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Irrigation and fertilization are vital to increasing crop yield, but their application often exceeds crop requirements. Excessive fertilization under inefficient irrigation depletes the already scarce water resources while contributing to water pollution. To overcome these problems, the introduction of fertigation in combination with modern irrigation technologies has been promoted in the North China Plain (NCP), but farmers have been reluctant to adopt such technologies. To better understand the current situation and farmers' perceptions, we performed a case study in the People's Victory Canal Irrigation District (PVCID) of NCP. A field survey was carried out using a participatory approach, and field monitoring was conducted on a representative farm. We found that farmers are generally satisfied with their irrigation and fertilization practices, although they result in low application efficiency and distribution uniformity. In principle, the lack of knowledge about how to implement fertigation technology, the small-scale farming conditions, and the high cost of developing advanced fertigation systems are the main obstacles for fertigation adoption. We further conclude that (i) to improve the on-farm performance in terms of efficiency and uniformity of irrigation and fertilization, evidence-based guidelines are required to help farmers to implement; (ii) for effective adoption of new technologies, consideration of farmers' situation and perspectives is critical; and (iii) surface fertigation might be a good start for fertigation promotion.

Although there seems enough water available for our global food needs, there are large areas with growing water scarcity. Food security in these water scarce areas cannot be met through self-sufficiency. The only option is to become more dependent on food imports which is increasingly risky due to volatility in production and food prices. Before 2008, declining food prices and increasing global cereal production favoured the food import strategy. The 2008 world food crisis represented a shock to this strategy and renewed attention was paid to the self-sufficiency strategy. The aim of this paper is to compare the food security strategies of Egypt and Jordan, two water-stressed, increasingly populated, oil-poor countries, pre and post 2008, by means of a food-water analytical framework using FAOSTAT data. Findings show that Egypt and Jordan have many similarities in their food security situation as both are highly dependent on food imports (Egypt 50%, Jordan 95%), and both have a reduced capacity to absorb future price increases. As food imports are inevitable under the water scarce context of Egypt and Jordan, it is important to focus on how to cope with volatilities. Our analysis shows that Jordan has better absorbed the costs of rising food imports than Egypt and that Egypt is trapped by its high domestic cereal production. Having revealed the limited options available to water-scarce countries for food security, we discuss the potential of grain reserves to cope with future price hikes and production shocks.The online version contains supplementary material available at 10.1007/s12571-022-01310-y.

Applying nitrogen fertilizer is commonly used to increase yields of surface-irrigated crops, despite often low application efficiency (AE) and distribution uniformity (DU). Surface fertigation, the application of fertiliser dissolved in irrigation water, is a promising technique for improved on-farm performance. This study evaluated surface fertigation strategies in a field experiment and by modelling with WinSRFR. The field experiment was conducted in the North China Plain in 2017–2019. The aim was to test different practices and for model validation, then to develop optimisation scenarios. The study found, first, that conventional practices resulted in low AE of irrigation, around 40 % in wheat season and 60 % in maize season. DU, however, was satisfactory in both wheat and maize seasons, averaging 80 %. Second, surge border irrigation showed no significant advantage in terms of performance compared to the conventional practice of continuous border irrigation. Third, the WinSRFR model offered satisfactory accuracy compared to field-measured data; and soil infiltration parameters, such as the Kostiakov K, showed temporal variation during the crop seasons. Fourth, improved fertigation scenarios were developed by optimising the cut-off ratio in tandem with changes in border length and fertigation timing. The optimised strategies resulted in AE and DU increasing to some 90 %.

In this paper a framework is presented for comparing the values derived from the different dimensions of water, without incurring the problems of commensurability. The framework is based on the concept of opportunity cost, which values any good by what one is willing to sacrifice to get it, which is a way of comparing seemingly different things. By simulating changes to a water resource and then measuring the economic, social and environmental impacts in metrics common and accepted by each dimension, a curve of the trade-offs between each metric can be derived. This makes trade-offs intrinsic to decision-making explicit.

Developments such as climate change and a growing demand for drinking water threaten the sustainability of drinking water supply worldwide. To deal with this threat, adaptation of drinking water supply systems is imperative, not only on a global and national scale but particularly on a local scale. This investigation sought to establish characteristics that describe the sustainability of local drinking water supply. The hypothesis of this research was that sustainability characteristics depend on the context that is analysed, and therefore, a variety of cases must be analysed to reach a better understanding of the sustainability of drinking water supply in the Netherlands. Therefore, three divergent cases on drinking water supply in the Netherlands were analysed. One case related to a short-term development (2018 summer drought), and two concerned long-term phenomena (changes in water quality and growth in drinking water demand). We used an integrated systems approach, describing the local drinking water supply system in terms of hydrological, technical, and socio-economic characteristics that determine the sustainability of a local drinking water supply system. To gain a perspective on the case study findings that are broader than the Dutch context, the sustainability aspects identified were paired with global aspects concerning sustainable drinking water supply. This resulted in the following set of hydrological, technical, and socio-economic sustainability characteristics: (1) water quality, water resource availability, and impact of drinking water abstraction; (2) reliability and resilience of the technical system and energy use and environmental impact; (3) drinking water availability, water governance, and land and water use. Elaboration of these sustainability characteristics and criteria into a sustainability assessment can provide information on the challenges and trade-offs inherent in the sustainable development and management of a local drinking water supply system.

