrain using multi criteria decision analysis (MCDA) in ArcGIS environment. The result suggests around 66% (48,516 km2) of the crop area in the northern Ghana available for the technology are within moderate to very high suitable sites, of which 44% (29,490 km2) fall into the high and very high suitable sites. This could imply high potential for the artificial groundwater storage system in northern Ghana given other conditions.

Groundwater samples were collected from 44 wells in the Ramganga Sub-Basin (RSB), India, and analysed for major ions, nutrients and trace metals. The primary goal of this study is to evaluate the hydrochemistry and to identify the geochemical processes that govern the water chemistry in the shallow and deep tube wells in the study area using geochemical methods. The knowledge of changes in hydrochemistry of the aquifers is important for both groundwater recharge and use in the region. This study found that there are substantial differences of water chemistry between shallow and deep wells. In the shallow wells, the average concentrations of total dissolved solid (TDS), Na, K, Ca, Mg, HCO3, Cl, SO4, NO3, PO4, F, Cu, Mn, Fe and Cr are twofold higher than the deep wells. The concentrations of dissolved silica in the groundwater do not vary with the depth, which implies that the variation in the water chemistry is not due to mineral dissolution alone. Major ion ratios and saturation indices suggest that the water chemistry is predominantly controlled by dissolution of carbonate minerals, silicate weathering and ion exchange reactions. Thermodynamic evaluation (ion activity ratios and stability filed diagrams) indicates that the kaolinite and gibbsite controlled the water chemistry in the both shallow and deep wells. In addition, the groundwater chemistry in the shallow wells is affected by the vertical infiltration of contaminated water from surface contamination sources and nitrification process. In the deep wells, absence of NO3 and low concentrations of Cl, SO4, PO4 and F imply the role of regional flow and denitrification in the groundwater. Results concluded that proper management plan is necessary to protect the shallow aquifer in the RSB since shallow aquifer pumping is less expensive than the deeper one.

Groundwater from the shallow aquifers of the Vientiane Plain, Laos is used for domestic needs including to some extent for drinking and for household gardening. The objective of this study is to assess the groundwater quality for drinking and irrigation activities and to determine the processes that lead to the presence of major ions in groundwater. Twenty groundwater samples were collected from a village on the Plain in December 2014, January 2015, and May 2015, and analysed for major ions and selected suite of minor ions and heavy metals. Groundwater is largely acidic, fresh and soft in nature. Geochemistry showed dominant Ca–Mg–HCO3 and mixed Ca–Na–HCO3 groundwater. Sodium impacts the suitability of water for irrigation to some extent. Hydrogeochemical processes identified and verified through factor analysis indicate weathering, carbonate dissolution, ion exchange, and anthropogenic sources including salinisation, due to irrigation and use of fertilizers as sources for the occurrence of major ions at such concentrations in this area. Only concentrations of lead and iron were above the permissible limits with arsenic, copper, zinc, mercury, and uranium found to be within safe limits. Background sample (groundwater) collected 5 km from the study area and the bottled water sample were all within suitable limits for drinking. This study is the first to provide a local-level assessment of geochemical processes in groundwater of this area indicating that the groundwater does not pose any threat to human health if used for drinking based on major ions, minor ions and a suite heavy metals except for iron and lead.

Although Ethiopia has abundant land for irrigation, only a fraction of its potential land is being utilized. This study evaluates suitability of lands for irrigation using groundwater in Ethiopia using GIS-based Multi-Criteria Evaluation (MCE) techniques in order to enhance the countryapos;s agricultural industry. Key factors that significantly affect irrigation suitability evaluated in this study include physical land features (land use, soil, and slope), climate (rainfall and evapotranspiration), and market access (proximity to roads and access to market). These factors were weighted using a pair-wise comparison matrix, then reclassified and overlaid to identify suitable areas for groundwater irrigation using a 1-km grid. Groundwater data from the British Geological Survey were used to estimate the groundwater potential, which indicates the corresponding irrigation potential for major crops. Results indicated that more than 6 million ha of land are suitable for irrigation in Ethiopia. A large portion of the irrigable land is located in the Abbay, Rift Valley, Omo Ghibe, and Awash River basins. These basins have access to shallow groundwater (i.e., depth of groundwater less than 20 m from the surface) making it easier to extract. The comparison between available groundwater and total crop water requirements indicate that groundwater alone may not be sufficient to supply all suitable land. The study estimates that only 8% of the suitable land can be irrigated with the available shallow groundwater. However, groundwater is a viable option for supplementing surface water resources for irrigation in several basins in the country.

Using groundwater for agricultural production has the potential to build resilience in food insecure regions of the world. Use of groundwater can boost agricultural production, improve rural incomes and strengthen farmers’ ability to withstand climate shocks and water variability. However, for groundwater to contribute to sustainable intensification of agriculture, it is essential to know where to invest in groundwater development and how to sustainably manage groundwater resources. WLE has identified potentially usable groundwater resources in Africa, supported important policy changes to enhance the sustainable use of groundwater in eastern India, and has developed maps and new tools that can be used to implement new policies supporting sustainable use of groundwater.

Storing excess rainwater underground can become key in mitigating the frequency and magnitude of flood events. In this context, assessment of depleted groundwater storage that can be refilled in water surplus periods is imperative. The study uses Gravity Recovery and Climate Experiment (GRACE) data to identify variations in groundwater storage in the monsoonal Ramganga River basin (tributary of the Ganges, with an area of 32,753 km2) in India, over the nine-year period of 2002–2010. Results indicate that basin groundwater storage is depleting at the rate of 1.6 bill. m3 yr 1 . This depleted aquifer volume can be used to store floodwater effectively – up to 76% of the rainfall on average across the Ramganga with a maximum of 94% in parts of the basin. However, the major management challenge is to find and introduce technical and policy interventions to augment recharge rates to capture excess water, at required scales.

Avoiding the negative effects of intensive groundwater resource use is challenging, especially when the interactions and causal pathways between biophysical and socioeconomic processes are complex, and when users, management, and regulatory bodies are spatially dispersed. The plain of Haouaria, in north-eastern Tunisia, has witnessed an important development of groundwater abstraction, fueled by the multiplication of wells tapping the underlying shallow and deep aquifers. As the economic activities linked to such development are threatened by the degradation of groundwater quantity and quality, the aim of this paper is to investigate actors’ perceptions of these processes and to emphasize the undertaken mitigation measures. The study builds on semi-directive surveys with the different groundwater users and archive data in order to understand the technical, institutional and agricultural practices driving groundwater development. The paper starts by investigating the historical context of groundwater development and the progressive degradation of the resource. Then, the paper identifies the main constraints and adaptation strategies of the various users (public and private), before examining the challenges faced by groundwater users. Results show varied patterns of actorsapos; behavior, interest, and perception of the groundwater resource. This analysis show that farmersapos; lack of collective action, land tenure insecurity, labor shortage, the monopoly of production inputs by suppliers, and the cost of energy for pumping are the main challenges faced by groundwater users. The study finally explores different management and policy options that can lead to a more environmentally and socioeconomically sustainable socio-hydrological system.

The Nile Delta of Egypt is known for its large irrigated area supplied with water diverted from the Nile River, with a limited use of groundwater, largely for domestic and industrial use. Official statistics for the whole delta indicate that there are a few thousand individual wells used for agriculture by a population of over 2 million farmers. This study, however, shows that a phenomenon of groundwater development for irrigation has been unfolding over the last few years, largely below the radar of managers and researchers. A survey was carried out in the central part of the delta with the objective of (1) uncovering the actual situation of groundwater use in this part of the delta and (2) speculating on its implications. The results of the survey pointed to a recent and booming tube-well drilling industry, with well densities in some parts reaching one well every 2 ha. The development of groundwater abstraction in the central delta is strongly linked to inadequate and/or untimely availability of surface water in the canals. A technical, economic, and management characterization of wells complements the study, showing a continuum between purely private/individual ownership of wells and collective investments and management. Lastly, the article explores the implications of unchecked abstraction at the farm, local and delta scales.

Runoff generated in the monsoon months in the upstream parts of the Ganges River basin (GRB) contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the potential for subsurface storage (SSS) in the Ganges basin to mitigate floods in the downstream areas and increase the availability of water during drier months. The Soil and Water Assessment Tool (SWAT) is used to estimate “sub-basin” water availability. The water availability estimated is then compared with the sub-basinwise unmet water demand for agriculture. Hydrological analysis reveals that some of the unmet water demand in the subbasin can be met provided it is possible to capture the runoff in sub-surface storage during the monsoon season (June to September). Some of the groundwater recharge is returned to the stream as baseflow and has the potential to increase dry season river flows. To examine the impacts of groundwater recharge on flood inundation and flows in the dry season (October to May), two groundwater recharge scenarios are tested in the Ramganga sub-basin. Increasing groundwater recharge by 35 and 65 % of the current level would increase the baseflow during the dry season by 1.46 billion m3 (34.5 % of the baseline) and 3.01 billion m3 (71.3 % of the baseline), respectively. Analysis of pumping scenarios indicates that 80 000 to 112 000 ha of additional wheat area can be irrigated in the Ramganga sub-basin by additional SSS without reducing the current baseflow volumes. Augmenting SSS reduces the peak flow and flood inundated areas in Ramganga (by up to 13.0 % for the 65 % scenario compared to the baseline), indicating the effectiveness of SSS in reducing areas inundated under floods in the sub-basin. However, this may not be sufficient to effectively control the flood in the downstream areas of the GRB, such as in the state of Bihar (prone to floods), which receives a total flow of 277 billion m3 from upstream sub-basins.

Study region: Kathmandu Valley, Capital city of Nepal. Study focus: This study applied three hydrological models (i.e., SWAT, HBV, and BTOPMC) to analyze the water balance components and their temporal and seasonal variations in the Kathmandu Valley, Nepal. The water balance components were investigated using the same precipitation, climatic data, and potential evapotranspiration (PET) as input variables for each model. The yearly and seasonal variations in each component and the interactions among them were analyzed. There was a close agreement between the monthly observed and calibrated runoff at the watershed scale, and all the three models captured well the flow patterns for most of the seasons. New hydrological insights for the region: The average annual runoff in the study watershed calculated by the SWAT, HBV, and BTOPMC models was 887, 834, and 865 mm, corresponding to 59%, 55%, and 57% of the annual precipitation, respectively. The average annual evapotranspiration (ET) was 625, 623, and 718 mm, and the estimated yearly average total water storage (TWS) was 5, -35, and 29 mm, respectively. The long-term average TWS component was similar in all three models. ET had the lowest inter-annual variation and runoff had the greatest inter-annual variation in all models. Predictive analysis using the three models suggested a reasonable range for estimates of runoff, ET, and TWS. Although there was variation in the estimates among the different models, our results indicate a possible range of variation for those values, which is a useful finding for the short- and long-term planning of water resource development projects in the study area. The effects of historical water use, water stress, and climatic projections using multi-model water balance approaches offer a useful direction for future studies to enhance our understanding of anthropogenic effects in the Kathmandu Valley.

Since independence, India has emerged as the world’s largest groundwater economy, with annual groundwater use increasing from less than 50 BCM in the 1950s to over 230 BCM today. While this groundwater boom has been the bedrock of India’s agricultural growth, it has also created formidable challenges in groundwater governance. Meeting the challenge of water security in the face of hydro-climatic change requires a paradigm shift in our official thinking about groundwater governance. Although the Central Ground Water Board is the custodian of the nation’s groundwater resource, in reality, multiple agencies in public and private sectors have emerged as major players in India’s groundwater economy. This paper reviews international experience in groundwater governance and argues for greater synergy and coordination among various stakeholders group to improve productivity, equity and ecological sustainability of India’s groundwater economy.

