Aplikasi Pemnafaatan Data Karakteristik DAS untuk Mitigasi Banjir dan Tanah Longsor

Abstract

The currently use of natural resources in Indonesian's watershed is quite aggressive, explorative, and expansive and also exceeds its carrying capacity and capability, as a results a number of critical watershed continuously increases and the watershed functions as an environmental control continuously decreases, e.g., increase of flood and landslide frequencies. The role of watershed characteristics data as a tool for early warning of susceptibility hazard detection and watershed problem need accurately to be known to implement effective watershed management. By using a formula from "Quick Detection of Sub watershed Degradation Book", o sub-watershed characteristic in the form of a map of susceptibility level of flood disaster (potentially flood ond sensitively flooding area) and sensitively landslide with map scale of 1:25.000 i:50.o00 could be easily conducted. Data compiler of parameters of a flood disaster vulnerability formula are rainfall, watershed shape, river gradient, drainage density, watershed slope averages, landform, meandering, impounding water flow, river side slopes, land use-cover, and the existing of water control structures. Data compilers of parameters of a landslidesusceptibility formula are rainfall, landslope, geology (rock type and fault-strike existence), soil depth, land use, infrastructures, and settlement density. The availability of data input of each parameters, either format, scale or the age of data and map, mostly varies and need to be corrected, verified, and validated through a uniformly format, scale, and a field check, e.g., rainfall, land use-cover, infrastructures, water controlstructures, andsettlement density data. Theuse ofavailabledata must be criticized and corrected in order that susceptibility information from the produced mop becomes more objective and factual. This method used in the study on evaluating susceptibility of flood and landslide disasterareas isonly valid to be implementedinasub watershed level within district administrative level.