Analisis ketersediaan air untuk kebutuhan air baku wilayah Kabupaten Banjarnegara melalui daerah aliran sungai (DAS) Merawu

Abstract

The Merawu River is located in the upper reaches of the Serayu River and is a priority sub-watershed. With the population growth in Banjarnegara Regency, for example in 2019 there were 923,215 people and an increase in 2020 to 1,017,767 people, it will affect the fulfillment of raw water needs. Therefore, an analysis of the potential water availability for raw water needs in the Merawu watershed. The analysis of 90% mainstay discharge used observational discharge data from Clangap Station, but for completing the discharge data loss using The FJ Mock Model. In the FJ Mock Model, there was data analysis. Evapotranspiration calculation uses climatological data from Karangkobar Station in 2003 using the Penman Modification method. The data used are monthly rainfall data from 2 rain gauge stations (Kalisapi and Karangkobar Stations). The results of the calculation of water availability with 90% reliability obtained calculated discharge from January to December are 46.28; 47.02;42.09; 21.27; 12.93; 9.18; 5.62; 3.11; 4.53; 10.24; 22.68; and 26.65 m 3 /second respectively. The value of raw water demand in the Merawu watershed in 2033 is 0.363 m3/second. The results of water availability were sufficient for raw water needs. Even if the calculation used all data on the population of Banjarnegara Regency, the mainstay discharge also still met the raw water demand of 1.67 m3/second.