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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 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.

Antibiotics have revolutionised medicine in the last century and enabled the prevention of bacterial infections that were previously deemed untreatable. However, in parallel, bacteria have increasingly developed resistance to antibiotics through various mechanisms. When resistant bacteria find their way into terrestrial and aquatic environments, animal and human exposures increase, e.g., via polluted soil, food, and water, and health risks multiply. Understanding the fate and transport of antibiotic resistant bacteria (ARB) and the transfer mechanisms of antibiotic resistance genes (ARGs) in aquatic environments is critical for evaluating and mitigating the risks of resistant-induced infections. The conceptual understanding of sources and pathways of antibiotics, ARB, and ARGs from society to the water environments is essential for setting the scene and developing an appropriate framework for modelling. Various factors and processes associated with hydrology, ecology, and climate change can significantly affect the fate and transport of ARB and ARGs in natural environments. This article reviews current knowledge, research gaps, and priorities for developing water quality models to assess the fate and transport of ARB and ARGs. The paper also provides inputs on future research needs, especially the need for new predictive models to guide risk assessment on AR transmission and spread in aquatic environments.

Over the past century, the world has experienced an unprecedented surge in population growth, accompanied by a significant increase in economic activity and fuelled by an intensive utilization of natural resources, including water. This phenomenon has brought about profound alterations in land cover and land use patterns across various regions. Knowledge of land use changes is key to unlocking an understanding of water use changes and associated impacts on water resources, and potential threats to sustainability. However, the pace and nature of land use transitions vary widely across the globe, shaped by a complex interplay of local, regional and global factors, making systematic assessments important.; This report presents the results of a land cover change analysis conducted in two river basins in sub-Saharan Africa: the Upper Great Ruaha River Basin (UGRRB) in Tanzania and the Upper Awash River Basin (UARB) in Ethiopia. The spatio-temporal analysis spans a recent 15-20-year period up until 2015/16 and utilizes remote sensing imagery, secondary maps and ground truth information for the two end point times (resolution: 30 m). The basins are significantly different in terms of agricultural development and water resource use. UARB represents an area with emerging commercial farms, urban expansion and diminishing natural vegetation, whereas UGRRB still retains significant natural vegetation but is experiencing an increase in smallholder agriculture as well as intensive commercial irrigation potentially affecting fragile wetland systems. In UGRRB, surface water is the main source of irrigation water, while in UARB, groundwater resources are increasingly used for irrigation by smallholder farmers. The findings reveal a common overall trend in both basins that is similar to many low-income countries, illustrating an expansion of agricultural and irrigated areas and human settlements at the expense of natural land cover. The report presents a detailed systematic remote sensing-based methodology to quantify and compare land cover transitions in time and space with high resolution, within and between agricultural landscapes of larger basins. The study highlights that land cover changes in the basins follow diverse and unique trajectories, providing critical insights into evolving land use patterns.; In its conclusion, the study underscores the profound implications of recent land use changes for groundwater resources within these agro-pastoral systems. Overall, the report highlights the importance of sustainable land management and integrated water resources management, and provides valuable insights into the complexities of land use change in these regions.

Quantifying water-saving potential (WSP) is crucial for sustainable water resource management in canal command areas and river basins. Previous studies have partially or fully ignored the importance of groundwater in WSP assessments, particularly in irrigated areas. This study is aimed at quantifying WSP in the Lower Chenab Canal (LCC) command area of the Indus River Basin, Pakistan, under various scenarios of future climate change and groundwater recharge. These quantifications are conducted using an empirical model based on the Budyko theory. The model was forced using observed, remote sensing, and CMIP6 future climate data for two Shared Socioeconomic Pathways (SSP245 and SSP585) and their ensembles (cold-dry, cold-wet, warm-dry, and warm-wet) for possible futures. The results showed that the average WSP in the LCC command area was 466 48 mm/year during the historical period (2001–2020). The WSP is projected to decrease by – 68 3% under the warm-dry ensemble scenario (SSP245 and SSP585) and – 48 13% under the ensembled cold-wet scenario by 2100. The results also demonstrated that WSP could be increased by up to 70 9% by artificially recharging 20% of the abstracted groundwater per year in the LCC command area by the late twenty-first century. Our findings highlight the importance of adopting artificial groundwater recharge to enhance the WSP and sustainably manage water resources in the LCC command area. Policymakers should consider these findings when deciding on water resource management in the Indus River Basin.

Although Ghana is a leading global cocoa producer, its production and yield have experienced declines in recent years due to various factors, including long-term climate change such as increasing temperatures and changing rainfall patterns, as well as drought events. With the increasing exposure of cocoa-producing regions to extreme weather events, the vulnerability of cocoa production is also expected to rise. Supplemental irrigation for cocoa farmers has emerged as a viable adaptation strategy to ensure a consistent water supply and enhance yield. However, understanding the potential for surface and groundwater irrigation in the cocoa-growing belt remains limited. Consequently, this study aims to provide decision-support maps for surface and groundwater irrigation potential to aid planning and investment in climate-smart cocoa irrigation. Utilizing state-of-the-art geospatial and remote sensing tools, data, and methods, alongside in-situ groundwater data, we assess the irrigation potential within Ghanaapos;s cocoa-growing areas. Our analysis identified a total area of 22,126 km2 for cocoa plantations and 125.2 km2 for surface water bodies within the cocoa-growing regions. The multi-criteria analysis (MCA) revealed that approximately 80% of the study area exhibits moderate to very high groundwater availability potential. Comparing the MCA output with existing borehole locations demonstrated a reasonable correlation, with about 80% of existing boreholes located in areas with moderate to very high potential. Boreholes in very high potential areas had the highest mean yield of 90.7 l/min, while those in low groundwater availability potential areas registered the lowest mean yield of 58.2 l/min. Our study offers a comprehensive evaluation of water storage components and their implications for cocoa irrigation in Ghana. While groundwater availability shows a generally positive trend, soil moisture and surface water have been declining, particularly in the last decade. These findings underline the need for climate-smart cocoa irrigation strategies that make use of abundant groundwater resources during deficit periods. A balanced conjunctive use of surface and groundwater resources could thus serve as a sustainable solution for maintaining cocoa production in the face of climate change.

There is currently no water cooperation between Afghanistan and Pakistan. Of the nine rivers that flow across the border, none possess a formal agreement or mechanism to manage shared water resources. Further, there is very little information available about the status of environment, hydrology and water resources management for these river basins that could be used as a starting point for dialogues on transboundary water coordination. This State of the Basins book co-develops an overview of the three most important river basins, in collaboration with international experts and water professionals from Afghanistan and Pakistan. It covers water resources, land resources, ecological health, environment, climate change, and the social and economic conditions for sustainable management of these precious resources. It will inform decision making within the two countries, and begin to establish benefits that can accrue from more active collaboration on these shared waters.; This book: Focuses on portions of the Indus shared by Afghanistan and Pakistan.; Features extensive engagement and co-development with Afghan and Pakistani professionals.; Is the first book on the shared waters in the Indus, developed in the context of regional realities associated with post-August 2021 Taliban takeover.; The book is aimed at students and researchers in water rights and resources, and government decision makers, private sector investors, donors, intermediary organizations that work directly with farmers, researchers and students. It is a reference book for graduate students and researchers working on these basins, and on transboundary river basin management in Asia and beyond.

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.

The potential for profitable groundwater irrigated area development in Nigeria is 5.04 million hectares (ha), almost all of it located in the country’s central and northern states. To develop this vast area, granular water budgets, financial service provision and support to grow sustainability of production will be needed. Increasing temperature, erratic rainfall, and other extreme events, such as floods and droughts, pose severe threats to development in Nigeria, and particularly in central and northern Nigeria where rainfall is limited, natural resources are threatened by degradation and agriculture, including livestock production, is the major economic driver. Climate change has significant adverse impacts on agricultural production and livelihoods, making the regions’ poor and disadvantaged people even more vulnerable. Agricultural productivity is already affected by climate extreme events and further land expansion would increase degradation and deforestation. At the same time, the central and northern regions of the country are blessed with substantial underground water resources that have been barely tapped. At this point, the potential of farmer-led irrigation, a system where farmers acquire the irrigation technology and access to a water source themselves, is barely exploited. What role could farmer-led, small-scale irrigation play in growing agricultural productivity, rural employment and incomes, and reducing climate stress? And what mechanisms are needed to make this happen?

Using water-energy-food-environment (WEFE) nexus as the prism, this review explores evolution of groundwater governance in Iran, Saudi Arabia, Mexico, China, Bangladesh and India – which together account for two-thirds of the global groundwater-irrigated area. Global discourse has blamed widespread water scarcity squarely on supply-side policymaking and advocated a broader template of water governance instruments. Integrated Water Resources Management (IWRM) presented just such a template – with pricing, participation, rights and entitlements, laws, regulations, and river basin organizations – as additional water governance tools. However, the IWRM template faced disillusionment and pushback in many emerging economies. WEFE nexus, the new paradigm, prioritizes system-level optima over sectoral maxima by harnessing synergies and optimizing trade-offs between food, water, energy, soil, and eco-system sustainability within planetary boundaries. Realizing this vision presents a complex challenge in groundwater governance. Global groundwater economy comprises three sub-economies: (a) diesel-powered unregulated, as in Nepal terai, eastern India, Bangladesh, Pakistan Punjab and Sind, and much of Sub-Saharan Africa, where use-specific energy subsidies are impractical; (b) electricity-powered regulated, as in North America and Europe, where tubewells are authorized, metered and subject to consumption-linked energy charges; and (c) electricity-powered unregulated, as in geographies covered by our review – barring China, Bengal and Bangladesh – where unmeasured electricity subsidies have created a bloated groundwater economy. This last sub-economy represents the heartland of global groundwater malgovernance, least equipped to meet the sustainability challenge. It has an estimated 300 million horsepower of grid-connected electric pumps that are either unauthorized and/or unmetered and/or use free or heavily subsidized or pilfered power for irrigating 50–52 million hectares, nearly half of global groundwater-irrigated area. In (a) and (b), groundwater scarcity inspires water-energy saving behavior via increased energy cost of pumping. In sub-economy (c), users are immune to energy costs and impervious to groundwater depletion. Here, the WEFE nexus has remained blind to the irrigation realpolitik that catalyzes or constrains policy action. We explore why the political costs of rationalizing subsidies are prohibitive and exemplify how a smart transition from fossil to solar energy for pumping may offer an opportunity to turn the perverse WEFE nexus into a virtuous one.

Groundwater is the single largest source of water for irrigation and domestic use in India. Climate change further exacerbates the threat of depletion, reducing food security and increasing the vulnerabilities of resource users. Governance is complicated by externalities associated with its attributes as an invisible and fluid resource which create problems of rivalry and exclusion. Based on theory-based case studies for evaluation of selected World Bank projects, we analyse challenges for groundwater governance and identify factors that contribute to depletion. It highlights the need for integrating and balancing demand and supply-side approaches, including water-efficient irrigation and climate-smart practices.

Land-use-change-induced increases in shallow groundwater levels across parts of the Sahel in recent years have coincided with expanded use of groundwater for irrigation. This study was conducted to assess the potential linkages and livelihood implications based on a field survey of nine villages building on previous hydrological studies. The results show that irrigators lack effective means of production and mostly rely on manual methods. Borehole usage is more profitable and reliable than shallower wells. Overall incomes from irrigation are relatively small and severely constrained by the limited field scale due to high establishment and operating costs.

This study uses a modified Granger and Gray model to estimate evapotranspiration and then groundwater recharge in Ghana. The overall results show that the model is capable of reliably predicting regional evapotranspiration using a small number of monitoring stations with meteorological data only. This information allows the estimation of groundwater recharge via the water balance equation. The results indicate that the aquifer system is sufficiently recharged, especially in northern Ghana, where dry conditions prevail, to allow the development of groundwater resources to satisfy increasing water demands.

The government of Ethiopia has invested in groundwater development for smallholder irrigation in the Raya Valley and Kobo Valley, north-eastern Ethiopia, where the hydrogeological potential is large but not fully developed. A cost-benefit analysis shows that investment in deep groundwater irrigation development is viable at a 9.5% discount rate in 75% of the wells. Assuming full cost recovery of capital investment, the annual payment rates (annuity) that irrigation users should pay over the wells’ service life (25 years) were estimated. It is recommended that future investment be based on cost sharing rather than full cost recovery to facilitate uptake and address financial realities.

This paper explores gender aspects of smallholders’ private technology adoption for groundwater irrigation in Ghana and Zambia. It focuses on two variables of quantitative farm-household surveys: household headship and gendered plot management. The paper compares adoption rates and types of technologies for female- and male-headed households; examines adoption rates when women have their own plots; and compares women’s decision making on irrigated plots and rainfed plots. The findings suggest that there are largely untapped synergies between gender-equality and irrigation-policy goals. Systematic gender differentiation in surveys is recommended.

During the past decade, smallholder groundwater irrigation with motor pumps has increased considerably in Zambia. This study analyzes an important but hitherto ignored factor for adoption: the supply chain of imported motor pumps. The main obstacles for farmers are identified as: the highly centralized supply chain and financing facilities in urban hubs; lack of information about prices, which vary significantly for the same make and model of pump; lack of information and training on proper use and maintenance; and lack of financing facilities. The Zambia National Farmers Union seems best placed to remove these obstacles.

The expansion of irrigation in Sub-Saharan Africa has been slow. In Asia, the rapid expansion of smallholder irrigation systems was attributed in part to the availability and affordability of motorized pumps. This paper appraises the current extent of pump-based irrigation in Sub-Saharan Africa; profiles the socio-economic and demographic attributes of current pump adopters; and assesses the poverty outreach of small-pump technology. It shows that private smallholder irrigation is practised mainly by the wealthier farmers. The development of groundwater irrigation requires targeted and deliberate public-policy interventions and institutional support focusing on the more marginal farmers.

Smallholder irrigation is emerging as a development priority in Sub-Saharan Africa. Based on a survey of 1554 smallholders from nine countries, this paper compares rainfed farming with gravity-flow, manual-lift and motor-pump irrigation. Motor-pump-irrigation farmers reported the highest net value added per acre and per family worker, with gravity-flow and manual-irrigation farmers earning marginally more than rainfed-only farmers. In addition to making affordable pumps more readily available, improving the availability of working capital, enhancing security of tenure and ensuring the availability of affordable fuel are all likely to accelerate smallholder irrigation development in Sub-Saharan Africa.

The abundance of groundwater resources of Sub-Saharan Africa is generally well recognized, but quantitative estimates of their potential for irrigation development are lacking. This study derives estimates using a simple and generic water balance approach and data from secondary sources for 13 countries. Even with conservative assumptions and accounting for water demands from other sectors, including the environment, a 120-fold increase (by 13.5 million hectares) in the area under groundwater irrigation is possible for the countries considered. This expansion could improve the livelihoods of approximately 40% of the present-day rural population.