Due to extensive groundwater development in the recent past, Pakistan now faces enormous challenges of groundwater management as it struggles to ensure food security for its rapidly growing population. These management challenges require a re-balancing of surface and groundwater monitoring objectives and approaches in the country. This article presents the current status of the groundwater monitoring and management in Pakistan. A compelling case is presented for optimization of material resources in improving groundwater level and quality data by proposing to use farmer organizations as a source of crowd sourced groundwater information. The authors showcase new methods to collect groundwater data and demonstrate use of automatic recording instruments for groundwater monitoring in a tertiary canal command area in the Pakistan’s Punjab. The results suggest that the potential for broader impact by engaging farmer organization and expanding monitoring networks is attractive. A common concern about long term deployment of automatic instruments is that the observation wells are not purged before extracting water quality samples. The authors address this concern through a field experiment by utilizing capabilities of automatic recording instruments.

Environmental flows (EF) are an important component of Goal 6 (the ‘water goal’) of the Sustainable Development Goals (SDGs). Yet, many countries still do not have well-defined criteria on how to define EF. In this study, we bring together the International Water Management Institute’s (IWMI’s) expertise and previous research in this area to develop a new methodology to quantify EF at a global scale. EF are developed for grids (0.1 degree spatial resolution) for different levels of health (defined as environmental management classes [EMCs]) of river sections. Additionally, EF have been separated into surface water and groundwater components, which also helps in developing sustainable groundwater abstraction (SGWA) limits. An online tool has been developed to calculate EF and SGWA in any area of interest.

Groundwater recharge remains almost totally unknown across the Mekong River Basin, hindering the evaluation of groundwater potential for irrigation. A regional regression model was developed to map groundwater recharge across the Lower Mekong Basin where agricultural water demand is increasing, especially during the dry season. The model was calibrated with baseflow computed with the local-minimum flow separation method applied to streamflow recorded in 65 unregulated sub-catchments since 1951. Our results, in agreement with previous local studies, indicate that spatial variations in groundwater recharge are predominantly controlled by the climate (rainfall and evapotranspiration) while aquifer characteristics seem to play a secondary role at this regional scale. While this analysis suggests large scope for expanding agricultural groundwater use, the map derived from this study provides a simple way to assess the limits of groundwater-fed irrigation development. Further data measurements to capture local variations in hydrogeology will be required to refine the evaluation of recharge rates to support practical implementations.

The second issue of the GRIPP Case Profile Series documents the use of water quotas and pricing mechanisms in Northwest China to control and manage groundwater. Since the 1970s, this region has experienced intensive groundwater abstraction by smallholder farmers. In 2002, however, the revised Water Law urged local authorities to regulate groundwater use in regions with overdraft. The Case Profile reviews, in detail, the use of smart card machines installed on wells by the local government to control abstraction. The study compares the situation in two counties where local authorities opted for two different types of regulatory mechanisms enabled by the smart cards: Minqin County - where they chose quotas, and Guazhou County - where they opted for a tiered water pricing system.; This Case Profile highlights how the success of smart card machines depends on the design and implementation of the regulatory mechanism behind the machines. In Minqin, quotas have successfully affected farmers’ groundwater use practices, whereas in Guazhou, water pricing has had little impact on farmers’ individual groundwater use practices. Moreover, the case of Minqin exemplifies that quotas enable equitable water access to all farmers and maintain the buffer function of conjunctive surface water and groundwater use. These are important principles to design effective groundwater regulation policies, both in and outside China.

This study is the first to assess land subsidence in the Kathmandu Valley, Nepal. Land subsidence simulations were based on a fully calibrated groundwater (GW) flow model developed using a coupled surface–subsurface modelling system. Subsidence is predicted to occur as a result of deep aquifer compaction due to excessive GW abstraction. The north and north-east areas at the periphery of the GW basin are hotspots for this subsidence. The estimated subsidence is most sensitive to changes in land cover within the recharge areas. The model shows the Melamchi water supply project assists in the control of subsidence to some extent. In the absence of land subsidence measurements, this paper highlights the location and the potential levels of the subsidence hazard which will be useful for hazard prevention management. Additionally, this work provides a basis to design field investigations, monitoring networks for land subsidence and upgrading the present GW monitoring network. Although the study has presented a preliminary analysis, a more comprehensive model inclusive of clay subsidence is required to address the subsidence vulnerability of the central densely populated core of the valley, which reflects the need for a comprehensive database of the hydrogeology in the valley.

This paper presents a historical analysis of the different policy tools used to manage and regulate groundwater abstraction in the Western Mancha aquifer. Without much initial regulation and control, groundwater resources and aquifer levels decreased dramatically, threatening agriculture and also highly valuable groundwater-dependent wetland ecosystems. The interplay between sticks and carrots used in La Mancha shows the necessity for regulatory bodies to complement soft management approaches based on incentives with the threat of sanctions and limitations. However, as this case study shows, each policy modality has its legal, administrative and practical loopholes, which can be negotiated and exploited by groundwater users to their own advantage. The paper also studies the distribution of decision-making power and how local dynamics and individual behaviors are linked to higher level policies and their impacts on groundwater management, with an emphasis on the effectiveness and limitations of these tools.

This paper serves international water con ict resolution efforts by examining the ways that states contest hegemonic transboundary water arrangements. The conceptual framework of dynamic transboundary water interaction that it presents integrates theories about change and counter-hegemony to ascertain coercive, leverage, and liberating mechanisms through which contest and transformation of an arrangement occur. While the mechanisms can be active through sociopolitical processes either of compliance or of contest of the arrangement, most transboundary water interaction is found to contain elements of both. The role of power asymmetry is interpreted through classi cation of intervention strategies that seek to either in uence or challenge the arrangements. Coexisting contest and compliance serve to explain in part the stasis on the Jordan and Ganges rivers (where the non-hegemons have in effect consented to the arrangement), as well as the changes on the Tigris and Mekong rivers, and even more rapid changes on the Amu Darya and Nile rivers (where the non-hegemons have confronted power asymmetry through in uence and challenge). The framework also stresses how transboundary water events that may appear isolated are more accurately read within the many sociopolitical processes and arrangements they are shaped by. By clarifying the typically murky dynamics of interstate relations over transboundary waters, furthermore, the framework exposes a new suite of entry points for hydro-diplomatic initiatives.

The increasing demand for solar-powered irrigation systems in agriculture has spurred a race for projects as it potentially offers a cost-effective and sustainable energy solution to off-grid farmers while helping food production and sustaining livelihoods. As a result, countries such as Morocco and Yemen have been promoting this technology for farmers and national plans with variable finance and subsidy schemes like in India have been put forward. By focusing on the application of solar photovoltaic (PV) pumping systems in groundwater-fed agriculture, this paper highlights the need to further study the impacts, opportunities and limitations of this technology within the Water-Energy-Food (WEF) nexus. It shows how most policies and projects promoting solar-based groundwater pumping for irrigation through subsidies and other incentives overlook the real financial and economic costs of this solution as well as the availability of water resources and the potential negative impacts on the environment caused by groundwater over-abstraction. There is a need to monitor groundwater abstraction, targeting subsidies and improving the knowledge and monitoring of resource use. Failing to address these issues could lead to further groundwater depletion, which could threaten the sustainability of this technology and dependent livelihoods in the future.

This study investigated the dependence of three riparian communities on ecosystem services in northern Ghana. Participatory mapping and ranking exercises in gender-segregated groups were used to elicit information on the communities’ livelihoods. The most important ecosystem-based activities (EBA) are farming, fishing, livestock watering and grazing, collection of wild fruits and vegetables, and provision of water for domestic use. The major EBA are dependent on the seasonal flows of the White Volta River, which are under pressure due to climatic and other anthropogenic changes. For example, observed delays in the start of the rainy season are affecting rainfed agricultural activities on the floodplains. Delayed planting on the floodplains results in damage to, or loss of, crops as floods arrive before the harvest. Moreover, the Bagr Dam in Burkina Faso, built upstream of the communities, has impacted the natural river flow. The planned Pwalugu Dam may, depending on the final operations, support or affect EBA. We, therefore, recommend that operations of the Pwalugu Dam should take into consideration the flow requirements of EBA downstream of the dam.

Irrigation experiments were conducted during November to April under wheat crop in the winter season of 2012-13 and 2013-14 in the farmer’s field at Galibkhedi village located in Karnal District, Haryana State, India. In the study, collapsible multi-outlet pipe (MOP) along with single outlets pipe (SOP) was tested in farmer’s field under wheat cultivation. Irrigation was carried out in five treatments including tillage (T) with SOP and MOP; zero-tillage (ZT) with SOP and MOP, and furrow irrigation with raised bed (FIRB). Iso-time profile of waterfront spreading and advance indicated that irrigation water distribution was uniform under the plot irrigated using MOP as compared to plot irrigated using SOP. In addition, water distribution was uniform under zero tilled plots as compared to tilled plot. Results implied that MOP has several advantages over SOP in terms of application efficiency (AE) and uniformity of water distribution. Average application efficiency for the first study year was found to be in the order of ZT-MOP (82.41%) gt; FIRB (76.79%) gt; ZT-SOP (75.25%) gt; T-MOP (74.85%) gt; T-SOP (69.79%). Average application efficien-cy for the second study year was found to be in the same order as first year with some deviation in values. In the second year values of mean application efficiencies were ZT-MOP (82.58%) gt; FIRB (77.13%) gt; ZT-SOP (73.04%) gt; T-MOP (69.65%) gt; T-SOP (66.13%). Overall, this study concludes that irrigation under wheat crop using collapsible multi-outlet pipe (MOP) with zero tillage practices is a suitable option for surface irrigation that accomplishes uniform distribution of water with higher application efficiency.

Although the Ganges River Basin (GRB) has abundant water resources, the seasonal monsoon causes a mismatch in water supply and demand, which creates severe water-related challenges for the people living in the basin, the rapidly growing economy and the environment. Addressing these increasing challenges will depend on how people manage the basin’s groundwater resources, on which the reliance will increase further due to limited prospects for additional surface storage development. This report assesses the potential of the Ganges Water Machine (GWM), a concept proposed 40 years ago, to meet the increasing water demand through groundwater, and mitigate the impacts of floods and droughts. The GWM provides additional subsurface storage (SSS) through the accelerated use of groundwater prior to the onset of the monsoon season, and subsequent recharging of this SSS through monsoon surface runoff. It was identified that there is potential to enhance SSS through managed aquifer recharge during the monsoon season, and to use solar energy for groundwater pumping, which is financially more viable than using diesel as practiced in many areas at present. The report further explores the limitations associated with water quality issues for pumping and recharge in the GRB, and discusses other related challenges, including availability of land for recharge structures and people’s willingness to increase the cropping intensity beyond the present level.

