Land use Changes Impact on extreme flood events in the Hulu Kelang River Basin, Malaysia

Abstract

Hulu Kelang is a flood prone area near to Kuala Lumpur. Urban development has caused numerous landslides and mudflow events in this region. The current research tried to study the area inundated by a rainfall period of a hazard to be determined in relation to the land use. The assessment of land use impact in the Hulu Kelang basin focused on the runoff contributions from different land cover classes and the potential impact of land use changes on runoff generation. To minimize losses incurred by mudflow events, A hydrological regional modeling of rainfall induced runoff event were employed in this study. Five approaches were considered in this research, i.e: (1) Drainage Basins Delineation; (2) Calculation the rate of Loss/ Infiltration; (3) Assessment of basins in term of flood potential; (4) Land Cover Change analysis, and (5) Change to runoff volume due to land cover change. In this regard, the results showed that the transient rainfall infiltration and grid based regional modeling (TRIGRS) provides important information about the flood intensity and significantly improves our ability to model future flood scenarios through other area. On the other hands, impact of land cover on runoff volume was computed with TRIGRS model based on the transient infiltration changes, and attendant changes in the runoff, due to rainfall period. Computation for the effects of rainfall infiltration on the land cover showed that the direct runoff from development area, agricultural area, and grass lands are dominant for a flood event compared with runoff from other land covered areas in the study area. The urban areas or lower planting density areas tend to increase for runoff and for the monsoon season floods, whereas the inter flow from forested and secondary jungle areas contributes to the normal flow.