Groundwater irrigation for smallholder farmers in Sub-Saharan Africa is growing in extent and importance. This growth is primarily driven spontaneously by the farmers themselves, spurred by improved access to low-cost technologies for pumps and drilling services as well as market opportunities for produce. This paper presents a review of the current status and knowledge of the prospects and constraints for sustainable and pro-poor groundwater irrigation in Sub-Saharan Africa. Further unlocking the potential of groundwater irrigation for smallholders will require better integrated approaches, simultaneously addressing groundwater-access constraints as well as enabling factors.

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.

Climate variability and insufficient irrigation are primary constraints to stable and higher agricultural productivity and food security in Nepal. Agriculture is the largest global freshwater user, and integration of surface- and ground-water use is frequently presented as an strategy for increasing efficiency as well as climate change adaptation. However, conjunctive management (CM) planning often ignores demand-side requirements and a broader set of sustainable development considerations, including ecosystem health and economics of different development strategies. While there is generic understanding of conjunctive use, detailed technical knowhow to realize the CM is lacking in Nepal. This article presents a holistic framework through literature reviews, stakeholders consultations and expert interviews for assessing CM and implementation prospects from a systems-level perspective. We demonstrate the framework through a case study in Western Nepal, where climatic variability and a lack of irrigation are key impediments to increased agricultural productivity and sustainable development. Results show that knowledge of water resources availability is good and that of water demand low in the Western Terai. Additional and coordinated investments are required to improve knowledge gaps as well as access to irrigation. There is therefore a need to assess water resources availability, water access, use and productivity, to fill the knowledge gaps in order to pave pathways for CM. This paper also discusses some strategies to translate prospects of conjunctive management into implementation.

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.

This study developed the SEWAGE-TRACK model for disaggregating lumped national wastewater generation estimates using population datasets and quantifying rural and urban wastewater generation and fate. The model allocates wastewater into riparian, coastal, and inland components and summarizes the fate of wastewater into productive (direct and indirect reuse) and unproductive components for 19 countries in the Middle East and North Africa (MENA) region. As per the national estimates, 18.4 km3 of municipal wastewater generated in 2015, was disaggregated over the MENA region. Results from this study revealed urban and rural areas to contribute to 79 % and 21 % of municipal wastewater generation respectively. Within the rural context, inland areas generated 61 % of the total wastewater. The riparian and coastal regions produced 27 % and 12 %, respectively. Within the urban settings, riparian areas produced 48 %, while inland and coastal regions generated 34 % and 18 % of the total wastewater, respectively. Results indicate that 46 % of the wastewater is productively used (direct reuse and indirect use), while 54 % is lost unproductively. Of the total wastewater generated, the most direct use was observed in the coastal areas (7 %), the most indirect reuse in the riparian regions (31 %), and the most unproductive losses in inland areas (27 %). The potential of unproductive wastewater as a non-conventional freshwater source was also analyzed. Our results indicate that wastewater is an excellent alternative water source and has high potential to reduce pressure on non-renewable sources for some countries in the MENA region. The motivation of this study is to disaggregate wastewater generation and track wastewater fate using a simple but robust approach that is portable, scalable and repeatable. Similar analysis can be done for other regions to produce information on disaggregated wastewater and its fate. Such information is highly critical for efficient wastewater resource management.

Introduction: In rainfed agricultural systems, sustainable and efficient water management practices are key to improved agricultural productivity and natural resource management. The agricultural system in sub-Saharan Africa (SSA) relies heavily on the availability of rainfall. With the erratic and unreliable rainfall pattern associated with poor and fragile soils, agricultural productivity has remained very low over the years. Much of the SSA agricultural land has been degraded with low fertility as a result of ongoing cultivation and wind and water erosion. This has resulted in an increased food shortage due to the ever-increasing population and land degradation. Better agricultural and nutritional security are further hampered by the lack of reliable access to the available water resources in the subsurface hydrological system. Methods: This study used socio-economic data from 112 farm households and Boolean and Fuzzy methods to understand farmersapos; perceptions and identify suitable areas to implement Solar Based Irrigation Systems (SBISs) in the agro-ecologies of Bougouni and Koutiala districts of southern Mali. Results and discussion: Results revealed that the usage of SBISs has been recent (4.5 years), majorly (77%) constructed by donor-funded projects mainly for domestic water use and livestock (88%). With regards to irrigation, vegetable production was the dominant water use (60%) enabling rural farm households to gain over 40% of extra household income during the dry season. Results further showed that 4,274 km2 (22%) of the total land area for the Bougouni district, and 1,722 km2 (18%) of the Koutiala district are suitable for solar-based irrigation. The affordability of solar panels in many places makes SBISs to be an emerging climate-smart technology for most rural Malian populations.

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.

Small-scale irrigation has gained momentum in recent years as one of the development priorities in Sub-Saharan Africa. However, farmer-led irrigation is often informal with little support from extension services and a paucity of data on land suitability for irrigation. To map the spatial explicit suitability for dry season small-scale irrigation, we developed a method using an ensemble of boosted regression trees, random forest, and maximum entropy machine learning models for the Upper East Region of Ghana. Both biophysical predictors including surface and groundwater availability, climate, topography and soil properties, and socio-economic predictors which represent demography and infrastructure development such as accessibility to cities and proximity to roads were considered. We assessed that 179,584 49,853 ha is suitable for dry-season small-scale irrigation development when only biophysical variables are considered, and 158,470 27,222 ha when socio-economic variables are included alongside the biophysical predictors, representing 77-89% of the current rainfed-croplands. Travel time to cities, accessibility to small reservoirs, exchangeable sodium percentage, surface runoff that can be potentially stored in reservoirs, population density, proximity to roads, and elevation percentile were the top predictors of small-scale irrigation suitability. These results suggested that the availability of water alone is not a sufficient indicator for area suitability for small-scale irrigation. This calls for strategic road infrastructure development and an improvement in the support to farmers for market accessibility. The suitability for small-scale irrigation should be put in the local context of market availability, demographic indicators, and infrastructure development.

In recent years, farmer-led irrigation development has gained the interest of development partners and governments in the Global South following its success in enhancing agricultural production and livelihoods in South Asia. However, little is known about the socio-economic situation of farmers who receive public support for its expansion. Considering its rapid expansion in sub-Saharan Africa, we take the case of Ethiopia and explore the relationship between irrigation suitability and farmers’ socio-economic status. We find that high-value crop producers and wealthier farmers are most likely to make private investments and also benefit from public support in farmer-led irrigation expansion if investments are directed to land areas highly suitable for irrigation. Cultivation of high-value crops (fruit, vegetables) was common in areas more suitable for irrigation but staple crop cultivation (cereals, legumes) was negatively associated with irrigation suitability. Wealth status (consumption expenditure, asset index, and land size) was also positively correlated with irrigation suitability. A 10 per cent increase in groundwater irrigation suitability score was associated with a 2 per cent increase in per-capita consumption expenditure. Results imply that policies aiming to facilitate farmer-led irrigation development should combine biophysical information on land and water suitability for irrigation with household socio-economic characteristics and existing agricultural systems.

Groundwater depletion in India is a result of water, energy, and food policies that have given rise to a nexus where growth in agriculture has been supported by unsustainable trends in water and energy use. This nexus emanates from India’s policy of providing affordable calories to its large population. This requires that input prices are kept low, leading to perverse incentives that encourage groundwater overexploitation. The paper argues that solutions to India’s groundwater problems need to be embedded within the current context of its water-energy-food nexus. Examples are provided of changes underway in some water-energy-food policies that may halt further groundwater depletion.

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.

The Meki catchment in the Central Rift Valley basin of Ethiopia is currently experiencing irrigation expansion and water scarcity challenges. The objective of this study is to understand the basin’s current and future water availability for agricultural intensification. This was done by simulating scenarios through an integrated SWAT-MODFLOW model to assess the water balance. The scenarios were co-developed with communities who expressed their aspirations for agricultural intensification in conjunction with projected climate change. The results show that with the present land use and climate, the catchment is already water stressed and communities cannot meet their irrigation water demand, particularly in the first irrigation season (October–January). However, in the second irrigation season (February–May) water resource availability is better and increasing irrigated area by 50% from the present extent is possible. With a climate change scenario that favours more rainfall and shallow groundwater use, agricultural intensification is feasible to some extent.

Indus and Ganga Basins (IGB), which spread over 220 million ha and with over one billion population, grapples with multiple risks. Climate change will exacerbate the water-related recurrent disasters of floods and droughts. Variability and extreme events of rainfall and temperature are increasing. Monsoon rains in four months from June to September bring 80% of the total rainfall. Irrigation is critical, especially for dry-season agriculture and for livelihoods and food security. Groundwater depletion, water quality, and environmental issues reached critical points threatening sustainable agriculture in many locations. This paper focuses on innovative water-related adaptation strategies being pilot tested and implemented to reduce the risks and enhance productivity and resilience in the agriculture sector in the Basins.

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.

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.

The use of improved technologies has been encouraged to improve irrigation on farms, especially in drought-prone areas. However, farmersapos; irrigation decisions may be rather motivated by a desire to reduce risk of crop loss than to reduce water use. Using the case of Jordan, we contribute to the water-saving debate by examining whether current irrigation frequency is influenced by past experiences of losses due to water shortage and whether preferences for technologies and irrigation advisory services are mediated by water shortage experiences. Our data are based on a survey of 304 fruit farms in the highlands that were all using drip irrigation, a popular way to “save” water globally. We find that farms that faced losses due to water shortages in the past are more likely to irrigate more frequently. More frequent irrigators who have such shortages are more likely to prefer receiving irrigation advisory information rather than upgrading technologies, while more frequent irrigators who have not faced such shortages are more likely to prefer upgrading irrigation technologies. Results suggest that irrigation management is motivated by risk reduction, not just by water conservation. Irrigation advisory services, hitherto neglected, may be an important component of agricultural water management in Jordan.

Increased variability of the water cycle manifested by climate change is a growing global threat to agriculture with strong implications for food and livelihood security. Thus, there is an urgent need for adaptation in agriculture. Agricultural water management (AWM) interventions, interventions for managing water supply and demand, are extensively promoted and implemented as adaptation measures in multiple development programs globally. Studies assessing these adaptation measures overwhelmingly focus on positive impacts, however, there is a concern that these studies may be biased towards well-managed and successful projects and often miss out on reporting negative externalities. These externalities result from coevolutionary dynamics of human-water systems as AWM interventions impact hydrological flows and their use and adoption is shaped by the societal response. We review the documented externalities of AWM interventions and present a conceptual framework classifying negative externalities linked to water and human systems into negative hydrological externalities and unexpected societal feedbacks. We show that these externalities can lead to long term unsustainable and inequitable outcomes. Understanding how the externalities lead to undesirable outcomes demands rigorous modeling of the feedbacks between human and water systems, for which we discuss the key criteria that such models should meet. Based on these criteria, we showcase that differentiated and limited inclusion of key feedbacks in current water modeling approaches (e.g., hydrological models, hydro-economic, and water resource models) is a critical limitation and bottleneck to understanding and predicting negative externalities of AWM interventions. To account for the key feedback, we find Agent Based Modeling (ABM) as the method that has the potential to meet the key criteria. Yet there are gaps that need to be addressed in the context of ABM as a tool to unravel the negative externalities of AWM interventions. We carry out a systemic review of ABM application to agricultural systems, capturing how it is currently being applied and identifying the knowledge gaps that need to be bridged to unravel the negative externalities of AWM interventions. We find that ABM has been extensively used to model agricultural systems and, in many cases, the resulting externalities with unsustainable and inequitable outcomes. However, gaps remain in terms of limited use of integrated surface-groundwater hydrological models, inadequate representation of farmersapos; behavior with heavy reliance on rational choice or simple heuristics and ignoring heterogeneity of farmersapos; characteristics within a population.

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).

Water scarcity and pollution are major threats for human development in the Middle East and North Africa (MENA) region, and Lebanon is no exception. Wastewater treatment and reuse in agriculture can contribute to addressing the increasing water crisis in the MENA region. However, what is the actual potential of water reuse as a solution for agriculture in Lebanon? This report addresses this question and provides the most comprehensive assessment of water reuse potential up to now. Using geographic information system (GIS) modelling and the best and most recent data available in the country, the report develops a detailed technical assessment of the quantities of treated water available for safe reuse in irrigation, and identifies the wastewater treatment plants that have the highest potential for that purpose. The report also examines the governance barriers that need to be overcome for the water reuse potential to materialize in practice. These barriers include structural shortcomings in the wastewater sector combined with challenges of governance and the lack of a regulatory framework for reuse management. Once the current economic, financial and political crisis in Lebanon eases, addressing these barriers will be key to achieving more and safer water reuse in the country.

The livelihoods of poor people living in rural areas of Indus Basin Irrigation System (IBIS) of Pakistan depend largely on irrigated agriculture. Water duties in IBIS are mainly calculated based on crop-specific evapotranspiration. Recent studies show that ignoring the spatial variability of factors affecting the crop water requirements can affect the crop production. The objective of the current study is thus to identify the factors which can affect the water duties in IBIS, map these factors by GIS, and then develop the irrigation response units (IRUs), an area representing the unique combinations of factors affecting the gross irrigation requirements (GIR). The Lower Chenab Canal (LCC) irrigation scheme, the largest irrigation scheme of the IBIS, is selected as a case. Groundwater quality, groundwater levels, soil salinity, soil texture, and crop types are identified as the main factors for IRUs. GIS along with gamma design software GS + was used to delineate the IRUs in the large irrigation scheme. This resulted in a total of 84 IRUs in the large irrigation scheme based on similar biophysical factors. This study provided the empathy of suitable tactics to increase water management and productivity in LCC. It will be conceivable to investigate a whole irrigation canal command in parts (considering the field-level variations) and to give definite tactics for management.

An understanding of water sufficiency provides a basis for informed-planning, development and management of water resources. This study assessed spatio-temporal distribution in water sufficiency in the Extended East Rapti watershed in Nepal. The “Palika” (local government unit) is considered as a spatial-scale and seasons and future periods as temporal-scale. The water sufficiency was evaluated based on water sufficiency ratio (WSR) and water stress index (WSI). A hydrological model was developed to simulate water availability. An ensemble of multiple Regional Climate Models was used for assessing climate change impacts. Results showed water sufficiency by mid-century is projected to decrease; WSR by 40% and WSI by 61%. Despite projected decrease in water sufficiency, annually available water resources are projected as sufficient for the demands until the mid-century, however, seasonal variability and scarcity in future is projected in most Palikas. Such results are useful for water security planning in the Palikas.

