Kajian berbagai alternatif perencanaan pengelolaan DAS Cisadane menggunakan model SWAT

EDY JUNAIDI. Study of the various alternative of Cisadane Watershed management planning using SWAT Model. Supervisory commitees: Dr. Ir. SURIA DARMA TARIGAN, MSc. (Chair) and Dr. Ir. DWI PUTRO TEJO BASKORO, MSc. (Members). Effective watershed management should take hydrologic response unit into consideration. Analysis in watershed management uses the hydrology model. SWAT (Soil and Water Assessment Tool) is a distributed hydrologic model interfaced with GIS and integrated with Decision Support System. SWAT can be used to simulate different physical processes in watershed. The objective of the research were (1) applicating SWAT model to identify the sub watershed and land unit categorized as having problem on Cisadane Watershed and (2) evaluating various alternative of the Cisadane Watershed management planning and selecting best Cisadane Watershed management planning by observing their impact on Cisadane Watershed hydrology. The research was carried out in two phases, survey activity and implementation of SWAT hydrology model. Based on SWAT simulation result, Cisadane Watershed had relatively good performance. Watershed performance and indicator were evaluated based on SK Menhut nomer 52/Kpts-II/2001. According to SWAT analysis, some three sub–watersheds were categorized as having problem concerning water management and land use, i.e. one sub-watershed on the upper part, one on middle watershed and sub of Cisadane Hulu Watershed. Sub-watersheds that had tendency to give the highest peak flow were sub-Watershed Cianten Hilir and Sub-Watershed Cianten Hulu. Sub-watersheds that produced highest omount of sediment ware sub-Watershed Ciampea, sub-Watershed Cihedeung and sub-Watershed Cinangneng. Land unit which need close attention for potential problem was settlement on the slope bigger than 8 %. Land unit which contributed to highest peak flow was dry land farming and mixed garden on slope bigger than 8 %. Meanwhile, land unit which potentially contributed to the highest erosion was dry land farming with slope bigger than 40 % and settlement on slope bigger than 8 %. Some three scenarios in watershed management planning were evaluated using SWAT model. Ferst scenario using watershed management planning provided by Balai Pengelolaan DAS Ciliwung–Citarum, second scenario using watershed management planning by Bappeda Bogor and Tangerang and threed scenario using management planning by Balai Besar Wilayah Sungai Ciliwung Cisadane. Generally, water management releted criteria was classified as good, bud land use related criteria was classified as not good. Best Watershed management planning was provided by Balai Pengelolaan DAS Ciliwung– Citarum.