A Decision Support System for Beneficial Use of National Dam Water Resources in Swaziland

The Government of Swaziland has undertaken the development of water storage and distribution facilities as a process towards overcoming the unevenly distribution of the water resource. However, the current water storage facilities with a total capacity of 720.9 x 10⁶ m³ can not meet the water demand which stands at 1795 x 10⁶ m³ annually. The overall objective of this project was to develop an optimum and sustainable decision support tool for water allocation and rationing options for national water reservoirs. A Decision Support System (DSS) is defined as a user-oriented computer system which supports decision-makers in addressing unstructured problems. The rationing mode in the developed DSS was used to distribute the available stored water at the beginning of April in order to arrive at a priori predetermined reservoir storage level at the end of October. The DSS has three major components and that is the model input, modeling options and outputs screens. The model input component comprises of technical data (inflow, reservoir level, intended % volume at end of October and allowed lowest rationing %), and policy data (uniform rationing or differential rationing). The modeling options comprise of commands to determine optimum rationing %, provide % rationing and observed dam response and imposed rationing %. The output of the DSS comprises of the optimal rationing (%), monthly reservoir volume from April to end of October as well as a graphical representation of the reservoir response and the final recommendation.