STUDY OF THE INTERCONNECTION OF PIT LAKES TO FULFILL RAW WATER NEEDS IN UNDERDEVELOPED AREAS IN BANGKA DISTRICT

Pit lakes, known locally as kolong, are formed from abandoned open-pit mining areas that fill naturally with runoff and groundwater.In Bangka Regency, Sumatra, many communities rely heavily on groundwater from bore wells to meet their raw water needs.However, these sources often experience shortages during prolonged dry seasons.This study aims to explore the potential utilization of Kolong Dam 1 Pemali and Kolong Simpur Pemali as alternative raw water sources through an interconnection system to improve water supply reliability in rural areas, particularly in Pemali District.Bias correction of satellite rainfall data was conducted using the quantile mapping method, significantly increasing the accuracy of precipitation data.Water availability was analyzed using the NRECA method, and future water demand was projected over a 20-year period .Two operational scenarios were simulated: the first, using only Kolong Dam 1 Pemali, failed to meet demand during dry seasons, showing a 91.3% reliability rate.The second, with an interconnected system between both kolong, significantly improved performance, achieving a 97.2% reliability rate.The findings demonstrate that interconnecting kolong provides a technically feasible and effective solution to enhance the reliability of water supply systems in Bangka, especially during seasonal fluctuations in water availability.