Distribution of rainfall events in northern region of Peninsular Malaysia

Abstract

Understanding of rainfall characteristics is important in designing Best Management Practices (BMPs) facilities. Because of intermittent rainfall, many researches on hydrology employ the concept of rainfall events. The selection of appropriate rainfall events for treatment design is essential to ensure the effectiveness of BMPs systems. Thus, the objective of this study is to identify the distribution of rainfall event using 6-hour Minimum Inter Event Time (MIT) and to identify the extreme rainfall thresholds over the study area. It shows that the rainfall data series consist of a large number of small events and rainfall depth of less than 2.5 mm (Type 1) contributes the highest percentage toward the overall record. About 63% of the rainfall record consists of Type 2 rainfall depth between 2.6 mm to 80 mm and only 1.3% recorded for rainfall event Type 3 with a depth exceeding 80 mm. It was found that the extreme rainfall threshold in Northern region of Peninsular Malaysia vary from 45 mm to 80 mm for R95 indices and 72 mm to 175 mm for R99 indices. These findings could be used as reference for better BMPs facilities design with extreme rainfall adaptation strategies.