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The United Nation 2023 Water Conference offers a critical opportunity to catalyse actions and innovations that bring increased water security to vulnerable communities across the globe. Researchers have an important role in supporting the delivery of needed on-the-ground impact, but their work must be informed by the priorities and necessities of Global South implementors.

Climate change is affecting the agriculture, water, and energy sectors in East Africa and the impact is projected to increase in the future. To allow adaptation and mitigation of the impacts, we assessed the changes in climate and their impacts on hydrology and hydrological extremes in East Africa. We used outputs from seven CMIP-6 Global Climate Models (GCMs) and 1981–2010 is used as a reference period. The output from GCMs are statistically downscaled using the Bias Correction-Constructed Analogs with Quantile mapping reordering method to drive a high-resolution hydrological model. The Variable Infiltration Capacity and vector-based routing models are used to simulate runoff and streamflow across 68,300 river reaches in East Africa. The results show an increase in annual precipitation (up to 35%) in Ethiopia, Uganda, and Kenya and a decrease (up to 4.5%) in Southern Tanzania in the 2050s (2041–2070) and 2080s (2071–2100). During the long rainy season (March–May), precipitation is projected to be higher (up to 43%) than the reference period in Southern Ethiopia, Kenya, and Uganda but lower (up to -20%) in Tanzania. Large parts of Kenya, Uganda, Tanzania, and Southern Ethiopia show an increase in precipitation (up to 38%) during the short rainy season (October–December). Temperature and evapotranspiration will continue to increase in the future. Further, annual and seasonal streamflow and hydrological extremes (droughts and floods) are projected to increase in large parts of the region throughout the 21st century calling for site-specific adaptation.

The projected climate change substantially impacts agricultural productivity and global food security. The cropping system models (CSM) can help estimate the effects of the changing climate on current and future crop production. The current study evaluated the impact of a projected climate change under shared socioeconomic pathways (SSPs) scenarios (SSP2-4.5 and SSP5-8.5) on the grain yield of winter wheat in the North China Plain by adopting the CSM-DSSAT CERES-Wheat model. The model was calibrated and evaluated using observed data of winter wheat experiments from 2015 to 2017 in which nitrogen fertigation was applied to various growth stages of winter wheat. Under the near-term (2021–2040), mid-term (2041–2060), and long-term (2081–2100) SSP2-4.5 and SSP5-8.5 scenarios, the future climate projections were based on five global climate models (GCMs) of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The GCMs projected an increase in grain yield with increasing temperature and precipitation in the near-term, mid-term, and long-term projections. In the mid-term, 13% more winter wheat grain yield is predicted under 1.3 C, and a 33 mm increase in temperature and precipitation, respectively, compared with the baseline period (1995–2014). The increasing CO2 concentration trends projected an increase in average grain yield from 4 to 6%, 4 to 14%, and 2 to 34% in the near-term, mid-term, and long-term projections, respectively, compared to the baseline. The adaptive strategies were also analyzed, including three irrigation levels (200, 260, and 320 mm), three nitrogen fertilizer rates (275, 330, and 385 kg ha-1 ), and four sowing times (September 13, September 23, October 3, and October 13). An adaptive strategy experiments indicated that sowing winter wheat on October 3 (traditional planting time) and applying 275 kg ha-1 nitrogen fertilizer and 260 mm irrigation water could positively affect the grain yield in the North China Plain. These findings are beneficial in decision making to adopt and implement the best management practices to mitigate future climate change impacts on wheat grain yields.

Improving the preparedness of agricultural systems to future climate-change-induced phenomena, such as drought-induced water stress, and the predictive analysis of their vulnerability is crucial. In this study, a hybrid modeling approach based on the SWAT model was built to understand the response of major crops and streamflow in the Bouregreg catchment in Morocco to future droughts. During dry years, the simulation results showed a dramatic decrease in water resources availability (up to -40%) with uneven impacts across the study catchment area. Crop-wise, significant decreases in rainfed wheat productivity (up to -55%) were simulated during future extremely dry growing seasons.

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.

This paper follows the transition from ethnobotany to a deeper scientific understanding of the food and medicinal properties of African agroforestry tree products as inputs into the start of domestication activities. It progresses on to the integration of these indigenous trees as new crops within diversified farming systems for multiple social, economic and environmental benefits. From its advent in the 1990s, the domestication of indigenous food and non-food tree species has become a global programme with a strong African focus. This review of progress in the third decade is restricted to progress in Africa, where multi-disciplinary research on over 59 species has been reported in 759 research papers in 318 science publications by scientists from over 833 research teams in 70 countries around the world (532 in Africa). The review spans 23 research topics presenting the recent research literature for tree species of high priority across the continent, as well as that in each of the four main ecological regions: the humid zone of West and Central Africa; the Sahel and North Africa; the East African highlands and drylands; and the woody savannas of Southern Africa. The main areas of growth have been the nutritional/medicinal value of non-timber forest products; the evaluation of the state of natural resources and their importance to local people; and the characterization of useful traits. However, the testing of putative cultivars; the implementation of participatory principles; the protection of traditional knowledge and intellectual property rights; and the selection of elite trees and ideotypes remain under-researched. To the probable detriment of the upscaling and impact in tropical agriculture, there has been, at the international level, a move away from decentralized, community-based tree domestication towards a laboratory-based, centralized approach. However, the rapid uptake of research by university departments and national agricultural research centres in Africa indicates a recognition of the importance of the indigenous crops for both the livelihoods of rural communities and the revitalization and enhanced outputs from agriculture in Africa, especially in West Africa. Thus, on a continental scale, there has been an uptake of research with policy relevance for the integration of indigenous trees in agroecosystems and their importance for the attainment of the UN Sustainable Development Goals. To progress this in the fourth decade, there will need to be a dedicated Centre in Africa to test and develop cultivars of indigenous crops. Finally, this review underpins a holistic approach to mitigating climate change, as well as other big global issues such as hunger, poverty and loss of wildlife habitat by reaping the benefits, or ‘profits’, from investment in the five forms of Capital, described as ‘land maxing’. However, policy and decision makers are not yet recognizing the potential for holistic and transformational adoption of these new in

Existing climate projections and impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications. This study evaluates future scenarios of extreme climate indices from the list of the Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali are made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low-and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors is undertaken. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. The compounding effects of the increase in extreme temperature and precipitation events will have largely negative implications for the six climate-sensitive sectors considered here.