Groundwater is an important resource for multiple uses in South Africa. Hence, setting limits to its sustainable abstraction while assuring basic human needs is required. Due to prevalent data scarcity related to groundwater replenishment, which is the traditional basis for estimating groundwater availability, the present article presents a novel method for determining allocatable groundwater in quaternary (fourth-order) catchments through information on streamflow. Using established methodologies for assessing baseflow, recession flow, and instream ecological flow requirement, the methodology develops a combined stepwise methodology to determine annual available groundwater storage volume using linear reservoir theory, essentially linking low flows proportionally to upstream groundwater storages. The approach was trialled for twenty-one perennial and relatively undisturbed catchments with long-term and reliable streamflow records. Using the Desktop Reserve Model, instream flow requirements necessary to meet the present ecological state of the streams were determined, and baseflows in excess of these flows were converted into a conservative estimates of allocatable groundwater storages on an annual basis. Results show that groundwater development potential exists in fourteen of the catchments, with upper limits to allocatable groundwater volumes (including present uses) ranging from 0.02 to 3.54 × 106 m3 a-1 (0.10–11.83 mm a-1) per catchment. With a secured availability of these volume 75% of the years, variability between years is assumed to be manageable. A significant (R2 = 0.88) correlation between baseflow index and the drainage time scale for the catchments underscores the physical basis of the methodology and also enables the reduction of the procedure by one step, omitting recession flow analysis. The method serves as an important complementary tool for the assessment of the groundwater part of the Reserve and the Groundwater Resource Directed Measures in South Africa and could be adapted and applied elsewhere.

Strict hydrologic definitions of basins coupled with technological advances including the use of remote sensing and geographic information systems have given us more accurate and detailed knowledge than ever before about the scale and extent of transboundary waters. This information has had both research and policy impact. The knowledge of the vast number and extent of basins has been used to bring attention to the overall issue of transboundary water management and understand how and why countries conflict and cooperate over water. Combining this information with ideas embedded in legal instruments such as the UN Convention on the Law of the Non-Navigational Uses of International Watercourses has given us new ways to look at the adequacy, and inadequacy, of existing transboundary institutions and to suggest policy change and institution building. But do precise data and clearly codified definitions always improve our understanding and decision making? Might they even lead us to incorrect conclusions and poor priority setting? This paper examined how the combination of universalized basin scale principles for international water management and increased mapping precision has resulted in policy prescriptions that sometimes run counter to what negotiators and managers have consistently and thoughtfully done in practice. The conclusion is not a call to cease using new technology nor to end the search for principles to guide our resource management actions. Rather it is a call for caution and balance as we apply technology and logic to specific locations in a complex world.

The province of Punjab is the main food basket of India. In recent years, many regions of Punjab are facing acute waterlogging problems and increased secondary salinity, which have negative impacts on food security of the nation. In particular, these problems are more pronounced in the Muktsar district of Punjab. The observed groundwater levels trend between 2005 and 2011 implies that groundwater levels are coming towards the land surface at the rate of 0.5 m/year in Lambi and Malout blocks. In this study, a groundwater flow model was constructed using MODFLOW to understand the groundwater table dynamics and to test the groundwater evaporation ponds to draw down the groundwater levels in the waterlogging areas of Muktsar district. The predicted flow model results indicate that groundwater levels could be depleted at the rate of 0.3 m/year between 2012 and 2018 after the construction of Groundwater Evaporation Ponds (GEP). In addition, the constructed ponds can be used for aquaculture that generates additional income. The proposed GEP method may be a promising tool and suitable for the reduction of waterlogging in any region if there is no proper surface drainage, and also for enhancement of agricultural production that improves the social and economic status of the farming community.

Groundwater quality is gaining more importance in groundwater management due to rapid growth in population, agriculture and industrial sectors worldwide. The goal of the present study is to evaluate the groundwater chemistry and to identify the geochemical processes governing the water chemistry in the shallow uncon ned and deeper con ned aquifers in the Eastern Ganges Basin using geochemical methods. Groundwater samples were analysed for major ions and metals (Fe, Mn, Zn, Cu, Pb and As). Shallow wells are found to have high pH, EC, TDS, Ca, Mg, Cl and SO4, and low HCO3/Cl ratio compared to the deep wells. However, the average concentration of Na, HCO3, NO 3, PO 4, F and Mn is not signi cantly varied with depth which indicates that the variation in the water chemistry between uncon ned and con ned aquifers is not only due to the natural processes but also indicates that surface contamination sources could have affected the water chemistry in the uncon ned aquifer. In the uncon ned aquifer, processes like wastewater in ltration, denitri cation, reverse ion exchange and mineral weathering govern the water chemistry. The water chemistry in the con ned aquifer is regulated by weathering of silicate and carbonate minerals and regional ow.

This study examines the socioeconomic features that underpin the expansion of groundwater-dependent irrigation in Northern State, Sudan. Groundwater development in the region serves as an economic lifeline given the poor Nile-based irrigation infrastructure and future changes in Nile hydrology. Groundwater-dependent irrigation is found to be expanding in previously uncultivated regions increasingly distant from the Nile. The study finds these historically marginal lands are targeted for capital-intensive agricultural projects because landholding patterns in traditionally cultivated areas preclude new large developments and improved infrastructure has lowered farming costs in distant terraces. Private companies and large landholders have a history of successful agricultural ventures in Northern State and are reliant on easily accessible and reliable groundwater resources for these new farms.

The Indian Ocean Tsunami of December 26, 2004 devastated coastal ecosystems across South Asia. Along the coastal regions of South India, increased groundwater levels (GWL), largely caused by saltwater intrusion, infiltration from inundated land, and disturbance of freshwater lenses, were reported. Many agencies allocated funding for restoration and rehabilitation projects. However, to streamline funding allocation efforts, district-level groundwater inundation/recession data would have been a useful tool for planners. Thus, to ensure better preparedness for future disaster relief operations, it is crucial to quantify pre- and post-tsunami groundwater levels across coastal districts in India. Since regional scale GWL field observations are not often available, this study instead used space gravimetry data from NASA’s Gravity Recovery and Climate Experiment (GRACE), along with soil moisture data from the Global Land Data Assimilation Systems (GLDAS), to quantify GWL fluctuations caused by the tsunami. A time-series analysis of equivalent groundwater thickness was developed for February 2004–December 2005 and the results indicated a net increase of 274 % in GWLs along coastal regions in Tamil Nadu following the tsunami. The net recharge volume of groundwater due to the tsunami was 16.8 km3, just 15 % lower than the total annual groundwater recharge (19.8 km3) for the state of Tamil Nadu. Additionally, GWLs returned to average within 3 months following the tsunami. The analysis demonstrated the utility of remotely sensed data in predicting and assessing the impacts of natural disasters.

Monitoring water stored in lakes and reservoirs is much needed in various countries for energy generation, food security and mitigating floods, among recurrent global issues. Natural and human-made open water bodies do not all have monitoring systems, this lack of regular information generates uncertainties in modeling, and increases unaccounted time-bound residuals in water balances. A large amount of water bodies storage variations are not monitored around the World. Here we show that this can be changed by the creation and the implementation of the concept of water Level Virtual Gauges (wLVGs) based on slope tracks upstream of water bodies, correlated to publicly available satellite remote sensing information returning water levels bi-monthly on average, sometimes weekly. An operational RMSE is found to be 12-52 cm height, depending on the characteristics of the upstream slopes used to calibrate wLVGs. This methodology is simple enough to be implemented for all medium to large reservoirs, but is alsofound successful for smaller rural reservoirs in tropical/sub-tropical countries. We anticipate that this can open globally distributed pathways to monitor open water bodies across the World, improve public databases on water storages and give management information for non/less-monitored water bodies.

Groundwater quality receives increasing attention in water management in India. The purpose of this paper is to highlight the emerging issues of groundwater quality in the Ramganga Sub-Basin (RSB), a tributary joining the Ganga River from the northern plains, which extends over 30,839 Sq. km and covers 15 districts in both Uttarakhand and Uttar Pradesh. The groundwater in most of the districts of the RSB has high concentration of nitrate, iron, salinity and fluoride, which exceed the standards prescribed for drinking water by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). Arsenic contamination in groundwater is an emerging issue in few groundwater development blocks. Moreover, groundwater with substantial hardness, high sulfate, and high manganese is emerging issue in some districts. Additionally, shallow aquifers have high concentration of ions. In the RSB, the quality of groundwater, especially in the shallow aquifers, is influenced by the contamination of poor quality surface water, due mainly to poor sanitation, improper disposable of domestic sewage water, manures and irrigation return flows. To reduce deterioration of water quality further, the RSB requires proper sanitation facilities, efficient usage of agrochemicals, as well as an awareness program of water-related disease.

Reviving the Ganges Water Machine (GWM), coined 40 years ago, is the most opportune solution for mitigating the impacts of recurrent droughts and floods in the Ganges River Basin in South Asia. GWM create subsurface storage (SSS) by pumping more groundwater from the aquifers before the monsoon for irrigation and other uses and recharge it during the monsoon. The present study uses fully processed and physically based numerical models, MODFLOW and SWAT, in a semi-coupled modelling framework to examine the technical feasibility of recharging the SSS. The aquifer was simulated as a two-layer system using hydrogeological and groundwater data, model was calibrated from 1999 to 2005 and validated from 2006 to 2010. It assesses the impacts of gradual increase of SSS in 10 years from the base year 2010 under two scenarios (increased rainfall or controlled pumping and recharge) to meet a potential unmet demand of 1.68 billion cubic meters (Bm3) in the Ramganga sub-basin with an area of 18,668 km2. The results show that 3–4 m of subsurface storage can be created by groundwater pumping of 0.25 Bm3/year by 2020. Under the controlled pumping and recharge scenario, groundwater recharge and river seepage could increase by 14% (4.21–4.80 Bm3) and 31% (1.10–1.44 Bm3), respectively. However, baseflow will decrease by 30% (0.18–0.12 Bm3) over the same time period. The results also show that recharge increased 44% (4.21–6.05 Bm3) under an increased rainfall scenario. Simultaneously, river seepage and baseflows would increase 36% (1.10–1.14 Bm3) and 11% (0.18–0.20 Bm3), respectively. A well-designed managed aquifer recharge program is required to eliminate the negative impact of river flows in the low flow season.

Springs are the major source of freshwater in many small mountainous watersheds within the Himalayan region. In recent years, their flow rates have diminished, but the reasons for this are not self-evident, and hence this paper reviews the methods to investigate Himalayan springs. The review reveals that chemical and isotope analyses – mostly water dating and stable isotope (e.g., d18O) analyses – could be an appropriate entry point to commence field investigations, because of their potential to map complex spring pathways, including linkages between aquifers. This should be combined with the building of hydrogeological maps with the available data. Output from desktop analyses, field investigations and hydrogeological maps could then contribute to the establishment of a conceptual model, which could form the basis for a numerical model.

The Ganges River basin faces severe water challenges related to a mismatch between supply and demand. Although the basin has abundant surface water and groundwater resources, the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Water availability and flood potential is high during the 3–4 months (June–September) of the monsoon season. Yet, the highest demands occur during the 8–9 months (October–May) of the non-monsoon period. Addressing this mismatch, which is likely to increase with increasing demand, requires substantial additional storage for both flood reduction and improvements in water supply. Due to hydrogeological, environmental, and social constraints, expansion of surface storage in the Ganges River basin is problematic. A range of interventions that focus more on the use of subsurface storage (SSS), and on the acceleration of surface–subsurface water exchange, has long been known as the Ganges Water Machine (GWM). The approach of the GWM for providing such SSS is through additional pumping and depleting of the groundwater resources prior to the onset of the monsoon season and recharging the SSS through monsoon surface runoff. An important condition for creating such SSS is the degree of unmet water demand. The paper shows that the potential unmet water demand ranging from 59 to 124 Bm3 year-1 exists under two different irrigation water use scenarios: (i) to increase irrigation in the Rabi (November–March) and hot weather (April–May) seasons in India, and the Aman (July–November) and Boro (December–May) seasons in Bangladesh, to the entire irrigable area, and (ii) to provide irrigation to Rabi and the hot weather season in India and the Aman and Boro seasons in Bangladesh to the entire cropped area. However, the potential for realizing the unmet irrigation demand is high only in 7 sub-basins in the northern and eastern parts, is moderate to low in 11 sub-basins in the middle, and has little or no potential in 4 sub-basins in the western part of the Ganges basin. Overall, a revived GWM plan has the potential to meet 45–84 Bm3year-1 of unmet water demand.

