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水管理与控制提供新的途径。通过野外调查，对萨嘎地区明渠系统的水质和自净功能进行了研究。利用新开发的计算机模型对两种改善水质的方法进行了评价。第一种方法是从一条主要河流引入清洁水的稀释法。二是通过控制生物反应来改善水质。为了直接改善佐贺溪的水质，稀释法显然是一个合适的应用。同时，应从水质综合管理的角度，选择稀释和还原相结合的系统。最后，从水综合管理的角度对乌什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。简单的一系列措施可以显著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.