The development of inflow discharge for the karian multipurpose reservoir in the pursuit of reservoir management optimization

Abstract

Climate change and land cover modifications result in alterations in hydrological regimes. The demand for water and electrical energy continually rises along with population growth. Consequently, optimizing the Karian Multipurpose Reservoir (Hydroelectric Exploitation) operation requires considering hydrological regime changes. The Karian multipurpose reservoir is designed to meet water needs in Banten Province. The strategic policy for the Reservoir is to provide raw water at a rate of 14.6 m3/s. Of this, 9.1 m3/s is diverted to Tangerang Regency, and 5.5 m3/s is directed to Serang City through Ciujung River. Before being released into the Ciujung River, a flow of 5.5 m3/s is channeled through turbines to generate 1.8 MW of electricity. This study compares two models for estimating discharge to support Karian Reservoir management: (1) The Rainfall Conversion Ratio (CR) and Catchment Area, and (2) The Continuous model. The Rainfall CR and Catchment Area has a correlation value of 0.523 with CR KOICA, Absolute Relative Error (ARE) of 0.54, and Root Mean Square Error (RMSE) of 10.61. Meanwhile, the continuous model has a correlation value of 0.877 with CR KOICA, ARE of 0.18, and RMSE of 3.64. The results indicate the continuous model is the most effective in estimating input discharge.