Numerical Quantification of Surface Runoff and Soil Erosion using PCRaster

Authors

Victorino A. Bato, Division of Soil Science, Agricultural Systems Institute, College of Agriculture and Food Science, University of the Philippines Los BañosFollow

Publication Date

12-1-2023

Abstract

Surface runoff and soil erosion of the Upper Lagawe River Sub-watershed, Ifugao Province, Philippines were quantified using Geographic Information Systems (GIS)-based numerical simulation. PCRaster software was used as a framework for the model. Manning’s and Rose, and Freebairn’s Equations were utilized to compute surface runoff velocity and sediment mass. Analysis and comparison of the measured and predicted streamflow yielded a mean Nash and Sutcliffe Efficiency Index of 0.70, a mean percent bias of -8.38%, and a mean root mean square error (RMSE) of 0.16. Based on the model, super typhoon Lando (international name: Koppu) generated an estimated surface runoff volume of 186000 m³ and an estimated sediment mass of 36587 kg for the entire sub-watershed. The mass of eroded sediments equated to 18.6 kg/ha of erosion rate just for the said super typhoon. Stable ecosystems, such as the Upper Lagawe River Sub-watershed, where forest vegetation is intact and farmers practice soil conservation techniques are still vulnerable to the effects of extreme rainstorm events, can generate voluminous surface runoff and eroded sediments.

Recommended Citation

Bato, Victorino A. (2023) "Numerical Quantification of Surface Runoff and Soil Erosion using PCRaster," The Philippine Agricultural Scientist: Vol. 106: No. 4, Article 8.
Available at: https://www.ukdr.uplb.edu.ph/pas/vol106/iss4/8