Sri Lanka has no water scarcity within the country, and per capita, water availability is adequate to cater for the country’s estimated peak population. Nevertheless, the frequent variability of spatial and temporal water availability and extreme events have built up a water scarcity in Sri Lanka, which has been observed during the last two to three decades. Therefore, effective and efficient water governance is most important in today’s context, and regular review and amendment of policies, laws, and regulations are crucial to mitigate water scarcity. Although a few attempts were initiated, none of them succeeded. In this study, historical and present water governance mechanisms, including coordinating mechanisms and implementing water management agencies in Sri Lanka, were comprehensively reviewed. Further, the previously proposed water policies, their status and reasons for the failures of policies were discussed. Finally, the formulation of a novel institutional arrangement or altering the existing institutional arrangement with shared data and allocating non-shared responsibilities to each institution is suggested for better water governance in Sri Lanka.

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.

Food, land, and water systems are facing unprecedented change. The world’s population is projected to grow to approximately 10 billion people by 2050, while aging and declining in some regions. Global average incomes are expected to keep increasing at a slow but steady pace. With increasing incomes and the ability of consumers to purchase more and better food in combination with population growth, food demand is projected to grow substantially over the next three decades. Meanwhile, demographic changes and economic development also drive urbanization, migration, and structural transformation of rural communities. At the same time changes to precipitation and temperature as well as the occurrence of extreme events driven by climate change are becoming more prevalent and impacting society and the environment. Currently, humanity is approaching or exceeding planetary boundaries in some areas, with over-use of limited productive natural resources such as water and phosphate, net emissions of greenhouse gases, and decreases in biodiversity. Much is published about food and agriculture and the supporting/underpinning land and water systems, but no single source focuses regularly and systematically on the future of agriculture and food systems, particularly on the challenges and opportunities faced by developing countries. This working paper is part of an effort by the CGIAR foresight team to help fill that gap. The effort recognizes that there is much to learn from past experience, and there are clearly many urgent and immediate challenges, but given the pace and complexity of change we are currently experiencing, there is also an increasing need to look carefully into the future of food, land, and water systems to inform decision making today.

Understanding the spatiotemporal distribution of future droughts is essential for effective water resource management, especially in the Mediterranean region where water resources are expected to be scarcer in the future. In this study, we combined meteorological and hydrological drought indices with the Soil and Water Assessment Tool (SWAT) model to predict future dry years during two periods (2035–2050and 2085–2100) in a typical Mediterranean watershed in Northern Morocco, namely, Bouregreg watershed. The developed methodology was then used to evaluate drought impact on annual water yields and to identify the most vulnerable sub-basins within the study watershed. Two emission scenarios (RCP4.5 and RCP8.5) of a downscaled global circulation model were used to force the calibrated SWAT model. Results indicated that Bouregreg watershed will experience several dry years with higher frequency especially at the end of current century. Significant decreases of annual water yields were simulated during dry years, ranging from -45.6% to -76.7% under RCP4.5, and from -66.7% to -95.6% under RCP8.5, compared to baseline. Overall, hydrologic systems in sub-basins under the ocean or high-altitude influence appear to be more resilient to drought. The combination of drought indices and the semi-distributed model offer a comprehensive tool to understand potential future droughts in Bouregreg watershed.

With the objective to provide a basis for regional climate models (RCMs) selection and ensemble generation for climate impact assessments, we perform the first ever analysis of climate projections for Western Nepal from 19 RCMs in the Coordinated Regional Downscaling Experiment for South Asia (CORDEX-SA). Using the climate futures (CF) framework, projected changes in annual total precipitation and average minimum/maximum temperature from the RCMs are classified into 18 CF matrices for two representative concentration pathways (RCPs: 4.5/8.5), three future time frames (2021–2045/2046–2070/2071–2095), three geographic regions (mountains/hills/plains) and three representative CF (low-risk/consensus/ high-risk). Ten plausible CF scenario ensembles were identified to assess future water availability in Karnali basin, the headwaters of the Ganges. Comparison of projections for the three regions with literature shows that spatial disaggregation possible using RCMs is important, as local values are often higher with higher variability than values for South Asia. Characterization of future climate using raw and bias-corrected data shows that RCM projections vary most between mountain and Tarai plains with increasing divergence for higher future and RCPs. Warmer temperatures, prolonged monsoon and sporadic rain events even in drier months are likely across all regions. Highest fluctuations in precipitation are projected for the hills and plains while highest changes in temperature are projected for the mountains. Trends in change in annual average discharge for the scenarios vary across the basin with both precipitation and temperature change influencing the hydrological cycle. CF matrices provide an accessible and simplified basis to systematically generate application-specific plausible climate scenario ensembles from all available RCMs for a rigorous impact assessment.

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

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.

Billions of people currently lack clean water and sanitation. By 2050 the global population will have grown to nearly 10 billion, over two-thirds of whom will live in urban areas. This Voices asks: what are the research and water-management priorities to ensure clean water and sanitation in the world’s cities?

As the scientific consensus concerning global climate change has increased in recent decades, research on potential impacts of climate change on water resources has been given high importance. However in Sub-Saharan Africa, few studies have fully evaluated the potential implications of climate change to their water resource systems. The Volta River is one of the major rivers in Africa covering six riparian countries (mainly Ghana and Burkina Faso). It is a principal water source for approximately 24 million people in the region. The catchment is primarily agricultural providing food supplies to rural areas, demonstrating the classic water, food, energy nexus. In this study an Integrated Catchment Model (INCA) was applied to the whole Volta River system to simulate flow in the rivers and at the outlet of the artificial Lake Volta. High-resolution climate scenarios downscaled from three different Global Climate Models (CNRM-CM5, HadGEM2-ES and CanESM2), have been used to drive the INCA model and to assess changes in flow by 2050s and 2090s under the high climate forcing scenario RCP8.5. Results show that peak flows during the monsoon months could increase into the future. The duration of high flow could become longer compared to the recent condition. In addition, we considered three different socio-economic scenarios. As an example, under the combined impact from climate change from downscaling CNRM-CM5 and medium+ (high economic growth) socio-economic changes, the extreme high flows (Q5) of the Black Volta River are projected to increase 11% and 36% at 2050s and 2090s, respectively. Lake Volta outflow would increase +1% and +5% at 2050s and 2090s, respectively, under the same scenario. The effects of changing socio-economic conditions on flow are minor compared to the climate change impact. These results will provide valuable information assisting future water resource development and adaptive strategies in the Volta Basin.

