Development of Performance Index Model for Assessing the Multipurpose Reservoir Storage Capacity

This research intends to assess the storage capacity performance of multi-purpose reservoir in design stage. However, the performance size of reservoir storage capacity shows the reliability in guaranteeing water demand-supply and flood control storage. The methodology consists of data collecting, data analysis, calibration of low flow and high flow model by using HEC-HMS, analysis of reservoir storage capacity by using SPA, assessment analysis to the performance index model of reservoir storage capacity for water demand-supply by using McMahon approach, preparation of model for determining the influenced variables by using SEM-PLS, regression model for developing the performance index of multi-purpose reservoir storage capacity by using GRG approach, and performance classification model of multi-purpose reservoir storage capacity by using zonation approach. The result shows that the performance index model of multi-purpose storage capacity by using the variable, indicator, and variable index weight is as follows: KT** = 0.20030 CV + 0.457672 D + 0.16677 KA + 0.175258 DF (with RMSE = 0.218483 and NSE = 0.758675). This research is hoped to predict the feasibility of reservoir storage capacity and performance of reservoir storage capacity based on the ability to fulfil water demand in various conditions of storage capacity for monthly and annual requirements. In addition, it can be a reference in assessing the performance of reservoir storage capacity and utilization so it can be used as the base for decision making to design the dimension of dam completion structure and design of reservoir management.