One-Dimensional Water Quality Model for Water Management in Tidal Rivers.

Abstract

Water systems in lowlands consist of tidal rivers, open channel networks and several water structures. The water management of such systems requires problem analysis on water quantity and water quality. In this paper the water problems of tidal rivers in Indonesia are analyzed and the problems to be solved for the future and present time are proposed. As major subjects, it is pointed out that the integrated water management for the water systems from the aspect of water quantity and water quality is necessary. Additionally, the concept for the development of tools (computer models) is proposed. The major water quality parameters for the water management of tidal rivers in Indonesia are chloride and suspended solids. Through the water quality problem analysis, one-dimensional water quality model, so called branch-node model, is developed and the applicability of the model is examined in the Rokkaku River in Japan. The water movement is simulated using existing computer model for water management systems. It shows that those calculated results of water movements, water level and discharge, agree with the observed data. The calibration of chloride concentration is carried out to estimate dispersion coefficient and the calculated results agree with the observed data. The calculations for the suspended solid concentration match with observed data.