Study on soil erosion under alternative management scenarios in Bang Kloy Bon sub-watershed, Kaeng Krachan National Park, THAILAND

ABSTRACT

Analysis of soil erosion in the Bang Kloy Bon sub-watershed under three site management simulations to assess the area of severity of soil erosion and the amount of sediment flowing into the river at the water outlet using the Sediment Delivery Ratio (SDR) model, which was analyzed under the International Soil Loss Equation (USLE). It was found that the amount of soil erosion under a imaginary forest simulation, the current scenario is later not allowed to farm, and a scenario for permission to operate in swidden cultivation; the average amount of soil erosion is 100,295, 702,918 and 10,194,965 tons per year; The amount of sediment into the river by each model; 3,123, 62,441 and 1,570,368 tons per year respectively. By simulating the current condition, severe and very severe soil erosion occurred at 3,756 and 64,600 hectares but its will be increased to 6,589 and 538,367 hectares, respectively, if farming permits. The value of soil loss caused by the forest being partially cleared at present is 1,314,814.9 million baht per year and in the case of agriculture in this area, the value of soil loss that will occur up to 22,024,752,899.4 million baht per year. Therefore pointed out that Bang Kloy Bon sub-watershed should be managed according to the 1A-class watershed area management, which is to be preserved as a watershed area because of its characteristics and properties that may have an environmental impact from land use change easily and severely.