An interval-stochastic-fuzzy policy analysis model is proposed to generate optimal security management policy for a water–energy–food nexus system of the urban agglomeration under multiple uncertainties. A number of planning policies under interval-stochastic surface water and groundwater conditions are obtained. Ranking scores of all policies in descending order, policy with the highest score is the best choice. Results disclose that (a) interval-stochastic available water resources lead to changing system benefits. (b) The shares of cropland area targets are 2.7% (Xiamen), 42.6% (Zhangzhou), and 54.7% (Quanzhou). (c) Different available water scenarios result in varied irrigation patterns. (d) Surface water takes a high fraction of the total water supply (about [71.34, 73.68]%), diesel agricultural machinery service more than 60% of the total cropland. (e) Zhangzhou contributes about 50.01% of total TN and TP emissions, while Quanzhou contributes about 50.61% of total carbon emission. (f) Security level of policies would change with the varied σ and α values, due to the risk attitudes of policy makers. (h) Sweet potato and others are the crops with the highest safety performance; (i) Zhangzhou is the city with highest comprehensive safety performance.

Hybrid hydropower and floating photovoltaic power generation has far-reaching effects on the intertwined water, food and energy (WFE) nexus, but the complementary operation is fundamentally challenging especially under high uncertainties of hydro-meteorological conditions. This study proposed an artificial intelligence-based WFE system-overarching solution driven by hybrid hydro-floating photovoltaic power generation for promoting nexus synergies. A multi-objective optimization model grounded upon the Grasshopper Optimization Algorithm was developed to simultaneously maximize hydro-floating photovoltaic power output, the ratio of water storage to reservoir capacity, and the ratio of water supply to water demand. The Shihmen Reservoir watershed and its WFE system in northern Taiwan constituted the case study. The results demonstrated that the proposed optimization model could significantly improve synergistic benefits of the WFE nexus by reaching 13%, 13.3% and 15.1% in water storage, food production and hydro-floating photovoltaic power output, respectively. The optimal tilt angles of floating photovoltaic installation would vary between −11.9° (Summer) and 44.3° (Winter). This study opens up new perspectives on green energy production expansion while stimulating WFE nexus synergies in support of policy-makers with feasible schemes on floating photovoltaic deployment in the interest of social sustainability. In consequence, new niches are exploited for floating photovoltaic deployment and give rise to impact mitigation concerning hydro-meteorological uncertainties on WFE nexus management.

Residual resources in agriculture provide prime raw material for bioenergy production whose optimization has potential to promote agricultural economy while mitigating environmental side-effects. Food, energy, water, and land resources are intertwined in agricultural systems. Effective management of bioenergy production, considering the nexus of these resources, is needed for the sustainable development of agriculture, which is challenging because of the uncertainties involved therein. This study proposes an optimization-assessment approach (input/output relationship) for sustainable bioenergy production in agricultural systems. The approach is capable of (1) providing decision makers with the ability to determine optimal policy options among water, land, energy, and livestock, considering the tradeoff between economic and environmental impacts for bioenergy production; (2) helping decision makers identify the level of sustainability of agricultural systems and where the effort should be made for various regions; and (3) dealing with the uncertainties to provide decision alternatives. The proposed approach is applied to a case study in the particular context of northeast China, which is predominantly an agricultural region with large bioenergy potential. The changing range of bioenergy production potential, system costs, and environmental impacts were obtained, based on different schemes for the allocation of agricultural resources among different regions. Economic-environmental impact and sensitivity analyses were conducted, and agricultural system sustainability was assessed in a changing environment. Considering the complexity due to uncertainty, the proposed approach can help manage bioenergy production in agricultural systems in a sustainable way, and will be applicable for similar agriculture-centered regions.

The water-energy-food nexus concept is criticized as not yet fit for deeply integrated and contested governance agendas. One problem is how to achieve equitable risk governance and management where there is low consensus on priorities, poor inclusion and coordination of risk assessment procedures, and a weak emphasis placed on cross-scale and sectoral interactions over time. Participatory system dynamics modeling processes and analyses are promising approaches for such challenges but are currently underutilized in nexus research and policy. This paper shares our experience implementing one such analysis in the Mekong river basin, a paradigmatic example for international nexus research. Our transdisciplinary research design combined participatory causal loop diagramming processes, scenario modeling, and a new resilience analysis method to identify and test anticipated water-energy-food risks in Kratie and Stung Treng provinces in northeastern Cambodia. Our process generated new understanding of potential cross-sectoral and cross-level risks from major hydropower development in the region. The results showed expected trade-offs between national level infrastructure programs and local level food security, but also some new insights into the effects local population increases may have on local food production and consumption even before hydropower developments are built. The analysis shows the benefit of evaluating risks in the nexus at different system levels and over time because of how system dynamics and inflection points are taken into account. Additionally, our case illustrates the contribution participatory system-thinking processes can make to risk assessment procedures for complex systems transitions. We originally anticipated that any new capacity reported by partners and participants would come from our modeling results produced at the end of the process. However, participants in the modeling procedures also found the experience powerful the information sharing, rapid risk assessment, and personal learning it enabled. A lesson from our experience reinforces a message from the transdisciplinary research field that has not yet been absorbed into the nexus research and policy field wholeheartedly: we do not have to wait for perfect data and incontestable results before making a positive contribution to anticipating and responding to risks that emerge from nexus relations if we apply participatory and systems-thinking informed approaches.