The Russian invasion of Ukraine is disrupting global agricultural commodity markets, creating pressure on wheat supplies and stocks and consequently on food prices. The wider effects are felt around the world due to the dependencies inherent to global trade. But how to assess the vulnerability of countries food security and how to deal with it? To assess for which countries food security is at risk, dependencies along with a set of coping capacity indicators to absorb shocks need to be identified. Addressing vulnerabilities at this scale requires a global food security approach, because the food security of vulnerable countries depends on measure taken by other countries, together with a holistic approach to water, energy and food security. The Russian invasion brings to the fore the need to reassess the socio-economic value of agriculture and open trade, in terms of food security for stability in vulnerable regions.

Adaptation strategies are essential to manage water demand and ensure optimal use of available water resources under climate change. Identification and prioritization of adaptation options would greatly support decision-making in drought-prone Northwest Bangladesh. This study identified climate adaptation options by literature review and stakeholder consultation, then used multi-criteria analysis to evaluate and prioritize the options. The complexity of the options was also evaluated, specifically social, institutional, and technical obstacles to their local uptake. Seventy-two adaptation options were identified, spanning six sector categories. The options were further classified as in-system dependent, i.e., options that could be implemented by local actors, or as out-system dependent, i.e., options reliant on actions by external actors. Finally, they were defined as on-farm or off-farm strategies. Transboundary cooperation to increase surface water flows was ranked as the overall top-priority option, though this option is very complex and out-system dependent. Integrated water resources management and integrated crop management were the top-ranked options in the water management and crop production management sectors, respectively. Clustering scattered households and offering training programs in on-farm water management were the most and least complex measures, respectively. Stakeholders exhibited a clear preference for higher scale out-system dependent strategies, rather than in-system dependent options focused on changing the agricultural system itself to cope with climate change. Nonetheless, it is recommended that short-term and medium-term planning focus on opportunities to implement achievable adaptation measures within the local agricultural system. Investment in complex, externally dependent strategies is important for long-term planning.

Surface irrigation worldwide exhibits low efficiency due to excessively deep percolation and runoff. To optimize surface irrigation practice, two questions must be answered simultaneously: when to irrigate and how to irrigate (what stream size to use and for how long) to meet crop water requirements. Current surface irrigation optimization models are one-dimensional, meaning they can only simulate surface water flow, neglecting subsurface flow. They therefore indicate only how to irrigate, not when to irrigate. Furthermore, the required depth of irrigation is needed as input data for optimization, though this parameter is difficult to establish accurately. In addition, the effects of different irrigation practices on crop transpiration and yield, and variations in these across an irrigated field, are unknown. The present study adopts two one-dimensional simulation models – WinSRFR (for surface flow) and SWAP (for subsurface flow) – to determine when and how best to irrigate in a blocked-end furrow irrigation system for sugarcane cultivation in southwestern Iran. SWAP is used to determine irrigation schedule, required irrigation depth and crop transpiration along furrows, while WinSRFR is used to determine the soil infiltration function and evaluate and optimize irrigation practice. The results of the combined model approach indicate that some 2.7 times more water is applied than required in current practice, imposing high waterlogging stress on sugarcane crops. According to the SWAP simulations, the required irrigation depth is some 75 mm and the number of irrigation applications can be reduced from 26 to 19. The irrigation optimization in WinSRFR indicates that irrigation depth can be reduced from 162 mm to 81 mm, resulting in application efficiency increasing from 47% to 92%. Furthermore, as furrow slope increases from 0.02% to 0.12%, optimized stream size decreases from 3.0 to 1.6 l/s and optimized irrigation cutoff times increase from 3.2 to 6.5 hrs. Overall, optimization of irrigation practice using the combined model approach could result in 63% water conservation and 22% higher sugarcane yield.

Irrigation and fertilisation are often over-applied, which exceeds crop requirements. Surface fertigation, a technique of applying pre-dissolved fertilisers together with irrigation water, seems to be a viable way to improve the on-farm performance in the North China Plain (NCP). Thus, we conducted a field experiment based on farmers’ practices from 2017 to 2019. Moreover, we calibrated and validated SWAP-WOFOST-N, a seasonal integrated agro-hydrology and crop growth model, to assess the effects of different practices on yield, water and nitrogen use efficiency (WUE and NUE) and resource loss. Lastly, we developed various scenarios using the model to determine improved strategies. The results showed that the SWAP-WOFOST and extended Soil-N model offered satisfactory accuracy when compared with field measured data for the tested domain of the hydrological and nitrogen cycle; farmers’ current irrigation and fertilisation practices resulted in low WUE and NUE, but the practice of split top-dressing nitrogen did not show significant improvement in the surface irrigation system; WUE, NUE and nitrogen loss were closely related to irrigation practices. We further concluded that an optimised irrigation practice combined with an optimal fertigation scenario is the feasible strategy to achieve sustainable crop yield, high WUE and NUE and reduced nitrogen loss.

