RESEARCH ON FACILITIES CAPACITY OF STORM WATER STORAGE TANK WITH CONSIDERATION OF COST-BENEFIT

Abstract

Nonpoint sources in an urban rivers catchment have a significant environmental impact on the quality in the public receiving waters. Therefore, it is important to minimize the pollutant loads from nonpoint source in the catchment. In this study, we analyzed rainfall dataset during the past 20 years (1985-2004) collected by the Kobe Marine Observatory, and determined stochastic characteristics of rainfall that are closely related to pollutant loads. We performed a pollutant load simulation analysis by using the Storm Water Management Model, SWMM, with consideration of runoff and pollutant load control by a stormwater storage facility. Through the analysjs, the optimal capacity for the storage tank was determined by means of a cost-benefit analysis considering the removal rate of the pollution load and construction costs. It was found that the storm water storage tank is efficient not only for controlling runoff discharge but also for minimizing pollutant loads.