This study characterizes the hydrological regime of the Upper Ayeyarwaddy River Basin (UARB) of Myanmar under current and future climate change scenarios by using the Soil and Water Assessment Tool (SWAT). The model simulation results show that the annual precipitation, actual evapotranspiration and water yields are 1,578, 524 and 1,010 mm, respectively. These will increase by 13–28%, 11–24% and 42–198% under two representative concentration pathways (RCPs), RCP 4.5 and RCP 8.5, for the future. There is seasonal variability across the cool, hot and rainy seasons in the agro-ecological regions – mountains, hills and inland plains. As in other Asian regions, the model shows that the wet (rainy) season is becoming wetter and the dry (cool) season is becoming drier in the UARB too.

Agricultural production in arid and semi-arid regions is particularly vulnerable to climate change, which, combined with projected food requirements, makes the sustainable management of water resources critical to ensure national and global food security. Using South Africa as an example, we map the spatial distribution of water use by seventeen major crops under current and future climate scenarios, and assess their sustainability in terms of water resources, using the water debt repayment time indicator. We find high water debts, indicating unsustainable production, for potatoes, pulses, grapes, cotton, rice, and wheat due to irrigation in arid areas. Climate change scenarios suggest an intensification of such pressure on water resources, especially in regions already vulnerable, with a country-scale increase in irrigation demand of between 6.5% and 32% by 2090. Future land use planning and management should carefully consider the spatial distribution and local sustainability of crop water requirements to reduce water consumption in water risk hotspots and guarantee long-term food security.

Irrigated agriculture in South Asia depends on meltwater, monsoon rains and groundwater. Climate change alters the hydrology and causes shifts in the timing, composition and magnitude of these sources of water supply. Simultaneously, socio-economic growth increases water demand. Here we use a high-resolution cryosphere–hydrology–crop model forced with an ensemble of climate and socio-economic projections to assess how the sources of irrigation water supply may shift during the twenty-first century. We find increases in the importance of meltwater and groundwater for irrigated agriculture. An earlier melt peak increases meltwater withdrawal at the onset of the cropping season in May and June in the Indus, whereas increasing peak irrigation water demand during July and August aggravates non-renewable groundwater pumping in the Indus and Ganges despite runoff increases. Increasing inter-annual variability in rainfall runoff increases the need for meltwater and groundwater to complement rainfall runoff during future dry years.

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.

Study region: White Volta River Basin, Ghana. Study focus: Groundwater sustainability is becoming a major concern in the face of population growth, land use land cover (LULC), and climate changes. The Water Evaluation and Planning (WEAP) model is used in this study to analyse the current and future groundwater demands for the period of 2015–2070. Two Representative Concentration Pathways (RCP4.5 and RCP 8.5) scenarios from statistically downscaled fifteen CMIP5 models were combined three Shared Socioeconomic Pathways (SSPs 2,3 and 5) scenarios in the nine sub-catchments of the White Volta River Basin. New hydrological insights for the study region: The WEAP model was calibrated (2006–2012) and validated (2013–2020) using streamflow data from six gauges in five sub-catchments. The findings show that climatic change and socio-economic development will result in a disparity between groundwater supply and demand in sub-catchments with greater socioeconomic growth, especially those with higher population density and arable agricultural land. Among the basin’s nine sub-catchments, four will experience water scarcity under all future scenarios. While the groundwater flow and recharge data may be evaluated using several physical hydrological models, the calibration and validation results suggest that the current modeling approach is capable of reliably predicting future groundwater demand with associated uncertainties. The study establishes a link between climate change, socio-economic growth, and groundwater availability in the White Volta River Basin.

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 offers smallholder farmers in the lowlands of Lao PDR opportunities to diversify cropping beyond wet season paddy and thus enhance their livelihoods while reducing climate risks. This chapter focuses on evaluating existing and specifically developed groundwater irrigation options on the Vientiane Plain, and framing the findings around the livelihood priorities of different farming groups against a backdrop of agrarian change. Results show that cultivating a range of cash crops using shallow dugwells managed by individual farmers and deeper boreholes managed by the community can be profitable for farmers, while helping to increase the resilience of farming households’ livelihoods. Both options may also represent a viable investment option for farming households lacking access to surface water irrigation, and thus contribute to more equitable growth. The results identify drivers and conditions that incentivize and enable groundwater irrigation to generate positive development outcomes. It also highlights that farmers will not intrinsically engage in groundwater irrigation simply because a good resource is available, but instead, weighs up the pros and cons of a mix of biophysical, socioeconomic, technical, and institutional factors. Agricultural policies aiming to intensify small-scale groundwater irrigation should be cognizant of these nuances as they are critical to successful implementation and management.

West Bengal, India’s largest rice-producing state, has over seven million small and marginal farmers. The rice economy of the region especially that of summer (Boro) paddy is backed by groundwater – an abundant resource in most parts of this State. Despite the rich and shallow aquifers, most of the farmers do not have access to a private source of irrigation and there is a huge dependence on informal irrigation services market where owners of electric tubewells sell irrigation to neighboring farms. Unlike other states of India, West Bengal charges farmers near-commercial metered tariff for the power used to run electric submersible pumps, creating oligopolistic irrigation markets and subsequently leading to exorbitant irrigation costs for small and marginal farmers. This is making paddy farming unviable for many irrigation buyers who are quitting paddy farming altogether. In this chapter, we explore an alternate energy pricing regime with flat-cum-metered electricity tariff structure, which was piloted in Manoharpur village of West Bengal. The pilot throws light into the dynamics of the market players, price setting mechanisms, motivations of pump owners, and provides evidence in support of a flat-cum-seasonally metered tariff structure that has the potential to uplift gains from paddy farming in the State. Without a change in the energy policy of the State, the trend of small farmers leaving agriculture is likely to continue and their livelihoods and food security will continue to be at risk.

Kachchh, the westernmost district of India is historically known for its unique landscape, distinct traditions and arid climate. For a long time, the arid region of Kachchh had limited economic growth and limited habitation due to water scarcity caused by erratic rainfall. In 2001, the seismically active region of Kachchh experienced a large earthquake measuring 7.7 Mw but, the region has shown considerable development post-disaster. Growth strategies for agriculture, manufacturing and tourism implemented by the government and supported by industries and other agencies have not only made the region a dynamic economic hub in the state of Gujarat, but also has highlighted the long-neglected region on the world map. Due to the lack of perennial surface water availability and limited rainfall, the development has been fuelled by exploiting the groundwater resources to a great extent. The objective of this chapter is to highlight groundwater use in Kachchh, known as one of the most arid regions of India with low rainfall and high variability. Groundwater is playing a vital role in meeting the demand for all societal usage, irrigation, domestic requirements and industries. The authors highlight how the region is blessed with a suitable geological formation, forming a potential freshwater aquifer system which has served society for centuries even with a grossly adequate recharge. They highlight the importance of looking into the sustainable use of groundwater, a priceless natural resource of the region.

In many areas of the world, groundwater represents the primary source of water for domestic supply and agriculture, supporting livelihoods and lifting many out of poverty. However, the hidden nature of groundwater often means that its important role both historically and in the present is overlooked, hampering its effective management and putting future supplies at risk. For the benefits of groundwater abstraction to continue to be realized and sustained, the links between groundwater availability and quality, climate change, and groundwater-dependent livelihoods need to be explored and articulated. This becomes even more important with growing climate uncertainty and decreasing water security in some marginal and vulnerable areas, with an increasing threat to livelihoods. This introductory chapter presents the main concepts of this book, introduces the different chapters, and discusses emerging themes. There is compelling evidence that the development of groundwater has profoundly improved many people’s lives and continues to lift people out of poverty today. The examples in this book provide a wide variety of case studies from Asia, Africa, and South America that show how groundwater, often invisibly, improves people’s lives and livelihoods and promotes equitable growth. However, the studies also demonstrate how vulnerable groundwater can be over-used and contaminated, and how ignorance of the nature of groundwater is one of the greatest threats to its sustainable use. It is, therefore, of critical importance to increase investment in characterizing, monitoring, and governing groundwater, to explore links between science, policy, and practice, and to effectively communicate existing knowledge so that groundwater will continue to improve people’s lives for centuries to come.

The use of polluted water to irrigate is an increasing problem in the developing world. Lebanon is a case in point, with heavily polluted irrigation waters, particularly in the Litani River Basin. This study evaluated the potential health risks of irrigating vegetables (radishes, parsley, onions, and lettuce) using three water sources (groundwater, river water, and treated wastewater) and three irrigation methods (drip, sprinkler, and surface) over two growing seasons in 2019 and 2020. Water, crop, and soil samples were analyzed for physicochemical parameters, pathogens, and metals (Cu, Cd, Ni, Cr, and Zn). In addition, the bioaccumulation factor, estimated dietary intakes, health risk index, and target hazard quotients were calculated to assess the health risk associated with metal contamination. The study showed that, for water with less than 2 log E. coli CFU/100 mL, no pathogens (Escherichia coli, salmonella, parasite eggs) were detected in irrigated vegetables, irrespective of the irrigation method. With over 2 log E. coli CFU/100 mL in the water, 8.33% of the sprinkler-and surface-irrigated vegetables, and 2.78% of the drip-irrigated root crops (radishes and onions), showed some degree of parasitic contamination. E. coli appeared only on root crops when irrigated with water having over 3 log CFU/100 mL. The concentrations of most metals were significantly lower than the safe limits of the FAO/WHO of the Food Standards Programme Codex, except for zinc and chromium. The trends in the bioaccumulation factor and the estimated dietary intakes of metals were in the order of Cu lt; Cd lt; Ni lt; Cr lt; Zn. The target hazard quotient values for all metals were lower than 1.0. Under trial conditions, the adoption of drip irrigation with water with less than 3 log E. coli CFU/100 mL proved to be safe, even for vegetables consumed raw, except for root crops such as onions and radishes that should not be irrigated with water having over 2 log E. coli CFU/100 mL. Treated wastewater had no adverse effect on vegetable quality compared to vegetables irrigated with other water sources. These results support efforts to update the Lebanese standards for water reuse in agriculture; standards proposed in 2011 by the FAO, and currently being reviewed by the Lebanese Institution of Standards. This research will inform a sustainable water management policy aimed at protecting the Litani River watershed by monitoring water quality.

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

Groundwater is the main available freshwater resource and therefore its use, management and sustainability are closely related to the Sustainable Development Goals (SDGs). However, Land Use Land Cover (LULC) and climate change are among the factors impacting groundwater recharge. The use of land-use and climate data in conjunction with hydrological models are valuable tools for assessing these impacts on river basins. This systematic review aimed at assessing the integrated modeling approach for evaluating hydrological processes and groundwater recharge based on LULC and climate change. The analysis is based on 200 peer-reviewed articles indexed in Scopus, and the Web of Science. Continuous research and the development of context-specific groundwater recharge models are essential to increase the long-term viability of water resources in any basin. The long-term impacts of natural and anthropogenic drivers on river basin interactions require integrating knowledge and modeling capabilities across biophysical responses, environmental problems, policies, economics, social, and data.

While extreme rainfall events may provide rare opportunities for replenishment of surface water and groundwater resources in vulnerable (semi)arid areas, they are typically also associated with widespread flooding. The impacts on contaminant movement associated with spatio-temporally complex relationships between surface water and groundwater during such events in these regions are largely unknown. The catchment area (~4350 km2) upstream of Gaborone Dam on the Notwane River in south-east Botswana and northern South Africa experienced extreme rainfall and major flooding in 2016/17, following a severe 5-year drought. In this generally data-sparce area, we collected a unique data set that combined traditional water quantity observations with stable water isotope, major ion, trace metal and geophysical data. These were analysed to gain insights into water quantity and quality dynamics following flooding, including contaminant movement using trace metals as pollution indicators. Results revealed that the extreme rainfall and flooding was responsible for replenishment of surface water and groundwater resources, but also contaminant mobilisation from the surface. This subsequently resulted in increased concentrations of contaminants during the recession. Overall, hydrogeological heterogeneity dictated spatially variable surface water - groundwater interactions, characterised by poor connectivity in low productivity aquifer areas as opposed to good connectivity in moderate to high productivity aquifers. This in turn affected water quality dynamics and contamination, locally superimposed by land use impacts, primarily from urban landfill and local agricultural practices. Groundwater-connected streams had consistently lower (responses in) contaminants. We also found that Gaborone Reservoir facilitated prolonged conditions for recharge but likely also enhanced contamination of groundwater through maintaining a high water table in urban areas located immediately downstream. Management implications of our findings include a requirement for careful consideration of land use and landfill planning in relation to bedrock geology and presence of surface water reservoirs, conjunctive surface water and groundwater management, but also the need for even higher (space-time) resolution of monitoring in these data sparce environments. This could contribute to enhancing the benefits that extreme rainfall events provide in terms of surface water and groundwater resources replenishment for future dry seasons and periods of drought.

Climate change and rapid population growth are already putting increasing demand and pressure on the worldapos;s freshwater resources. Irrigated agriculture is responsible for about 70% of global freshwater withdrawals, consuming the most amount of water. However, the diverted water in irrigation systems is often not utilized efficiently because of poor water management at different spatial scales, resulting in a system efficiency of only 30–50% in most Asian countries. Typically, improving water management in irrigated areas requires accurate information on various water balance parameters while also considering a changing climate across different spatial scales. There have been technical limitations in getting accurate and reliable information on various key water balance parameters with the conventional approaches used in the recent past. In the twenty-first century, considerable advances have been made in using satellite imagery, including processing and geospatial algorithms, to estimate hydro-meteorological fluxes and relevant components at different spatial scales. This paper provides a perspective on the application of innovative and non-conventional approaches to water resources management in the Murray Darling basin, Australia, the Indus basin, Pakistan and the Amu Darya basin, Uzbekistan. Examples of the state-of-the-art tools described in this paper include: (i) using geoinformatics to monitor the diagnostic and operational performance of large irrigation schemes; (ii) quantifying groundwater and surface water to better manage these two resources using geoinformatics; (iii) forecasting irrigation supply and demand at high spatial and temporal scales using hydrological modelling based on the nodal network; (iv) forecasting crop yield production by satellite remote sensing. The approaches in this study clearly demonstrate that new monitoring and planning tools and methods are highly effective in improving irrigation water management in the ‘space age’ (for the purposes of this paper, space age refers to a period in which earth observation satellites are available to accurately monitor agricultural practices and water balance parameters such as soil moisture and evapotranspiration). The application of these innovative tools can assist in strategizing, diagnosing, monitoring and improving the performance of irrigation systems to grow more crop per drop of water while minimizing environmental impacts and dealing with climate change impacts.

