Global challenges have exacerbated a search for solutions to poverty and environmental degradation. Integration it was argued would help address the twin challenge. Integrated Water Resources Management (IWRM) was supposed to be that magic bullet and was embraced by scientists because of the clinical efficiency with which it argued for integrated analysis of sectors and resources and of systems and scale conditions. This paper argues that effective implementation of the Water-Energy-Food (WEF) Nexus can be supported by robust science. The corollary that robust science automatically leads to effective implementation is not always known to be true. The nexus approach sheds light on the challenges of implementation by introducing concepts of trade-offs and thresholds and consequently emphasizes the importance of transdisciplinary approaches to sustainable development. This paper reviews the results of recent research to offer tentative answers to the following questions: (a) Why is the governance dimension important to undertake an integrated analysis of water-energy-food challenges? (b) What does the nexus approach connote in normative and institutional terms? (c) What does implementation mean in nexus terms? (d) How can we establish if the nexus approach is an improvement over business as usual? and (e) What tools are available that would enable translation of results of scientific research to create an evidence base that would enable decision makers to act in support of sustainable development?

Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated with the environmental degradation and, in some regions, resource scarcity. This paper proposes a multiobjective optimization model for the design of a water distribution network from a water–energy–food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, because the objectives are opposites, a multistakeholder assessment is proposed in order to analyze and quantify the relationship of the water–energy–food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water–energy–food nexus.

Relying on published literature, we reviewed water-energy-food issues in Lao PDR in the context of a policy shift to more sustainable ‘green growth’ and significantly increased infrastructure investment resulting from China’s Belt and Road Initiative. The BRI provides the prospect for the country to address its infrastructure deficit and transform from a ‘land-locked’ to a ‘land-linked’ country. However, great care is needed to ensure that future investments do not result in further environmental degradation and harm to communities. An integrated ‘nexus’ approach, in which enhanced water management is central, is a prerequisite for more inclusive and sustainable development.

Optimal allocation of available water in a middle Himalayan watershed by a linear programming model for maximizing production from crops and livestock, after meeting the present and future demands of human and environmental flows, was analyzed. Present and future water availability under different environmental scenarios at various locations in the watershed was considered. Rice Equivalent Production from the watershed was found to improve by 207% (to 919 tonnes) and Rice Equivalent Yield by 58% (to 4427 kg ha⁻¹) through optimal allocation of available water resource. Occurrence of drought of 60% intensity would limit production to 737 tonnes. Environmental degradation by 2025 would though reduce production marginally, the surplus water available within the watershed would, however, decrease significantly during January to March. Future competition for water would adversely affect economy of the watershed and the region. The government should, therefore, undertake water resource development programmes after making a proper inventory of available resources at watershed level by analyzing the current and future supply and demand scenarios.

Vicious competition for limited water resources hinders the synergetic and sustainable development of Central Asian countries, which further threatens food security and exacerbates ecological degradation. In this study, a copula-based bi-level decentralized programming (CBDP) method is developed and applied to planning water-food-ecology (WFE) nexus system. CBDP has advantages in balancing tradeoffs between different decision levels, analyzing synergies among multiple managers and reflecting joint risks of interrelated uncertain parameters. Then, a CBDP-WFE model is formulated for Central Asia, where the upper-level model aims to maximize system benefit for the region (i.e. regional-scale), and the lower-level model involves five objectives to maximize five countries’ benefits (i.e. national-scale) respectively. Totally 108 scenarios are designed to analyze the impacts of joint constraint-violation risk, agricultural irrigation efficiency, and ecological water demand. Results reveal that (i) improving agricultural irrigation efficiency can optimize the water allocation pattern as well as increase the system benefit; (ii) in order to restore the regional eco-environment, the proportion of ecological water allocation should increase from 7% (of the current level) to 14.9–23.8% (by 2050); (iii) water allocations to Uzbekistan and Tajikistan should be properly controlled especially when available water is scarce. The results are helpful for managers in not only making decisions of water allocation among multiple users and countries but also gaining insight into synergetic management of WFE nexus under various system conditions.

This paper critically analyses the potentials and frontiers of an agribusiness model developed along the arid coastal area of Peru. To make this model work, water from Andean rivers and lakes have been dammed and transferred to the coastal area through sophisticated and highly expensive hydraulic infrastructures. Although this ‘water transfer-agribusiness’ (WATA) model has attained its objectives to let the desert bloom and increase agro-exports from Peru, it does so at the cost of local environmental degradation, social unrest and gender disparities. These unintended consequences arose, in part, because the WATA model is anchored in ideologies of domination of nature and colonization of empty territories. The construction of water infrastructure, namely ‘Large Scale Irrigation’ (LSI) left aside the sociocultural, gender and environmental aspects that these kinds of interventions should include. Based on studies of water transfer from the Colca River to the ‘Pampas de Majes’ in the Arequipa region in the south-west of Peru, this paper analyses, from an interdisciplinary perspective, the consequences of such interventions on the food/water security and environmental health of the affected population.

Activities in the food-energy-water nexus require ecosystem services to maintain productivity and prevent ecological degradation. This work applies techno-ecological synergy concepts in an optimization formulation to design a system for co-producing food and energy under constraints on ecological sustainability. The system includes land use activities and biomass conversion processes for the production of energy carriers, as well as supporting ecosystems that increase the supply of key ecosystem services. The co-production system was linearized and reduced to a mixed-integer linear program, which was optimized for single objectives under a variety of production and sustainability constraints. Results indicate that for the system considered to achieve high food and energy co-production, land use options should be balanced between food-producing crops and electricity-producing wind turbines and solar panels. Results also show that ecological sustainability can be achieved for this system with relatively small changes in land use patterns. The inclusion of nature in the design enables the system as a whole to achieve ecological sustainability for multiple ecosystem services with moderate sacrifices of food and energy productivity.

Land Use Land Cover Change (LULCC) has a significant impact on water resources and ecosystems in sub-Saharan Africa (SSA). On the basis of three research projects we aim to describe and discuss the potential, uncertainties, synergies and science-policy interfaces of satellite-based integrated research for the Kilombero catchment, comprising one of the major agricultural utilized floodplains in Tanzania. LULCC was quantified at the floodplain and catchment scale analyzing Landsat 5 and Sentinel 2 satellite imagery applying different adapted classification methodologies. LULC maps at the catchment scale serve as spatial input for the distributed, process-based ecohydrological model SWAT (Soil Water Assessment Tool) simulating the changes in the spatial and temporal water balance in runoff components caused by LULCC. The results reveal that over the past 26 years LULCC has significantly altered the floodplain and already shows an impact on the ecosystem by degrading the existing wildlife corridors. On the catchment scale the anomalies of the water balance are still marginal, but with the expected structural changes of the catchment there is an urgent need to increase the public awareness and knowledge of decision makers regarding the effect of the relationship between LULCC, water resources and environmental degradation.