EFFECTS OF WATERSHED REPRESENTATION ON RUNOFF AND SEDIMENT YIELD MODELING

• Published in: Journal of the American Water Resources Association Vol. 40; no. 2; pp. 311 - 319
• Main Authors: Lopes, Vicente L., Canfield, H. Evan
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-04-2004
• Subjects: erosion; scale effects; sediment transport; semiarid watersheds; storm runoff; watershed modeling; watershed representation
• ISSN: 1093-474X; 1752-1688
• DOI: 10.1111/j.1752-1688.2004.tb01031.x

Using hydrology and scale data generated on a 4.4-ha experimental rangeland watershed in southeastern Arizona, the effect of watershed representation on runoff and sediment-yield simulations was investigated. KINEROS2, which is a kinematic runoff erosion model based on Hortonian overland flow theory, was used. Landscape form was characterized using topographic surveys, and the materials on the landscape were characterized using soil particle size analysis. The model was applied to four representations of the watershed to examine the effect of the different representations on simulations of storm runoff volume, peak runoff, and sediment yield. The representations differed in the complexity of the average contributing source area. For small rainfall events, decreasing the complexity in watershed representation reduced runoff volume and peak runoff through increased infiltration on hillslopes and transmission losses in channels, but sediment yield was not affected significantly. For large rainfall events, decreasing complexity in watershed representation had a substantial effect on sediment yield, but relatively little impact on runoff volume and peak runoff.