The projected implications of climate change for water and agriculture to meet diverse and competitive water demands requires smart water management solutions. Science- and evidence-based, agricultural water management (AWM) can significantly contribute to reduce unsustainable water use and help enhance water resilience and adaptation to climate change. This paper presents a brief overview of potential AWM practices focusing on enhancing water resilience, increasing yields, and wherever possible, reducing emissions. This is achieved via increased land and water use efficiency, water and energy savings, and improved water productivity with considerable scope to improve agricultural resilience. In this context, the prioritization of a location-specific portfolio of smart AWM practices to make the right investment decisions is very important. We present two distinct and complementary approaches to prioritize AWM practices in this paper: one follows stakeholder analysis to build a prioritized portfolio of climate-smart AWM practices and the other employs a simple water balance-based approach to prioritize interventions. The way forward in mainstreaming and scaling out context-specific climate-smart AWM interventions is also discussed with a focus on capacity building, water management extension services, and the mobilization of resources through the convergence of institutions and co-financing from relevant development schemes.

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.

The irrigation suitability classification was achieved by using physical factors that include slope, rainfall, landuse, closeness to waterbodies (surface and groundwater) and soil characteristics for selected districts in Zimbabwe, Zambia, Malawi, and Kenya, some of the UU target countries. As cereals form the main food basket of the selected countries, and cereals are not tolerant to saline conditions, the report also provides maps showing high soil salinity areas of Makueni and Nakuru of Kenya, where soils are highly saline. However, soil salinity is insignificant in the other study districts and therefore not mapped. This report provides (a) a conceptual framework and detailed methodology for irrigation suitability mapping, including details of identified boundary maps and geospatial data, and (b) a synthesis model and maps on irrigation suitability mapping for the selected districts in the four target countries.

International Water Management Institute (IWMI) brought together in collaboration the CGIAR initiative “Transforming Agrifood Systems in South Asia” (TAFSSA), the “Solar Irrigation for Agricultural Resilience” (SoLAR) project, funded by the Swiss Agency for Development and Cooperation (SDC) and CGIAR initiative MITIGATE+ for organizing a national stakeholder workshop in Bangladesh in partnership with the Infrastructure Development Company Limited (IDCOL) and NGO Forum. The aim was to facilitate deliberations and develop a better understanding of challenges such as replacing diesel with solar irrigation pumps, the consequences of rapid electrification on the groundwater market, and the threat to groundwater sustainability posed by cheaper irrigation. Based on this the workshop envisages strengthening the policy research on the challenges and opportunities of Bangladeshapos;s evolving groundwater irrigation sector.

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 mitigation benefits of solar irrigation pumps (SIPs), when those SIPs replace diesel pumps, are well understood. What is not equally known are the adaptation co-benefits of SIPs. This brief evaluates the co-benefits of using SIPs instead of widely used diesel pumps for farmers in Bangladesh. It estimates the impact of access to SIP on household and crop levels outcomes for improving farmer livelihoods and food security. In doing so, it explores the potential pathways of these impacts.

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.

Sustainable and resilient food systems depend on sustainable and resilient water management. Resilience is characterised by overlapping decision spaces and scales and interdependencies among water users and competing sectors. Increasing water scarcity, due to climate change and other environmental and societal changes, makes putting caps on the consumption of water resources indispensable. Implementation requires an understanding of different domains, actors, and their objectives, and drivers and barriers to transformational change. We suggest a scale-specific approach, in which agricultural water use is embedded in a larger systems approach (including natural and human systems). This approach is the basis for policy coherence and the design of effective incentive schemes to change agricultural water use behaviour and, therefore, optimise the water we eat.

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 examines the effects of such power sector reforms on the functioning of groundwater markets at the local level by comparing the cases of Gujarat and West Bengal. In Gujarat, an innovative power sector reform program (called Jotigram Yojona) was launched. The West Bengal state government, on the contrary, introduced a metering system to agriculture in place of the flat tariff while abolishing the electric tube well permit system. Consequently, the groundwater markets shrunk and/or the water charges paid by less resourceful farmers to the well owners increased in both states. The results imply that the power sector reforms, although they contributed to the reduction of the nexus problem, produced severe ill effects upon the farmers placed in weaker market positions.

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.

Livestock is an integral part of the agricultural system in sub-Saharan Africa, serving as a food source, income, fertilizer, and power for farming and transportation. However, the productivity of the livestock system has been hampered due to a lack of sufficient quantity and quality feed. This study evaluates the gaps and constraints of fodder and nutritional potential for livestock feed using small-scale irrigation (SSI). The study comprised of 30 randomly selected farmers from two different ecological zones in Ethiopia. Half of the farmers cultivated Napier grass (Pennisetum purpureum) in the Robit watershed in northern Ethiopia, and the other half cultivated mixed vetch (Lathyrus cicera) and oats (Avena sativa) in Lemo watershed in southern Ethiopia. The Soil and Water Assessment Tool (SWAT) and Agricultural Policy Environmental eXtender (APEX) were applied in an integrated manner to assess the impacts of SSI at the watershed and field-scale levels, respectively. The watershed-scale analysis showed that there is a substantial amount of surface runoff and shallow groundwater recharge that could be used for dry season fodder production using irrigation. Field data calibrated APEX model indicated that Napier yield could be maximized with 550 mm of water in Robit watershed. While in the Lemo watershed, maximum vetch and oats yield may be achieved with 250 mm of water. The major constraints for Napier and oats production in the study sites were soil fertility, especially nitrogen and phosphorus, and vetch production was limited by high temperature. Fodder samples were collected at the time of harvest to evaluate feed quality. The nutritional analysis indicated that Napier grass has a higher dry matter and ash (mineral) content compared to oats and vetch. However, vetch has higher crude protein content (18%) compared to Napier (10%) and oats (6%). Overall the study indicated that cultivating vetch provided superior performance in terms of providing quality feed and environmental services.

With the impulse to control and order the disorderly, the threads or tributaries of affect and emotion, which mimic the meanderings of the aquifer itself, are often oversimplified or ignored. These are not anomalies of citizen science (CS) but ‘normal’ and expected ‘disconnects’ that surface when working within a multidisciplinary environment. The article adds value to current discourse on CS by reflecting on the confusing configurations and shifting allegiances that are part and parcel of CS experience. In presenting research from a current project in the Hout Catchment, Limpopo Province in South Africa, it suggests that CS is often oversimplified and does not capture the array of emotions that emerge at multiple scales around CS projects. The authors reflect on the field, which is fraught, fragile and fleeting—and on the intrusions into the field—similar itself to an aquifer with its dykes and flows. Considering CS within the frame of feminist philosophy, it is emancipatory and personally transformative with the element of ‘surprise’ that the end point is undetermined—and the process, however much ‘planned’ is unknown. CS in this instance is a powerful tool for creating virtuous cycles of inclusion and equality and promoting sustainable development through improved water literacy through a grassroot, out-of-the-classroom pedagogy.

Water management in the irrigation-dominated Indus Basin of Pakistan is under pressure to ensure equitable, long-term, stable and flexible water supplies for meeting crop water demands, growing non-agricultural water demands (domestic and industrial supplies), and minimising adverse environmental impacts of one of the largest irrigation systems in the world. In this chapter, we focus on the irrigation system in Punjab by carrying out a sustainability analysis of its current irrigation water application methods. Cai et al.’s (Sustainability analysis for irrigation water management: concepts, methodology, and application to the Aral Sea region. Environment and production technology division, discussion paper no. 86, International Food Policy Research Institute, Washington, DC, 2001) analytical framework is used, which comprises indicators of risk and vulnerability, environmental system integrity, and economic acceptability and equity. The analysis suggests that irrigation water management in Punjab is currently unsustainable due to declining surface water supplies and excessive pressure on groundwater to support intensive agriculture and increasing demand from non-agricultural uses. Furthermore, climate change projections suggest reduced overall water availability leading to reduced crop productivity. Groundwater exploitation, unsustainable irrigation and agricultural practices, and industrial effluents are affecting water quality and worsening the overall health of the Indus Basin and its ecosystem. The cost of irrigation water management is economically not viable due to the high level of subsidies for technological interventions at the farm level and minimal water charges. The gap between collected water charges and overall operation and maintenance costs has reached USD 76 million. Water productivity in the Punjab is one of the lowest in the South Asia region due to use of traditional irrigation practices with low irrigation and application efficiency. Equitable distribution of water in the province has become a big challenge for water managers given increasing water allocation conflicts, especially between upstream and downstream water users. We thus suggest adopting an approach that is more inclusive of all major stakeholder interests keeping in view the competing inter-sectoral water demands in future and the ongoing challenges of climate change, urbanisation and economic growth. Such efforts are required to improve water use efficiency as well as equity in the distribution of water among users.

Worldwide, off-grid solar photovoltaic irrigation is currently being developed with the expectation that it will help secure water access to increase food production, reduce fuel-based carbon emissions and energy costs, and increase human resilience to climate change. In developing countries across the Middle East and North Africa, South East Asia and Sub-Saharan Africa, the adoption of solar technology in agriculture to lift groundwater is rapidly expanding, following decreases in pump costs, economic incentives, and development partner initiatives. Solar irrigation potentially provides a cost-effective and sustainable energy source to secure food production and sustain livelihoods in line with multiple Sustainable Development Goals, but achieving such potential requires improved policies and institutions to coordinate across numerous stakeholders, objectives, and approaches. This paper uses cases and observations from across regions to propose a framework to support policy, regulation, and monitoring for environmentally sustainable and socio-economically inclusive solar irrigation investments. While not exhaustive, the components seek to address the intersection of energy, water and food security, as well as social equity. The paper emphasizes the need for an understanding of how solar irrigation can be scaled to be both accessible for smallholder farmers and environmentally sustainable.

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.

Irrigation with electric pumps is cheaper than with diesel pumps in West Bengal where electricity and diesel are unsubsidised, and where pump owners typically irrigate their winter rice crop and often sell water to farmers who do not own pumps. Using purposefully selected primary data, we examine whether electric-pump owners have greater water access and rice production during the monsoon and winter seasons compared to diesel-pump owners and water buyers. We also examine whether electric pump-owners provide greater access to irrigation services through water sales. We find that electric-pump ownership increased agricultural outputs both at the extensive and intensive margins in both seasons. The number of clients served by electric-pump owners was greater than those served by diesel-pump owners, but there was only a small difference in total irrigated areas, suggesting that electric-pump owners sell water to farmers with smaller land holdings. The evidence indicates that in an environment where inadequate irrigation has been one of the factors constraining agriculture, electric pumps have the potential to support agricultural growth and generate pro-poor side effects.

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 proposes scenarios to achieve more crop per drop and irrigation for all in water-scarce irrigation systems, with a particular reference to India. It uses economic water productivity (EWP) and water cost curve for EWP as tools to reallocate irrigation consumptive water use (CWU) and identify economically viable cropping patterns. Assessed in the water-scarce Sina irrigation system in Maharashtra, India, the method shows that drought-tolerant annual crops such as fruits and/or fodder should be the preferred option in irrigated cropping patterns. Cropping patterns with orchard or fodder as permanent fixtures will provide sustainable income in low rainfall years. Orchards in combination with other crops will increase EWP and value of output in moderate to good rainfall years. Governments should create an enabling environment for conjunctive water use and allocation of CWU to achieve a gradual shift to high-value annual/perennial crops as permanent fixtures in cropping patterns.

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.

Achieving rice self-sufficiency in West Africa will require an expansion of the irrigated rice area under water-scarce conditions. However, little is known about how much area can be irrigated and where and when water-saving practices could be used. The objective of this study was to assess potentially irrigable lands for irrigated rice cultivation under water-saving technology in Burkina Faso. A two-step, spatially explicit approach was developed and implemented. Firstly, machine learning models, namely Random Forest (RF) and Maximum Entropy (MaxEnt) were deployed in ecological niche modeling (ENM) approach to assess the land suitability for irrigated rice cultivation. Spatial datasets on topography, soil characteristics, climate parameters, land use, and water were used along with the current distribution of irrigated rice locations in Burkina Faso to drive ENMs. Secondly, the climatic suitability for alternate wetting and drying (AWD), an irrigation management method for saving water in rice cultivation in irrigated systems, was assessed by using a simple water balance model for the two main growing seasons (February to June and July to November) on a dekadal time scale. The evaluation metrics of the ENMs such as the area under the curve and percentage correctly classified showed values higher than 80% for both RF and MaxEnt. The top four predictors of land suitability for irrigated rice cultivation were exchangeable sodium percentage, exchangeable potassium, depth to the groundwater table, and distance to stream networks and rivers. Potentially suitable lands for rice cultivation in Burkina Faso were estimated at 21.1 × 105 ha. The whole dry season was found suitable for AWD implementation against 25–100% of the wet season. Soil percolation was the main driver of the variation in irrigated land suitability for AWD in the wet season. The integrated modeling and water balance assessment approach used in this study can be applied to other West African countries to guide investment in irrigated rice area expansion while adapting to climate change.

India’s agricultural economy has undergone profound transformation in the past 50 years with the rapid spread of groundwater irrigation. The tube well revolution has democratized irrigation, made famines history, helped alleviate agrarian poverty and made India food secure. However, the spread of private tube wells has cannibalized canals and tanks. The large-scale withdrawal of groundwater has caused acute groundwater stress in several parts of the country, leading to adverse environmental and sustainability challenges. Unlike the United States, Australia, and Spain, where tube wells are instruments of wealth creation in industrial agriculture, in India groundwater governance pits livelihoods of the poor against environmental protection. This study explores this unique challenge. It discusses several efforts undertaken to effectively manage groundwater such as direct regulation, indirect levers like energy pricing and rationing, and community-based groundwater governance. It emphasizes on the arrival of solar irrigation and its potential to reform the perverse energy-groundwater nexus. The paper stresses on the need to move away from resource development to resource management mode to solve the groundwater challenge.

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.

Groundwater, the largest available global freshwater resource, plays a crucial role in human sustenance and global food security through drinking water supplies and irrigated agriculture. In recent times, many parts of the world have been experiencing discernable, large-scale groundwater depletion, and pollution. A large groundwater-dependent population, uncertain climate-reliant recharge processes, transboundary water sources, major geogenic-sourced, nonpoint contaminants, inefficient irrigation methods and human practices, and indiscriminate land use change with rising urbanization underscore the urgent need to develop models of sustainability and security for global groundwater, in terms of both quantity and quality. Climate change is expected to exacerbate these issues. We need to understand the main factors that control groundwater availability (quantity and quality) in a changing world, where climate change and human factors (overexploitation, pollution, economics, agro-food aspects and their socioeconomic side, and governance intervention) deeply influence water availability. Because groundwater represents a critical source of water in many areas, especially in developing countries, there is a need to analyze physical (hydrological), chemical (hydrogeochemistry), and human (socioeconomic) aspects within a comprehensive framework to define sustainability. Groundwater, which forms a large component of attaining the sustainable development goals, is difficult to manage (mostly not visible, limited monitoring of groundwater levels, recharge, and abstraction, poorly defined flow boundaries; transboundary issues; poor management of abstraction; uncertainty in groundwater–surface water inter-connections) and hence requires comprehensive scale–dependent governance plans. From an economic and governance point of view, there has been insufficient attention given to groundwater as a resource, which is both hidden but widely considered ubiquitous. Solutions, incorporating emerging and innovative technologies, need to be integrated with traditional knowledge, to develop future groundwater security.

