THE EFFECT OF LAND USE CHANGE TO THE DEPTH AND AREA OF INUNDATION IN THE BANG SUB-WATERSHED-MALANGINDONESIA

Abstract

More than 50% of East Java Province area has the high potential flood disaster, one of them is
the Bang sub-watershed. The aim of this paper is to analyze the area and depth of inundation on the river of
Bank sub-watershed due to the land use change in surrounding it. This study is located in the Bang subwatershed, Tamban coast, Tambakrejo village, Sumbermanjing Wetan district, East Java Province-Indonesia.
The methodology consists of predicting the inundation area and flow pattern in the Bang river by using the
software of HEC-GeoRAS (Hydrologic Engineering Centre and River Analysis System) version 3.1 which
compiling the two main software that are HEC RAS version 4.1.0 and Arc View GIS version 3.3. The result
shows that the maximum inundation is 4.99 km2 on the return period of 50 years based on the land use on
2010. The land use change from 2001 to 2010 indicates that the increasing inundation area is 0.4%, however,
the inundation depth is increasing 0.5%.