STUDY ON WATER ENVIRONMENTAL MANAGEMENT AND CONTROL IN OPEN CHANNEL NETWORK IN LOWKLAND

本研究的主要目的是为低地明渠网的水管理和控制提供新的途径。通过对佐贺地区明渠系统的实地调查，研究了该地区明渠系统的水质状况及水体的自净功能。利用新开发的计算机模型对两种改善水质的途径进行了评价。第一种方法是从主要河流中引入清洁水的稀释方法。二是通过控制生物反应来改善水质。为直接改善佐贺溪水质，显然稀释法是一种适当的应用。从综合水质管理的角度出发，选择稀释还原法的组合系统。从水资源综合管理的角度，对牛津地区进行了政策分析。案例研究的结果表明，在日本进行小规模的政策分析是可能的。一些简单的措施可以大大改善一些与水有关的问题。

In this study, the main purpose are to davelop new approach for water management and control in open channel network in lowlands. water quality and self-purification function are investigated trough field survey in open channel systems in Saga area. Two approach for improving water quality are evaluated by using newly developed computer model. The first approach is a dilution method of inducing clean water from a main river. The second one is to improve the water quality by controlling biological reaction. For improving water quality directy in Saga creeks, it is clear that the dilution method is an appropriate application. Also, combined systems of the dilution and reduction method should be selected from the view point of integrated water quality management. A policy analysis is applied to Ushizu area as a case study from the view point of the integrated water management. The results of the case study show that it is possible to do a small scale policy analysis in Japan. Simple sets of measures can improve some of the water related problems considerably.