South Asiaapos;s groundwater economy stands at the threshold of a revolution in adoption of solar irrigation pumps (SIPs). This has potential to unlock the regionapos;s perverse energy-groundwater nexus. In much of South Asia, the price of energy used in irrigation, the only surrogate for water price, fails to signal the abundance or scarcity of groundwater, resulting in myriad distortions. We analyse these in South Asiaapos;s eight distinct energy-groundwater interaction settings. We then explore SIP promotion policies to ease pressure on scarce groundwater in South Asiaapos;s apos;groundwater depletion zoneapos; and accelerate groundwater irrigation for poverty reduction in its apos;groundwater abundance zoneapos;.

Purpose - Agricultural intensification to meet the food needs of the rapidly growing population in developing countries affects water quality. In regions such as the Lake Tana basin, knowledge is lacking on measures to reduce non-point source pollutants in humid tropical monsoon climates. The aim of this paper was, therefore, to develop a non-point model that can predict the placement of practices to reduce the transport of sediment and phosphorus (P) in a (sub) humid watershed.; Materials and methods - In order to achieve the objective, hydrometeorological, sediment, and P data were collected in the watershed since 2014. The parameter efficient semi-distributed watershed model (PED-WM) was calibrated and validated in the Ethiopian highlands to simulate runoff and associated sediments generated through saturation excess. The P module added to PED-WM was used to predict dissolved (DP) and particulate P (PP) loads aside from discharge and sediment loads of the 700 ha of the Awramba watershed of Lake Tana basin. The PED-WM modules were evaluated using the statistical model performance measuring techniques. The model parameter based prediction of source areas for the non-point source sediment and P was also evaluated spatially and compared with the Topographic Wetness Index (TWI) of the watershed.; Results and discussion - The water balance component of the non-point source model performed well in predicting discharge, sediment, DP, and PP with NSE of 0.7, 0.65, 0.65, and 0.63, respectively. In addition, the predicted discharge followed the hydrograph with insignificant deviation from its pattern due to seasonality. The model predicted a sediment yield of 28.2 t ha-1 year-1 and P yield of 9.2 kg ha-1 year-1 from Awrmaba. Furthermore, non-point source areas contributed to 2.7 kg ha-1 year-1 (29%) of DP at the outlet. The main runoff and sediment source areas identified using PED-WM were the periodically saturated runoff areas. These saturated areas were also the main source for DP and PP transport in the catchment.; Conclusions - Using the PED-WM with the P module enables the identification of the source areas as well as the prediction of P and sediment loading which yields valuable information for watershed management and placement of best management practices.

Background: Sub-Saharan Africa (SSA) has embarked on a new era of dam building to improve food security and promote economic development. Nonetheless, the future impacts of dams on malaria transmission are poorly understood and seldom investigated in the context of climate and demographic change. Methods: The distribution of malaria in the vicinity of 1268 existing dams in SSA was mapped under the Intergovernmental Panel on Climate Change (IPCC) representative concentration pathways (RCP) 2.6 and 8.5. Population projections and malaria incidence estimates were used to compute population at risk of malaria in both RCPs. Assuming no change in socio-economic interventions that may mitigate impacts, the change in malaria stability and malaria burden in the vicinity of the dams was calculated for the two RCPs through to the 2080s. Results were compared against the 2010 baseline. The annual number of malaria cases associated with dams and climate change was determined for each of the RCPs. Results: The number of dams located in malarious areas is projected to increase in both RCPs. Population growth will add to the risk of transmission. The population at risk of malaria around existing dams and associated reservoirs, is estimated to increase from 15 million in 2010 to 21–23 million in the 2020s, 25–26 million in the 2050s and 28–29 million in the 2080s, depending on RCP. The number of malaria cases associated with dams in malarious areas is expected to increase from 1.1 million in 2010 to 1.2–1.6 million in the 2020s, 2.1–3.0 million in the 2050s and 2.4–3.0 million in the 2080s depending on RCP. The number of cases will always be higher in RCP 8.5 than RCP 2.6. Conclusion: In the absence of changes in other factors that affect transmission (e.g., socio-economic), the impact of dams on malaria in SSA will be significantly exacerbated by climate change and increases in population. Areas without malaria transmission at present, which will transition to regions of unstable transmission, may be worst affected. Modifying conventional water management frameworks to improve malaria control, holds the potential to mitigate some of this increase and should be more actively implemented.

Planning adaptation strategies in response to climate change (CC) can be a daunting task, especially in regions such as the Koshi Basin in the Himalayas; where CC impacts are still uncertain. This paper recommends targeting adaptation strategies by focusing on changes in variability between the past and future climates at smaller scales. The Soil and Water Assessment Tool (SWAT) and the Indicators of Hydrologic Alteration (IHA) are used for analysis. Results show: (i) higher maximum precipitation during monsoon and post-monsoon, and lower maximum precipitation during winter; (ii) increase in precipitation and flows in the trans mountain region during all seasons, except for flows during monsoon; (iii) increase in post-monsoon precipitation and routed flow volumes; (iv) decrease in precipitation during winter and routed flow volumes in all the regions, except the trans mountain region; and (v) increase in frequency of high peak flows and decrease in baseflows.