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.

Improving water security is critical to delivering the best outcomes for development. In Ethiopia, the upper Awash sub-basin supports expanding urban and industrial areas, with increasing water demands. Studies have preferentially focused either on surface water hydrology or on groundwater characterization. However, novel tools are required to support the conjunctive use of surface and groundwater for competing users under potential climate change impacts. In this paper, we present research based on a WEAPMODFLOW link configured for four catchments in the upper Awash sub-basin (Akaki, Melka Kunture, Mojo, and Koka). The Akaki catchment supplies water for Addis Ababa city. Unlike most surface water hydrological models, both supply (surface water and groundwater) and demand (domestic, industrial, and livestock) are modeled. The tool was used to evaluate the impacts of population growth, leakage, expansion of surface and groundwater supply schemes, and climate change scenarios up to the year 2030. Considering the high population growth rate scenario for Addis Ababa city, the unmet domestic water demand may increase to 760 MCM in 2030. Water leakage through poor water supply distribution networks contributed about 23% of the unmet water demand. Though not significant compared with population and water loss stresses, climate change also affect the supply demand condition in the basin. Planning for more groundwater abstraction without considering additional surface water reservoir schemes will noticeably impact the groundwater resource, with groundwater levels projected to decline by more than 20 m. Even more groundwater level decline is observed In the Akaki catchment, where Addis Ababa city is located. Conjunctive use of surface and groundwater not only boosts the supply demand situation in the basin but will lift off some of the stresses from the groundwater resources. Even under the likely increase in temperature and low precipitation climate scenarios, the conjunctive use resulted in a significant increase in domestic water demand coverage from 26% for the reference condition to 90% in 2030, with minimum effect on the groundwater resources. To improve water security conditions through sustainable utilization of both surface and groundwater resources, policy responses need to consider surface and groundwater conjunctive use. Minimizing water leakage should also be given the highest priority.

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.

Data exchange in transboundary waters is fundamental to advance cooperation in water management. Nonetheless, the degree to which data are actually shared is falling short of basin-level and international targets. A global assessment revealed that a reasonable proportion of river basins exchange some data, but the breadth of such exchange is often limited and not regular. More in-depth examination of African basins nonetheless suggests that a real need for, and use of, water data appears to motivate exchange. Indeed, evidence suggests that data exchange needs which are more directly felt enhance exchange, e.g., the direct need to minimize flood impacts or manage transboundary infrastructure. As such, data sharing is much more likely to be considered as being successful if it responds to a palpable need and serves practical uses. Also, in developing data exchange programs, it may be prudent to adopt a focused and sequential approach to data exchange that starts with a short-list of most needed parameters.

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.

Solar-powered irrigation has expanded in India at an unprecedented pace—the number of solar irrigation pumps—from less than 4,000 in 2012 to more than 2,50,000 by 2019. It has been argued that besides giving farmers an additional and reliable source of income, grid-connected SIPs also incentivise efficient energy and water use—critical for sustaining groundwater irrigation. The Surya Raitha scheme was the country’s first, state-driven initiative for solarisation of agriculture feeders by replacing subsidy-guzzling, inefficient electric pumps with energy-efficient, net-metered SIPs. An early appraisal of Surya Raitha lauded the scheme as a smart initiative and argued that it could set an example for promoting solar power as a remunerative crop. However, the scheme was eventually executed as a single feeder pilot with some design changes in Nalahalli panchayat from 2015–18. The authors visited the pilot in 2017–18 and 2018–19 to assess if it had delivered the promises of Surya Raitha scheme. The results are a mixed bag and offer important lessons for implementation and scaling out of component C of the Government of India’s Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan policy.

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.

Little is known about the occurrence of emerging pollutants (EPs) in waters in the Middle East and North Africa (MENA) region despite the extensive use of low-quality water there. Available data dealing with the sources, occurrence and removal of EPs within the MENA region in different categories of water is collected, presented and analyzed in this literature review. According to the collected database, the occurrence and removal efficiency of EPs in the water matrix in the MENA region is available, respectively, for 13 and six countries of the 18 in total; no available data is registered for the rest. Altogether, 290 EPs have been observed in different water matrices across the MENA countries, stemming mainly from industrial effluents, agricultural practices, and discharge or reuse of treated wastewater (TWW). Pharmaceutical compounds figure among the most frequently reported compounds in wastewater, TWW, surface water, and drinking water. Nevertheless, pesticides are the most frequently detected pollutants in groundwater. Worryingly, 57 cases of EPs have been reported in different fresh and drinking waters, exceeding World Health Organization (WHO) and European Commission (EC) thresholds. Overall, pharmaceuticals, organic compounds, and pesticides are the most concerning EP groups. The review revealed the ineffectiveness of treatment processes used in the region to remove EPs. Negative removals of some EPs such as carbamazepine, erythromycin, and sulfamethoxazole were recorded, suggesting their possible accumulation or release during treatment. This underlines the need to set in place and strengthen control measures, treatment procedures, standards, and policies for such pollutants in the region.

The Middle East and North Africa region experiences severe socioeconomic and political impacts during droughts and faces increasing drought risk in future climate projections. The UN Office for Disaster Risk Reduction’s Sendai Framework and the International Drought Management Programme provide a global standard (a norm) to manage droughts through natural hazard risk reduction approaches. We use participatory engagement to evaluate whether norm diffusion has taken place in four countries. Data were collected in interviews, focus groups, workshops, and policy documents. Analysis reveals incomplete norm diffusion; stakeholders subscribe to relevant values, but national policies and implementation do not fully reflect the norm. Process tracing reveals that the availability of drought early warning data is a key barrier to risk reduction. Further more, a drought early warning system would not be feasible or sufficient unless paired with policy measures and financial mechanisms to reduce the political and economic costs of a drought declaration.

Commercial farming of banana for export has rapidly expanded across northern uplands of Laos since 2008 with the establishment of new plantations by foreign companies. Heavy reliance on agrochemical usage warrants examination of possible environmental and human health risks. This study presents a preliminary assessment of the environmental risks from pesticide usage associated with bananas and other major crops in Oudomxay province. Surface water, groundwater, soil and sediment samples collected from the study area were analyzed for pesticide residues in the laboratory during the wet and dry seasons. Results of the analysis revealed that samples from banana farms had higher concentrations of residues from currently used (CU) pesticides compared with samples from adjacent farms producing maize, rubber, upland rice and gourd. Residues from highly persistent organochlorine (OC) pesticides, such as dichlorodiphenyltrichloroethane, heptachlor, dieldrin and lindane, which are no longer used in Laos, were also detected. Laboratory results were compared against a low-cost pesticide residue detection method and a simple pesticide risk assessment tool. However, neither approach was comparable to laboratory analysis. The potential environmental risk from pesticides and pesticide breakdown products was found to be substantial. For example, concentrations of some CU compounds exceeded the limits set by the World Health Organization. The report highlights several mitigation measures to reduce the environmental risks from hazardous pesticides: (i) increase efforts to eliminate the import and use of hazardous and persistent pesticides; (ii) promote targeted education programs to implement best practices, including the selection and use of pesticides as per international standards, and Integrated Pest Management techniques; (iii) identify and protect drinking water sources with a high risk of contamination; and (iv) maintain vegetated buffers and sediment traps to detain farm runoff, which will allow CU pesticides to degrade to safe levels before entering watercourses.

This article investigates water security in Nepal from the perspective of the water-energy-agriculture (food) nexus, focusing on pathways to water security that originate in actions and policies related to other sectors. It identifies promoting development of Nepal’s hydropower potential to provide energy for pumping as way to improve water security in agriculture. Renewable groundwater reserves of 1.4 billion cubic meters (BCM), from an estimated available balance of 6.9 BCM, could be pumped to irrigate 613,000 ha of rainfed agricultural land in the Terai plains, with a potential direct economic gain of USD 1.1 billion annually and associated benefits including promotion of energy-based industry, food security and local employment. Governance also plays an important role in addressing water security. We conclude that a nexus-based approach is required for effective water management and governance.

The general perception of canal irrigation systems in India is one of built infrastructure with low service performance. This paper presents an analytical framework, applied to the Sina medium irrigation system in Maharashtra state of India, to study the performance of an expanded water influence zone (WIZ) including a buffer zone outside the canal command area (CCA) influenced by the irrigation system’s water resources. The framework used satellite-based estimates of land-use and cropping patterns. The results indicate that there is hardly any gap between the irrigation potential created (IPC) and the irrigation potential utilized (IPU) in the CCA. The fraction of consumptive water use (CWU) of irrigation is low in the CCA, but almost one in the WIZ, due to the reuse of return flows in the WIZ. Future investments should focus on increasing economic water productivity ($/m3 ) in order to enhance the resilience of the farming community in the WIZ, which is frequently affected by water scarcity.

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.

With adverse impacts of climate change growing in number and intensity, there is an urgent need to reduce emissions from food systems to net zero. This can only be achieved if rural areas in low- and middle-income countries gain access to clean energy. A review of the research and capacity building contributions of the CGIAR Research Program on Water, Land and Ecosystems (WLE) over the last 10 years suggests important contributions in the areas of energy policy and energy investment planning, cost and feasibility frameworks, and business models for clean energy technology uptake. WLE has also conducted successful pilot projects on solar irrigation to provide an evidence base for scaling up innovative energy initiatives. Finally, the program also considered non-agricultural uses of energy where relevant to food systems, and implemented capacity building activities. Going forward, CGIAR has a key role to play in providing information, supporting access and piloting innovative, scalable clean energy interventions to support the achievement of multiple impacts for the poorest and most food-insecure women and men farmers and entrepreneurs.

Depleting groundwater resources and increasing energy demand with the huge dependence of India’s agriculture on groundwater and energy, and especially in water deficit rice-based production systems, are posing a serious threat to sustained food, water, and energy security. Sustainability concerns of water, energy, and input-intensive rice-based crop production systems have increased the realization for developing and scaling up alternative agro-techniques that can significantly reduce the water and energy requirements in crop production without compromising on crop yield. The interconnectedness between water, energy, and food makes the concept of water, energy, and food (WEF) nexus more relevant to explore integrated solutions to efficient use of limited and/or declining water and energy resources. Conservation agriculture (CA) is gaining currency as an alternate system for rice/cereal-based production systems to conserve water and energy, improve soil health, reduce cost of cultivation, and preserve ecology. This paper explores the concept of WEF nexus and how CA addresses the challenge of harmonizing the synergy among water, energy, and food though WEF ‘nexus gains’ especially in the context of groundwater irrigated rice/cereal based cropping systems.

While drinking water is known to create significant health risk in arsenic hazard areas, the role of exposure to arsenic through food intake is less well understood, including the impact of food trade. Using the best available datasets on crop production, irrigation, groundwater arsenic hazard, and international crop trade flows, we estimate that globally 17.2% of irrigated harvested area (or 45.2 million hectares) of 42 main crops are grown in arsenic hazard areas, contributing 19.7% of total irrigated crop production, or 418 million metric tons (MMT) per year of these crops by mass. Two-thirds of this area is dedicated to the major staple crops of rice, wheat, and maize (RWM) and produces 158 MMT per year of RWM, which is 8.0% of the total RWM production and 18% of irrigated production. More than 25% of RWM consumed in the South Asian countries of India, Pakistan, and Bangladesh, where both arsenic hazard and degree of groundwater irrigation are high, originate from arsenic hazard areas. Exposure to arsenic risk from crops also comes from international trade, with 10.6% of rice, 2.4% of wheat, and 4.1% of maize trade flows coming from production in hazard areas. Trade plays a critical role in redistributing risk, with the greatest exposure risk borne by countries with a high dependence on food imports, particularly in the Middle East and small island nations for which all arsenic risk in crops is imported. Intensifying climate variability and population growth may increase reliance on groundwater irrigation, including in arsenic hazard areas. Results show that RWM harvested area could increase by 54.1 million hectares (179% increase over current risk area), predominantly in South and Southeast Asia. This calls for the need to better understand the relative risk of arsenic exposure through food intake, considering the influence of growing trade and increased groundwater reliance for crop production.

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.

While water security is widely regarded as an issue of global significance and concern, there is not yet a consensus on a methodology for evaluating it. The difficulty in operationalizing the concept comes from its various interpretations and characteristics at different spatial and temporal scales. In this paper, we generate a dashboard comprised of 52 indicators to facilitate a rapid assessment of a country’s water security and to focus the first step of a more comprehensive water security diagnostic assessment. We design the dashboard around a conceptualization of water security that builds upon existing framings and metrics. To illustrate its usefulness, we apply the dashboard to a case study of Pakistan and a regional cross-country comparative analysis. The dashboard provides a rapid view of the water security status, trends, strengths, and challenges for Pakistan. The cross-country comparative analysis tentatively identifies relationships between indicators such as water stress and the transboundary dependency ratio, with countries exhibiting high values in both variables being especially vulnerable to transboundary water risk. Overall, this dashboard (1) provides quantitative information on key water-related variables at the country level in a consistent manner and (2) helps to design and focus more in-depth water security diagnostic studies.

Gully erosion has many negative impacts on both cultivated and grazing lands in Ethiopian highlands. The present study was conducted in Chentale watershed, Ethiopia, to quantify the contribution of gully erosion, and to assess its temporal changes. Within the Chentale watershed, we selected a sub-watershed (104.6 ha) and nested gully catchment, and gauged for stream flow and sediment concentration data in 2015 and 2016. We measured gully dimensions before and after the onset of the rainy season in 2016 to determine soil loss due to gully erosion. The temporal changes of gully expansion were determined by digitizing gully plain area from Google earth images taken in 2005 and 2013. The results support that gullies were expanding at higher rate in recent years. Area covered by gullies in the watershed increased from 1.84 to 3.43 ha between 2005 and 2013, indicating that the proportion of the watershed covered by gullies was nearly doubled in the investigated period. The estimated soil loss from the main watershed and gullies catchment was 6 and 2 t ha-1 year-1 in 2015, and was 7 and 9 t ha-1 year-1 in 2016, respectively. The results support that gullies were the main contributors of soil erosion in the watershed, and that integrated soil and water conservation measures are required to reduce soil erosion.

