Measuring rill erosion rates in a steep forest environment

Robichaud, P.R.; Brown, R.E. 1999 Measuring Rill Erosion Rates in a Steep Forest Environment. Presented at the 1999 American Geophysical Union Spring Meeting, June 1-4, Boston, MA. Poster.

Keywords: rill erosion

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Abstract: Erosion rates in a forest environment are generally small except when the ground surface is disturbed by human or natural causes. Concentrated flow can detach soil particles if the hydraulic energy is greater than the erosion resistance of the soil. In steep forest environments ample hydraulic energy is available to move the sediment load down slope; thus erosion is generally limited by the amount of detached sediment available for transport. The objective of this study was to measure the rill erosion rates for various surface conditions and slope steepness. Rills were allowed to form naturally in each of four surface conditions [natural cover, low severity burn areas, high severity burn areas, and skid trails] at two field sites for three replications. Concentrated flow was projected downslope at five discharge rates (7, 22, 15, 30, 48 l min^-1) on three slopes classes (20, 45, 65 %) for a 4 m length. Timed bottle samples, velocities, and flow depths were measured for each flow rate. Results suggest a detachment limiting condition existed with sediment concentration decreasing with each flow discharge rate. Calculated erosion rates were greater for the highly disturbed surface conditions than the less-disturbed surface conditions.

Moscow FSL publication no. 1999j