Water Resources Planning and Management for Lower Dong Nai River Basin, Vietnam: Application of an Integrated Water Management Model

Abstract

An integrated water management model has been proposed to investigate the water resources planning and management problem for a tidal basin having a complex reservoir-river network system. The model addresses an optimal operating policy for the interlinked reservoir system, hydropower plant and water-treatment facilities as well as the irrigation systems that utilize both surface water and groundwater to obtain the optimum benefit from the water supply, agriculture and hydropower production. The integrated water-management model is, essentially, a linkage between the optimization model and the hydrodynamic flow and transport model. A modified constraint approach is suggested to incorporate the implicit nonlinear salinity constraints in the optimization model. The present model has been applied to the Lower Dong Nai River Basin, and two scenarios for water resources planning and management have been analysed. The results showed that the energy production of Tri An hydropower plant will reduce significantly as the water supply has to meet the increase in water demands for irrigation and public use during the low-flow period by the year 2010. Consequently, the construction of Phuoc Hoa Reservoir and its diversion channel to Dau Tieng Reservoir will improve the effectiveness of this system's operation. With this additional system component implementation, the power production requirement could be maintained. Also the total water requirement up to the year 2010 is satisfied, and the area of cultivation could be increased for agricultural development.