A Study of Engineering Properties of the Soil on Si–Chung Island for SWAT Modeling

Abstract

Si–Chung Island is a tourist destination, although it covers an area of 4square kilometers. The geologic stratification consists of marble and sandstone. The heavy rain fell in rainy season, but the water was insufficient in dry season. The governor needs to buy fresh water from Siracha’s mainland, which high cost. Water shortage can reduce economic potential and negatively impacts of lives. The discovered groundwater resources were insufficient for demand due to the aquifers. Thus, surface water exploitation must perform properly. Estimation of surface runoff on small islands can be performed using Geographic Information System (GIS), which contains an extension Soil and Water Assessment Tool (SWAT) for calculate hydrological cycle, many parameters required. Some of them are SOL (Soil parameters) that impact surface runoff quantities. In case of Si–Chung Island, there are no available data for soil series, it was unable to meet reliable soil data. The purpose of this research to determine soil map and soil parameters, based on testing result. Soil sample was collected 14 locations all over the island, divided soil region by using Thiessen polygon. The initial soil data of Si–Chung Island was generated. The results showed that most of the soils on Si–Chung were classified as sandy clay soils. Hydrological soils can be classified to group C and D. Saturated hydraulic conductivity is low and high surface runoff potential.