Subsidising irrigation is a legitimate approach that governments have used to achieve a set of social objectives. Yet it may simultaneously impose negative externalities, especially in the form of environment degradation. Could subsidies be reformed to be less harmful? To answer this question requires an insight into how various kinds of subsidies work, the interplay between subsidies and externalities, and the political complexity of subsidy reform. In this paper these insights are investigated using supply-demand graphs. It is argued in this paper that a broad definition of subsidies should be used, one that includes the implicit subsidies that result from partial cost recovery. It is also shown that even without subsidies, externalities due to irrigation would still exist and that any reform of existing subsidies will counter the positive impact irrigation may have, which may not be a desirable outcome.

Groundwater depletion is a problem in many parts the world. We developed an approach to investigate the drivers of groundwater depletion in data-scarce regions. The approach combines natural and human-induced drivers, with the latter focusing on the link between human activities and government policies. We tested the approach in Wadi Zabid, Yemen. Forty years of rainfall-runoff data were analyzed, alongside changes in land cover, groundwater abstraction and related policies. No decrease in rainfall was observed, but runoff did decrease slightly. Significant expansion of agricultural lands led to increased demand for irrigation water, which was provided by drilling wells and building water harvesting/diversion structures. In Wadi Zabid, human activities, stimulated by policy measures, were the main drivers of groundwater depletion (water table here fell by 1 m/yr on average over 1972–2016). We conclude that combining natural and human-induced factors is indeed a valuable approach for investigating groundwater depletion drivers.

Organic inputs as a substitution for, or addition to, chemical fertilizers can potentially mitigate N losses. However, it is not well known how their effects on N leaching and runoff depend on application approaches. We conducted a global meta-analysis of 129 studies to compare the effects of organic inputs on N export via leaching and runoff. We compared three application approaches: chemical fertilizer N substituted by organic fertilizer with: 1) equal amounts of total N or, 2) equal amounts of mineral N and 3) additional organic fertilizer N on top of chemical fertilizer. The meta-analysis showed that organic inputs reduced overall N leaching and runoff by 15% and 29%, respectively, without compromising crop yield, and that this effect was significantly influenced by the application approach taken. Organic substitution of chemical fertilizer N with equal amounts of total N decreased both leaching and runoff by more than 30% and hardly affected crop yield. Substitution with equal amounts of mineral N generally increased crop yield by 6% but also increased N leaching by 21%. Organic inputs in addition to chemical fertilizer N did not affect leaching and runoff. The differences between application approaches were reinforced with increased treatment duration. The loss ratios of leaching and runoff were 14% and 4.5%, respectively, from chemical fertilizer, and 9.2% and 2.6%, respectively, from organic fertilizer. The optimal substitution rates differed between leaching (40–60%) and runoff (60–100%) when substitution was based on equal amounts of total N. We conclude that substitution of chemical for organic fertilizer at equal amounts of total N is most effective in reducing N export via leaching and runoff without compromising crop production.

As global demand for food increases and impacts of climate-related extremes become more severe new governance mechanisms have become relevant. Individual and collective efforts by actors in water-for food governance could all contribute to sustainably managing the locally scarce water resources that are mobilized to meet the world's demand for food. This review synthesises insights from agricultural water management, water resources management and socio-hydrology to contribute to a knowledge base for informing joint efforts by networks of actors teaming up for sustainable water-for-food governance. The interpretation of water-for-food indicator values is complicated by spatiotemporal variations, different interests and perspectives. However, incorporating these complexities is crucial for governing a globalized food system that depends on water resources of which the availability varies in space and time.

Virtual water flows, incorporated in global food trade has increased the last decade. The drivers and consequences are complex. These complex relations between humans and water resources are studied from different perspectives. In this article, an overview of four such perspectives on water in global food production and trade is provided. These four perspectives are: (1) More crop per drop for increasing production, (2) Less drop per crop for reducing impacts, (3) National food security and import dependency; and (4) Local values and implications of water used in export food production. Each of the perspectives is valuable in the sense of representing different value frameworks, which represent contrasting norms and convictions, belief systems, and discourses; which are often incommensurable.

Despite its obvious advantages, pricing irrigation water is not widely practiced because it is not easy to deploy effectively. Water authorities require an understanding of the objectives they hope to gain from it, the performance different pricing instruments have and the preconditions that must be met to enable them to work. Also, pricing instruments work under assumptions that do not hold in an environment where multiple market failures exist and their introduction may lead to a number of unintended consequences those who operate irrigation systems never considered. The aim in this paper is to outline the difficulties that are associated with implementing pricing instruments in the irrigation sector.

The regional effects of local water storage are largely unknown. This study identifies, categorizes and discusses the challenges in assessing the potential of local water storage. These are illustrated using a structured method applied to a Dutch case. We conclude that the focus must shift from storage ‘potential’ (the quantity of water that can be stored) to storage ‘feasibility’, which depends on exploitability, purpose and interactions between storage alternatives. Spatial and temporal scale also influence feasibility. Finally, farmers’ investment preferences are a factor, though these are shrouded in uncertainty. This overview is a first step towards improving storage assessment tools and processes.

