Analisis Ekologi Bentanglahan untuk Penentuan Potensi Sumberdaya Air (Studi Kasus: DAS Cimadur, Banten)

Abstract

Indonesia was predicted would have water crisis in 2025 in the World Water Forum II in the Hague in March 2000. Most of the cause has been by the weaknesses in water management. Study of water and its high demand has been associated with shapes and physical characteristics of an area. Topographic factors play an important role in determining spatial pattern water resources. In this research, Topographic Wetness Index (TWI) is implemented to determine spatial pattern of surface water saturation zone. Cimadur watershed was selected as one of main watersheds in Lebak, Banten which has been contributing on flood hazard. Study on TWI in Cimadur watershed has became important because it could show distribution points containing concentration of water and therefore useful for determining potential inundation as well as areas potentially storing water in the watershed. This research aims to: (1) Identify types of landform, land use, and slopes using remote sensing data (Google Earth imagery, ALOS AVNIR-2 imagery, and SRTM imagery), (2) Conduct analysis of TWI to obtain the distribution of spatial pattern of surface water saturation zones, and (3) Conduct an analysis of the landscape ecology (landform, land use, slope, and grade TWI) using landform as unit of analysis for determination of potential water storage. Landscape ecological analysis shows that Cimadur watershed is dominated by Tertiary denudational volcanic landforms (DV1 and DV2), which covers 10.046 Ha, mixed-use garden covers 8.952 Ha, the slope of 15-30% (steep) covers 8.534 Ha, and middle TWI class (= grade 2) covers 20.987 Ha. It shows that ecological conditions in test site are still at safe water saving, however, the area is fairly vulnerable to climate change or land cover/land use change. These are due to dynamics of water flow in the area during rainy and dry seasons.