The absence of either state regulations or markets to coordinate the operation of individual wells has focussed attention on community level institutions as the primary loci for sustainable groundwater management in Rajasthan and Gujarat, India. The reported research relied on theoretical propositions that livelihood strategies, groundwater management and the propensity to cooperate are associated with the attitudinal orientations of well owners in the Meghraj and Dharta watersheds, located in Gujarat and Rajasthan respectively. The research tested the hypothesis that attitudes to groundwater management and farming practices, household income and trust levels of assisting agencies were not consistent across the watersheds, implying that a targeted approach, in contrast to default uniform programs, would assist communities craft rules to manage groundwater across multiple hydro-geological settings. Hierarchical cluster analysis of attitudes held by survey respondents revealed four statistically significant discrete clusters, supporting acceptance of the hypothesis. Further analyses revealed significant differences in farming practices, household wealth and willingness to adapt across the four groundwater management clusters. In conclusion, the need to account for attitudinal diversity is highlighted and a framework to guide the specific design of processes to assist communities craft coordinating instruments to sustainably manage local aquifers described.

Soil water management is critical for sustainable crop production, particularly in drought-prone environments. A range of strategies can be used to address spatial (need to improve in-situ infiltration) and temporal (need to improve water holding capacity /storage) to increase soil water availability for crop water uptake and improved yield production and productivity. This paper presents the results from field studies of rainfall and run-off monitoring in rainfed maize-based cropping systems in northern Ghana. Rainfall was measured using rain gauges and run-off was estimated using run-off pits in selected fields plots. Long-term 20-year weather data were used in simulation experiments using a deterministic water balance model to represent smallholder rainfed maize crop system. The field studies in the three regions of northern Ghana resulted in the development of regression rainfall-runoff relationships with R2 in the range 0.75 to 0.97 for fields with/without in situ. Further, estimation of size of water conservation/storage structures could be designed based on long-term rainfall-runoff relations to increase timely crop water availability and reduce spatial losses of water through surface runoff.

Agriculture is a major occupation for people who inhabit the state of West Bengal in India. In order to boost irrigation, 570 tube wells per year were installed during 2002-2008, and 12,000 wells per year were installed during 2009-2013, contributing to higher groundwater (GW) withdrawal. However, the impact of tube wells on GW storage levels has not been well-studied, both spatially and temporally. Hence, this study used remote sensing data from NASAapos;s Gravity Recovery and Climate Experiment and the Global Land Data Assimilation Systems to assess change in GW storage. Results showed that GW is being depleted at 8, 5.3, and 14.7 cm (Billion Cubic Meters)/year during the study period. After tube well intensification, the state-wide average net GW recharge was 15.33 BCM/year, while the net GW discharge was at 19 BCM/year. The spatiotemporal GW storage data presented in this paper will benefit managers and policymakers in identifying suitable mitigation plans for future management of GW resources.

Climatic condition, geology, and geochemical processes in an area play a major role on groundwater quality. Impact of these on the fluoride content of groundwater was studied in three regions-part of Nalgonda district in Telangana, Pambar River basin, and Vaniyar River basin in Tamil Nadu, southern India, which experience semi-arid climate and are predominantly made of Precambrian rocks. High concentration of fluoride in groundwater above 4 mg/l was recorded. Human exposure dose for fluoride through groundwater was higher in Nalgonda than the other areas. With evaporation and rainfall being one of the major contributors for high fluoride apart from the weathering of fluoride rich minerals from rocks, the effect of increase in groundwater level on fluoride concentration was studied. This study reveals that groundwater in shallow environment of all three regions shows dilution effect due to rainfall recharge. Suitable managed aquifer recharge (MAR) methods can be adopted to dilute the fluoride rich groundwater in such regions which is explained with two case studies. However, in deep groundwater, increase in fluoride concentration with increase in groundwater level due to leaching of fluoride rich salts from the unsaturated zone was observed. Occurrence of fluoride above 1.5 mg/l was more in areas with deeper groundwater environment. Hence, practicing MAR in these regions will increase the fluoride content in groundwater and so physica or chemical treatment has to be adopted. This study brought out the fact that MAR cannot be practiced in all regions for dilution of ions in groundwater and that it is essential to analyze the fluctuation in groundwater level and the fluoride content before suggesting it as a suitable solution. Also, this study emphasizes that long-term monitoring of these factors is an important criterion for choosing the recharge areas.

Around 27% of aquifers in Tunisia are being overexploited. Groundwater extractions is mainly for the irrigation sector, where more than 40% of the water used for irrigation comes from GW sources. The objective of this study is to critically review and analyze GW management instruments adopted in Tunisia during the last four decades. Evaluation of current instruments was based on a set of criteria (the impact of the instrument on increasing water productivity, reducing aquifer withdrawals, acceptability of the instrument and its implementation cost) assessed through interviews with policy makers and experts, in addition to discussions at farmersapos; focus groups. Results show that regulatory instruments are widely used but weakly enforced, which can explain their limited impact. To be more effective, economic instruments need a better vertical interplay between different stakeholders. Analysis of stakeholders’ participation shows limited awareness by farmers and a lack of collective actions for GW management at local levels. The alignment of GW policies to other cross-sectorial policies, the enhancement of the vertical interplay between water users’ associations and local and national water administrations, and the horizontal integration of different water users and managers at the local and regional levels, are among the main recommendations of this study.

Recent development activities in the Jaffna Peninsula are threatening the viability of the region’s natural groundwater supply. Rainwater Harvesting (RWH) represents one important approach to remedying this situation. By accumulating freshwater during Jaffna’s wet season, household RWH systems can supply drinking and cooking water for use during the water-limited dry season. Additionally, a RWH calculator created by the International Water Management Institute (IWMI) can be used to customize a RWH system for each family given particular household parameters such as rooftop size and daily extraction rate. When paired with cost estimates for tank construction, a RWH installation cost-benefit analysis can be determined for either a specific household or for a collection of households within the Jaffna region.

Indus basin irrigation system (IBIS) is one of the largest contiguous irrigation systems of the world. The surface canal water supplies are far less than the crop water demands which lead farmers to use groundwater to cope surface water scarcity. Although many studies in the IBIS are conducted to analyze the equitable distribution of canal water, there is hardly any study which comprehensively analyze the equitable use of canal water and groundwater at different spatial and temporal scales. One of the main reasons is lack of reliable information on the volume of groundwater abstraction. The objective of the current study is to develop an approach for estimating the equity of canal water and groundwater use at different spatial (canal command, distributaries, head, middle and tail end reaches) and temporal (daily, monthly and seasonal) scales of Hakra canal command area of IBIS. Results show that canal water and groundwater use to meet actual evapotranspiration is 34 and 42 %, respectively, which makes groundwater as an integral part of the large canal irrigation schemes of IBIS. The canal water and groundwater use varies significantly during the cropping colander. The maximum groundwater use is during May (51 mm) whereas the maximum canal water use is during August (24 mm). Farmers located at the head end reaches of Hakra canal use 42 % groundwater of total groundwater use whereas farmers located at the middle and tail end reaches use only 35 and 23 %, respectively. The canal water use at the head, middle and tail end reaches is 40, 34 and 26 %, respectively. These results show that the farmers located at the head of Hakra canal command area use more canal water and groundwater as compared to those located at the middle and tail end reaches. This methodology can provide guidelines to water managers in the region for equitable use of both canal water and groundwater.

Groundwater provides nearly 100 % of the water supplies in some districts of Sri Lanka and is a major source of domestic water in all other districts. However, the resource remains largely neglected and invisible to society and policymakers. Groundwater offers the advantage of being a more reliable and readily available resource for agriculture, and offers the basis for a ‘silent revolution’ in many areas. A groundwater-supported agricultural boom has, while imparting a large number of benefits, created its own set of obstinate problems, including over-exploitation and depletion of groundwater resources. In some districts, over-exploitation is putting the livelihoods of farmers that have come to depend on groundwater resources in jeopardy. Micro-irrigation technologies have been widely promoted as a means of reducing water demand by enhancing farm-level water-use efficiency. These technologies are proven to improve irrigation uniformity; increase irrigation application efficiency, by reducing soil evaporation and seepage losses; and increase crop productivity. It is assumed that using these technologies will enable water to be reallocated for other uses. The Government of Sri Lanka has made repeated attempts to promote micro-irrigation as a means of improving irrigation performance to minimize water scarcity in areas of the Dry Zone. These attempts have involved providing substantial heavy subsidies, but have met with little success in terms of adoption of ‘professionally designed’ installations. However, in Kalpitiya, farmers have adopted a locally designed sprinkler technology within a short period of time without subsidies and professional design inputs. This paper reviews the evolving agricultural boom as a result of groundwater and sprinkler irrigation that has occurred on the Kalpitiya peninsula. The development of a farmer-led sprinkler technology is assessed with reference to improving livelihoods of the people, and the potential consequences on sustainable management of groundwater resources. The experiences in Kalpitiya show that, in the absence of effective groundwater governance and policies, supported with appropriate institutions, micro-irrigation has enabled the expansion of the cultivated area and crop intensification. This has increased, rather than decreased, net water use on the peninsula. The estimated increase in water withdrawals is 14,490 m3/ha /y. This indicates that promoting efficient technologies alone is not sufficient to achieve water savings, which requires control of overall abstractions and recharge levels to stabilize aquifer storage. In the absence of an appropriate regulatory framework and lack of political will to manage groundwater, it is recommended that the social framework and community governance arrangements are developed and strengthened to enable sustainable use of groundwater resources.

Agricultural practices are changing at an unprecedented rate in small pockets of the dry zone of Sri Lanka. Commercial vegetable production is flourishing underwritten by groundwater accessed via agro-wells, increased market access and new business opportunities. Since the early 1990s, small-holder farmers have been excavating agro-wells for highland field irrigation and reaping unprecedented returns. Highland fields were previously subject to rain-fed shifting cultivation with long fallow periods. Water from agro-wells with the addition of chemical inputs, along with the advent of mobile phones, reliable road transport, new markets, greater access to credit and a more secure post-conflict environment, have now made frequent highland cropping viable and profitable. This has ignited the entrepreneurial spirit of farmers whose financial inputs and investments and labour is bringing rapid socio-economic transformation. In a country where the dry zone constitutes roughly a third of the land area, and where many dry zone households lack surface water for dry season cropping, these pockets of groundwater driven dry season production may pose a way out of poverty. While acknowledging the significant impact of agro-well-based farming in lifting farmers out of poverty, the paper ends on a cautionary note. This type of agricultural intensification is predicated on a social-ecological system linked to a specific institutional architecture and an aquifer with highly variable water availability. Current success in poverty alleviation masks an inherent fragility and risk that warrants further investigation before attempts are made to scale out groundwater based dry season farming to other parts of the dry zone.