Globally, groundwater is the major drinking water resource. Improving the sustainability of groundwater abstraction for drinking water calls for adaptation on a local scale. The aim of this research is to develop a locally oriented, integrated sustainability assessment framework to support the adaptation planning process for local drinking water abstractions. The framework uses 45 socio-economic, physical and technical sustainability criteria. Future developments that affect the sustainability of local drinking water abstractions are the increasing water demand, land use change, climate change and soil energy transition. Based on the sustainability challenges of local drinking water abstractions, water saving, protection and restoration of raw water quality, mitigation or reduction of impact of abstraction and improvement of supply security are identified as adaptation strategies. To illustrate the proposed approach the sustainability assessment framework was applied to two local drinking water abstractions in the Netherlands. The paper concludes that the proposed framework provides decision- makers with a transparent understanding of trade-offs that decisions have, and the information generated by the framework supports a careful balancing of relevant aspects playing a role in a decision on adapting local drinking water abstractions. Further development and upscaling of the proposed framework to a drinking water company’s level will contribute to sustainable development of drinking water abstraction on a strategic level.

Suitable adaptation strategies for dry season Boro rice cultivation under future climate change scenarios are important for future food security in Bangladesh. This study assessed the effect of shifting trans−/planting date of dry season Boro rice as an adaptation strategy, with focus on water requirements under future climate scenarios. Potential crop water requirement, effective rainfall and irrigation requirement to satisfy crop evapotranspiration of Boro rice were estimated using CropWat 8.0 for early, normal and late planting dates for 2050s and 2080s. Future climate scenarios were constructed using five global circulation model (GCM) outputs for RCP 4.5 and 8.5 by statistical downscaling and bias correction. Number of days exceeding the threshold temperatures (maximum of 35 °C and minimum of 25 °C) was counted for critical period of Boro rice to understand compatibility of the changed planting dates. Results indicate that late planting can substantially reduce irrigation demand by increasing rainfall availability during Boro growth duration, but the option is very limited due to both day- and night-time heat stress. An early planting, on the other hand, accounts for high water demand but ensures suitable temperature during the critical growth stages of the crop. The normal planting dates show the possibility of day-time heat stress. So, late planting of temperature-tolerant cultivars or early planting of high-yielding varieties would be recommended based on local water availability. However, adjustment of the planting date is currently limited because high temperature-tolerant cultivars are not available in the study region.

Subsurface drains, when installed in non-cohesive soil, are typically covered with an envelope to tackle problems of clogging and siltation. Selecting a suitable envelope material, however, is complicated and depends primarily on soil characteristics in the area where the drains are to be installed. A new promising drainpipe-envelope concept, Hydroluis, has been developed which the designers claim works in a wide range of soils. The Hydroluis drainpipe consists of a corrugated inner pipe with three rows of perforations at the top and an unperforated outer pipe that covers the top two thirds of the inner pipe. We analysed the hydraulic and filter functions of this new drainpipe in a soil tank laboratory model with a saline-sodic problem soil from south-western Iran and compared Hydroluis performance with that of a locally-manufactured synthetic envelope material (PP450). The silty clay soil used in this study was 40 % clay, with a plasticity index (IP) of 16.9 and an exchangeable sodium percentage (ESP) of 60.4 %. The Hydroluis drainpipe clogged during the first two weeks of the test due to invasion of the test soil into the space between the inner and outer pipes. Of the substantial volume of sediment that entered the Hydroluis inner pipe, 38 % removed from the pipe in the first day. In contrast, the PP450 drainpipe showed good hydraulic and filter functions, entering very little sediment to drainpipe during the entire test period and stabilizing at drainage rate of 28 mm/day and entrance resistance of 55 days/m, at around day 50. Our analyses suggest that the clogging and poor drainage function of the Hydroluis drainpipe was caused by the higher flow velocity (21.5 times higher) at the soil-envelope interface of the drainpipe, in addition to the lower Hydroluis drainpipe's soil retention capacity (18 times lower) compared to the PP450 drainpipe. Assuming Stokes’ Law governs filter function, the results of Hydroluis design evaluation also suggest that in stable soils, very fine sand or coarser soil particles (D > 0.05 mm) place no serious limitations for Hydroluis drainpipe application, whereas the current design is unsuitable for filtering fine silt particles (0.002 < D < 0.02 mm). In conclusion, we suppose the Hydroluis drainpipe does not perform well in silty saline-sodic soils, such as those found in south-western Khuzestan Province, Iran.

CONTEXT Climate change affects the timing and length of crop seasons. Adjusting sowing dates is a commonly recommended adaptation, but little is known about its efficacy in practice. OBJECTIVE This study investigated farm-level adjustments to sowing and harvesting dates (i.e., the growing period) in response to shifts in meteorological crop seasons during the last 30 years. Impacts on yields and farmers' complementary adaptation strategies were also examined. METHODS Using data from 287 farm households in four agroecological zones of the Indus Basin, Pakistan, we explored farmers' perceptions of shifts in seasons and adjustments in crop growing period. We verified these using meteorological station data on temperatures, precipitation and growing degree days. RESULTS AND CONCLUSIONS At lower altitudes (irrigated plains and mid-hills), the summer crop season had lengthened and the winter season shortened, but in both seasons the growing period was shorter, due to higher temperatures. The summer growing period was shorter by 5 (±11) days on the irrigated plains, while there was no significant change in length of the summer growing period in the mid-hills. The winter growing period was shorter by 15 (±6) days on both the plains and in the mid-hills, which negatively impacted yields. As an adaptation strategy, changing sowing dates was only somewhat effective in preventing yield losses. Farmers adopted complementary strategies, but these brought additional costs. At higher altitudes (valleys and mountains), the frost period had shortened, resulting in longer summer and winter crop seasons, and longer growing periods. The summer growing period was extended by 7 (±4) days in the valleys and 10 (±6) days in the mountains, while the winter growing period was extended by 3 (±3) days in the valleys and 13 (±5) days in the mountains, positively impacting yields. Farmers' adjustments in sowing dates did not necessarily parallel to seasonal shifts, as farm decision-making also had to consider risks linked to climate variability and management limitations. For the future, farmers at lower altitudes indicated limited further scope for adjusting sowing and harvesting dates. SIGNIFICANCE Our results contribute to a contextual understanding of farmers' responses to shifts in crop seasons. They indicate the need for adaptation planning to take advantage of extended growing periods in higher altitude zones, while supporting farmers in areas where seasonal shifts have negative impacts. Our findings furthermore indicate limits to adaptation in regions where agriculture is already challenged and provide suggestions for crop system-specific complementary measures.