A simulation study has been carried out using the InfoCrop mustard model to assess the impact of climate change and adaptation gains and to delineate the vulnerable regions for mustard (Brassica juncea (L.) Czernj. Cosson) production in India. On an all India basis, climate change is projected to reduce mustard grain yield by ~2 % in 2020 (2010–2039), ~7.9 % in 2050 (2040–2069) and ~15 % in 2080 (2070–2099) climate scenarios of MIROC3.2.HI (a global climate model) and Providing Regional Climates for Impact Studies (PRECIS, a regional climate model) models, if no adaptation is followed. However, spatiotemporal variations exist for the magnitude of impacts. Yield is projected to reduce in regions with current mean seasonal temperature regimes above 25/10 C during crop growth. Adapting to climate change through a combination of improved input efficiency, additional fertilizers and adjusting the sowing time of current varieties can increase yield by ~17 %. With improved varieties, yield can be enhanced by ~25 % in 2020 climate scenario. But, projected benefits may reduce thereafter. Development of short-duration varieties and improved crop husbandry becomes essential for sustaining mustard yield in future climates. As climatically suitable period for mustard cultivation may reduce in future, short-duration (lt;130 days) cultivars with 63 % pod filling period will become more adaptable. There is a need to look beyond the suggested adaptation strategy to minimize the yield reduction in net vulnerable regions.

This review paper intends to portray current scenario of agricultural productivity through yields and gaps of five major crops; wheat, cotton, rice, maize and sugarcane. The review discusses major constraints, identifies future prospects and makes policy recommendations for enhanced agricultural productivity in Pakistan. The review revealed that in Pakistan, on average current yield of wheat, cotton, rice, maize and sugarcane is 2.26, 1.87, 2.88, 1.77 and 48.06 tons per hectare, respectively against 6.80, 4.30, 5.20, 9.20 and 300 tons per hectare potential yield of wheat, cotton, rice, maize and sugarcane, respectively, obtained through research. This reflects a yield gap of 67, 57, 45, 81 and 84 % between average and potential yield of wheat, cotton, rice, maize and sugarcane, respectively. The review also informed that current Pakistan’s average yield of wheat, cotton, rice, maize and sugarcane is 70, 53, 61, 82 and 60%, respectively lower than the average yields obtained internationally. Major constraints include agronomic, irrigation management, environmental, technological, institutional and socio-economic constraints. Future prospects include upscaling of modern technology, enhanced seed production, improved inputs availability and use, improved irrigation, improved agriculture-education-training-research- extension-nexus, reclamation of salinized lands, improved agricultural credit and support price policies. Recommendations include improving agricultural research and extension systems, accelerating diffusion and adoption of latest agriculture technologies and inputs, enhancing good quality seed production, improving irrigation water management and improving reclamation and drainage.

The Water Futures and Solutions Initiative (WFaS) is a cross-sector, collaborative global project. Its objective is to developing scientific evidence and applying systems analysis to help identify water-related policies and management practices that work together consistently across scales and sectors to improve human well-being through water security. The Water Futures and Solutions (WFaS) initiative has produced a consistent and comprehensive projection for global possible water futures. Focusing on the near future until the 2050s, WFaS assessed how water future changes over time, employing a multi-model projection.

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

A review of global water demand projections (WDPs) show substantial overpredictions or under-predictions. The pre-1990 WDPs, with population as the main driver of change, overpredicted current water use by 20 to 130%. The post-1990 WDPs, with sophisticated modeling frameworks, show substantial underestimation under the ‘business-as-usual’ scenarios and are more downward biased under sustainable scenarios. Overall, the value of long-term country-level projections in global WDPs is inadequate for local water resource planning. To increase the accuracy and value of global WDPs, future WDPs should take into account the spatial variation and influence of rapidly changing key exogenous and endogenous drivers of water demand in different sectors across and within countries, and provide a sensitivity analysis of projections.

The basaltic aquifers of the Upper Bhima River basin in southern India are heavily utilized for small-scale agriculture but face increasing demand-related pressures along with uncertainty associated with climate change impacts. To evaluate likely groundwater resource impacts over the coming decades, a regional groundwater flow model for the basin was developed. Model predictions associated with different climate change and abstraction scenarios indicate that the continuation of current rates of abstraction would lead to significant groundwater overdraft, with groundwater elevations predicted to fall by -6 m over the next three decades. Groundwater elevations can however be stabilized, but would require 20–30% of the mean surface water discharge from the basin to be recharged to groundwater, along with reductions in pumping (5–10%) brought about by improved water efficiency practices and/or shifts towards lower-water use crops. Modest reductions in pumping alone cannot stabilize groundwater levels; targeted conjunctive use and improved water use efficiency are also needed.

The Melamchi Water Supply Project (MWSP) is designed to minimize the shortage of drinking water in the Kathmandu valley. Although the project was supposed to be completed by 2008, due to various problems, it is still diffi cult to forecast the exact date of completion. This paper quantifi es the downstream effects of diverting water from the Melamchi (Stage-I),Yangri (Stage-II) and Larke (Stage-III) rivers under current as well as future climate scenarios. The Soil Water Assessment Tool (SWAT) was used in the analysis. Result shows that in the Stage-I water transfer plan, average infl ow reduction in the immediate downstream sub-basin in the dry and wet seasons are 36% and 7% respectively, where as in Stage-II the infl ow reductions are 38% for the dry season and 8% for the wet season. In Stage-III, infl ow reductions are 38% in the dry season and 7% in the wet season.; The impact of the water transfer schemes on various changes in water management within the Melamchi River irrigation command area was also tested. BUDGET (soil, water and salt balance) model was used to quantify crop water requirement of Melamchi River command area when the irrigated area is increased and the cropping pattern is changed. Simulation results of crop water requirement in intensive water use conditions show that present Melamchi River command area can be increased by 2.2 times under current climate projection, whereas the area can be increased 1.4 times in 2030s and by 2.0 times in 2050s.

This paper examines the nexus between milk production and water use in India. The nexus is examined in the context of extended consumptive water use (CWU) of milk production beyond drinking water. It includes the real CWU (evapotranspiration (ETa) that occurs during the production of green fodder and feed grains) and the virtual CWU (ETa embedded in by-products for animal feed). The real CWU appears as large as that of sugarcane, and the real and virtual CWU combined is as large as that of rice. However, milk production generates more value than the outputs of rice and sugarcane combined. Sustainable water use and agricultural growth in major milk-producing areas require a drastic reduction in groundwater CWU, which, at present, exceeds natural recharge. It is suggested that diversifying to a mix of milk and high-value (but low water consuming) crops can reduce groundwater CWU while ensuring higher total output.

