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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Slope and Soil Roughness on Microrill Networks in a Laboratory Experiment

item Nearing, Mark

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: N/A

Technical Abstract: Rill and micro rill initiation is an area of increasing interest in the last few years. Our study consists of a laboratory experiment to study micro rill initiation in a 4-m length, 2-m width flume. Six different treatments were considered, combination of two different slopes and three different initial roughness, two replications each. For each treatment, flume runoff and sediment rate, and flow velocity in selected micro rills within the flume were measured during each of the five 1- hour duration rainfall simulations that were performed at, approximately, 48-hours intervals. After each rainfall simulation, and on the initial undisturbed surface, the DEM at 1.5-mm grid was acquired using a laser scanner. The provisional results show how, except in the early stages of each rainfall simulation, sediment and runoff rate are not significantly affected by the initial roughness, either the average flow velocity measured in selected rills, with slope had a significant effect on these variables. Some of the rill network characteristics, such as sinuosity or orientation, were significantly affected by the initial roughness. These characteristics evolved during the experiment towards, apparently, similar final values regardless the initial roughness. Once completely analyzed this, on-going, experiment the generated database is expected to be used to evaluate different models of rill initiation, eventually suggesting some modifications, and to evaluate the effect of different methods of rill network delineation.

Last Modified: 4/18/2014
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