Constructing sustainable and resilient cities to adapt to climate change and urbanization with the water-energy-food nexus approach

Abstract:

Water-Energy-Food (WEF) are indispensable resources for humans’ subsistence, and they have the connection of interlaced nexus, which is also called “Water-Energy-Food Nexus, WEF Nexus.” In recent years, influenced by rapid urbanization and climate change, metropolises may encounter some risks like WEF resources shortage, flooding and drought disasters. Therefore, this research provides a solution with implementation of Water-Energy-Food sustainable and resilient infrastructures (WEFSRI). To demonstrate this idea, the densely populated city, Taipei, Taiwan, is selected as a case study area. An spatial analysis is conducted to identify where to place WEFSRI and the scale of them. Then, under the WEF Nexus framework, the simulation of facility capability and life cycle assessment are carried out to evaluate the performance of WEFSRI. To construct the Water-Energy-Food sustainable and resilient city that can respond to climate change and urbanization, the optimization method is utilized to establish a spatial layout model. The model can display the potential sites of WEFSRI that can reach multi-objectives considering water, energy, and food benefit index, greenhouse gases reduction, and sponge city.

The WEFSRI discussed in this study include bioretention cell (BRC), permeable pavement (PP), building rainwater harvesting (BRWH), photovoltaic system (PVS), and urban agriculture (UA). The research outcome indicates that the optimum solution to water, energy, and food benefit index, greenhouse gases reduction, and sponge city are 37.47%, 14.50%, 1.77%, 19.46%, and 81.69%, respectively. Constructing WEFSRI in an urban area has better benefits to water and energy systems, greenhouse gases reduction, and sponge city, but no apparent improvement to the food system. In addition, according to the population projection model, the population of the study area would show a decreasing trend in the future, so water, energy, and food benefit index would increase year by year. Based on the sensitivity analysis, the prior policy to carry out should be constructing BRWH. With regard to technological innovation, promoting the power generation efficiency of PVS has the highest benefit. As for life cycles of WEFSRI, the used materials of BRC-Mulch should be the priority to improve.