Gullies that are expanding at alarming rate are responsible for the majority of soil losses in the (sub) humid highlands of Ethiopia. Few affordable and effective methods for gully erosion control are available in the highlands. The objective of the study was to develop cost-effective measures to halt gully expansion by determining stable-bank conditions under a variety of environmental situations using the Bank Stability and Toe Erosion Model (BSTEM). The study was carried out in the sub humid Debre Mawi watershed, located 30 km south of Lake Tana. Input data for the BSTEM model were collected using field surveys and soil sampling. After the BSTEM was tested on actual measured soil data, soil cohesion and internal friction angle were calibrated against observed gully bank retreat. Using the calibrated parameters, the model evaluated the stabilization of the existing gully bank under different scenarios in which groundwater table, bank angle and bank height, tension crack depth, vegetation, and toe protection were varied. Finally, the head-cut of the study gully was treated based on the model recommendation. The simulated results showed that a 5 m deep gully was stable under fully saturated conditions when the bank toe is protected, its upper surface is vegetated, and its bank angles do not exceed 45. If the depth of the gully is less than 5 m or if its water table is deeper than 0.5 m, only regrading the gully bank to an angle of 45 can stabilize the gully. BSTEM showed to be an effective tool that can be used to evaluate gully control measures.

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.

The Indus Basin Irrigation System is characterized as a gravity surface irrigation system, with minimal on-line or off-line storage and limited distribution control. An important characteristic is the limited water availability. On field irrigation within the Indus Basin Irrigation System is almost entirely using surface irrigation and only very few farms adopting pressurized irrigation systems. The objective of the warabandi management system that characterizes the Indus Basin Irrigation System is to distribute the limited available water as equitably as possible. This research evaluates surface irrigation under furrow and border strip irrigation using canal water and groundwater conjunctively. This paper presents results from a numerical model and field observations, to examine the precision surface irrigation paradigm within the water supply constraints imposed by the warabandi system of the Indus Basin Irrigation System. We conclude that laser grading within the IBIS is achievable at a modest cost and effort. Our findings suggest that the improved laser-graded profile persists for at least three crop seasons. Furrow irrigation can attain a high performance using either available canal or groundwater with low quarter distribution uniformity and low quarter application efficiency as performance indicators. Border irrigation can also attain a high performance provided irrigation is changed to fortnightly. Model predictions of advance curve and low quarter distribution uniformity are compared to field observations and in-situ measurement.

This study fills a knowledge gap about low-income rural communities’ holistic management of multiple water resources to meet their multiple needs through multiple or single-use infrastructure. Six low-income rural villages in Limpopo Province were selected with a diversity in: service levels, surface and groundwater resources, public infrastructure (designed for either domestic uses or irrigation but multiple use in reality) and self-supply (people’s individual or communal investments in infrastructure). Focusing on water-dependent livelihoods and water provision to homesteads, distant fields and other sites of use, three policy-relevant patterns were identified. First, most households have two or more sources of water to their homesteads as a vital buffer to irregular supplies and droughts. Second, infrastructure to homesteads is normally for domestic uses, livestock and, for many households, irrigation for consumption and sale. Public infrastructure to irrigate distant fields is multiple use. Exceptionally, self-supply point sources to distant fields are single use. Water bodies to other sites of use are normally multiple use. As for large-scale infrastructure, multiple-use infrastructure is cost-effective and water-efficient. Third, in four of the six villages people’s self-supply is a more important water source to homesteads than public infrastructure. In all villages, water provided through self-supply is shared. Self-supply improves access to water faster, more cost-effectively and more sustainably than public services do. In line with international debates, self-supply is there to stay and can be supported as a cost-effective and sustainable complementary mode of service delivery. A last potential policy implication regards community-driven planning, design and construction of water infrastructure according to people’s priorities. This may sustainably harness the above-mentioned advantages and, moreover, communities’ ability to manage complex multiple sources, uses and multiple-use infrastructure, whether public or self-supply, as a matter of daily life.

Peri-urban areas are characterized by multifunctional land-use patterns forming a mosaic of built-up and agricultural areas. They are critical for providing food and other agricultural products, livelihood opportunities and multiple ecosystem services, which makes them transformative where urban and rural spaces blend. We analyzed land use changes in a peri-urban micro-watershed in Southern India by using Google Earth data to understand the micro-level spatio-temporal dynamics. This study aims at understanding the peri-urban agriculture and landscape changes as related to the change in use of wastewater and groundwater for irrigation. The temporal dynamics of peri-urban system including the changes in built-up, paragrass, paddy rice and vegetable cultivation, groundwater and wastewater irrigated areas in the watershed were evaluated. The detected changes indicate that, as a consequence of urban pressures, agricultural landscapes are being converted into built-up areas and, at the same time, former barren land is converted to agricultural plots. The mapped land use data are used in landscape change modelling for predicting the peri-urban agricultural dynamics and the driving factors in the watershed. Combined with the mapping and modelling approaches for land use change analysis, our results form the basis for integrated resources management in the wastewater influenced peri-urban systems.

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.

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 article reviews the negative impact of anthropogenic changes on groundwater. The main changes in physical and geographical conditions that occur under the impact of anthropogenic pressures and that have the most significant influence on the state of groundwater, as well as a negative impaction the conditions of the formation of groundwater are: changes in the landscape caused by agricultural works, mining, construction of settlements, etc.; changes in the hydrographic network caused the construction of hydroelectric power facilities; changes in the composition of the atmospheric air; changes in the groundwater level regime, climatic conditions. The most significant factor of change in groundwater formation conditions is the progressive anthropogenic pollution of groundwater. It negatively influences the number of resources and their quality.

Investments in irrigation contribute to poverty reduction and enhance food security. This paper considers irrigation investments more broadly in the context of rural–urban linkages and thus examines rural irrigation schemes and peri-urban and urban agriculture using freshwater, groundwater and wastewater. We present case studies from East, West and Southern Africa, while focusing on the imperative of smallholders and of food security and nutrition. Evidence from Big Data and telecoupling show that, amid global change and sustainability issues, irrigation development strengthens connections between humans and nature with notable benefits to food security. Transforming investments to feed the future generation require priority investments in irrigation, solar energy for groundwater pumping, groundwater development policy, and integration of peri-urban and urban agriculture into food systems. Equally important will be no-regret interventions in wastewater reuse, water storage and groundwater buffer, micro-irrigation, and wholesale reconfiguration of farming systems, through anticipatory investments, to safeguard food security and sustainability into the distant future.

Study region: Karnali-Mohana (KarMo) river basin, Western Nepal. Study focus: This study has developed a hydrological model using multi-site calibration approach for a large basin, the Karnali-Mohana (KarMo) in Western Nepal, which has a lot of potential for water resources development and contribute to the national prosperity. It further applies the model to characterize hydrology and water resources availability across spatio-temporal scales to enhance understanding on water availability and potential uses. The newly developed hydrological model in Soil and Water Assessment Tool (SWAT) is capable of reproducing the hydrological pattern, the average flows, and the flow duration curve at the outlet of the basin and five major sub-basins. New hydrological insights for this region: The model simulated results showed that about 34 % of average annual precipitation in the KarMo basin is lost as evapotranspiration, but with a large spatio-temporal heterogeneity. The Hills and Tarai are relatively wetter than the Mountains. The average annual flow volume at the basin outlet is estimated as 46,250 million-cubic-meters (MCM). The hydrological characterization made in this study are further used for climate change impact assessment (Part-B in the same journal), environmental flows assessment and evaluating trade-offs among various water development pathways, which are published elsewhere. This model, therefore, has potential to contribute for strategic planning and sustainable management of water resources to fuel the country’s prosperity.

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.

India has an intricate nexus of groundwater irrigation, energy and climate. Subsidized electricity supply has led to unregulated groundwater pumping, causing a decrease in groundwater level and increase in carbon emissions. This complex nexus necessitates estimation of carbon emissions from groundwater irrigation. The study uses actual pumping data on 20.5 million groundwater structures from the Fifth Minor Irrigation Census (reference year 2013–14) to estimate carbon emissions. The estimates show that groundwater irrigation emits 45.3–62.3 MMT of carbon annually, contributing 8–11% of India’s total carbon emission. This analysis shows deep tubewells have a huge carbon footprint, and their growing number is a serious environmental concern. Spatial analysis reveals India’s western and peninsular region, which houses 85% of the country’s over-exploited groundwater blocks, contributes most to carbon emission. Moreover, this region hosts 27 districts which are groundwater–energy–climate nexus hotspots, together accounting for 34% of carbon emissions from groundwater irrigation. Comparison with the previous estimate reveals that carbon emission from groundwater irrigation nearly doubled between 2000 and 2013. Findings of this study are vital to the discourse on the increasing environmental costs of groundwater pumping in the country and will contribute to carbon emission mitigation strategies.

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 highlights where land–water linkages are expected to become apparent in terms of climate impacts and where practical approaches to land and water management offer scope for both climate adaptation and mitigation though agriculture. It also provides an agricultural perspective from which to further engage the United Nations Climate Change Conference in terms of water management.

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.

The Barind region, a water-stressed area in northwest Bangladesh, had an underdeveloped agricultural economy and high levels of poverty until two projects revitalized the area with enhanced groundwater irrigation. The Barind Integrated Area Development Project in 1985 and Barind Multipurpose Development Authority (BMDA) in 1992 used new water extraction technology and innovative management practices such as deep tubewells (DTWs) fitted with smart card–operated electric pumps to develop drought-resilient irrigation. Both projects have helped the Barind region reduce poverty and achieve self-sufficiency in rice. However, there are concerns about declining groundwater levels in the Barind and nearby regions, resulting in a temporary halt in DTW expansion. Preliminary evidence presented in this case study suggests farmers served by shallow tubewells (STWs) may be losing access to groundwater in some parts of the Barind region, which can have significant development implications because these tubewells remain the predominant source of irrigation. This evidence provides grounds to question whether an irrigation model reliant on DTWs is sustainable and equitable in the long term. Further research is needed to better establish groundwater conditions and understand the risk to STW users to inform future policy on DTW-driven agricultural development.

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.

This paper explores the impact of irrigation on India’s mixed crop-based dairy production system. It uses a four-equation recursive regression model to outline the impact of water applied under different modes (groundwater irrigation, surface water irrigation, and rainfall) on the bovine herd efficiency and dairy output. The results of the model show that rain-fed areas account for 47% of the total value of milk output, whereas area under groundwater irrigation and surface water irrigation account for 38% and 15%, respectively. Of all the different irrigation modes, groundwater irrigated areas have the most efficient bovine herd for milk production. The addition of one hectare of groundwater in an irrigated area adds around Indian Rupees (INR) 20,000 (~US $448) to the gross value of milk output of a district, which is twice the addition of one hectare of surface water in an irrigated area and five times the addition of one hectare of rainfed area. Based on the results of the model, the paper suggests that expanding well irrigation in the groundwater-abundant eastern and central tribal belt of India can yield a positive impact on milk production.

This paper examines whether there are systematic differences in the historical behaviors of households that are affected and unaffected by chronic kidney disease (CKD) in Sri Lanka pertaining to their water source choices, water treatment practices, and agrochemical use. This analysis is motivated by the Sri Lankan government’s largest policy response to this epidemic – to encourage communities to switch from untreated well water to publicly provided alternatives. We use recall methods to elicit information on the drinking water source and treatment choices of households over an 18-year period from 2000– 2017. Our analysis is based on a survey of 1497 rural ground-water dependent households in the most CKD-affected areas of the 10 districts of Sri Lanka with the highest prevalence of CKD. Our main findings are that (a) households that have ever used a pump to extract (typically deep) drinking water from a household well are more likely to be affected by CKD; (b) we fail to find a relationship between disease status and households’ use of buckets to extract (typically shallow) groundwater from their wells; and (c) those who have ever treated their shallow well water by boiling it are less likely to be affected by CKD. We also find that a greater share of CKD affected households historically used agrochemicals, used wells that were geographically removed from surface water sources, and displayed lower proxies of wealth. The implications of these findings are fourfold. First, since the systematic differences in the historical patterns of water sources and treatments used by CKD affected and non-affected households are modest, the sources of water and the treatment practices themselves may not be the sole risk factors in developing CKD. Second, although we find a negative association between boiling water and the probability of CKD, it is not obvious that a public policy campaign to promote boiling water is an appropriate response. Third, the hydrochemistry of deep and shallow well water needs to be better understood in order to shed light on the positive relationship between deep well water and disease status, and on why boiling shallow but not deep well water is associated with a lower probability of CKD. Fourth, there is a need for a deeper understanding of other risk factors and of the efficacy of preventative programs that provide alternative sources of household drinking water.

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 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.

Data exchange in transboundary waters is fundamental to advance cooperative water management. Nonetheless, the degree to which data are shared is not well understood. To gauge this degree, an assessment framework was developed and applied in 25 international river basins. The framework captures the degree to which a set of data parameters is exchanged among countries. A reasonable proportion of surveyed basins exchange some data, but the breadth of such exchange is often limited, and not regular. This paper highlights where data exchange can be improved and provides guidance on how indicators used in global assessment frameworks can motivate this improvement.

Declining water resources in dry regions requires sustainable groundwater management as trends indicate increasing groundwater use, but without accountability. The sustainability of groundwater is uncertain, as little is known about its extent and availability, a challenge that requires a quantitative assessment of its current use. This study assessed groundwater use for irrigated agriculture in the Venda-Gazankulu area of Limpopo Province in South Africa using crop evapotranspiration and irrigated crop area derived from the normalised difference vegetation index (NDVI). Evapotranspiration data was derived from the Water Productivity through Open access of Remotely sensed Actual Evapotranspiration and Interception (WaPOR) dataset (250 m resolution), and irrigated areas were characterised using dry season NDVI data derived from Landsat 8. Field surveys were conducted for four years to assess accuracy and for post-classification correction. Daily ET for the dry season (May to September) was developed from the actual ET for the irrigated areas. The irrigated areas were overlaid on the ET map to calculate ET for only irrigated land parcels. Groundwater use during the 2015 dry period was 3627.49 billion m3 and the irrigated area during the same period was 26% of cultivated land. About 82 435 ha of cultivated area was irrigated using 44 million m3 /ha of water, compared to 186.93 million m3 /ha on a rainfed area of 237 847 ha. Groundwater management is essential for enhancing resilience in arid regions in the advent of water scarcity.

