Optimization of a water distribution branch (Indonesia)

The availability of quality and adequate water is a crucial aspect in maintaining the continuity of life and environmental sustainability. The inadequacy of the drinking water distribution system to meet demand and pressure is usually caused by population increase and rapid urbanization, high leakage rate in the distribution system. One of the branches of Perumda Air Minum Tirta Lestari, namely Branch IV, has a crucial role in providing drinking water supply for the three sub-districts it serves. Population increases, pipe leakage, pipe disruption due to high pressure and flow often causing pipe rupture, and high operational costs are the main focus in planning for service coverage expansion. The existing capacity generated from 3 locations with 9 production units is 106 L/sec with a total of 10,535 SR customers and a water loss rate that reached 32% in 2023. This study aims to optimize and develop the drinking water distribution network in Branch IV of Perumda Air Minum Tirta Lestari in response to the challenges faced in order to meet the criteria of drinking water services, namely quantity, quality, continuity, and affordability. The evaluation was conducted using technical, financial and institutional analysis. Technical analysis was carried out based on data obtained in the field and distribution system simulation analysis using Epanet 2.2. The results of the distribution network analysis in Branch IV of Perumda Air Minum Tirta Lestari show that the UPK Palang and UPK Semanding networks meet the pressure and head loss standards, while UPK Grabagan still has low pressure at some points due to varying elevations. The low flow velocity in some pipes is intended to support customer development. Distribution system development is planned in two stages (2024- 2028 and 2029-2033) with sufficient water capacity for the next 10 years for UPK Palang and UPK Semanding, while UPK Grabagan requires additional new wells in 2031. The financial analysis showed a positive NPV (IDR 3.844.979.938,41), IRR of 20%, and BCR >1. Therefore, this development is feasible to achieve the main objectives, namely increasing water availability, expanding services in the area of Branch IV of Perumda Air Minum Tirta Lestari, and optimizing the existing distribution system.