GIS-BASED NON-POINT SOURCES POLLUTION SIMULATION IN CAMERON HIGHLANDS, MALAYSIA

Cameron Highlands is a mountainous area subjected to torrential tropical showers. It extracts 5.8 million liters of water per day for drinking supply from its rivers at several intake points. The water quality of rivers in Cameron Highlands, however, has deteriorated significantly due to land clearing for agriculture, excessive usage of pesticides and fertilizers as well as construction activities in rapidly developing urban areas. On the other hand, these pollution sources known as non-point pollution sources are diverse and hard to identify and therefore they are difficult to estimate. Hence, Geographical Information Systems (GIS) was used to provide an extensive approach to evaluate land use and other mapping characteristics to explain the spatial distribution of non-point sources of contamination in Cameron Highlands. The method to assess pollution sources has been developed by using Cameron Highlands Master Plan (2006-2010) for integrating GIS, databases, as well as pollution loads in the area of study. The results show highest annual runoff is created by forest, 3.56 × 10^8 m^3/yr followed by urban development, 1.46 × 10^8 m^3/yr. Furthermore, urban development causes highest BOD load (1.31 × 10^6 kgBOD/yr) while agricultural activities and forest contribute the highest annual loads for phosphorus (6.91 × 10^4 kgP/yr) and nitrogen (2.50 × 10^5 kgN/yr), respectively. Therefore, best management practices(BMPs) are suggested to be applied to reduce pollution level in the area.