Effective watershed planning requires an understanding of the hydrology. In the humid tropical monsoon climates and especially in volcanic highland regions such as the Ethiopian Highlands, the understanding of watershed processes is incomplete. The objective is to better understand the hydrology of the volcanic regions in the humid highlands by linking the hillslope processes with the discharge at the outlet. The Ene-Chilala watershed was selected for this study. The infiltration rate, piezometric water levels and discharge from two nested sub watersheds and at the watershed outlet were measured during a four-year period. Infiltration rates on the hillsides exceeded the rainfall intensity most of the time. The excess rain recharged a perched hillside aquifer. Water flowed through the perched aquifer as interflow to rivers and outlet. In addition, saturation excess overland flow was generated in the valley bottoms. Perched water tables heights were predicted by summing up the recharge over the travel time from the watershed divide. Travel times ranged from a few days for piezometers close to the divide to 40 days near the outlet. River discharge was simulated by adding the interflow from the upland to overland flow from the saturated valley bottom lands. Overland flow accounted only for one-fourth of the total flow. There was good agreement between predicted and observed discharge during the rain phase therefore the hillslope hydrologically processes were successfully linked with the discharge at the outlet.

Groundwater use for agriculture has the potential to improve rural households’ income and reduce poverty, but the linkages are not always straightforward. Taking Laos as a case study, this article illustrates how differential access to water, land, and capital shape farmers’ livelihood strategies in two nearby, yet contrasting villages on the Vientiane Plain. It examines the factors driving farm households’ decisions to invest in groundwater for agriculture. The findings highlight the need to better understand how farmers view groundwater in relation to their farm household characteristics if groundwater is to be successfully used as a means to improve rural livelihoods.

This report explores how women perceive participation and empowerment vis-a-vis access to water and other agricultural resources in the Tarai/Madhesh of Nepal. The report argues that gendered vulnerability is indeed intricately connected with other axes of difference, such as caste and economic status, despite women’s critical role in agricultural production and their active engagement in access to water and irrigation in agriculture. Overall, women’s well-being seems to have decreased as a consequence of male out-migration. However, there are women who have also become empowered in new ways, taking up enterprise opportunities. The authors point out that at the level of policy and external development interventions, a dominating narrative on women’s limited participation in agriculture being a result of ‘social norms’ exists. Public irrigation agencies have used this myth to absolve themselves of the responsibility for ensuring gender equality in program implementation. The report concludes that strengthening equitable irrigation user groups alongside capacity building for farmers and program implementers are critical measures for improving women’s access to irrigation and overall well-being. Women should be ensured meaningful participation, including leadership roles. Finally, this report recommends linking irrigation user groups to other income-generation schemes, and facilitating access to better credit, finance and agricultural inputs.

Despite increasing popularity of farmer-led irrigation in Ethiopia, little is known about socio-economics of farmers who receive public support in accelerating its expansion. We investigate this question by combining spatial land suitability for groundwater- and solar irrigation with pre-existing socioeconomic data. We find that if public support in farmer-led irrigation expansion were to be provided to farmers who own land areas that are also spatially highly suitable for irrigation, high-value crop cultivators and wealthier farmers would most likely benefit from such investments. Specifically, we find evidence that farmers in land areas more suitable for groundwater irrigation cultivated more high value crops such as vegetables, fruits, and cash crops. Cultivation of staple crops such as cereals, oilseeds, legumes and root crops were negatively associated with groundwater irrigation suitability. In addition, we find a positive correlation between farmers’ wealth status (measured by consumption expenditure, asset index, and land size) and groundwater irrigation suitability. Controlling for regional differences and current irrigation coverage, one percent increase in irrigation suitability score was associated with 0.2% increase in per-capita consumption expenditure. Land areas that were suitable for irrigation were more likely to belong to large-holders than smallholders. Results imply that policies which aim to facilitate farmer-led irrigation development in Ethiopia should not rely only on spatial suitability for irrigation. Household socio-economics and existing agricultural practices are equally important.

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.

The estimation of crop water demand and understanding groundwater use is an essential component for managing water effectively. Groundwater is the main source of irrigation in Dangila. However, there is a lack of information in the study area on amount of irrigated land, irrigation water use and demand, groundwater recharge. Consequently, the objective of this study is to determine the groundwater recharge and its potential for dry season irrigation. The study was conducted in Brante watershed of 5678 ha located in Dangila woreda, Ethiopia. Water table data from twenty-five wells and discharge data at the outlet of the watershed used to assess recharge amount in 2017. To calculate irrigation water demand, CROPWAT model was used. Questionnaires were undertaken to assess groundwater use. A KOMPSAT-2 image was used to map shallow groundwater irrigated vegetables in February 2017. From the soil water balance method, the annual groundwater recharge was 17,717,690 m3 which is 15.8% of annual rainfall, and recharge amount of 14,853,339 m3 was obtained using water table fluctuation method. From satellite image classification the area coverage of dry season irrigated vegetables (onion, tomato, pepper) below the main road was 4.02 ha. From CROPWAT result, seasonal irrigation water demand for onion, Tomato, and pepper was 333,314, and 261 mm respectively. However, the questioners result indicates that farmers apply in average 20% more water than crop water demand. In the watershed 60,150 m3, 62,750 m3 and 41,603 m3 of water was abstracted for irrigation, domestic and livestock use respectively. The ratio of groundwater use to groundwater recharge at the watershed scale was found to be only 1%. This study indicates that the current use of groundwater was sustainable. For better improvement of household livelihood irrigation can be further expand using ground water. Future work should be performed to determine if the method outlined in this research could be used to accurately estimate available water potential.

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.

With decreasing aquifer levels, increasing groundwater pollution, inequitable access, and generally poor management outcomes, better groundwater governance has been put forward as a recipe to address these challenges worldwide. Existing recommendations focus on improved legal frameworks, monitoring and control of access and abstraction through permits or formal rights. In addition, decentralized water management, enforcement of regulations, and supply-side technological solutions are seen as cornerstone components of good groundwater governance systems. However, until now, these approaches have generally failed to reconcile the fundamental dynamics and properties of groundwater as a natural resource and of governance as a social and political phenomenon. This has caused a disregard for local to planetary boundaries, power dynamics, and intra- and intergenerational inequalities in access to benefits from groundwater. As the current general notion of good groundwater governance is limited, solutions put forward are also partial and do not encompass the wider challenges affecting groundwater governance, in effect replacing sustainable management goals and policy for governance as a process. This paper takes a particular look at the Middle East and North Africa and agricultural groundwater use for irrigation to constructively redefine groundwater governance and fully address the multilayered and multifaceted core challenges of groundwater governance. Equally, the paper puts forward a new conceptual thinking that will help support the effective development of governance-based solutions to achieve sustainable, socially acceptable, resilient and equitable resource use.

This paper tries to shift the focus of research on the impact of natural disasters on economic growth from global and national levels to sub-national levels. Inadequate sub-national level information is a significant lacuna for planning spatially targeted climate change adaptation investments. A fixed-effect panel regression analyses of 19 states from 2001 to 2015 assess the impacts of exposure to floods and droughts on the growth of gross state domestic product (GSDP) and human development index (HDI) in India. The flood and drought exposure are estimated using satellite data. The 19 states comprise 95% of the population and contribute 93% to the national GDP. The results show that floods indeed expose a large area, but droughts have the most significant impacts at the sub-national level. The most affected GSDPs are in the non-agriculture sectors, positively by the floods and negatively by droughts. No significant influence on human development may be due to substantial investment on mitigation of flood and drought impacts and their influence on better income, health, and education conditions. Because some Indian states still have a large geographical area, profiling disasters impacts at even smaller sub-national units such as districts can lead to effective targeted mitigation and adaptation activities, reduce shocks, and accelerate income growth and human development.

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.

Since at least two decades, Chronic Kidney Disease of Uncertain Etiology (CKDu) has become an increasingly discussed health issue in Sri Lanka and as well as in other tropical regions. Areas that are particularly affected with the disease are mostly located in the dry zone of Sri Lanka. The disease is more prominent among communities that consume groundwater as their main source of drinking water. Hydrogeochemical investigations were carried out in the Ginnoruwa area, a known hotspot of CKDu. It revealed possible links between drinking water chemistry and the spreading of the disease. This work compares hydrogeochemical data of drinking water sources of wells whose consumers are affected by CKDu and other nearby wells whose consumers were not affected by the disease. A total of 63 groundwater samples were collected from selected wells. About one-third of these samples (i.e., 19) were collected from wells used by CKDu patients. Significantly higher values of pH, total hardness, electrical conductivity, Ca2+, Mg2+, F-, Cl-, PO4 3-, and SO4 2- were found in wells that were used by CKDu patients. Mean contents of Na+, Ca2+, and Mg2+ in CKDu affected wells were 33.8 mg/L, 30.1 mg/L, and 14.9 mg/L, respectively, compared to 23.1 mg/L, 26.7 mg/L, and 9.65 mg/L in non-CKDu wells. Differences in major ion geochemistry in groundwaters are possibly governed by variable time periods of water storage in fractured hard rock aquifers in this region. Hydrogeochemical parameters were statistically compared by a Mann–Whitney U test and indicated significant differences in total dissolved solids (TDS) (p=0.016), SO4 2- (p=0.005), PO4 3- (p=0.030), F- (p=0.048), Na+ (p=0.008), and Mg2+(p=0.008) between non-CKDu and CKDu wells at p=0.050 level. Other suspected solutes such as nephrotoxic trace elements including As, Cd, and Pb were similar in both types of wells. They were also lower than the accepted guideline limits of the World Health Organization (WHO). Results of this study suggest that fluoride in drinking water in combination with water hardness may be one of the responsible factors for kidney damage and progression of the disease. This may be particularly the case when elevated amounts of Mg2+ are present in hard groundwater.

Impact assessments on climate change are essential for the evaluation and management of irrigation water in farming practices in semi-arid environments. This study was conducted to evaluate climate change impacts on water productivity of maize in farming practices in the Lower Chenab Canal (LCC) system. Two fields of maize were selected and monitored to calibrate and validate the model. A water productivity analysis was performed using the Soil–Water–Atmosphere–Plant (SWAP) model. Baseline climate data (1980–2010) for the study site were acquired from the weather observatory of the Pakistan Meteorological Department (PMD). Future climate change data were acquired from the Hadley Climate model version 3 (HadCM3). Statistical downscaling was performed using the Statistical Downscaling Model (SDSM) for the A2 and B2 scenarios of HadCM3. The water productivity assessment was performed for the midcentury (2040–2069) scenario. The maximum increase in the average maximum temperature (Tmax) and minimum temperature (Tmin) was found in the month of July under the A2 and B2 scenarios. The scenarios show a projected increase of 2.8 C for Tmax and 3.2 C for Tmin under A2 as well as 2.7 C for Tmax and 3.2 C for Tmin under B2 for the midcentury. Similarly, climate change scenarios showed that temperature is projected to decrease, with the average minimum and maximum temperatures of 7.4 and 6.4 C under the A2 scenario and 7.7 and 6.8 C under the B2 scenario in the middle of the century, respectively. However, the highest precipitation will decrease by 56 mm under the A2 and B2 scenarios in the middle of the century for the month of September. The input and output data of the SWAP model were processed in R programming for the easy working of the model. The negative impact of climate change was found under the A2 and B2 scenarios during the midcentury. The maximum decreases in Potential Water Productivity (WPET) and Actual Water Productivity (WPAI) from the baseline period to the midcentury scenario of 1.1 to 0.85 kgm-3 and 0.7 to 0.56 kgm-3 were found under the B2 scenario. Evaluation of irrigation practices directs the water managers in making suitable water management decisions for the improvement of water productivity in the changing climate.

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.

A water and soil quality baseline study was carried out across the ~ 4500 km2 Vientiane Plain in Lao PDR. Eight water quality and nine soil parameters were analysed using field kits at 95 sites in March 2015. Elevated electrical conductivity and chloride were apparent at two sites due to geogenic leaching from the marine rock-salt present in some areas. Groundwater was acidic in most locations. Nitrate and faecal contamination were also observed from nitrogenous fertilizers (diffuse) and from leaky sewage pits (localised) respectively. Soil quality is neither nutrient deficient nor does it pose a threat to plant growth. Where groundwater is used for drinking, removal of bacterial contamination by simple filtration or boiling is sufficient. In the absence of a functional monitoring network in the Vientiane Plain, periodic surveys of this kind should be performed. The results should be made widely available to the relevant government departments and other stakeholders for better management of the land and water resources.

This analysis provides new estimates of chronic kidney disease (CKD) prevalence – including CKD of unknown etiology (CKDu) – across ten districts most affected by CKD in Sri Lanka, including an examination of rural householdsapos; historical reliance on groundwater consumption. A carefully designed household survey provides information on whether these households self-reported having a member in the decade prior to 2018, who had been clinically diagnosed with CKD. Households were classified according to whether or not they had used groundwater (from household wells, agro-wells or springs) as their primary source for drinking or cooking for at least five years between 1999 and 2018. More than 98% of households reported having consumed groundwater as their primary source of drinking or cooking water for at least five of those years and gt;15% of households reported having at least one CKD-affected member in the ten-year period up to 2018, but these numbers varied across and within districts. The reported characteristics of symptomatic individuals reveal that the incidence of CKD was significantly higher among females (62%) than males (38%). In addition to CKD, about 63% of symptomatic individuals had hypertension and about one-third of them also had diabetes. About 33% of the symptomatic individuals had neither diabetes nor hypertension, where this group most closely fits commonly used definitions of CKDu. With a survey response of over 8000 households comprising as many as 30,000 individuals, these data illustrate the scale of CKD in the most-affected districts of Sri Lanka on an aggregate basis as well as revealing differences across districts and at the sub-district level.

Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2 , maintains vital ecosystems, and strongly influences terrestrial water and energy budgets3 . Yet the hydrological processes that govern groundwater recharge and sustainability—and their sensitivity to climatic variability—are poorly constrained4,5 . Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation–recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation–recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the ‘high certainty’ consensus regarding decreasing water resources4 in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation–recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies.

Though springs are the primary source of water for communities in the mid-hills of Nepal, an in-depth scientific understanding of spring systems is missing, preventing the design of effective climate-resilient interventions for long-term sustainability of springs. This study marks the first attempt to combine environmental isotopes analysis with hydrometric and hydrogeological measurements to identify dominant recharge zones for springs in two mountainous catchments—Banlek and Shikarpur—in Far-Western Nepal. In total, 422 water samples collected from rainfall, springs and streams between March 2016 and March 2017 were analyzed for their isotopic composition (d18O and dD). Isotopic composition of rainwater shows seasonality, suggesting that different sources of water vapor cause rains in monsoon and in dry season. Rainfall responses of individual springs were used to identify connections to unconfined and deeper groundwater strata. The isotopic composition of springs in the two catchments ranges from -9.55 to -8.06‰ for d18O and -67.58 to -53.51‰ for dD. The isotopic signature of the spring sources falls close to the local meteoric water line for the corresponding season, indicating strong rainfall contribution to springs. Altitudinal isotopic gradients suggest mean recharge elevation of 2,600–2,700 m asl for springs in Shikarpur, which lies beyond the surface-water catchment, and a recharge elevation of 1,000–1,100 m asl for Banlek, which partially extends beyond the surface-water catchment. The demarcated recharge zones will be used by government agencies to implement recharge interventions to increase the resiliency and reliability of springs in Far-Western Nepal.

