Author(s)

N. Hirayama, S. Itoh & H. Nakajima

Abstract

In this study, a procedure is established for evaluating the watershed water quality risk reduction after earthquake disasters. Using the method of scenario planning, the risk scenario of watershed water quality in the aftermath was developed as a model of decision tree that can describe the uncertainty events, decision-making and emergency response. Using the watershed water quality risk scenario and the watershed flow model based on box model with mass balance, a model for evaluating the watershed water quality risk was developed. Numerical simulation analysis for estimating the watershed water quality risk in Lake Biwa and Yodo River basin after an earthquake disaster was conducted. Furthermore, the effectiveness of countermeasures against watershed water quality risk was estimated. As a result, it was pointed out that the comprehensive countermeasures with cooperation of stakeholders in the watershed water quality, including information sharing, would reduce considerable watershed water quality risk. Consequently, it was indicated that implementation of the cooperative countermeasures for preservation of watershed water quality for water supply with stakeholders related to watershed water quality would reduce watershed water quality risk in the aftermath effectively. Keywords: watershed water quality risk, scenario planning, stakeholders, countermeasures against watershed water quality risk, information sharing, numerical analysis.

Keywords

watershed water quality risk, scenario planning, stakeholders, countermeasures against watershed water quality risk, information sharing, numerical analysis