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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #79429
Title: EFFECTS OF HILLSLOPE HYDROLOGY AND SURFACE CONDITION ON SOIL EROSION

Author
item HUANG, CHI-HUA - PURDUE UNIVERSITY
item GABBARD, DANIEL - PURDUE UNIVERSITY
item Norton, Lloyd
item Laflen, John

Submitted to: Advances in Geoecology
Publication Type: Proceedings
Publication Acceptance Date: 1/24/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Seepage, the reemergence of soil water at the surface, is a common occurrence in fields with an impeding soil layer during periods of excessive soil moisture. The seepage zone has been associated with the development of 'seepage steps' and ephemeral gullies. Despite the linkage between seepage and landform development, little data are available for seepage induced surface erosion on gentle slopes when seepage flow alone will not cause any erosion. Laboratory experiments were designed to recreate the hydrologic conditions of a 5-m segment of the hillslope at different locations on the landscape. Variables considered are: slope steepness, seepage and drainage gradients. Runoff and sediment samples were collected under rainstorms, and rainfall with added inflows to emulate various level of erosive conditions as the hillslope position is changed. Results showed that seepage conditions greatly enhanced surface erosion. Sediment delivery was 3 to 4 times higher with seepage flow as compared to a free drained condition. The near-surface hydraulic gradient has a significant effect on runoff and sediment regime. This is supported by a data set collected during a rainfall run when the seepage condition was suddenly reversed to drainage. The rapid change from exfiltration to infiltration conditions caused a 70 percent reduction in sediment delivery. The knowledge of hydrologic effects on soil erodibility and erosion processes may lead to different erosion control strategies and management practices at regions where seepage occur.