Agricultural production in the Great Plains provides a significant amount of food for the United States while contributing greatly to farm income in the region. However, recurrent droughts and expansion of crop production are increasing irrigation demand, leading to extensive pumping and attendant depletion of the Ogallala aquifer. In order to optimize water use, increase the sustainability of agricultural production, and identify best management practices, identification of food&ndash:water conflict hotspots in the Ogallala Aquifer Region (OAR) is necessary. We used satellite remote sensing time series of agricultural production (net primary production, NPP) and total water storage (TWS) to identify hotspots of food&ndash:water conflicts within the OAR and possible reasons behind these conflicts. Mean annual NPP (2001&ndash:2018) maps clearly showed intrusion of high NPP, aided by irrigation, into regions of historically low NPP (due to precipitation and temperature). Intrusion is particularly acute in the northern portion of OAR, where mean annual TWS (2002&ndash:2020) is high. The Oklahoma panhandle and Texas showed large decreasing TWS trends, which indicate the negative effects of current water demand for crop production on TWS. Nebraska demonstrated an increasing TWS trend even with a significant increase of NPP. A regional analysis of NPP and TWS can convey important information on current and potential conflicts in the food&ndash:water nexus and facilitate sustainable solutions. Methods developed in this study are relevant to other water-constrained agricultural production regions.

This study uses Taiwan's WEF nexus as a case study to demonstrate how the resource flow and associated environmental impact of the WEF nexus can be assessed as basis for evaluating strategies for promoting the sustainable use of natural resources. In this study, material flow analysis (MFA) and life-cycle assessment (LCA), were combined. The MFA was used to examine the interdependence of the three natural resources, and the LCA was used to evaluate the environmental impacts of the WEF system. The WEF nexus analysis shows that tap water supply, oil refining, the cogeneration of steam and electricity, thermoelectric power plants, irrigation, animal husbandry, and aquaculture are the main interwoven nodes and have the most prominent impact on the three natural resources. When the unit products from the WEF system were determined, LCA was implemented for these products to identify 15 types of environmental impacts. The environmental impacts for the WEF system were then calculated based on the use of unit products. The results of LCA showed that the most prominent impacts are the impact of public electricity on climate change; oil products on ozone depletion and ionizing radiation; tap water on metal depletion; and animal husbandry on terrestrial ecotoxicity. Based on the assessment of the alternative resource management strategies, if both water and energy policies are modified simultaneously, the impact of the overall WEF system on most environmental impact categories could be reduced.

There is an increasing appreciation that food–energy–water (FEW) nexus problems are approaching criticality in both the developing and developed world. As researchers and managers attempt to address these complex resource management issues, the concept of the FEW nexus has generated a rapidly growing footprint in global sustainability discourse. However, this momentum in the FEW nexus space could be better guided if researchers could more clearly identify what is and is not a FEW problem. Without this conceptual clarity, it can be difficult to defend the position that FEW innovations will produce desired outcomes and avoid unintended consequences. Here we examine the growing FEW nexus scholarship to critically evaluate what features are necessary to define a FEW nexus. This analysis suggests that the FEW nexus differs from sector-focused natural resource or sustainability problems in both complexity and stakes. It also motivates two new foci for research: the identification of low-dimension indexes of FEW system status and approaches for identifying boundaries of specific FEW nexuses.

Yam peel (YP), cassava peel (CP), cocoyam peel (CoP) and plantain peel (PP) are common food wastes of the Niger Delta region. Anaerobic digestion (AD) of these wastes with water hyacinth (WH) presents a viable way of both providing renewable energy and cleaning up the environment. AD tests were carried out on the food wastes and WH to determine their biogas potentials. The experiments were carried out under mesophilic conditions at (37 ± 1 °C) over a period of 20 days and the tests were replicated to give an indication of repeatability. The results showed that YP+WH, CP+WH, CoP+WH and PP+WH had specific biogas yields of 0.42, 0.29, 0.39 and 0.38 m³/kg volatile solid (VS), respectively. The yields represented 76, 48, 70 and 69% of their respective theoretical values. Co-digesting the food wastes with WH in a VS ratio of 2:1 reduced the biogas yields of YP, CP, CoP and PP by 16, 22, 7 and 7%, respectively. The drop in gas production was due to indigestible complex molecules in the WH co-substrate. The results indicate that common food wastes in the Niger Delta can be used as feedstock for AD, but co-digesting with WH reduces the biogas yield.

A novel composite foam was prepared from native cassava starch and water hyacinth (WH) by baking in a hot mold. The effects of WH powder content (0, 3, 5, 7 or 10 wt%, dry starch basis) on the properties of the starch foam were investigated. A starch foam formulation with 5 wt% WH powder exhibited the highest flexural stress at maximum load (3.42 MPa), the highest flexural strain (extension) at maximum load (3.52%), the highest modulus (232.00 MPa), the lowest moisture content (6.77%) and the most uniform cell size distribution (0.44 ± 0.09 mm). Moreover, mechanical properties of starch foam with 5 wt% WH powder were better than the same properties of some commercial foams. After being coated with beeswax, the starch foams retained their shape after immersion in distilled water and their water solubility was significantly reduced. Results indicated that a starch foam/5 wt% WH composite with beeswax coating was a biodegradable foam that could possibly replace commercial non-degradable foam.