Accurate assessment of the soil salinization is an important step for mitigation of agricultural land degradation. Remote sensing (RS) is widely used for salinity assessment, but knowledge on prediction precision is lacking. A RS-based salinity assessment in Khorezm allows for modest reliable prediction with weak (R2=0.15–0.29) relationship of the salinity maps produced with RS and interpolation of electromagnetic EM38 during growth periods and more reliable (R2=0.35–0.56) beyond irrigation periods. Modeling with HYDRUS-1D at slightly, moderately and highly saline sites at various depths showed that irrigation forces salts to move to deeper layers: salts reappear in the upper profile during dry periods. Beyond irrigation events, salts gradually accumulated in the upper soil layers without fluctuations. Coupling RS techniques with numerical modeling provided better insight into salinity dynamics than any of these approaches alone. This should be of interest to farmers and policy makers since the combination of methods will allow for better planning and management.

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.

Sitting on one of the world’s best aquifers, large swathes of West Bengal has groundwater in abundance. Even so, the state’s farmers incur one of the highest irrigation costs in India. In spite of a series of groundwater and electricity policy changes, West Bengal’s farmers fare no better. This paper brings findings from a yearlong research pilot based in Monoharpur village of Birbhum district. The pilot shows how the current electricity tariff structure has made irrigation unaffordable for small and marginal farmers, and has made irrigation services market tightly oligopolistic. If not revised, the agricultural economy, especially that of summer paddy which ensures household security of poor farmers, is likely to taper off in future.

During the Green Revolution era, paddy cultivation was promoted with much vigor within Kerala. The canal systems that supplied timely irrigation played an important role in promoting food security within the state as rice self-sufficiency became a political concern. Under changing circumstances, paddy cultivation has seen a drastic downward trend in the last 30 years. One of the reasons for this trend is the irregularity in water supply through canals resulting from the flow fluctuations due to various hydroelectric projects that have come up in the upstream and inefficiencies arising out of low maintenance and performance management. At the same time, farmers in Kerala have largely shifted towards the cultivation of high valued cash crops. This paper presents a case study of the Chalakudy River Diversion Scheme which once served the irrigation requirements of paddy in the Chalakudy river basin. The paper tries to shed light on how farmers have adapted to the evolving nature of CRDS as they continually shift towards cash crops that require better water control. In this process, CRDS has ended up as an entity vastly different from the intent of its planners. The role of canal irrigation, changing from direct flow irrigation to complementing recharge or replenishment of groundwater and surface water storages, may point towards the imminent transformation of canal irrigation in the rest of India.

Groundwater irrigation has been central to India’s irrigated agriculture. India is the largest extractor of groundwater, pumping nearly 250 km3 every year for irrigation. The abstraction of groundwater is closely coupled with access to subsidized or free electricity in the country. Supply of free electricity has led to the perverse groundwater-energy nexus in the country. This nexus has resulted in grave economic and environmental repercussions. There is a mounting fiscal burden of energy subsidies in the country, which has led many power utilities at the helm of bankruptcy. At the same time, free power has attributed to the groundwater depletion at an alarming rate in many parts of the country. Hence, it becomes important to understand whether these economic and environmental costs of groundwater irrigation are commensurate with its benefits. This study takes a look at the energy productivity of groundwater irrigated agriculture in the districts of India and assesses its contribution to the agricultural output.

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

Piped distribution of irrigation water has helped in faster expansion of sub-minor distribution network of the Sardar Sarovar Project (SSP). An ITP study across six minor canal commands though shows that majority of the intended beneficiaries continue to depend on surface-lift or ground water sources for irrigation. The defunct status of WUAs, responsible for managing operation and maintenance at sub-minor level, in most of these locations raises question on the efficacy of the present participatory model. Farmers are however arranging for irrigation through private initiatives and are able to access assured irrigation using the same canal water. Is it time we provide legitimacy to these initiatives to enhance utilization of the SSP water?

The Arab region needs a new generation of policies and investments in agricultural water. Agricultural water management has always posed challenges and opportunities in the Arab world. However, unprecedented and accelerating drivers such as climate change, population growth, and land degradation make agricultural water management a more urgent priority than ever before. In addition, as part of the 2030 UN Agenda for Sustainable Development, Arab countries have committed to work towards an ambitious set of development targets, the Sustainable Development Goals (SDGs). Unless the right policies and investments are put in place, it will be difficult to achieve the SDGs, including ending hunger and providing clean water and sanitation for all. This paper is part of an ongoing collaboration between the Food and Agriculture Organization of the United Nations (FAO) and the International Water Management Institute to foster dialogue on agricultural water policies and investments in the context of the FAO led Regional Water Scarcity initiative. The purpose of the paper is to frame the key challenges and opportunities in the sector – including emerging innovations in digital agriculture, water accounting, water supply and wastewater reuse – and to lay out broad strategic directions for action.

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.

Climate-smart villages mean implementing a portfolio of best locally suited climate-smart agricultural practices in an integrated manner to build resilience of the local community. Land and water interventions form a crucial part of a climate-smart agricultural practices portfolio, with water availability being the key limiting factor of crop growth. To aid in this decision-making process of prioritizing land and water interventions, a simple and robust spreadsheet tool based on a water balance is developed. The tool integrates and simulates impacts of land and water interventions on the water balance to determine their impact across climate-smart agricultural objectives of agricultural productivity, climate change adaptation and mitigation. The tool was implemented in two villages in the state of Madhya Pradesh, India. The tool performs well in simulating village water balance and its impact on the yield of rainfed and irrigated crop areas. Results show that considerable differences exist within the portfolio of land and water interventions, with only a combination of supply, demand and moisture conservation practices being able to help achieve climate-smart agricultural objectives. In the best case scenario, yield can be increased by up to 10% and greenhouse gas emission intensity reduced up to 17%. Comparison with stakeholder perception analysis highlights the utility of this tool in providing additional quantitative information in the decision-making process.

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.

This report builds on prior work to provide a new, comprehensive, and balanced view of water security in Pakistan, stressing the importance of the diverse social, environmental, and economic outcomes from water. The report highlights the complex water issues that Pakistan must tackle to improve water security and sheds new light on conventional assumptions around water. It seeks to elevate water security as an issue critical for national development. The report assesses current water security and identifies important water-related challenges that may hinder progress in economic and human development. It identifies unmitigated water-related risks, as well as opportunities where water can contribute to economic growth and poverty reduction. The report analyzes how the performance and architecture of the water sector are related to broader economic, social, and environmental outcomes. It models alternative economic trajectories to identify where intervention can lead to a more water-secure future. A consideration of water sector architecture and performance and how these determine outcome leads to recommendations for improving aspects of sector performance and adjusting sector architecture for better outcomes. The sector performance analysis considers (a) management of the water resource, (b) delivery of water services, and (c) mitigation of water-related risks. The description of sector architecture considers water governance, infrastructure, and financing.

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.

For planning, development and management of water resources, understanding runoff mechanism and groundwater recharge is useful especially to watershed management and groundwater use for domestic and irrigation water supply. During the period of the study, stream flow, groundwater levels, infiltration tests, rainfall and soil moisture measurements were conducted. The result from these measurement showed that saturation excess runoff were dominant in Dangishta watershed while infiltration excess runoff also contributes in some parts of the upslope area. This result was also corroborated by better correlation of (R2 = 0.82) at the main outlet than upstream sub watershed outlet (R2 = 0.56) using SCS runoff equation. The result from groundwater level measurement using water table fluctuations approach showed that the total annual groundwater recharge were found to be 400 mm (i.e. 24% of the total annual rainfall) which is a significant amount likely because of the interflow processes to each well.

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.

Chamelia (catchment area = 1603 km2 ), a tributary of Mahakali, is a snow-fed watershed in Western Nepal. The watershed has 14 hydropower projects at various stages of development. This study simulated the current and future hydrological system of Chamelia using the Soil and Water Assessment Tool (SWAT). The model was calibrated for 2001–2007; validated for 2008–2013; and then applied to assess streamflow response to projected future climate scenarios. Multi-site calibration ensures that the model is capable of reproducing hydrological heterogeneity within the watershed. Current water balance above the Q120 hydrological station in the forms of precipitation, actual evapotranspiration (AET), and net water yield are 2469 mm, 381 mm and 1946 mm, respectively. Outputs of five Regional Climate Models (RCMs) under two representative concentration pathways (RCPs) for three future periods were considered for assessing climate change impacts. An ensemble of bias-corrected RCM projections showed that maximum temperature under RCP4.5 (RCP8.5) scenario for near-, mid-, and far-futures is projected to increase from the baseline by 0.9 C (1.1 C), 1.4 C (2.1 C), and 1.6 C (3.4 C), respectively. Minimum temperature for the same scenarios and future periods are projected to increase by 0.9 C (1.2 C), 1.6 C (2.5 C), and 2.0 C (3.9 C), respectively. Average annual precipitation under RCP4.5 (RCP8.5) scenario for near-, mid-, and far-futures are projected to increase by 10% (11%), 10% (15%), and 13% (15%), respectively. Based on the five RCMs considered, there is a high consensus for increase in temperature but higher uncertainty with respect to precipitations. Under these projected changes, average annual streamflow was simulated to increase gradually from the near to far future under both RCPs; for instance, by 8.2% in near-, 12.2% in mid-, and 15.0% in far-future under RCP4.5 scenarios. The results are useful for planning water infrastructure projects, in Chamelia and throughout the Mahakali basin, to ensure long-term sustainability under climate change.

The objective of this research is to develop a fuzzy-based groundwater sustainability index (FGSI) model to evaluate the sustainability of groundwater system at selected cities in Asian. The new Mamdani type fuzzy-based inference system known as FGSI was developed. It contains five components and twenty-four indicators, which covers five dimensions of sustainability, namely, environmental, social, economic, mutual trust, and institutional. The FGSI model offers a novel combination of indicators, which covers aspects of groundwater quality, quantity, and management. An attempt was made to develop a robust index for estimating the groundwater sustainability. The model was evaluated for selected cities in Asian with different difuzzification methods, and compared with the conventional method. The centroid defuzzification method produced well diversified results compared with other methods, including conventional method. The overall groundwater sustainability of Hyderabad of India was estimated as highly sustainable and, Lahore of Pakistan, Bangkok of Thailand, Ho Chi Minh City of Vietnam and Yangon City of Myanmar were estimated as moderately sustainable. The FGSI model may help to policy and decision makers to provide a reliable and resilient sustainable management system in the cities by identifying the indicators for the improvement.

Prioritising aviral dhara (uninterrupted flow) over nirmal dhara (unpolluted flow) can deliver quick outcomes in the Namami Gange Programme. Treating human, municipal and industrial waste released into the Ganga is a long-term project requiring vast resources and political energy, besides behavioural change on a mass scale. But, Ganga’s dry season flows can be quickly improved by basin-scale conjunctive management of the surface water and groundwater. Irrigation in the Ganga basin today depends on tubewells far more than canals. A multipronged protocol is outlined to manage the old canal network and new hydropower storages in order to maximise irrigation benefits and improve dry season river flows.

The vast majority of farmers in sub-Saharan Africa depend on rainfed agriculture for food production and livelihood. Various factors including but not limited to rainfall variability, land degradation, and low soil fertility constrain agricultural productivity in the region. The objectives of this study were to 1) estimate the water resources potential to sustain small-scale irrigation (SSI) in Ethiopia during the dry season so as to expand food supply by growing vegetables, and 2) understand the gaps and constraints of vegetable production. The case studies were conducted in the Robit and Dangishta watersheds of the Upper Blue Nile Basin, Ethiopia. To document farmers’ cropping practices, field-level data were collected from 36 households who had been cultivating tomato (Solanum lycopersicum L.) and onion (Allium cepa L.) during the dry season (November – April). Two components of the Integrated Decision Support System (IDSS) - the Soil and Water Assessment Tool (SWAT) and Agricultural Policy Environmental eXtender (APEX) – were respectively used to assess impacts of SSI at the watershed and field-scale levels. Results suggest that there is a substantial amount of surface runoff and shallow groundwater recharge at the watershed scale. The field-scale analysis in the Robit watershed indicated that optimal tomato yield could be obtained with 500 mm of water and 200 to 250 kg/ha of urea applied with 50 kg/ ha of diammonium phosphate (DAP). In Dangishta, optimum onion yield can be obtained with 400 mm of water and 120 to 180 kg/ha of urea applied with 50 kg/ha of DAP. The field-scale simulation indicated that the average shallow groundwater recharge (after accounting for other groundwater users such as household and livestock use) was not sufficient to meet tomato and onion water demand in the dry season (October to April). The fieldscale analysis also indicated that soil evaporation attributed a significant proportion of evapotranspiration (60% for onion and 40% for tomato). Use of mulching or other soil and water conservation interventions could optimize irrigation water for vegetable production by reducing soil evaporation and thereby increasing water availability in the crop root zone.

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.

Natural wetlands are green infrastructure systems that are energy-efficient for wastewater treatment and can be found in diverse geo-environmental settings around the world. Their structure and functions, which defines the treatment efficiencies are highly varied. Wetlands over shallow bedrock and geological lineaments (weak zones) have been known to contribute to groundwater contamination. However, not many studies have been performed to understand the structure in different geological settings to identify the efficiency determining factors. Therefore, it is important to investigate the geological suitability of the natural wetlands. We examined wastewater fed natural wetlands in diverse geological settings aiming at studying the depth, geo-stability, bio-chemical interactions, and hydrogeological attributes that improve the wastewater quality, within the Musi River basin, India. The integrated geophysical scans encompassing electrical resistivity tomography (ERT), hydrogeological test, bathymetric study and hydro-chemical analysis were carried out to explore the physical structure and hydro-dynamic processes in the wetlands. ERT investigations showed that, the depth to bedrock up to 20–25 m devoid of geo-fractures (lineaments) indicated the effective depth of saturated zone as a passable scope for potential bio-chemical interactions, implying the proportionality of the deep seated (deep bedrock) wetland to the pollutant removal efficiency. The lower order of electrical resistivity range 10–35 Om and hydraulic conductivity 2.938 md-1 acquired for saturated weathered zone were found catalyzing the bioremediation, sedimentation, adsorption, redox reactions and ion exchange processes. It caused the deep seated wetland removing nitrate 194.34 kgd-1 (97.18%); sulphate 333.75 kgd-1 (77.70%); phosphate 9.66 kgd-1 (82.53%); microbes 99.99%, BOD 80%, and COD 80% load with discharge 1408 m3d-1 of treated wastewater. Further, the strategies for designating the natural wetlands as wastewater treatment systems are also discussed in this paper.

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.