Evaluation of C and P Factors in Universal Soil Loss Equation on Trapping Sediment: Case Study of Santubong River

Kelvin K. K. Kuok, Darrien Y. S. Mah, P. C. Chiu

Department of Civil Engineering, Faculty of Engineering, University of Malaysia Sarawak, Kota Samarahan, Malaysia.
Department of Information System, Faculty of Computer Science and Information Technology, University of Malaysia Sarawak, Kota Samarahan, Malaysia.
Faculty of Engineering, Computing and Science, Swinburne University of Technology, Sarawak, Malaysia.

DOI: 10.4236/jwarp.2013.512121                

Abstract

Universal Soil Loss Equation (USLE) is the most comprehensive technique available to predict the long term average annual rate of erosion on a field slope. USLE was governed by five factors include soil erodibility factor (K), rainfall and runoff erodibility index (R), crop/vegetation and management factor (C), support practice factor (P) and slope length-gradient factor (LS). In the past, K, R and LS factors are extensively studied. But the impacts of factors C and P to outfall Total Suspended Solid (TSS) and % reduction of TSS are not fully studied yet. Therefore, this study employs Buffer Zone Calculator as a tool to determine the sediment removal efficiency for different C and P factors. The selected study areas are Santubong River, Kuching, Sarawak. Results show that the outfall TSS is increasing with the increase of C values. The most effective and efficient land use for reducing TSS among 17 land uses investigated is found to be forest with undergrowth, followed by mixed dipt. forest, forest with no undergrowth, cultivated grass, logging 30, logging 10^6, wet rice, new shifting agriculture, oil palm, rubber, cocoa, coffee, tea and lastly settlement/cleared land. Besides, results also indicate that the % reduction of TSS is increasing with the decrease of P factor. The most effective support practice to reduce the outfall TSS is found to be terracing, followed by contour-strip cropping, contouring and lastly not implementing any soil conservation practice.

Keywords

Universal Soil Loss Equation; Crop/Vegetation and Management Factor (C); Support Practice Factor (P); Outfall Total Suspended Solid; % Reduction of Total Suspended Solid

Conflicts of Interest

The authors declare no conflicts of interest.

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