Soil Erosion Assessment of a Hilly Terrain by RUSLE Model - A Case Study of Chittagong Hill Tracts

Abstract

Among many environmental problems, soil erosion poses a serious threat to the region known as Chittagong Hill Tracts (CHTs) in Bangladesh, comprising three districts, namely Bandarban, Rangamati, and Khagrachari. The annual soil erosion rate for this hilly terrain was calculated using the Revised Universal Soil Loss Equation (RUSLE) model integrated with Remote Sensing and Geographic Information System (GIS). The ranges of the estimated erosivity of rainfall, erodibility of the soil, slope length and slope steepness, crop management factor and conservation practices are 806.2 to 1513.2 MJ.mm.ha-1.h-1.yr-1 (or an average of 1121.5 MJ.mm.ha-1.h-1.yr-1), 0 to 0.02 t.h.MJ-1 mm-1, 0 to 78.8 (or average 0.41), 0 to 0.63 (or average 0.57) and 0.55 to 1 (or average 0.73), respectively. As per the findings, the study area is expected to lose 182621.5 tons of soil annually, with the estimated annual soil erosion rate of 15.18 t.ha-1.yr-1 also predicted. The weighted overlay index approach was used to produce the probability zone map, which shows that the majority of the research region falls within the slight probability zone and that only a small percentage falls inside the high and very high probability zones. This study proves RS-GIS is useful for predicting erosion and can be used in soil conservation programs.