Agriculture is at the forefront of the development objectives of the republics of Central Asia (CA). Since independence in 1991, these countries have undergone transitions from being centrally planned economies to market-oriented systems, which did not include the creation of agricultural extension systems. This paper provides information on the current status of the agricultural extension systems in CA with special reference to Kyrgyzstan, Tajikistan and Uzbekistan. We reviewed the existing extension strategies, donor- and state-driven initiatives to revitalize the agricultural extension systems, informal linkages that nongovernmental organizations play in helping a limited number of farmers, and provided recommendations on ways to further improve the agricultural extension services in CA. The information related to each country was analyzed separately. This is because, after independence, each republic in CA had initiated their agricultural reforms with specific objectives and has now established their unique agricultural systems that differ contextually. However, due to having the same history and agricultural system that existed during the Soviet times, we tried to give a historical perspective to the unified agricultural extension system that existed before independence.

The Olifants River Basin is located in the north-eastern part of the South Africa and southern to Mozambique.The Olifants River passes through three provinces of South Africa (Gauteng, Mpumalanga, Limpopo Province), through the Kruger National Park, into Mozambique, where it joins the Limpopo . it is the home to nearly 10 % of the total population of South Africa. The climate is semi-arid, with rain falling primarily during the summer (November to March). Precipitation averages 630 mm and potential evaporation is 1700mm. In South Africa, significant mining, industrial and agricultural activities (including intensive irrigation schemes) are concentrated within the catchment, so it is of considerable importance for the country’s economy.However, Water is especially scarce in this basin. Like many river basins in South Africa, water resources in the Olifants river basin are almost fully allocated. Water demand management, especially in the agricultural sector, which is the biggest user, is one of the possible solutions being considered by the South African Department of Water Affairs and Forestry (DWAF). The basin also faces significant water quality problems, due to mining activities, industries, power generation and agricultural use of water. The impact of these pollutions (high salinity, high concentrations of metals, low pH) are probably multiple with serious ecological impacts. Particularly of concern in the downstream Kruger National Park which is a major tourist attraction in South Africa and more importantly very worrisome health impacts, since some people are drinking surface water without any treatment. In South Africa it is of prime importance to maintain a minimum level of water quality and quantity in the rivers in order to maintain a healthy biophysical environment (DWAF, 1997). This requirement, referred to as the ‘Ecological Reserve’, is as important in the South African legislation as meeting the basic human needs and must be met before any other users can abstract water. Main activities on the Olifants basin have been done through the Challenge Program on Water and Food and the WETwin project but not only.

This study combines climate change (CC), hydrological and water resource evaluation models to assess the impact of one downscaled mid-range CC scenario (A1B) on the performance of existing and planned irrigation and hydropower schemes in the Volta basin. The models were run (1983-2100) to simulate the CC scenario in combination with three development scenarios, each reflecting different levels of water resource development in the basin. Results indicate a general trend of declining rainfall and increasing potential evapotranspiration in the basin. This trend was found to have caused: i) a significant reduction in flows at key stream gauge locations; ii) an increase in average basin-wide per hectare irrigation requirement and iii) a significant reduction in the percentage of the potential hydropower that could be generated in the basin. This has the tendency to undermine the economic development of the riparian countries unless due consideration is given to these impacts and suitable adaptation measures introduced.

In Lao PDR, one of the less developed countries, water represents a valuable natural resource via the development of hydropower dams and irrigation schemes. In the lower part of the Nam Ngum River Basin, the Vientiane plain is one of the largest food production areas of the country and the largest irrigated area in Lao PDR. While food demand is expected to continue to increase in the future, hydropower dams are under rapid development in the upper part of the basin, modifying the seasonal distribution of the river flow regimes. This study aims at assessing the current water supply and agricultural water demand in the Vientiane Plain and concluding whether the water resource is or may become a limiting factor for food production. The agricultural water demand is assessed from two types of data (characteristics of large-scale pumping stations and official statistics on irrigated areas) and using remote sensing analyses. Flow measurements of the Nam Ngum River were used to quantify the water supply. A 43-year time series (1962-2004) of daily river discharge was reconstructed from actual discontinuous data recorded in the river reach where most of the pumping stations are found. Distinctions in the water resource assessment were made between pristine conditions (before the construction of the hydropower dams) and current conditions of water infrastructure development. A comparison of the water supply and demand indicates that during the 4 driest months of the year (January to April) when the river reaches its minimum level and the irrigation water demand is the highest, pumped volumes represent less than 30% of the river discharge. This ratio should decrease as new hydropower dams are built, storing and releasing more water during the wet and the dry season, respectively. These figures indicate that the availability of water in the Nam Ngum River is not a limiting factor for irrigation, even during the dry seasons of exceptionally dry years. The water demand could exceptionally exceed the water supply in the case of an extreme scenario of irrigation development with irrigated areas 3-fold larger than the current ones. Next analyses will consist in assessing how this water balance will be altered by the development of new hydropower dams and irrigation projects. Possible uses of water surplus will be prioritized, depending on their economic viability and benefits.

Growing global population and a combination of dietary change, biofuels production, urban and industrial water demand and climate change will see food crises becoming more frequent in the next 40 years. Food and feed production must double to feed 9.1 billion people in 2050. This will require using twice as much water as at present or increasing water productivity. It is argued that we need a Blue-Green revolution to deliver water productivity increases. This revolution will depend on increases of both rainfed and irrigated production and has to include improvements in soil fertility and institutional and governance of agriculture and natural resources.