Increasing climate variability will put crop production at risk, undermining the sustainability of agriculture-based livelihoods. Much effort has gone into assessing differential vulnerability – or who is at risk. However, the time dimension of increased risk – the when – is often only implicitly included in modelling, statistical and empirical studies. We define and explore the concept of “critical moments” (CMs); that is, periods of heightened risk during the year when farm households are vulnerable to specific climate hazards. The climate modelling, agronomy and socio-economics literature is reviewed to define different types of critical moments. Climate modelling emphasizes hazards but is less specific about the time window of risks in relation to crop cycles. Agronomy research develops cause-and-effect relationships between weather variables and yields by crop stage but generally does not consider hazard frequency and associated vulnerability. Socio-economic research analyses associations between hazards, yields and farm income, but often lacks full process knowledge, neglecting other pathways that contribute to vulnerability. Our synthesis aims to bridge disciplinary silos, and proposes an integrated concept towards risk. In this study, three types of CM are identified: CM’s with immediate, compound and shifted impact. The concept of critical moments is novel as it considers direct and indirect impacts as well coping strategies. Viewing climate risk to agriculture through a CM lens can support greater interdisciplinary engagement to identify vulnerabilities and develop and promote effective coping options and user-relevant support mechanisms to reduce vulnerabilities specific to particular places and moments.

Wastewater reuse is identified as strategic to help ameliorate scarcity in water-stressed regions around the world. However, to develop it, there is a need to better understand the social, institutional and technological contexts in which it takes place. This article develops a novel socio-technical framework to inform such an analysis and applies it to current wastewater reuse in Egypt. Our analysis highlights the different actors, management activities and practices that shape wastewater collection, transfer, treatment, discharge and/or reuse in different social, technological and environmental contexts in Egypt. It points out bottlenecks of current wastewater reuse policies and programmes.

Developments such as climate change and growing demand for drinking water threaten the sustainability of drinking water supply worldwide. To deal with this threat, adaptation of drinking water supply systems is imperative, not only on a global and national scale, but particularly on a local scale. This investigation sought to establish characteristics that describe the sustainability of local drinking water supply. We use an integrated systems approach, describing the local drinking water supply system in terms of hydrological, technical and socio-economic characteristics that determine the sustainability of a local drinking water supply system. Three cases on drinking water supply in the Netherlands are analysed. One case relates to a short-term development, that is the 2018 summer drought, and two concern long-term phenomena, that is, changes in water quality and growth in drinking water demand. The approach taken recognises that next to extreme weather events, socio-economic developments will be among the main drivers of changes in drinking water supply. Effects of pressures associated with, for example, population growth, industrial developments and land use changes, could result in limited water resource availability, deteriorated groundwater quality and growing water demand. To gain a perspective on the case study findings broader than the Dutch context, the sustainability issues identified were paired with global issues concerning sustainable drinking water supply. This resulted in a proposed set of generally applicable sustainability characteristics, each divided into five criteria describing the hydrological, technical and socio-economic sustainability of a local drinking water supply system. Elaboration of these sustainability characteristics and criteria into a sustainability assessment can provide information on the challenges and trade-offs inherent in the sustainable development and management of a local drinking water supply system.

Crops are vulnerable to weather hazards throughout the growth season, with periods of heightened risk described as critical moments. Farmers have a number of ex-ante and in-season options for coping with these events, and ex-post adjustments to farm-household portfolios to further limit the impact on livelihoods if these options fail. Adaptation-related research has focussed mainly on ex-ante or ex-post coping strategies, because in-season approaches tend to be seen as a given, meaning their cost effectiveness is ignored. Based on detailed survey data collected from 287 households in four of the main cropping systems in Pakistan, this study evaluates the impact pathways of hazards and the cost effectiveness of in-season coping strategies. Yield losses varied by 10–30% for 43% of the cases and by 31–50% for another 39%, with the most severe losses caused by the compounding effect of two hazards in one crop season or if both crops in a multi-crop rotation were affected simultaneously. In-season coping options were mostly restricted to the early crop stages and constrained by a short window of time for the response. The application of in-season coping strategies resulted in a yield recovery of 40–95%, with an additional cost of 4–34% of the value of recovered yield. The major critical moments identified were the harvest season, with farming often affected by un-seasonal precipitation, and the germination stage, with an additional high risk for low temperatures at high altitude. A better understanding of the differentiated risks and effectiveness of in-season coping strategies could support the promotion of sustainable crop production in similar agro-ecologies. Moreover, the effectiveness of present-day coping strategies, rather than the use of coping approaches itself, could signal a potential ability to adjust to future climate change.