This article presents a simulation-optimization approach for evaluating the feasibility of managed aquifer recharge (MAR) in the Samail Lower Catchment, Oman. The objective is to provide a maximum recharge and extraction rate through MAR in an annual cycle of two successive injection and recovery periods, while meeting operational and system constraints such as water level, gradient, and travel time. Three groundwater management problems were solved by coupling a simulation model with successive linear programming (SLP) and the nondominated sorting genetic algorithm (NSGA-II) multiobjective genetic algorithm. Sensitivity analysis was also completed to examine the overall response of the simulation-optimization results to changes in hydraulic conductivities and maximum injection rates. Results using the SLP algorithm showed that the total volume of injected water for 4 months of injection without recovery is as high as 8 × 106 m3, and the total recovered volume of water for 4months injection and 8 months recovery is approximately 5.3 × 106 m3, giving a total recovery efficiency of approximately 66%. For the same setup the NSGA-II algorithm derived the entire nondominated front of solutions for two conflicting objectives: maximizing recovery rate and maximizing minimum groundwater head close to the sea (for preventing seawater intrusion). This algorithm includes travel time constraints directly in the optimization process. In conclusion, the proposed approach provides a cost-effective means to evaluate MAR in a coastal aquifer.

In Tanzania like in other parts of the global South, in the name of apos;developmentapos; and apos;poverty eradicationapos; vast tracts of land have been earmarked by the government to be developed by investors for different commercial agricultural projects, giving rise to the contested land grab phenomenon. In parallel, Integrated Water Resources Management (IWRM) has been promoted in the country and globally as the governance framework that seeks to manage water resources in an efficient, equitable and sustainable manner. This article asks how IWRM manages the competing interests as well as the diverse priorities of both large and small water users in the midst of foreign direct investment. By focusing on two commercial sugar companies operating in the Wami-Ruvu River Basin in Tanzania and their impacts on the water and land rights of the surrounding villages, the article asks whether institutional and capacity weaknesses around IWRM implementation can be exploited by powerful actors that seek to meet their own interests, thus allowing water grabbing to take place. The paper thus highlights the power, interests and alliances of the various actors involved in the governance of water resources. By drawing on recent conceptual insights from the water grabbing literature, the empirical findings suggest that the IWRM framework indirectly and directly facilitates the phenomenon of water grabbing to take place in the Wami-Ruvu River Basin in Tanzania.

Many rural communities in Nepal experience considerable water stress during the dry season. Water storage systems (WSSs) have been proposed to supplement rain-fed irrigation and augment domestic water services in these communities. We evaluate household preferences for WSSs using a choice experiment and latent class modeling techniques. Results indicate the presence of three classes. The majority of households (E92%) belong to two equally-sized classes, a relatively privileged group (i.e. wealthier, better educated, etc.) with strong preferences for supplemental irrigation and a less privileged group that is mainly interested in improved domestic water services. The remaining class’ preferences are dominated by the cost attribute and are consistent with households facing severe cash constraints. Estimated welfare effects reveal that WSSs disproportionately benefit the privileged, although this disparity is mitigated with the provision of domestic water. These findings highlight the potential welfare gains from WSS investments, but stress the need for multi-purpose water resource development and the potential for elite capture.

Responding to rainfall variability has always been one of the most critical risks facing farmers. It is also an integral part of the job of water managers, whether it be designing interventions for flood management, improving the reliability of water supply for irrigation or advising on priorities during drought conditions. The conventional tools and approaches employed are no longer sufficient to manage the increasing uncertainty and incidence of extreme climate events, and the consequent effects these have on human vulnerability and food security. To be effective, the technological advances need to be matched with physical, institutional and management innovations that transcend sectors, and place adaptation and responsiveness to variability at the centre of the approach. This chapter examines a number of these challenges and possible solutions at a range of scales, from ‘climate-smart villages’ to national policy, with a focus on Asia and India, in particular.

This study looks at the groundwater issues in the dry zone of Sri Lanka and shows how the use of remote sensing with high-resolution images can help in groundwater management. A new approach is developed for automatic extraction of the location of agrowells using high-spatial-resolution satellite imageries. As an example, three pilot sites in three different aquifer systems in the country are considered, and their highresolution images are analyzed over two temporal time periods. The analysis suggests that the well density in all three regions has increased over the last few years, indicating higher levels of groundwater extraction. Using the well inventory developed by this new approach, the water budgeting was prepared for the mainland of Jaffna Peninsula. The analysis shows a wide variation in well density in the Jaffna Peninsula, ranging from (as little as) less than 15 wells per square kilometer to (as high as) more than 200 wells per square kilometer. Calculations made for the maximum allowable water extraction in each administrative division of Jaffna show that less than 3 h of daily extraction per well is possible in some districts. This points to an increasing pressure on groundwater resources in the region and thus highlights the importance of understanding groundwater budgets for sustainable development of the aquifers.

In the present study, MODFLOW-MT3D groundwater model was employed to perform numerical experimentation to develop design and operational parameters for skimming wells based on hydrogeology and groundwater salinity conditions of Chaj Doab, Punjab, Pakistan. Numerical experimentation resulted in: (i) a 1-strainer SW (Skimming Wells) with discharge of 14 l/s (litres per second) and penetration of 30% resulted in more saltwater upconing at 8 hours/day well operation compared to that occurred at 4 hours/day operation; (ii) a 1-strainer well with penetration of 30% and operation of 8 hours/day caused higher saltwater upconing at 14 l/s discharge compared to that at 9 l/s discharge; (iii) a 4-strainer well with penetration of 30% and operation of 8 hours/day also caused more saltwater upconing at 14 l/s well discharge compared to that at 9 l/s discharge. Similar trend was found for a 8-strainer well; and (iv) 1- or 4- or 8-strainer well with 30-60% penetration, 9-14 l/s discharge and 4-8 hours/day operation could provide pumped groundwater of salinity less than 1000 ppm. Considering hydro-chemical performance and costs of wells, a 4-strainer well with 30% penetration, 9-14 l/s discharge and 4-8 hours/day operation is recommended to skim groundwater of salinity less than 1000 ppm in Chaj Doab of Punjab, Pakistan.

Rural people in Nepal and other developing nations are part of complex, social-ecological systems. Efforts to provide assistance to these people must integrate knowledge from a variety of perspectives. This report documents the use of a role-playing game, supported by an agent-based model, to demonstrate the interaction between migration, social capital and the effectiveness of water storage. The importance of these interactions was highlighted by fieldwork conducted at several sites in the Koshi River Basin. The model underlying the game was a stylized representation based on the Indrawati Subbasin northeast of Kathmandu, Nepal. The report highlights that (a) role-playing tournaments can be an effective way to engage technical and policy experts with the complex interactions between the social and physical dimensions of watershed management; and (b) migration and the economic changes which drive these interactions are forces that need to be accepted, and investments in water storage need to be selected depending on how they fit into these trends.

Global Hydrological Models (GHMs) have effectively become a separate research field in the last two decades. The paper reviews and compares 12 known global modeling efforts since 1989, the year the first GHM was published. Structure, strengths and weaknesses of individual models are examined, and the objectives of model development and their initial applications are documented. Issues such as model uncertainty, data scarcity, integration with remote sensing data and spatial resolution are discussed.

To minimize and counter decline of groundwater levels and improve the availability of water for cropproduction, Managed Aquifer Recharge (MAR) interventions are widely adopted across India, often ini-tiated or supported by, local communities, state and central governments to improve the availability ofwater for irrigation. While the literature on MAR in India is vast, the science of their construction is lack-ing. Furthermore, there is an absence of a structured approach to evaluate the performance and impactof MAR interventions. Often, performance and impacts of MAR have been commented upon together,without distinguishing the two.In this article, we aim to propose that performance and impact are different from each other, andthat the evaluation of MAR interventions should take into account such differences between them. Aframework for performance and impact analysis, based on three levels, viz. primary, secondary and ter-tiary, is outlined. It is then applied to seven selected MAR interventions in India, Adarsha watershed –Andhra Pradesh, Gokulpura-Goverdhanpura watershed – Rajasthan, Kodangipalayam watershed – TamilNadu, Chikalgaon watershed – Maharashtra, Rajasamadhiyala watershed – Gujarat, Satlasana watershed– Gujarat and Sujalam Sufalam Yojana – Gujarat. Although, the evaluations of these case studies reportedwere not categorized into performance and impact, most of them have addressed both. However, noneof them could explicitly demonstrate that reported impacts were uniquely related to MAR interventions.If impacts are used as a surrogate for performance, it must be shown that impacts are uniquely linked toMAR interventions.

Groundwater is an important resource for multiple uses in South Africa. However, setting limits to its sustainable abstraction while assuring basic human needs is a must. Due to prevalent data scarcity related to groundwater replenishment, which is the traditional basis for estimating groundwater availability, the present report presents a novel method for determining allocatable groundwater in quaternary catchment through information on streamflows. Using established methodologies for assessing baseflows, recession flows, and instream ecological flow requirements, the methodology develops a combined stepwise methodology to determine annual groundwater storage volumes in the catchments using linear reservoir theory, essentially linking low flows proportionally to upstream groundwater storages. The approach was trialled for twenty-one perennial and relatively undisturbed quaternary catchments with long-term and good streamflow records. Using the Desktop Reserve Model to estimate instream ecological flow requirements of the streams and equating these with ecological groundwater reserve, excess baseflows were converted into groundwater storages on an annual basis. Results show that groundwater development potential exists in nineteen of the catchments, with upper limits to allocatable groundwater volumes ranging from 0.01 to 1.58 MCM/yr over the catchments. With a secured availability of these volumes 75% of the years, variability between years is assumed to be manageable. A significant (R2 = 0.86) correlation between baseflow index and the drainage time scale for the catchments underscored the physical basis of the methodology and also enables the reduction of the procedure by one step, omitting recession flow analysis. The method serves as an important complementary tool for the assessment of the groundwater part of the Reserve and the groundwater directed measures.

In many urban and peri-urban areas of India, wastewater is under-recognized as a major water resource. Wastewater irrigated agriculture provides direct benefits for the livelihoods and food security of many smallholder farmers. A rapidly urbanizing peri-urban micro-watershed (270 ha) in Hyderabad was assessed over a 10-year period from 2000 to 2010 for changes in land use and associated farming practices, farmer perceptions, socio-economic evaluation, land-use suitability for agriculture and challenges in potential irrigated area development towards wastewater use. This integrated approach showed that the change in the total irrigated area was marginal over the decade, whereas the built-up area within the watershed boundaries doubled and there was a distinct shift in cropping patterns from paddy rice to paragrass and leafy vegetables. Local irrigation supplies were sourced mainly from canal supplies, which accounted for three-quarters of the water used and was largely derived from wastewater. The remainder was groundwater from shallow hard-rock aquifers. Farmer perception was that the high nutrient content of the wastewater was of value, although they were also interested to pay modest amounts for additional pre-treatment. The shift in land use towards paragrass and leafy vegetables was attributed to increased profitability due to the high urban demand. The unutilised scrubland within the watershed has the potential for irrigation development, but the major constraints appear to be unavailability of labour and high land values rather than water availability. The study provides evidence to support the view that the opportunistic use of wastewater and irrigation practices, in general, will continue even under highly evolving peri-urban conditions, to meet the livelihood needs of the poor driven by market demands, as urban sprawl expands into cultivable rural hinterlands. Policy support is needed for enhanced recognition of wastewater for agriculture, with flow-on benefits including improved public health and protection of ecosystem services.

