The Development of Equatorial Soil Loss and Sediment Yield Equations
| dc.contributor.author | Yong Leong Kong | |
| dc.date.accessioned | 2026-10-15T03:49:22Z | |
| dc.date.issued | 2018 | |
| dc.description | In equatorial region, soil erosion predominantly involves the detachment or movement of surface soil materials by raindrop impact and surface runoff, transportation of detached soil particles, and deposition or relocation of the detached materials at somewhere downslope. This research looks into the development of soil loss and sediment yield equations that can be used to estimate soil loss rate and sediment yield, respectively for small construction sites in equatorial region, namely the “Equatorial Soil Loss Equation or EQSLE” expressed as 𝐸𝑄𝑆𝐿𝐸 = [𝑅𝑒𝑞 × 𝐾 × (𝑇𝑇 ,𝑇𝐶 or 𝑇𝑃 ) × 𝐶 × 𝑃] and “Equatorial Sediment Yield Equation or EQMUSLE” expressed as 𝐸𝑄𝑀𝑈𝑆𝐿𝐸 = [95(𝑉 × 𝑄𝑝)0.56 × (𝑇𝑇 , 𝑇𝐶 or 𝑇𝑃 ) × 𝐾 × 𝐶 × 𝑃] ; where EQSLE=Soil Loss Per Unit Area (tons/ha•yr), 𝐸𝑄𝑀𝑈𝑆𝐿𝐸= Sediment Yield per storm event (ton/storm event), 𝑅𝑒𝑞=Rainfall-Runoff Erosivity Factor (MJ•mm/ha•hr), 𝑉= Runoff height on slope (in), 𝑄𝑝=Peak flow volume from observation plot (cfs) and 𝑇𝑇 , 𝑇𝐶 and 𝑇𝑃 = Triangular Prism-shaped, Cone-shaped and Pyramid-shaped Topographical Factors, respectively (unitless), and other sub-factors such as K = Soil Erodibility Factor (tons•ha•hr/ha•MJ•mm), C = Cover Management Factor (unitless), and P = Support Practice Factor (unitless). The outcomes of EQSLE and EQMUSLE can be used as references for conservation plan decisions for small construction sites in equatorial region. A rainfall simulator was designed to simulate Equatorial Rainfall Erosivity Factor (𝑅𝑒𝑞), where 𝑅𝑒𝑞 = 𝐸𝑒𝑞 𝐼30𝑞 MJ•mm/ha•hr, I30q = 30-minute Rainfall Intensity at typical equatorial rainfall intensity of approximately 150 mm/hr. It was found that the Equatorial Rainfall Kinetic Energy (Eeq) can be expressed as 𝐸𝑒𝑞 = 0.1499 + 0.0783 log10 𝐼30 MJ/ha•mm. It was also found that the Equatorial Topographical Factors (T) can be expressed as 𝑇𝑇 = 1.0𝐿𝑆 (Triangular Prism), 𝑇𝐶 = 0.8𝐿𝑆 (Cone) and 𝑇𝑝 = 0.77𝐿𝑆 (Pyramid) of RUSLE’s LS Factor. The Equatorial Rainfall iv Erosivity Factor (𝑅𝑒𝑞) was found to be 439.55 MJ•mm/ha•hr for year 2014 for Kuching area based on Kuching International Airport (KIA) hourly rainfall data. The key findings of this research are to experimentally determine the values of Equatorial Rainfall Kinetic Energy, 𝐸𝑞 (MJ/ha•mm), 𝑅𝑒𝑞=Equatorial Rainfall Erosivity Factor (MJ•mm/ha•hr) and T = Equatorial Topographical Factors (unitless), that lead to the development of Equatorial Soil Loss Equation (EQSLE) (while Erodibility Factor (K), Cover Management Factor (C) and Conservative Practice Factor (P)) would remain intact or adopt RUSLE. EQSLE can be expressed as: 𝐸𝑄𝑆𝐿𝐸 = 439.55 × 1.0𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Triangular Prism-Shaped Landscape) 𝐸𝑄𝑆𝐿𝐸 = 439.55 × 0.8𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Cone-Shaped Landscape) 𝐸𝑄𝑆𝐿𝐸 = 439.55 × 0.77𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Pyramid-Shaped Landscape) The Equatorial Sediment Yield Equation (EQMUSLE) for Triangle Prism-shaped, Coneshaped and Pyramid-shaped landscapes can be expressed as: 𝐸𝑄𝑀𝑈𝑆𝐿𝐸 = 95(𝑉 × 𝑄𝑝)0.56 × 1.0𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Triangular Prism-Shaped Landscape) 𝐸𝑄𝑀𝑈𝑆𝐿𝐸 = 95(𝑉 × 𝑄𝑝)0.56 × 0.8𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Cone-Shaped Landscape) 𝐸𝑄𝑀𝑈𝑆𝐿𝐸 = 95(𝑉 × 𝑄𝑝)0.56 × 0.77𝐿𝑆 × 𝐾 × 𝐶 × 𝑃 (Pyramid-Shaped Landscape) | |
| dc.identifier.uri | https://scholarhub.unimas.my/handle/123456789/3103 | |
| dc.language.iso | English | |
| dc.publisher | UNIVERSITI MALAYSIA SARAWAK | |
| dc.relation.ispartofseries | Faculty of Engineering | |
| dc.subject | EQSLE, EQMUSLE, Equatorial Rainfall Erosivity Factor, Equatorial Topographical Factor | |
| dc.title | The Development of Equatorial Soil Loss and Sediment Yield Equations | |
| dc.type | PhD |