Interplay between land-use dynamics and changes in hydrological regime in the Vietnamese Mekong Delta

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

A Synthesis on Strategic Delta Planning in Action: Wishful Thinking, Vested Practices and Unexpected Changes

In this review, we take stock of 10 research articles that cover strategic delta planning processes in Asia, Europe, and the US. We test working hypotheses about consent, innovations, actor coalitions, and planning tools in different phases. We posit that strategic delta planning is a deliberate effort to influence delta developments, wherein wishful thinking on how a delta could develop is repeatedly confronted with vested practices and interests. These confrontations produce expected (e.g., institutional embedment, changing people’s minds) and unexpected changes (e.g., actors suddenly consenting or stepping out). Strategic delta planning is therefore not only an ambitious planning process, it is also highly uncertain, as consent on strategic directions has to be renegotiated across phases and arenas. Recommendations for practice are therefore highlighted that cover vocabulary, persuasiveness and tools. Further research is proposed to study the vagaries of strategic delta plans in urbanising deltas.</p

Strategic delta planning: launching new ideas on managing a Delta, and their travels along actor coalitions, participatory planning tools and implementation timelines

Policy Analysi

Food security under water scarcity : a comparative analysis of Egypt and Jordan

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

Mapping uses and competition for shared water resources: conflicts and values in Mkoji sub-catchment, Tanzania

Proceedings of the workshop on water management for local development, 8-11 November 2011.Conflicts over water are a common feature in closing basins and the difficulties in resolving them provide a serious barrier for the formulation of an effective IWRM strategy. Understanding the specifics of a conflict, including its dynamics and its evolution, provides an essential basis for subsequent efforts towards conflict resolution. Since conflicts are driven by interests and values of stakeholders, insight into the values underlying conflicts may further help the identification of promising ways to resolve them. Especially the latter is of crucial importance, as the identification of effective solutions to conflicts still remains more of an art than a craft. This paper discusses the use of two analytic frameworks that support a better understanding of local conflicts over water: conflict analysis and value- focused thinking. It illustrates the use of these frameworks to analyse local water conflicts in a closed sub-catchment in Tanzania. It shows how these frameworks support the identification of solutions that can help local stakeholders to “create value” in closing basins. On the basis of this illustrative analysis, the paper argues that these two frameworks deserve a wider use in the field of local water management

Mapping uses and competition for shared water resources: conflicts and values in Mkoji sub-catchment, Tanzania

Proceedings of the workshop on water management for local development, 8-11 November 2011.Conflicts over water are a common feature in closing basins and the difficulties in resolving them provide a serious barrier for the formulation of an effective IWRM strategy. Understanding the specifics of a conflict, including its dynamics and its evolution, provides an essential basis for subsequent efforts towards conflict resolution. Since conflicts are driven by interests and values of stakeholders, insight into the values underlying conflicts may further help the identification of promising ways to resolve them. Especially the latter is of crucial importance, as the identification of effective solutions to conflicts still remains more of an art than a craft. This paper discusses the use of two analytic frameworks that support a better understanding of local conflicts over water: conflict analysis and value- focused thinking. It illustrates the use of these frameworks to analyse local water conflicts in a closed sub-catchment in Tanzania. It shows how these frameworks support the identification of solutions that can help local stakeholders to “create value” in closing basins. On the basis of this illustrative analysis, the paper argues that these two frameworks deserve a wider use in the field of local water management

Interplay between land-use dynamics and changes in hydrological regime in the Vietnamese Mekong Delta

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

Scoping agriculture – wetland interactions: Towards a sustainable multiple-response strategy

The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries

The dual-purpose use of orange-fleshed sweet potato (Ipomoea batatas var. Bophelo) for improved nutritional food security