Saline formations are considered to be candidates for carbon sequestration due to their great depths, large storage volumes, and widespread occurrence. However, injecting carbon dioxide into low-permeability reservoirs is challenging. An active demonstration project for carbon dioxide sequestration in the Ordos Basin, China, began in 2010. The site is characterized by a deep, multi-layered saline reservoir with permeability mostly below 1.0×10-14 m2. Field observations so far suggest that only small-to-moderate pressure buildup has taken place due to injection. The Triassic Liujiagou sandstone at the top of the reservoir has surprisingly high injectivity and accepts approximately 80 % of the injected mass at the site. Based on these key observations, a three-dimensional numerical model was developed and applied, to predict the plume dynamics and pressure propagation, and in the assessment of storage safety. The model is assembled with the most recent data and the simulations are calibrated to the latest available observations. The model explains most of the observed phenomena at the site. With the current operation scheme, the CO2 plume at the uppermost reservoir would reach a lateral distance of 658 m by the end of the project in 2015, and approximately 1,000 m after 100 years since injection. The resulting pressure buildup in the reservoir was below 5 MPa, far below the threshold to cause fracturing of the sealing cap (around 33 MPa).

In sub-Saharan Africa, motor pump irrigation is at an earlier stage than in Asia but is growing rapidly in many countries. The focus of both policy and research in Africa to date has been on facilitating supply chains to make pumps available at a reasonable price. In Africa, pump irrigation is mainly based on two sources: shallow groundwater aquifers and small streams and rivers. Both usually have limited and variable yields. We present a case study from Ethiopia where pump irrigation based on small rivers and streams is expanding rapidly, and draw parallels to experiences in Asia and other African countries. We show that while farmers understand the social nature of community-managed irrigation, they share with policymakers a narrow understanding of pump irrigation as being primarily apos;technicalapos;. They perceive pumps as liberating them from the apos;socialapos; limitations of traditional communal irrigation. However, the rapid expansion of pump irrigation is leading to increasing competition and conflict over the limited water resource. We analyse the wider implications for Africa of this blindness to the social dimension of pump irrigation and offer suggestions on future policy and applied research to address the problem before it becomes a widespread crisis.

Suitability of groundwater for domestic and irrigation purposes as well as its hydrochemical characteristics was estimated in a part of Nalgonda district, Telangana state in southern India. Water samples were collected from 45 wells once every 2 months from March 2008 to January 2010. EC and pH were measured in situ while concentrations of calcium, magnesium, sodium, potassium, sulphate and chloride in groundwater were analysed using ion chromatograph. Carbonate and bicarbonate concentration were determined by acid base titration. General order of dominance of cations in the groundwater of this study area is Na?[Ca2?[Mg2?[ K? while that for anions is HCO3 -[Cl-[SO4-2. Ca–HCO3, Na–Cl, mixed Ca–Na–HCO3 and mixed Ca–Mg–Cl types of groundwater were dominant in this area. Groundwater is generally fresh with medium to high salinity and low alkalinity. Chloride and bicarbonate concentrations were present within the permissible limits for drinking whereas, some samples exceed the permissible limits of the Bureau of Indian Standards for pH, TDS, TH,sodium, calcium, magnesium and sulphate. Potassium exceeded the maximum permissible limits for drinking proposed by World Health Organisation. Sodium adsorption ratio, sodium percentage, residual sodium carbonate and permeability index indicates that the groundwater quality was suitable for irrigation in most parts of the study area.

Surface runoff generated in the monsoon months in the upstream parts of the Ganges River Basin contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the parts (sub-basins) of the Ganges that have the potential for augmenting subsurface storage (SSS), increase the availability of water for agriculture and other uses, and mitigate the floods in the downstream areas. The Soil and Water Assessment Tool (SWAT) is used to estimate sub-basin-wise water availability. The water availability estimated is then compared with the sub-basin-wise un-met water demand for agriculture. Hy-drological analyses revealed that five sub-basins produced more than 10 billion cubic meters (B m3) of annual surface runoff consistently during the simulation period. In these sub-basins, less than 50 % of the annual surface runoff is sufficient to irrigate all irrigable land in both the Rabi (November to March) and summer (April to May) seasons. Further, for most of the sub-basins, there is sufficient water to meet the un-met water demand, provided that it is possible to capture the surface runoff during the wet season. It is estimated that the average flow to Bihar State from the upstream of the Ganges, a downstream basin location, is 277 121 B m3, which is more than double the rainfall in the state alone. Strong relationships between outflows from the upstream sub-basins and the inflows to Bihar State suggested that flood inundation in the state could be reduced by capturing a portion of the upstream flows during the peak runoff periods.

The Ganges River Basin may have a major pending water crisis. Although the basin has abundant surface water and groundwater resources, the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Water availability and flood potential is high during the 3–4 months of the monsoon season. Yet, the highest demands occur during the 8–9 months of the non-monsoon period. Addressing this mismatch requires substantial additional storage for both flood reduction and improvements in water supply. Due to hydrogeological, environmental, and social constraints, expansion of surface storage in the Ganges River Basin is problematic. A range of in- terventions that focus more on the use of subsurface storage (SSS), and on the acceleration of surface–subsurface water exchange, have long been known as the “Ganges Water Machine”. One approach for providing such SSS is through additional pumping prior to the onset of the monsoon season. An important necessary condition for creating such SSS is the degree of unmet water demand. This paper highlights that an unmet water demand ranging from 59 to 119 Bm3 exists under two different irrigation water use scenarios: (i) to increase Rabi and hot weather season irrigation to the entire irrigable area, and (ii) to provide Rabi and hot weather season irrigation to the entire cropped area. This paper shows that SSS can enhance water supply, and provide benefits for irrigation and other water use sectors. In addition, it can buffer the inherent variability in water supply and mitigate extreme flooding, especially in the downstream parts of the basin. It can also increase river flow during low-flow months via baseflow or enable the re-allocation of irrigation canal water. Importantly, SSS can mitigate the negative effects of both flooding and water scarcity in the same year, which often affects the most vulnerable segments of society – women and children, the poor and other disadvantaged social groups.

Groundwater for agricultural purposes is of utmost importance in the Indian state of Gujarat. To augment existing agricultural water resources, the Gujarat Government invested in many large-scale and smallscale water infrastructures (WI). In order to increase water storage and groundwater recharge and to justify further investments in WI, a better understanding on the impacts of past WIs is needed. This study uses data from NASA’s Gravity Recovery and Climate Experiment (GRACE), along with soil moisture data from the Global Land Data Assimilation Systems, to estimate water storage before and after the intensification in the investment in WIs. In addition, Normalised Difference Vegetation Index (NDVI) data from the Moderate Resolution Imaging Spectrometer (MODIS) sensor was used to show changes in seasonal cropped areas during the same period. The analysis of data showed that the water storage in the state was estimated to be 24 BCM in 2003–2004 and 30 BCM in 2010–2011, an increase of 29% pre and post WI intensification. The Pixel Crop Duration Index (PCDI) indicated an increase in cropped area (at district level) in 2010–2011 when compared with 2003–2004 period, by 30% on yearly basis and about 80% during non-monsoon period. Results also indicates a significant net increase in water storage (by 5890 M m3 after water used for crop intensification) and increase in agricultural crop area (by 63,862 km2) in Gujarat during the period of intensification in infrastructures for water storage and groundwater recharge. Results also indicate that some districts have higher net water storage (compared to 2003), however the cropped area duration - PCDI has not increased much (e.g., Valsad and Navsari). The findings of this study can increase the understanding of the potential of WIs and provide valuable guidance for increasing cropped area in high water storage regions of Gujarat.

Identification of a suitable overlay and index method to map vulnerable zones for pollution in weathered rock aquifers was carried out in this study. DRASTIC and four models derived from it, namely Pesticide DRASTIC, modified DRASTIC, modified Pesticide DRASTIC and Susceptibility Index (SI) were compared by applying them to a weathered rock aquifer in southern India. The results were validated with the measured geochemical data. This study also introduces the use of temporal variation in the groundwater level and nitrate concentration in groundwater as input and for validation respectively to obtain more reliable and meaningful results. Sensitivity analysis of the vulnerability index maps highlight the importance of one parameter over another for a given hydrogeological setting, which will help to plan the field investigations based on the most or the least influential parameter. It is recommended to use modified Pesticide DRASTIC for weathered rock regions with irrigation practises and shallow aquifers (lt;20 m bgl). The crucial input due to land use should not be neglected and to be considered in any hydrogeological setting. It is better to estimate the specific vulnerability wherever possible rather than the intrinsic vulnerability as overlay and index methods are more suited for this purpose. It is also necessary to consider the maximum and minimum values of input parameters measured during a normal year in the models used for decision making.

This paper argues that sequential in-channel reservoirs in the Syrdarya River Basin of Central Asia are not sufficient to meet the needs of both upstream and downstream water users. Some of the consequences of the use of in-channel reservoirs include fresh water discharges into the saline depression and flooding of irrigated land in winter and water shortages in summer, which causes low water productivity. This study examines the feasibility of two alternative management strategies (1) building additional off-channel reservoirs, and (2) managed aquifer recharge (MAR). First, the potential for MAR in the upstream Fergana Valley is estimated through a regional assessment of MAR potential, field-scale pilot experiments, and simulation modeling. Second, the potential for MAR is analyzed for lift canal irrigation areas, which cover 70% of the irrigated highlands and the foothills in the river midstream, with a focus on energy use intensity and water and energy productivity. Third, the potential for building off-channel reservoirs and MAR is compared in the downstream portion of the river. Specifically for the Makhtaral Irrigation Project (MIP), a scenario of shifting from lift canal irrigation and groundwater extraction for drainage purposes is compared with groundwater irrigation and MAR. The MIP, located in the tail-end of the transboundary Dustyk Canal, faces waterlogging and salinity issues because of the shallow water table. The study concludes that transboundary cooperation in transboundary water transfers for MAR may increase the amount of water that could be stored underground. Overall, it is shown that there is a high potential for MAR in the Syrdarya River Basin with benefits at both the state and farm levels.

The concept of ‘Underground Taming of Floods for Irrigation’ (UTFI) is introduced as an approach for co-managing floods and droughts at the river basin scale. UTFI involves strategic recharge of aquifers upstream during periods of high flow, thereby preventing local and downstream flooding, and simultaneously providing additional groundwater for irrigation during the dry season for livelihood improvement. Three key stages in moving UTFI from the concept stage to mainstream implementation are discussed. An analysis of prospects in the Ganges River Basin are revealed from the earliest stage of mapping of suitability at the watershed level through to the latest stages of identifying and setting up the first pilot trial in the Upper Ganges, where a comprehensive evaluation is under way. If UTFI can be verified then there is enormous potential to apply it to address climate change adaptation/mitigation and disaster risk reduction challenges globally.

