Land subsidence induced by agriculture activity in Bandung, West Java Indonesia

Abstract

Bandung, the capital city of West Java Indonesia, is known as a large basin surroundings by mountains and highlands. In the last few decades, the industries grown in the region, leaving fewer agricultural area which used to be the livelihood for the local peoples. The growth of industries and increasing of population also increase the extraction of ground water which is believed to be the cause of land subsidence in Bandung. However, the use of ground water are not only addressed to industries and household, it is also used by agricultural activity. We use 45 ALOS PALSAR images, range from January 2007 to March 2011 from both ascending and descending direction to investigate the land subsidence in agricultural area. We exploit the SBAS method on persistent scatterers to find the subsidence rate over the period. Our study shows LOS displacement associated to land subsidence in two agricultural area, Sukamanah and Rancaekek with similar rate of 5 cm/year in both location. The rate of subsidence is indeed higher in industrial area with the rate as high as 15 cm/year in Cimahi and Gedebage which shows much higher ground water extraction. Our field investigation finds that there used to be water pumping for cultivation and had been done for several years in both location. Over exploitation of ground water in those location lead to the deeper ground water level and higher the risk of drought. Further study and better data verification using GPS is still needed in the future.