Long-term rainfall trends and their effects on surface erosion: Implications for the Sultan Azlan Shah new campus site, Tanjong Malim

Rain is an important element in the course of terrain changes. Analyses of rainfall data would determine the various impacts that occur on the earth surface such as the rate of discharge, surface flow, water in the soil, soil erosion, and flood forecasts and determination. Long-term rainfall trends and intensities often contribute to increases in the rate of surface erosion in areas undergoing development. In this paper, the focus is on the effects of rainfall on soil erosion at the site of the UPSI new campus which was being developed. The study area was located at the foothills of the Titiwangsa Mountain Range which had always received heavy orographic and convectional rainfalls. November and April were the months with the higher average of monthly rainfall. The rainfall characteristics, the monsoons influences, the long-term rainfall trends and the connection between rainfall and occurrence of erosion were examined. The findings revealed that there was an increasing long-term rainfall trend in Tanjong Malim amounting to more than 2400 mm per year. Soil erosion was serious here because adequate mitigation measures were not adopted by the parties responsible for the earlier site development of the Proton City resulting in severe siltation of local rivers and lakes. The situation would have been greatly helped had artificial drainage and sediment traps been constructed, slope management practised, and soil protection vegetation planted.