The development of water storage schemes in Sub-Saharan Africa (SSA) is considered a major aid for those regions with unequal water distribution, limited accessibility and anticipated climate change impacts. Great attention is given by many SSA countries to set up different water storage schemes that may improve rural and urban development on a national level. The funding for the water storage schemes is often derived from foreign agencies which conduct feasibility studies for the financing of potential investments. Often however, the feasibility studies rely on a single monetary criterion which may not identify the most appropriate water storage in each case. In addition, limited data availability in many SSA countries increases the difficulty of identifying the most suitable storage option. This paper develops a multicriteria framework for the integrated evaluation of water storage strategies in Sub-Saharan African countries. A set of economic, agronomic and opinion-based criteria are assessed through the PROMETHEE II outranking approach. The introduction of crop modeling complements the limited field data available in agronomic criteria and enhances the scientific rigor of the method. Ethiopia is adopted as a representative case of SSA countries where a diverse set of water storage options is currently under construction, often financed by foreign agencies.

Because of the logics of both colonization or de-colonization, the need to counter the anarchy of groundwater use, or the dissemination of global apos;best practicesapos; of IWRM, states have often assumed full ownership or custody of groundwater. Regulating groundwater use includes giving drilling and abstraction authorizations/licenses, establishing an inventory of wells and reducing use in existing wells. Although laws and regulations look neat and straightforward on paper, registration, regularization, and metering have been bedeviled by a host of logistical nightmares, policy contradictions, legal challenges, and vested private interests. The overall outlook is bleak and questions the overstating of state power in reordering groundwater use. Co-management with users, while in itself not sufficient to ensure success, often arises as a possible way out of the failure of state control.

Groundwater economic models have refined optimal extraction rules while lagging behind in the study of optimal spatial policies. This paper develops a theoretical model to estimate welfare gains from optimal groundwater management when the choice variable set is expanded to include well location decisions as well as optimal groundwater extraction paths. Our theoretical results show that if there is spatial heterogeneity in groundwater, the welfare gains from optimal location of wells are substantial even if extraction rates are unregulated. Furthermore, second-best economically defined spacing regulations may possibly have better efficiency results (and lower implementation costs) than first-best uniform taxes or quotas. An application of the model to a real-world aquifer shows the importance of including well location decisions in spatially differentiated groundwater models and the need for (1) robust estimates of the gains from optimal management and; (2) spatially explicit regulations.

Water resources of the Koshi Basin (87,311km2) are largely untapped, and while proposals for their development exist, their impacts on current and future water demands are not quantified. The current study is the first to evaluate the impacts of 11 proposed development projects on hydropower generation and water storage. Results revealed that 29733GWh hydropower can be generated and 8382Million m3 (MCM) of water can be stored annually. This can satisfy unmet demands in current (660MCM) basin situation and future scenarios - i.e. population, agricultural and industrial growth – that are projected to have 920, 970 and 1003MCM unmet-demands, respectively by 2050.

Groundwater management practices need to take hydrogeology, the agro-climate and demand for groundwater into account. Since agroclimatic zones have already been demarcated by the Government of India, it would aid policy makers to understand the status of groundwater recharge and discharge in each agroclimatic zone. However, developing effective policies to manage groundwater at agroclimatic zone and state levels is constrained due to a paucity of temporal data and information. With the launch of the Gravity Recovery and Climate Experiment (GRACE) mission in 2002, it is now possible to obtain frequent data at broad spatial scales and use it to examine past trends in rain induced recharge and groundwater use. In this study, the GRACE data were used to estimate changes to monthly total water storage (TWS) and groundwater storage in different agroclimatic zones of Rajasthan, India. Furthermore, the long-term annual and seasonal groundwater storage trends in the state were estimated using the GRACE data and the trends were compared with those in rainfall data. The methodology based on GRACE data was found to be useful in detecting large scale trends in groundwater storage changes covering different agroclimatic zones. The analysis of data shows that groundwater storage trends depend on rainfall in previous years and, therefore, on the antecedent moisture conditions. Overall, the study indicates that if suitable groundwater recharge methods and sites are identified for the state, there is potential to achieve more groundwater recharge than what is currently occurring and, thus, enhancing the availability of water for irrigated agriculture.

In the Dry Zone of Myanmar, improved access to water is widely acknowledged as being vital for livelihood enhancement and the general well-being of around 10 million people, most of whom depend on agriculture. Thus, expanding the sustainable use of groundwater is of great importance for socioeconomic development. According to this study, opportunities for accessing groundwater are generally good, and development of the resource has steadily increased over the years. However, there still appears to be good prospects for expanding groundwater use for irrigation, with a view to increasing agricultural production. Provision of affordable mechanical technologies for drilling wells and support with credit facilities to purchase small-capacity motorized pumps for irrigation could improve food security and livelihoods, where there is potential to expand groundwater use. Replenishable groundwater resources of the Dry Zone are likely to be less than previously thought. Thus, it is important to find the right balance between increasing development of the resource for enhanced irrigation, while also protecting its existing beneficial use for communities and the environment.

Groundwater irrigation is the most predominant method used across India. The south Indian state of Tamil Nadu is one of the largest producers of agricultural products, and is largely dependent on groundwater for irrigation. The impact of increased irrigation due to intensification of agricultural activities on groundwater levels has not been well researched, both spatially and temporally. Hence this study has used remote sensing data from NASA’s Gravity Recovery and Climate Experiment and the Global Land Data Assimilation Systems to assess the total change in groundwater storage across the state of Tamil Nadu over a period of 11 years, from 2002 to 2012. The results show groundwater depletion at the rate of 21.4 km3 yr-1, which is 8% more than the annual recharge rate (19.81 km3 yr-1) owing to the total rainfall of 1016 mm yr1. Maximum depletion was observed in 2008, while the least depletion was observed in 2002 with rates of 41.15 and 0.32 cm yr-1, respectively. Districts such as Dharmapuri, Vellore and Thiruvannamali encountered intense groundwater depletion. Observed spatiotemporal groundwater storage will benefit India’s water resource managers and policymakers for the future management of groundwater resources to enhance food and water security.

Gujarat state in Western India exemplifies all challenges of an agrarian economy founded on groundwater overexploitation sustained over decades by perverse energy subsidies. Major consequences are: secular decline in groundwater levels, deterioration of groundwater quality, rising energy cost of pumping, soaring carbon footprint of agriculture and growing financial burden of energy subsidies. In 2009, Government of Gujarat asked the present author, an economist, to chair a Taskforce of senior hydro-geologists and civil engineers to develop and recommend a Managed Aquifer Recharge (MAR) strategy for the state. This paper summarizes the recommended strategy and its underlying logic. It also describes the imperfect fusion of socio-economic and hydro-geologic perspectives that occurred in course of the working of the Taskforce and highlights the need for trans-disciplinary perspectives on groundwater governance.

The ‘silent revolution’ is a phenomenon describing the individualistic behaviour of farmers in the adoption of intensive groundwater abstraction technologies, which in some cases has led to groundwater over-abstraction and environmental degradation in semiarid areas such as La Mancha, Spain. However, a lacuna exists as to the extent to which state politics have affected the development of groundwater abstraction technologies in Spain. With new quantitative and qualitative data from the irrigation community of Manzanares and public irrigation and colonisation plans, this report studies the adoption of groundwater abstraction technology and investigates the historical role of the state in the development of modern groundwater-fed irrigation socio-ecologies in the semiarid area of La Mancha in Spain.

Climate change could have a critical impact on agriculture in Nepal due to dry-season water shortages, and changes in the variability of water availability and associated uncertainty. This makes water storage systems (most notably ponds and tanks) increasingly important. This report explores the potential role of small-scale water storage infrastructure in two subbasins within the larger Koshi River Basin in central and eastern Nepal, yet shows that upscaling such infrastructure requires an appreciation of the other drivers of change in agriculture aside from climate (e.g., rising cost of living and poor terms of trade for agriculture). It also identifies the social relations and dynamics (distribution of land, water and labor) which could mediate the success of future interventions. It is clear from the research that, while small-scale water storage has the potential to significantly strengthen livelihoods in the Nepali hills, it is necessary to tailor projects to the existing political-economic context.

The potential to increase agricultural production in inland valleys in West Africa has received a good degree of attention in both national development strategies and academic literature, and improving agriculture productivity in inland valleys has been an active area of donor engagement. Despite this attention, documentation of the degree to which benefits are enhanced through construction of built water storage infrastructure in such sites is somewhat scant. This paper examines evidence from eight inland valley sites with recently-built water retention infrastructure (4 in southwest Burkina Faso, 4 in southeast Mali) to determine how economic returns derived from agricultural production have changed through built infrastructure construction. Farmer interviews were undertaken at each site to identify costs and benefits of agricultural production before and after small built infrastructure construction. Overall results indicate that net present value increased substantially after built infrastructure was constructed. The results nonetheless highlight substantial variation in economic impacts across sites. A central variable explaining such variation appears to be the degree to which water retention is exploited for groundwater-based offseason cultivation. These findings will help development planners to better predict the degree and nature of change engendered by water storage projects in inland valley sites, and help to ground-truth grand statements about the development potential of this piece of natural infrastructure.

Irrigated agriculture in Oman relies solely on groundwater and Aflaj (Falaj is a canal system, which provides water for a community of farmers for domestic and agricultural use). With the increasing scarcity of freshwater available to agriculture, the need to use of reclaimed water (RW) from Sewage Treatment Plants (STP) in agriculture has increased. In this study, we explored how RW from an STP can be used directly, without Aquifer Storage and Recovery, as a source of irrigation water in conjunction with groundwater for agriculture. Average data from Muscat, Oman in the years from 1996 to 2010 was used for calculation of crop water requirement. Wheat, cowpea and maize were chosen as crops to be grown in rotation through the year. Using RW irrigation conjunctively with groundwater cropping areas of wheat, cowpea and maize can be increased by 323, 250 and 318% respectively, against utilization RW only. Of the total irrigation requirement 57.6% was met with reclaimed water (RW) and 42.4% was met with groundwater (GW). Therefore, it is recommended that decision makers should consider piping RW to areas where groundwater of good quality is available to conjunctively use and meet crop water requirements, rather than piping it to areas where groundwater is saline and unsuitable for irrigation. This will prevent disposal of RW to the sea and minimize stress on fresh groundwater zones.

Groundwater development across much of sub-Saharan Africa is constrained by a lack of knowledge on the suitability of aquifers for borehole construction. The main objective of this study was to map groundwater potential at the country-scale for Ghana to identify locations for developing new supplies that could be used for a range of purposes. Groundwater potential zones were delineated using remote sensing and geographical information system (GIS) techniques drawing from a database that includes climate, geology, and satellite data. Subjective scores and weights were assigned to each of seven key spatial data layers and integrated to identify groundwater potential according to five categories ranging from very good to very poor derived from the total percentage score. From this analysis, areas of very good groundwater potential are estimated to cover 689,680 ha (2.9 % of the country), good potential 5,158,955 ha (21.6 %), moderate potential 10,898,140 ha (45.6 %), and poor/very poor potential 7,167,713 ha (30 %). The results were independently tested against borehole yield data (2,650 measurements) which conformed to the anticipated trend between groundwater potential and borehole yield. The satisfactory delineation of groundwater potential zones through spatial modeling suggests that groundwater development should first focus on areas of the highest potential. This study demonstrates the importance of remote sensing and GIS techniques in mapping groundwater potential at the country-scale and suggests that similar methods could be applied across other African countries and regions.

