Perubahan penggunaan lahan DAS Citarum dan dampaknya terhadap suplai air irigasi (studi kasus : periode tahun 2002-2009)

Abstract

The research used secondary data between 2002 to 2009 in PJT II Jatiluhur and Citarum-Ciliwung watershed Management Agency. Generally, this research was done in Citarum watershed area, West Java province, from August to October 2010.The research aims to investigate: 1). Land use change in Citarum watershed area; 2). Effect of land use change on water yield; 3). Changes in water yield and its impact on irrigation needs; and 4). Effect of irrigation water supply to changes in rice acreage. According to the digital citra analysis, Citarum watershed area that located above Jatiluhur dams has changed land use (450.649 ha) between 2002 and 2008. In agriculture areas land use change significantly increased from 59.76% in 2002 to 70.52% in 2008. Changes in water results continue to demonstrate the value decreases with increasing area of agriculture following the equation ym = 2987.74-0.00766887x2 (x2 is an extensive agricultural area in ha; ym is the result of water in million m3/th). Decrease in water yield has not been an adverse impact on irrigation needs, seen from an index value of the use of water in the reservoir continues to decline, resulting in increased efficiency of reservoirs. Index decreased use of water reservoirs affected by the increase in annual precipitation, so as to reduce the effects of the decline that occurred in the water. Changes in area of rice fields terjadididuga because of land conversion to non-agricultural activities that are not triggered by lack of water.