Policies supporting rice production and investments in water infrastructure enabled intensification and diversification of farming systems in the Vietnamese Mekong Delta (VMD) over the past 20 years. Yet, demands of food security, economic development, and climate change continue to pose diverging and often conflicting challenges for water resources management in the upper, central, and coastal zones of the delta. The major changes effected in the VMD’s hydrological regime and land-use patterns are acknowledged in the literature, but few studies have examined the interplay between these dynamics at the delta scale. Based on time-series maps and statistical data on land-use, flooding, and salinity intrusion, we investigated the interrelations between land-use dynamics and changes in hydrological regime across the VMD in three representative periods. Land-use was found to be highly variable, changing by 14.94% annually between 2001 and 2012. Rice cropping underwent the greatest change, evolving from single cropping of traditional varieties towards double and triple cropping of high-yielding varieties. Aquaculture remained stable after rapid expansion in the 1990s and early 2000s. Meanwhile, flooding and salinity intrusion were increasingly controlled by hydrological infrastructure erected to supply freshwater for agriculture. Effects of this infrastructure became particularly evident from 2001 to 2012. During this period, spatial and temporal impacts on flooding and salinity intrusion were found, which extended beyond the rice fields to affect adjacent lands and livelihood activities. Unforeseen effects will likely be aggravated by climate change, suggesting a need to rethink the scale of planning towards a more integrated hydrologic approach.

Recent flood dynamics of the Mekong Delta have raised concerns about an increased flood risk downstream in the Vietnamese Mekong Delta. Accelerated high dike building on the floodplains of the upper delta to allow triple cropping of rice has been linked to higher river water levels in the downstream city of Can Tho. This paper assesses the hydraulic impacts of upstream dike construction on the flood hazard downstream in the Vietnamese Mekong Delta. We combined the existing one-dimensional (1-D) Mekong Delta hydrodynamic model with a quasi-two-dimensional (2-D) approach. First we calibrated and validated the model using flood data from 2011 and 2013. We then applied the model to explore the downstream water dynamics under various scenarios of high dike construction in An Giang Province and the Long Xuyen Quadrangle. Calculations of water balances allowed us to trace the propagation and distribution of flood volumes over the delta under the different scenarios. Model results indicate that extensive construction of high dikes on the upstream floodplains has had limited effect on peak river water levels downstream in Can Tho. Instead, the model shows that the impacts of dike construction, in terms of peak river water levels, are concentrated and amplified in the upstream reaches of the delta. According to our water balance analysis, river water levels in Can Tho have remained relatively stable, as greater volumes of floodwater have been diverted away from the Long Xuyen Quadrangle than the retention volume lost due to dike construction. Our findings expand on previous work on the impacts of water control infrastructure on flood risk and floodwater regimes across the delta.

Sustainable Development Goal indicator 6.4.1 is defined as the change in water use efficiency over time and measured as the change in the ratio of gross economic value added by irrigated agriculture, industry and the services sector to the volume of water withdrawn over time. The rationale behind this indicator is to decouple a country's economic growth from its water use. Yet, this unwittingly results in an economic distortion of the water balance, favouring increased water withdrawal in service of higher water-use efficiency, at the expense of environmental sustainability. This paper discusses three methodological flaws. First, aggregation of only economic values across all sectors ignores social and environmental values and is very sensitive to changes in the relative water use by agriculture versus industry and services. Second, the economic value derived from agriculture and from imports cannot in fact be decoupled from agricultural water use. Third, the indicator completely ignores the effects of diminished return flows to the environment due to increased re-use of water. A novel alternative, disaggregated WUE approach is therefore proposed, which links water consumption to the water balance. It is defined as the economic value of irrigated and rainfed agriculture combined with water consumption (ETa) by rainfed and irrigated agriculture per area based on earth observation data. It is measured as the change in the ratio of gross economic value added by irrigated and rainfed agriculture to the volume of water consumed by rainfed and irrigated agriculture over time. This approach is more consistent and objective, while being methodologically, hydrologically and environmentally sound. It acknowledges the coupling of economic growth and water depletion, and the need to strike a balance between opportunities for economic growth and environmental sustainability. This better serves the full breadth of the water and sanitation goal as defined in SDG 6.

A participatory rural appraisal (PRA) conducted in the Al-Mujaylis area, Tihama Coastal Plain, Yemen provided a contribution, as a bottom-up approach, to the assessment of the needs of communities and their views on how to avoid groundwater degradation. It was found that PRA tools could be applied usefully in an area with data scarcity and a culturally different context. It is concluded that adopting a research approach between top down and bottom up is most valuable and effective.