A framework of climate change (CC) analysis is developed using the Decision Support Framework models of the Mekong River Commission (SWAT hydrological, IQQM basin simulation and hydrodynamic iSIS models) to analyze impacts of CC and water resources development on Mekong flow regime. This analysis is based on six model run scenarios defined as combinations of a development scenario, either baseline or 20-year plan and a climate dataset, either observed or from regional downscaling model simulating the past in 1985-2000 or projecting the future climate in 2010-2050. The projected climate shows a slight increase in precipitation throughout the Mekong basin except in the delta. Temperature is projected to increase by 0.023C/year. During the high-flow season, impacts of CC and development are in contrasting directions. The development brings a decrease of about -8 to -17% of river flow but CC increases +2 to +11%. The combined effect causes changes in discharge from +3% to -13% depending on CC scenarios and location of stations. In the low-flow season, both CC and development will increase river flow, with +30 to +60% due to development and +18 to +30% due to CC. The combined effect is up to +40 to +76%. While development reduces the flooded area, CC will make it larger in a wet year. Salinity intrusion area in the delta could be larger in a dry year under CC but development can reduce the affected area. The analysis shows that adaption strategies are needed to achieve the development objectives under CC conditions.

Lake Tana, located in the headwaters of the Blue Nile, is valuable for many people including the communities who live around the lakeshore and those who live immediately downstream. The area has been identified as a region for hydropower and irrigation development, vital for economic growth in Ethiopia. A multidisciplinary study was conducted to assess the possible impacts of this development. This study found that current development has benefited some local people but adversely affected others. Future development will exacerbate pressure on the lake. Hard choices must be made about how the water is best utilized. It is important that all stakeholders, including local people, are involved in the decision-making process.

Agriculture development has been the main strategy for the socioeconomic development in the country since time immemorial, even though its contribution to GDP has been declining recently. Successive governments of Sri Lanka since independence have invested heavily in the irrigated agriculture sector to address the food security concerns of the country. The continuous investment in irrigation was required to address problems such as spatial and temporal variations in monsoonal rainfall in the country, which has a serious negative impact on food production and livelihoods of people. The need for pursuing irrigation development and management has become more important in the country in the face of rapid population growth and increasing food prices in the world market. In this context, managing irrigation schemes for productivity increase is becoming increasingly important and different irrigation management models have also emerged through attempts made in this direction by countries including Sri Lanka, where irrigation plays a leading role in food production and nation development. Farmers’ active involvement in irrigation management, especially operation and maintenance (Oamp;M) and decision-making as well, has been identified as a key requirement to attain productivity goals and the sustainability of irrigation systems. This paper aims at reviewing participatory irrigation management approaches adopted in medium and major irrigation systems in Sri Lanka with a view to identifying their past and present trends and future directions. The review will contribute to an improved understanding by policymakers, managers of irrigation schemes and farmers of the role of participatory irrigation management, its past and present including institutional structures, responsibilities and performance and the directions it should take to meet future challenges as a dynamic institutional mechanism. As all the medium and major irrigation schemes in the country are jointly managed by farmers and government agencies, the inferences drawn from the review would be important for the agencies and farmers alike to introduce necessary changes in their programs to address future needs and requirements.

The global demand for water in agriculture will increase over time with increasing population, rising incomes, and changes in dietary preferences. Increasing demands for water by industrial and urban users, and water for the environment will intensify competition. At the same time, water scarcity is increasing in several important agricultural areas.We explore several pathways for ensuring that sufficient food is produced in the future, while also protecting the environment and reducing poverty. We examine four sets of scenarios that vary in their focus on investments in rainfed agriculture and irrigation, and the role of international trade in adjusting for national disparities in water endowments. Rainfed agriculture holds considerable potential but requires adequate mechanisms to reduce inherent risks. Irrigation expansion is warranted in places where water infrastructure is underinvested such as sub-Saharan Africa. In South Asia the scope for improving irrigation performance and water productivity is high. International trade can help alleviate water problems in water-scarce areas, subject to economic and political considerations. We examine also a regionally optimized scenario that combines investments in rainfed and irrigated agriculture with strategic trade decisions. Compared to ‘business as usual’, this scenario reduces the amount of additional water required to meet food demands by 2050 by 80%. Some of that water could be made available for the environment and other sectors. We conclude that there are sufficient land and water resources available to satisfy global food demands during the next 50 years, but only if water is managed more effectively in agriculture.

The authors were asked to answer the question ‘small-scale irrigation: is this the future?’. Taking as a starting point the analyses and of the IWMI-FAO-ADB study on Revitalizing Asia’s Irrigation and its key strategies, the paper compares atomistic irrigation, traditional small-scale and large-scale irrigation options, outcomes and potentials in their socio-economic and river basin environments. Atomistic irrigation has exploded, river basins are closing and energy prices are soaring. This new reality, its benefits, its sustainability crisis, but also the potential for new strategies that this phenomenon has demonstrated must first be acknowledged.; In most countries and river basins, additional development of irrigation at whatever scale is not an option and the focus will be on improving the productivity and sustainability of existing systems. In areas where irrigation development is still possible, options remain open. Demography, market pull, water constraints and energy will largely determine the mix of atomistic, small-scale and large-scale irrigation and their evolution, expansion and decline over time.; The paper explores tactics and strategies for the modernization of existing and the potential for new large-scale systems and for supporting and sustaining atomistic and small-scale irrigation, institutional and policy innovations, and tools to facilitate dynamic planning and management of the sector, the evolution of different systems and the design of measures to support an enabling environment.; A considerable body of knowledge exists on how to support these strategies, transform large-scale irrigation systems and promote various forms of atomistic, small-scale and large-scale irrigation systems. Tools that support long-term sectoral planning and management for future investment and the design of measures to support an enabling environment are proposed. The deployment of sound water accounting and auditing systems will be critical. Planning and policy mechanisms will require looking outside the irrigation sector and this is often where effective interventions will be found.; We need to move from competition and conflict between atomistic, small-scale and large-scale irrigation to a fluid logic of complementarily, combination and convergence. For this to happen, the virtual reality of official agency outlooks, imported frameworks, and descriptions of the sectors and the basins will often need to be reformed, as a preliminary to the reform of the institutions and programmes that embody them. Then, the mobilization of resources from the public sector, the private sector and water users can be greatly enhanced and result in positive outcomes and more sustainable results, and enable new solutions to old problems that have long nagged the sector.; Changing the outlook of the sector and effecting the necessary structural and policy reforms, which are required to change decision-making on future investments in the sector will be difficult. Cap

