Soil erodibility and surface runoff potentiality for water pollution management of Melaka Tengah watersheds in Malaysia

Abstract

The relationships among surface runoff, precipitation and soil erodibility are significant in addressing environmental pollution as like water pollution and in predicting the benefits of Melaka Tengah watershed management practices. Land use pattern, soil series and slope percentage are also major factors to develop these relationships. Rainfall data (2009 to 2012) were collected from six rainfall station and analyzed for variations in precipitation at monthly and daily scale for calculating the surface runoff of these watersheds. Soil texture and structure, organic matter percentage, and hydraulic conductivity were analyzed for the particular soil series in this study area. Soil Conservation Services (SCS) and Weighted Curve Number (CNw) methods were introduced to calculate the surface runoff on daily basis. Henceforth, monthly surface runoff was calculated by summing the daily runoff and surface runoff map was produced by ArcGIS tools. Thenceforth, Tew equation was introduced to identify the soil erodibility of watershed soils for predicting the soil erosion probability. Results indicated the weighted curve number varies from 82 to 85 and monthly runoff varies from 23% to 30% among the five watersheds. Soil erodibility varies from 0.038 to 0.06 (ton/ha)(ha.hr/MJ.mm). Linau-Telok-Local Alluvium, Malacca-Munchong, Munchong-Malacca-Serdang and Malacca-Munchong-Tavy are the dominant soil series of this region having the average soil erodibility of about 0.042 (ton/ha)(ha.hr/MJ.mm). The main focus of this study is to provide the information of surface runoff potentiality, and soil erodibility for watershed water resources management, water pollution and flood control for watersheds.