A dense dike system has been built in the upstream floodplains of the Vietnamese Mekong Delta, allowing large scale rice production based on compartmentalized fields and optimized water management. Intensive cultivation has enabled farmers to greatly increase their rice productivity and augment the national food bowl. However, flood-control structures have undermined the water retention capacity, compromising various benefits of floodwaters for delta ecosystems. Effects are both internal and external to farming. Negative internal effects are the large investment requirements and higher farming costs. Negative externalities include increased flood damage, reduced sediment flows, saltwater intrusion and riverbank erosion. In this study, we assessed the effects of three dike–agricultural system scenarios on delta-level sustainability, considering both internal and external effects. Direct and indirect costs were estimated using various methodologies and the literature. Our findings show that extensive development of high dikes on the floodplains is the least economical and most ecologically risky alternative. In this scenario, accelerated high-dike construction exacted a cost 136% greater than the situation represented by the baseline year of 2011. Externalities in this scenario contributed to rising economic losses in both aquaculture and agriculture. The scenario of transforming high-dike into low-dike systems revealed lower water management costs combined with lesser environmental impacts and greater capacity to exploit floodwater benefits. Our findings provide a useful input for decision-makers considering the unintended economic consequences of existing water management strategies. They support a transition to low-dike farming systems for a more sustainable delta.

Development of joint irrigation infrastructure increasingly depends on investment decisions made by individual farmers. Farmers base their decisions to invest on their current knowledge and understanding. As irrigation infrastructure development is ultimately a group decision, it is beneficial if individuals have a common understanding of the various values at stake. Sharing the personal reasoning behind individual decisions is a promising approach to build such common understanding. This study demonstrates application of participatory crossover analysis at a workshop in Tasmania, Australia. The workshop gave farmers the opportunity to discuss their broader considerations in investment decisions, beyond just financial or monetary factors. It centered on the question, &ldquo, In what conditions would you&mdash, the individual farmer&mdash, invest?&rdquo, The participants&rsquo, willingness to pay, in the form of crossover points, was presented as a set of scenarios to start an explorative discussion between irrigators and non-irrigators. Evaluation feedback indicates that the workshop enabled participants to share new information, improved understanding of differences between neighbors, and generated more respect for others and their decisions. As expected, reasoning went beyond economic concerns, and changed over time. Lifestyle choices, long-term intergenerational planning, perceived risks, and intrinsic motivations emerged as factors influencing water valuation. Simply having a facilitated discussion about the reasons underlying individuals&rsquo, willingness to pay seems to be a useful tool for better informed decision-making about joint irrigation infrastructure, and is worth testing in further case studies.

Increasing water reliability in a catchment requires reducing the total quantity of water available to users in some years in order to supply it in more years when its supply is constrained. Thus, the more reliable the supply the more water that needs to be withheld. Consequently, increased levels of water reliability to a catchment, which reduces the costs associated with an unreliable supply, often comes at an incremental increase in costs that researchers do not consider; that of the water foregone that could be have been used productively if the system had been run less reliably. In this paper the trade-offs between the costs of water foregone to maintain a level of reliability and the costs associated with an unreliable supply of water at different levels of reliability in an irrigation system are discussed. The concepts developed are applied to the irrigation sector in the Musi catchment in Andhra Pradesh, India from 2011 to 2040. In this catchment it was found that the costs of water foregone to increase reliability rise as the level of reliability rises, while the benefits generally fall. When the level of reliability exceeded approximately 85% (where water is so scarce that it is used on only the most valuable output), the costs of greater reliability exceed the benefits resulting in net losses to the system. These results were found to vary in each demand centre across the catchment. These results have implications for those considering innovations that improve the level of reliability in a catchment.

Regional long-term water management plans depend increasingly on investments by local water users such as farmers. However, local circumstances and individual situations vary and investment decisions are made under uncertainty. Water users may therefore perceive the costs and benefits very differently, leading to non-uniform investment decisions. This variation can be explored using crossover points. A crossover point represents conditions in which a decision maker assigns equal preference to competing alternatives. This paper presents, applies, and evaluates a framework extending the use of the concept of crossover points to a participatory process in a group setting. We applied the framework in a case study in the Coal River Valley of Tasmania, Australia. Here, farmers can choose from multiple water sources. In this case, the focus on crossover points encouraged participants to engage in candid discussions exploring the personal lines of reasoning underlying their preferences. Participants learned from others&rsquo, inputs, and group discussions elicited information and insights considered valuable for both the participants and for outsiders on the factors that influence preferences. We conclude that the approach has a high potential to facilitate learning in groups and to support planning.

This article uses the lens of the Multiple Streams Approach to explore whether the agendas set by political actors in Vietnam converged with the agenda set in the Mekong Delta Plan (MDP). The MDP presents policy choices for the development of the Vietnamese Mekong Delta. The plan offers economically attractive, climate adaptive and environmentally sustainable paths forward in the face of climate change and economic uncertainties. We collected our data using qualitative techniques, including a literature review and interviews. We found convergence between the MDP’s agenda and political actors’ agendas, though divergences were also detected. Between the delivery of the MDP in 2013 and formal endorsement of its ideas in 2017, the problem stream, policy stream and politics stream were brought together by the actions of “policy entrepreneurs” (scientists and experts). Our findings suggest that agenda-setting and convergence were a crucial step towards endorsement of the strategic delta planning process for the Mekong Delta. Further research could explore issues of power mobilization in enabling or constraining decision-making. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

