Author(s): Ana Nurganah Chaidar; Indratmo Soekarno; Agung Wiyono; Joko Nugroho
Linked Author(s): Retno Utami Agung Wiyono
Keywords: Runoff; Land cover; Critical
Abstract: The land-use changes at Upper Citarum Watershed caused an increase in the runoff coefficient. The Arc-GIS program from Geographic Information System (GIS) can be used to map increasing runoff changes in land cover use at the Upper Citarum Basin. The land cover map issued by the Citarum-Citanduy River Basin Management Body (BP) is used. This research aims to observe the detailed description of the rate of land use change which resulted in the increased of runoff coefficient. Furthermore, this condition will affect the water drainage system and harm the overall water system and cause damage to the environment. This study conducted at eight sub-basins in Upper Citarum for 23 years (1990-2013) data analysis. The results demonstrate that almost all the runoff coefficient in the upper Citarum watershed exceeded the critical limit of 0.2. The Cikapundung sub-watershed has experienced a near-critical runoff coefficient of 0.417 since most of the Cikapundung River Basin is the center of the city with dense housing. The increased in runoff coefficient at Cikapundung sub-watershed followed by the Cihaur watershed with 0.397 in 1990 and has exceeded Cikapundung watershed in the year 2013 with 0.421%. In addition, there are many sand mines in this area. Consequently, the vegetation-covered regions are reduced faster. Moreover, it is estimated that over the next five years will be very critical with coefficients above 0.50. Other watershed conditions have an average runoff coefficient number above 0.2, i.e. Citarik Sub-Watershed, Cikeruh Sub-Watershed, Ciwidey Sub-Watershed, Cisangkuy Sub-Watershed and Ciminyak Sub-Watershed. While Cirasea Sub-Watershed is still in stable condition with runoff coefficient reaches 0.183. The high land coefficient is the main factor causing frequent flooding in upstream Citarum watershed, which has different values in each sub-watershed then different handling plans are required.
Year: 2018