Despite a significant growth in food production over the past half-century, one of the most important challenges facing society today is how to feed an expected population of some nine billion by the middle of the 20th century. To meet the expected demand for food without significant increases in prices, it has been estimated that we need to produce 70–100 per cent more food, in light of the growing impacts of climate change, concerns over energy security, regional dietary shifts and the Millennium Development target of halving world poverty and hunger by 2015. The goal for the agricultural sector is no longer simply to maximize productivity, but to optimize across a far more complex landscape of production, rural development, environmental, social justice and food consumption outcomes. However, there remain significant challenges to developing national and international policies that support the wide emergence of more sustainable forms of land use and efficient agricultural production. The lack of information flow between scientists, practitioners and policy makers is known to exacerbate the difficulties, despite increased emphasis upon evidence-based policy. In this paper, we seek to improve dialogue and understanding between agricultural research and policy by identifying the 100 most important questions for global agriculture. These have been compiled using a horizon-scanning approach with leading experts and representatives of major agricultural organizations worldwide. The aim is to use sound scientific evidence to inform decision making and guide policy makers in the future direction of agricultural research priorities and policy support. If addressed, we anticipate that these questions will have a significant impact on global agricultural practices worldwide, while improving the synergy between agricultural policy, practice and research. This research forms part of the UK Government’s Foresight Global Food and Farming Futures project.

The Atankwidi Catchment, which lies in the White Volta Basin in West Africa, is intensively cultivated by locals for economic gains. During dry seasons, farmers irrigate their crops, chiefly tomatoes, using shallow groundwater harvested from shallow ponds they dig using simple tools like an axe, hoe, bucket and bowls. Recent expansion in cultivated areas has brought to the fore the need to estimate the volume of shallow groundwater stored in the catchment’s underlying aquifer and to what extent it can sustain the incremental growth in irrigated areas.

We compare water availability, water use, water productivity and poverty across the diverse river basins studied by the CGIAR Challenge Program on Water and Food. Water productivity tends to be higher in drier areas and where livestock grazing is integrated with rainfed crop production. We find that links among water, food security and poverty are best understood within a historical perspective. We identify opportunities to reduce poverty through water-related interventions. The way in which waterrelated investments affect poverty is influenced by changes in demography, climate, and rural society. In most basins, these trends involve trade-offs that require good governance at local, regional and basin scales.

The riparian countries of the Nile have agreed to collaborate in the development of its water resources for sustainable socioeconomic growth. Currently there is significant potential for expansion of hydropower and irrigation in the Blue Nile River in both Ethiopia and Sudan. However, the likely consequences of upstream development on downstream flows have not been fully assessed and the water resource implications of development in both countries are unclear. Against this background, the Water Evaluation And Planning (WEAP) model was used to provide an assessment of both the current situation and a future (2015) scenario. The future scenario incorporated new irrigation and hydropower schemes on the main stem of the Nile and its principal tributaries. Data for all existing and planned schemes were obtained from the basin master plans as well as from scheme feasibility studies. Water use was simulated over a 32-year period of varying rainfall and flow. Preliminary results indicate that currently irrigation demand in Sudan is approximately 8.5 Bm3y-1 for 1.16 million hectares (mha). This compares to a total irrigation demand in Ethiopia of just 0.2 Bm3y-1. By 2015, with many existing schemes being extended in Sudan and new schemes being developed in both countries, irrigation demand is estimated to increase to 13.4 Bm3y-1 for 2.13 mha in Sudan and 1.1 Bm3y-1 for 210 thousand hectares (tha) in Ethiopia. The flow of the Blue Nile is estimated to decline from an average of 46.9 Bm3y-1 to 44.8 Bm3y-1 at the Ethiopia-Sudan border and from a current average of 43.2 Bm3y-1 to 36.2 Bm3y-1 at Khartoum (including evaporation from all reservoirs). Although total flows are reduced, greater regulation results in higher dry season flows at both locations.

Growing competition for scarce water resources is a growing business risk, a major economic threat, and a challenge for the sustainability of communities and the ecosystems upon which they rely. It is an issue that has serious implications for the stability of countries in which businesses operate, and for industries whose value chains are exposed to water scarcity. Charting our water future: Economic frameworks to inform decision-making shows that while meeting competing demands for water will be a considerable challenge, it is entirely possible to close the growing gap between water supply and demand. This report provides greater clarity on the scale of the water challenge and how it can be met in an affordable and sustainable manner. The report offers case studies from four countries with drastically different water issues, which will collectively account for 40 percent of the world’s population, 30 percent of global GDP and 42 percent of projected water demand in 2030: China, India, South Africa and Brazil. The report’s methodology identifies supply- and demand-side measures that could constitute a more cost effective approach to closing the water gap and achieve savings in each country.

This document was prepared by the Consumer Industry Team of the World Economic Forum as part of the Industry Partner Programme. Industry Partners are select member companies of the World Economic Forum that are actively involved in the Forum’s mission at the industry level. Partnership brings visibility and insight to strategic decision-making on the most important industry and cross-industry related issues and the opportunity to engage in actions of global corporate citizenship. Partners: Peter Brabeck-Letmathe, Chairman and Chief Executive Officer, Nestl; Member of the FoundationBoard of the World Economic Forum. Margaret Catley-Carlson, UN Secretary-General’s Advisory Board on Water and Sanitation. Colin Chartres, Director- General, International Water Management Institute (IWMI). E. Neville Isdell, Chairman and Chief Executive Officer, The Coca-Cola Company. Andrew N. Liveris, Chairman and Chief Executive Officer, The Dow Chemical Company. Graham Mackay, Chief Executive, SABMiller. Julia Marton-Lefvre, Director General, IUCN. David Molden, Coordinator, Comprehensive Assessment of Water Management, International Water Management Institute (IWMI). Indra Nooyi, Chairman and Chief Executive Officer, PepsiCo. Letitia Obeng, Chair, Global Water Partnership. Ralph R. Peterson, Chairman and Chief Executive Officer, CH2M HILL Companies. Klaus Schwab, Founder and Executive Chairman, World Economic Forum.

