Geological Behavior (GBR)

Soil erosion is one of the principal causes of soil degradation in Sandakan, Sabah, Malaysia. The natural phenomenon of erosion is now accelerated by human activities that alter the natural mechanisms. This acceleration is caused by destruction of plant cover, the growing of wrong cultivations, unsuitable farming techniques etc., all of which may be prevented with correct management and land planning. Soil erosion has been identified as one of the important environmental issues and therefore, detail assessment on prediction of soil loss and its impacts has been carried out using the application of the Modified Soil Loss Equation (MUSLE) and Geographical Information System (GIS). ARC-INFO was used for the storage of the data layer on each factor controlling soil erosion. Identification of potential high-risk erosion areas was made using a thematic data layering approach to analyze risk areas. The quantitative soil loss (t ha-1 yr-1) ranges estimates by MUSLE model by a spatial information analisis approach (GIS) were computed: (a) Very High risk (>150 tons/ha/year); (b) High risk (100-150 tons/ha/year); (c) Moderate risk (50-100 tons/ha/year); (d) Low risk (10-50 tons/ha/year); and (e) Very low risk (<10 tons/ha/year). About 46.33% of the area was classified as very low, 43.50% as low, 5.23% as moderate, 4.49% as high and 0% as very high. Soil erosion hazard has been identified and found to be significant in areas with slope above 36.96o. All findings showed that integration of GIS can be used for spatial analysis in a large scale. Production of A total value maps can be applied to particular development planning areas especially for housing and agriculture developments.