Model Panen Air Hujan untuk Penanggulangan Banjir; Studi Kasus di Kawasan Sentul City-Bogor, Indonesia

Abstract

The aim of the study was to determine the volume of rainwater harvesting (RWH) and its relationship to the Bekasi flood. The case study was conducted in the Sentul City (SC) area, which is the upstream of the Bekasi Watershed (DAS), while in the lower reaches of the watershed, the Bekasi area is often affected by flooding. The data needed in this study are population, population growth, daily rainfall data, and water needs. The method for determining the existing rainwater catchment area is through analysis of SPOT-2017 imagery. It is assumed that urban and rural water needs are 120 liters/day and 60 liters/day respectively, while non-domestic needs are 35% from domestic (Directorate General of Human Settlements, 1998). Determine the RWH volume with the formulation: RWH = 0.8 x A x Ch (where: RWH = daily harvestable rainwater volume (m3); 0.8 = correction factor, after evaporation and infiltration; A = Rainwater catchment area (m2), and Ch = daily rainfall (mm)). The results of the 2017 SPOT image analysis obtained that the existing residential area of SC urban is 7,054,700 m2 and rural is 2,250,700 m2. The prediction of the average daily need for clean water in the SC area in 2018 is 14,619 m3/day. The potential for rainwater that can be harvested with scenario-1 is 6,061,538 m3/year and with scenario-2 is 12,123,075 m3/year. Scenario-1 can meet water needs until 2026, and scenario-2 until 2050. Implementation of RWH in SC can increase the supply of raw water, reduce clean water supply from PDAM, reduce runoff, reduce the frequency of flooding events and cope with flooding in the area. Bekasi.