This paper seeks to identify some promising policy options which could be part of a strategic and holistic effort to address India’s future water challenges. Significant increases in agricultural water productivity would be a major factor in reducing the need for developing new water sources. Crop diversification, appropriately targeted to account for the present agricultural systems and available water resources, will increase productivity. Furthermore, much more emphasis needs to be placed on effective management of the groundwater resources through renewed efforts to enhance artificial recharge and conservation. Also, efforts should be revived to improve the existing surface irrigation systems. In particular, systems could be reconfigured to provide a more reliable water supply and allow effective community level management, where appropriate. Finally, while some of the increasing demands from domestic and industrial users will be met by the development of groundwater and reallocation of water from the agricultural sector, this will not be sufficient. Given that such conditions are emerging in states with high economic growth and relatively water scarce basins, this will require the further development of water resources. In some cases, these conditions along with the demand for reliable water for high value crops, will be part of the justification for inter-basin transfers.

This report projects India’s water futures to 2025-2050. And it incorporates the recent changes of demographic patterns and economic environments into the water demand projections. The Business as Usual (BAU) scenario in this report projects the total water demand to increase by 22 and 32 percent by 2025 and 2050, respectively, from the present level of 680 billion cubic meters (BCM). The industrial and the domestic sectors account for 85 percent of the additional demand by 2050. Groundwater dominates irrigation growth of the BAU scenario. This, combined with higher irrigation efficiencies, decreases the irrigation water demand over the 2025-2050 period. The food grain demand under the BAU scenario is projected to decrease. However, the nutritional intake will increase with more non-grain products in the diet, with non-grain products providing 54 percent of the daily calorie supply by 2050. Although the value of grain crop production shows a surplus, the BAU scenario projects substantial imports of maize and pulses and exports of rice and wheat. The BAU scenario envisaged substantial investments for increasing groundwater recharge, spreading water saving technologies, and crop productivity growth. And failing so could require substantial surface water resources, perhaps transfers between basins, especially for meeting the rapidly increasing water demand of industrial and domestic sectors.

With a rapidly expanding economy many changes are taking place in India today. The business-as-usual (BAU) scenario, which assumes the continuation of current trends of key water demand drivers, will meet the future food demand. However, it leads to a severe regional water crisis by 2050, where many river basins will reach closure, will be physically water-scarce and will have regions with severely overexploited groundwater resources. While the alternative scenarios of water demand show both optimistic and pessimistic water futures, the scenario with additional productivity growth is the most optimistic, with significant scope for reducing future water demand.

Water resource development has played a significant role in the expansion of agriculture and industry in the Olifants River Catchment. However, currently water deficit is one of the major constraints hampering development in the catchment; both the mining and agricultural sectors are producing below optimal levels because of their reliance on insufficient supplies. In this study, the Water Evaluation and Planning (WEAP) model was used to evaluate scenarios of historic, current and future water demand in the catchment. For each scenario, the WEAP model was used to simulate demand in five different sectors (rural, urban, mining, commercial forestry and irrigation) over a 70-year period of varying rainfall and hydrology. Levels of assured supply were estimated for each sector and the economic cost of failing to provide water was predicted. For the future scenarios, the impact of infrastructure development and water conservation measures were assessed. The study illustrates how a relatively simple model can provide useful insight for resource planning and management.

This paper uses 314 irrigation projects implemented from 1960-2000 in six regions worldwide to identify: (1) whether the perception of high cost of irrigation projects in SSA can be empirically supported; (2) what factors determine the costs and performance of irrigation projects; and (3) whether there are cheaper and better performing irrigation investments for SSA. This study shows that the popular view that African irrigation projects are prohibitively expensive is not tenable, and demonstrates that there are viable investment options for irrigation development in SSA.

Exploiting the nutrient and water value in wastewater through agriculture and aquaculture may also help limit uncontained pollution that results from unregulated disposal of wastewater in surface water bodies. Treatment processes form an important part of wastewater reuse strategies, alongside other measures to protect health, but a concerted effort to promote capacity at all levels is required to enable the benefits of wastewater reuse to be realized.

The use of shallow wells, equipped with small pumps, to lift groundwater has spread rapidly in many agricultural regions of tropical monsoonal Asia. In Sri Lanka, the rapid and pervasive invasion of agro-wells and pumps drew the attention of policymakers and researchers, but many questions were left unanswered due to lack of research in the area. This study aims to fill this gap in knowledge, based on observations and data obtained in field surveys conducted in major and minor irrigation schemes in the dry zone of Sri Lanka. This report gives the key findings of this study into the pattern, extent and causes of the spread and use of agro-wells and pumps in traditional villages and irrigated settlement schemes. It investigates farmer investments in agro-wells and pumps, the private internal rate of return to these investments, the economic viability of investments and incentives for farmers to make investments

Its focus is on small-scale agricultural water use technologies (irrigation in its widest sense) in sub-Saharan Africa. Section 1 provides an overview of the current status of natural resources, rural development and poverty, irrigation investment trends, and emerging new irrigation technology options. Section 2 discusses IPTRID’s contribution to these emerging options. Section 3 proposes some ideas for consideration in terms of the future directions of IPTRID’s work on small-scale irrigation in sub-Saharan Africa.

The world is facing severe and growing challenges in maintaining water quality and meeting the rapidly growing demand for water resources. In addition, water used for irrigation, the largest use of water in most developing countries, will likely have to be diverted increasingly to meet the needs of urban areas and industry whilst remaining a prime engine of agricultural growth. Finally, environmental and other in-stream water demands become more important as economies develop. The river basin has been acknowledged to be the appropriate unit of analysis to address these challenges facing water resources management; and modeling at this scale can provide essential information for policy makers in their decisions on allocation of resources. This paper reviews the state of the art of modeling approaches to integrated water resources management at the river basin scale, with particular focus on the potential of coupled economic hydrologic models, and concludes with directions for future modeling exercises.

Prepared as a paper to support IMPSA Policy Paper 3 - Achieving high performance: Strategic institutional framework for the management of irrigation systems and building farmersapos; organizations.

Symposium on irrigation design for management, 16-18 February 1987, Kandy, Sri Lanka