Managing Surface Water Contamination in Nagoya, Japan: An Integrated Water Basin Management Decision Framework

Abstract

The water quality of rivers in Japan has received greater attention in recent years due to a number of factors, including human-induced land subsidence and an increase in water demand. Surface waters are adversely affected by high frequency, low level risks (such as the continuous release of hazardous substances) and less frequent, high impact risks (such as the release of chemicals due to natural disasters or industrial accidents). This paper puts forth an integrated Water Basin Management (WBM) decision framework to study the latter: these relatively infrequent, but often catastrophic hazards, are less well-studied than the more familiar high frequency, low level risks. The six main components of this WBM decision framework involve (a) determining possible threats to surface waters; (b) identifying surface waters most at risk to contamination; (c) identifying weaknesses (gaps) in current monitoring systems; (d) using accident analysis to determine proactive WBM; (e) analyzing the temporal-spatial impact of policies on water basins, (f) designing new policies and approaches for integrated WBM. Japan's recently published Pollutant Release and Transfer Register (PRTR) is used to develop a WBM decision framework for managing surface water contamination in Nagoya, Japan. Participatory surface water management is emphasized in order to achieve a holistic and sustainable WBM decision making process.