Integrated assessment and scenarios simulation of water security system in Japan

Abstract

Water security is one of the most important hot topics facing humanity in the 21st century, as it affects people's lives, property and ecology. Water security system (WSS) consists of three major subsystems: water resource, water environment, and water disasters. Firstly, a set pair analysis (SPA) method is applied to evaluate the WSS in Japan from the spatial dimension. Then, the system dynamics (SD) model is used to simulate water resources, water environment, water disasters, and future changes from 1995 to 2025 from the temporal dimension. Further, this study designs four different scenarios: water resources prioritized scenario, water environment leading scenario, water disaster dominated scenario and balanced scenario to compare with the base scenario. The results show that the current situation of WSS in Japan is good except for the water disasters subsystem in Shikoku. It is also found that a balanced model can achieve not only steady water supply and demand, protect the water environment, and mitigate water disasters, but also maximize the benefits for both the economy and population. This study provides a map for water management and achieving water security in the different administrative divisions of Japan.