Orange-fleshed sweet potato (OFSP) leaves can be utilised as a fresh green leafy vegetable, in addition to the traditional use of storage root; therefore, OFSP can be seen as a “dual-purpose’’ crop. We hypothesized that no vine harvesting combined with fertiliser application and irrigation will improve the storage root yield and selected plant parameters (water productivity, leaf and storage root nutrient concentrations, nutritional yield, and nutritional water productivity). The objectives of the study were to (i) evaluate the effect of vine harvesting on the selected plant parameters, and, (ii) assess the effect of irrigation regimes and soil fertilisation on these selected parameters. Field experiments were conducted at ARC-VOP, Pretoria, South Africa, during the 2013/14 and 2014/15 seasons. Treatments included irrigation regimes [well-watered (W1) and supplemental irrigation (W2)], soil fertilisation [well-fertilised (F1) and no fertiliser application (F2)], and vine harvesting [no vine harvesting (H1) and vine harvesting (H2)]. For the 2014/15 season, the well-watered regime improved total storage root yield (W1 = 13.0 t DM ha−1; W2 = 7.5 t DM ha−1). Under the practice of vine harvesting, soil fertility treatments did not affect (total dry storage root yield and dry marketable storage root yield) storage root production. Our results further revealed that vine harvesting reduced storage root nutrient concentrations (23% for iron; 14% for zinc; 12% for β-carotene). Nevertheless, total nutritional yields increased; the highest total nutritional yields for iron, zinc, and β-carotene were found under the water and nutrient input regime (W1F1). Assessments showed that boiled orange-fleshed sweet potato aboveground edible biomass could potentially contribute to the daily-recommended nutritional requirement of iron and vitamin A for a family of six people. More water was needed to meet the daily-recommended nutrient intake (iron, zinc, and vitamin A) with OFSP grown as a storage root crop only than when grown as a dual-purpose crop. Our results indicated that there is an opportunity to utilise OFSP as a dual-purpose crop for rural resource-poor households because total nutritional yields (iron, zinc, and β-carotene) and total nutritional water productivities (iron, zinc, and β-carotene) were improved. More research is needed to assess the effect of vine harvesting on a range of OFSP varieties and should be conducted on the farm. Rural resource-poor households are encouraged to produce OFSP for their own consumption and the surplus could be sold at the local market.The South African Water Research Commission (WRC) and the Netherlands University Foundation For International Cooperation (NUFFIC).http://www.elsevier.com/locate/agwathj2020Plant Production and Soil Scienc

Whole-tree water balance and indicators for short-term drought stress in non-bearing 'Barnea' olives

Drainage-weighing lysimeters allowed monitoring of water balance components of non-bearing olive (Olea europaea cv Barnea) trees over a 3-month period including short-term events of controlled but severe water stress. The objective of the study was to evaluate a variety of soil and plant-based water status and drought stress monitoring methods on the basis of tree-scale evapotranspiration (ET). As the trees entered into and recovered from water stress, meteorological data, actual ET (ETa), soil water content and changes in leaf turgor pressure were continuously monitored. Additionally, midday measurements of stem water potential, stomatal conductance, canopy temperature, and quantum yield of PSII photochemistry were conducted. Diurnal (dawn to dusk) measurements of all the above were made hourly on days of maximum stress. Shoot elongation rate was measured for periods of stress and recovery. Quantum yield of PSII photochemistry, stomatal conductance, and stem water potential all successfully indicated reductions in whole-tree water consumption beginning at moderate stress levels. These measured parameters fully recovered to the levels of non-stressed trees soon after water application was renewed. Shoot elongation was reduced 25-30% for the 10-day period during and following drought and recovered thereafter to levels of non-stressed trees. Whole-tree ETa was reduced by as much as 20% even following full recovery of the leaf level parameters, suggesting reduced canopy size and growth due to the stress period. Non-destructive, continuous (turgor pressure) and remotely sensed (canopy temperature) methods showed promising potential for monitoring effects of water stress, in spite of technological and data interpretation challenges requiring further attention.Lysimeter Plant growth Transpiration Physiological monitoring Water status Olea europaea