The increasing policy interest in valuing water raises questions about practical roles or applications. Is valuing water intended, for example, to inform public policy and businesses, guide resource allocation, support a multi-stakeholder process, manage conflicts of interest, or to inform realistic pricing systems and support investment decisions? Decisions affecting water often fail, however, to consider ecosystem needs and social objectives and impacts in other geographical areas. This paper reflects on the essence of valuing water in practice. The paper concludes that in practice, valuing water is indeed useful in decision-making, not solely in the sense of it contributing to the value determination (as values are typically disputed, partial, incommensurable and imperfect), but more in offering a structured and transparent mechanism that supports an inclusive stakeholder water resources management process. Water valuation can play a key role in making explicit the trade-offs intrinsic to decision-making and priority setting, especially when it concerns societal needs such as food security and stability, which are not revealed in the marketplace. As such, valuing water may be a key tool in water diplomacy, whereby its value lies not so much in its numerical assessment as in the process it offers to engage stakeholders across different perspectives and interests in water use.

Climate change poses an acute threat to the Vietnamese Mekong Delta (VMD). To respond to this threat, the structure of the delta’s agriculture-based economy must transform, becoming more adaptive to changing conditions. One adaptive livelihood option is the use of flood-based farming systems in the upper VMD. The present study examines local perceptions of such a system in Dong Thap Province, a lowland, flood-affected area of the upper VMD. Specifically, we explored lotus farming as a potential flood-based adaptive livelihood model for the region. The study advances the current literature by using historical research, embedded in narrative analysis applying the social construction of technology (SCOT) lens. We collected data through in-depth interviews and field surveys to qualitatively analyze the emergence and status of lotus cultivation in the study area, zooming in on how local society evolved with expansion of this farming model. The findings suggest that as an innovative idea, lotus farming initially emerged due to unfavorable natural conditions, and then was developed as an attractive nature-based livelihood, and thus received increased attention. It has been accepted and modified over time according to the new interests of further stepped-in stakeholders. Our findings echo the social construction of technology perspective as we found lotus farming to be a technological artifact that did not develop on its own, by was driven by different interpretations and re-negotiation process. This made more room for stakeholders to shape and reshape it in a way that fits their interests.

A better use of land and water resources will be necessary to meet the increasing demand for food in the Nile basin. Using a hydro-economic model along the storyline of three future political cooperation scenarios, we show that the future of food production in the Basin lies not in the expansion of intensively irrigated areas and the disputed reallocation of water, but in utilizing the vast forgotten potential of rainfed agriculture in the upstream interior, with supplemental irrigation where needed. Our results indicate that rainfed agriculture can cover more than 75% of the needed increase in food production by the year 2025. Many of the most suitable regions for rainfed agriculture in the Nile basin, however, have been destabilized by recent war and civil unrest. Stabilizing those regions and strengthening intra-basin cooperation via food trade seem to be better strategies than unilateral expansion of upstream irrigation, as the latter will reduce hydropower generation and relocate, rather than increase, food production.

This study used crop budgets to assess the impact of declining groundwater levels on the economic value of irrigation water in the Wadi Zabid region of Yemen. The study found that returns to land and water were highly sensitive to changes in groundwater depths over time and the free availability of spate water for irrigation. Crops differed in the amounts of irrigation water applied and in their returns to land and water. Banana had the highest irrigation requirement, but also delivered the highest return to land. Banana&rsquo, s return to water was greater than that of date palm and feed sorghum, but lower than that of mango and food sorghum.

We have developed a social optimization model that integrates the financial and ecological costs associated with wastewater treatment and ecosystem damage. The social optimal abatement level of water pollution is determined by finding the trade-off between the cost of pollution control and its resulting ecosystem damage. The model is applied to data from the Lake Taihu region in China to demonstrate this trade-off. A wastewater treatment cost function is estimated with a sizable sample from China, and an ecological damage cost function is estimated following an ecosystem service valuation framework. Results show that the wastewater treatment cost function has economies of scale in facility capacity, and diseconomies in pollutant removal efficiency. Results also show that a low value of the ecosystem service will lead to serious ecological damage. One important policy implication is that the assimilative capacity of the lake should be enhanced by forbidding over extraction of water from the lake. It is also suggested that more work should be done to improve the accuracy of the economic valuation.

Although water harvesting is receiving renewed attention as a strategy to cope with increasing seasonal and inter-annual rainfall variability, many centuries-old local water-harvesting reservoirs (tanks) in India are rapidly deteriorating. Easy access to groundwater is seen as one of the major threats to their maintenance and functioning. Potentially, however, conjunctive use of water from rain, tanks and groundwater reserves, supported by proper monitoring, could improve the resilience and productivity of traditional tank irrigation systems. To date, few quantitative multi-annual analyses of such climate-smart systems have been published. To redress this, we assess the sustainability of a rehabilitated tank irrigation system, by monitoring all inputs and outputs over a period of six years (12 cropping seasons). Our results show that during the period considered, improved conjunctive use resulted in a more stable cropping intensity, increased economic water productivity and higher net agricultural income. Groundwater tables were not negatively affected. We argue that improved conjunctive use can considerably reduce the vulnerability of tank irrigation to rainfall variability and thus is a valuable strategy in light of future climate change.