Optimal Water Management for Reservoir Based Irrigation Projects Using Geographic Information System

Abstract

The shortage of reservoir water is the main constraint in establishing stable water management programs in the Muda Irrigation Project, Malaysia. In this study, a water balance equation was derived to evaluate the performance of the project. The water balance components were modeled without calibration, and compared with measured data, whenever possible. The overall project efficiencies for the main and off seasons were also obtained. A reservoir simulation model was developed from which simulated storage capacities compared satisfactorily with the observed storage capacities. An optimization model was also developed to solve the water resources management of the project in a computationally satisfactory manner. The optimal reservoir storage, optimal irrigation demand, and optimal reservoir release (i.e., optimal reservoir operating policy) were computed. The mean (1987–1997) optimized total water requirements for the dry and wet seasons were also computed as were the optimal contributions by rainfall, reservoir, uncontrolled river flow, and recycled water. The optimized water requirements were compared with other authors’ computed water requirements and found to be satisfactory. The mean water balance components results for different months were stored in Geographic Information System (GIS) databases, analyzed, and displayed as the monthly crop water requirements maps. The integration of the water balance model together with the models for reservoir simulation, efficiency, optimization, and GIS holds much promise in the analysis of optimal allocation of water resources of a project.