Doubling of population, since the 1970s, in the Aral Sea Basin of Central Asia led to the increased demand for water and energy. The shift of the key upstream reservoir on the Naryn River, main tributary of the Syrdarya River, from irrigation to hydropower generation reduced available water for irrigation in the summer and created excessive flows in the winter. The downstream reservoirs do not have free capacities for storing the excessive winter flows. This report examines the possibility of additional subsurface storages of water in a part of the Syrdarya River Basin, the Fergana Valley. The report aims to bring the attention of policymakers to alternative development of basin water management, which requires cooperation of riparian states in the use of water and energy.

Access to sufficient quantities of water of acceptable quality is a basic need for human beings and a pre-requisite to sustain and develop human welfare. In cases of limited availability, the allocation of water between different sectors can result in conflicts of interests. In this study, a modified version of the Building Block Methodology (BBM) was demonstrated for allocation of waters between different sectors. The methodology is a workshop-based tool for assessing water allocation between competing sectors that requires extensive stakeholder involvement. The tool was demonstrated for allocation of water in the Sri Ram Sagar water reservoir in the Godavari Basin, Andhra Pradesh, India. In this multipurpose reservoir, water is used for irrigation, drinking water supply and hydropower production. Possible water allocation regimes were developed under present hydrological conditions (normal and dry years) and under future climate change, characterized by more rain in the rainy season, more frequent droughts in the dry season and accelerated siltation of the reservoir, thus reducing the storage capacity. The feedback from the stakeholders (mainly water managers representing the various sectors) showed that the modified version of the BBM was a practical and useful tool in water allocation, which means that it may be a viable tool for application also elsewhere.

Doubling of population, since the 1970s, in the Aral Sea Basin of Central Asia led to the increased demand for water and energy. The shift of the key upstream reservoir on the Naryn River, main tributary of the Syrdarya River, from irrigation to hydropower generation reduced available water for irrigation in the summer and created excessive flows in the winter. The downstream reservoirs do not have free capacities for storing the excessive winter flows. This report examines the possibility of additional subsurface storages of water in a part of the Syrdarya River Basin, the Fergana Valley. The report aims to bring the attention of policymakers to alternative development of basin water management, which requires cooperation of riparian states in the use of water and energy.

The hydrological roles of glaciers and seasonal snow in the Indus, Ganges, Brahmaputra, Amu Darya, Syr Darya and Mekong basins are, for the first time, assessed comprehensively at a major river basin scale in this paper. Contribution of glacier runoff, subdivided into renewable and nonrenewable components, and seasonal snowmelt to mean annual flow is evaluated for two time slices: 1961-1990 and 2001-2010. The recent changes of the hydrological roles of glaciers and snow, and the most likely changes of those under future climate change are analyzed.

This paper presents a comprehensive assessment of the water storage properties of glaciers and seasonal snow, carried out for the first time at a major river basin scale, for the Indus, Ganges, Brahmaputra, Amu Darya, Syr Darya and Mekong basins. It analyzes the changes of glaciers and snow under recent climate change, i.e., between the baseline (1961-1990) and current (2001-2010) periods. The paper also addresses climate change sensitivity of glacier systems and the changes that might be expected under a warming scenario for the end of the twenty-first century.

The paper demonstrates the application of a new water accounting plus (WA+) framework to produce information on depletion of water resources, storage change, and land and water productivity in the Indus basin. It shows how satellite-derived estimates of land use, rainfall, evaporation (E), transpiration (T ), interception (I ) and biomass production can be used in addition to measured basin outflow, for water accounting with WA+. It is demonstrated how the accounting results can be interpreted to identify existing issues and examine solutions for the future. The results for one selected year (2007) showed that total annual water depletion in the basin (501 km3) plus outflows (21 km3) exceeded total precipitation (482 km3). The water storage systems that were effected are groundwater storage (30 km3), surface water storage (9 km3), and glaciers and snow storage (2 km3). Evapotranspiration of rainfall or “landscape ET” was 344 km3 (69% of total depletion). “Incremental ET” due to utilized flow was 157 km3 (31% of total depletion). Agriculture depleted 297 km3, or 59% of the total depletion, of which 85% (254 km3) was through irrigated agriculture and the remaining 15% (44 km3) through rainfed systems. Due to excessive soil evaporation in agricultural areas, half of all water depletion in the basin was non-beneficial. Based on the results of this accounting exercise loss of storage, low beneficial depletion, and low land and water productivity were identified as the main water resources management issues. Future scenarios to address these issues were chosen and their impacts on the Indus Basin water accounts were tested using the new WA+ framework.

Coping with water scarcity and growing competition for water among different sectors requires proper water management strategies and decision processes. A prerequisite is a clear understanding of the basin hydrological processes, manageable and unmanageable water flows, the interaction with land use and opportunities to mitigate the negative effects and increase the benefits of water depletion on society. Currently, water professionals do not have a common framework that links depletion to user groups of water and their benefits. The absence of a standard hydrological and water management summary is causing confusion and wrong decisions. The non-availability of water flow data is one of the underpinning reasons for not having operational water accounting systems for river basins in place. In this paper, we introduce Water Accounting Plus (WA+), which is a new framework designed to provide explicit spatial information on water depletion and net withdrawal processes in complex river basins. The influence of land use and landscape evapotranspiration on the water cycle is described explicitly by defining land use groups with common characteristics. WA+presents four sheets including (i) a resource base sheet, (ii) an evapotranspiration sheet, (iii) a productivity sheet, and (iv) a withdrawal sheet. Every sheet encompasses a set of indicators that summarise the overall water resources situation. The impact of external (e.g., climate change) and internal influences (e.g., infrastructure building) can be estimated by studying the changes in theseWA+ indicators. Satellite measurements can be used to acquire a vast amount of required data but is not a precondition for implementingWA+ framework. Data from hydrological models and water allocation models can also be used as inputs to WA+.

Recent attention to transboundary aquifers (TBAs) in Africa reflects the growing importance of these resources for development in the continent. However, relatively little research on these aquifers and their best management strategies has been published. This report recapitulates progress on mapping and management frameworks for TBAs in Africa. The world map on transboundary aquifers presented at the 6th World Water Forum in 2012 identified 71 TBA systems in Africa. This report presents an updated African TBA map including 80 shared aquifers and aquifer systems superimposed on 63 international river basins. Furthermore, it proposes a new nomenclature for the mapping based on three sub-regions, reflecting the leading regional development communities. The map shows that TBAs represent approximately 42 % of the continental area and 30 % of the population. Finally, a brief review of current international law, specific bi- or multilateral treaties, and TBA management practice in Africa reveals little documented international conflicts over TBAs. The existing or upcoming international river and lake basin organisations offer a harmonised institutional base for TBA management while alternative or supportive models involving the regional development communities are also required. The proposed map and geographical classification scheme for TBAs facilitates identification of options for joint institutional setups.

By mitigating the vagaries of climate variability, agricultural water storage is widely anticipated to make a key contribution to climate change adaptation in Africa. However, if the planning of water storage is not improved, it is likely that many investments will fail to fully deliver intended benefits. This report describes the agricultural water storage continuum and some of the possible implications of climate change. A simple diagnostic tool which can be used to provide a rapid evaluation of the need and effectiveness of different water storage options, under existing and possible future climate conditions, is presented.

A simple but comprehensive framework for analysing the potential for and constraints to groundwater development for irrigated agriculture in sub-Saharan Africa is proposed. The framework, based on food value chain principles, is applied to the sub-Saharan context and a specific catchment in Tanzania, the Usangu plains, where groundwater has been proposed as a strategic resource for augmenting food production and smallholder livelihoods and to alleviate seasonal water scarcity. The novel contribution of the work is the presentation of a tool that can be applied to support an interdisciplinary approach to systematically identify most significant barriers and most critical water management and development interventions for sustainable development of groundwater irrigation. The result of the case study shows that farmer economics, capacity, and pump and well drilling market constraints limit groundwater irrigation in the Usangu plains rather than hydrogeological conditions.

Indian agriculture is the largest user of rainfall, surface and groundwater resources. Some of the large river systems feedings the canal systems and the groundwater aquifers, like the Indus, the Ganges, the Brahmaputra and their several tributaries have their origin in the Himalayas. A large part of the discharge of these river systems is fed through melting of the snow and glaciers. Although there is a lack of adequate scientific evidence on regional scales, a number of recent observational and modelling studies do suggest that the climate is changing. According to IPCC, the most significant consequences of climate change will be its impact on the hydrologic cycle, as already experienced in many parts of the world including India. Changes in precipitation intensity and duration will probably be the main factors altering the hydrologic cycle leading to more floods and droughts. Availability or scarcity of water will vary greatly depending on the region. The impact of climate change will be greater in India, where a majority of the rural population depends on agriculture for their livelihoods, and where agriculture is primarily dependent on the monsoons. Governments and communities have not been able to adequately address climate related challenges to peopleapos;s livelihoods that follow from changes in water availability, loss of crops and income with the occurrence of extreme weather events like floods and droughts. After a brief introduction to the importance of the subject, this paper describes in detail the impact of climate change on water resources in India, with special reference to the Indus and the Ganges River systems which constitute the major food basket of the country. The impacts of climate change on agriculture sector, including the rainfed agriculture have been presented. An analysis of the potential opportunities presented by enhanced flows for the surface systems and recharge for the groundwater aquifers has been presented and the paper concludes by presenting adaptive mechanisms in the agriculture sector and the important recommendations for improving institutional capacity, development and management of water resources, adaptation to floods and prevention and management of droughts.

West and East Africa experience high variability of rainfall that is expected to increase with climate change. This results in uctuations in water availability for food production and other socioeconomic activities. Water harvesting and storage can mitigate the adverse effects of rainfall variability. But past studies have shown that when investments in water storage are not guided by environmental health considerations, the increased availability of open water surface may increase the transmission of waterrelated diseases. This is demonstrated for schistosomiasis associated with small reservoirs in Burkina Faso, and for malaria in Ethiopia around large dams, small dams, and water harvesting ponds. The concern is that the rush to develop water harvesting and storage for climate change adaptation may increase the risk for already vulnerable people, in some cases more than canceling out the bene ts of greater water availability. Taking health issues into account in a participatory approach to planning, design, and management of rainwater harvesting and water storage, as well as considering the full range of water storage options would enable better opportunities for enhancing resilience against climate change in vulnerable populations in sub-Saharan Africa.

The SWAT (Soil and Water Assessment Tool) was used to evaluate the impacts of a climate scenario based on IPCC A1B emissions on flows in the Volta River basin in West Africa for 2021–2050 and 2071–2100, using 1983–2012 as the reference period. Overall, the simulation indicates increased variability and a decrease of up to 40% in river flow as a consequence of decreasing rainfall and increasing temperature. In particular, the analysis shows smaller absolute but greater relative changes in the hydrology of the northern (upper) part of the basin, particularly at the end of the century.

Groundwater drought denotes the condition and hazard during a prolonged meteorological drought when groundwater resources decline and become unavailable or inaccessible for human use. Groundwater drought risk refers to the combined physical risk and human vulnerability associated with diminished groundwater availability and access during drought. An integrated management support tool, GRiMMS, is presented, for the mapping and assessment of relative groundwater drought risk in the Southern African Development Community (SADC) region. Based on composite mapping analysis of regionwide gridded relative indices of meteorological drought risk, hydrogeological drought proneness and human groundwater drought vulnerability, the mapping results highlight consistent areas across the region with highest groundwater drought risk and populations in the order of 39 million at risk of groundwater drought at present. Projective climate-model results suggest a potentially significant negative impact of climate change on groundwater drought risk. The tool provides a means for further attention to the key, but neglected, role of groundwater in drought management in Africa.