Development of an experimental technique for simulating sheet and rill erosion using multiple box plots and a rainfall simulator

Scientists must discover new methods to control erosion. Laboratory-scale box plots offer a way to test and compare these methods rapidly and with repeatability, but only for interrill or sheet erosion. Current box plot designs do not provide sufficient slope length for studying combined sheet and rill erosion on steep slopes. Constructing a single long box plot for this purpose is extremely difficult and impractical.

The purpose of this research was to develop a method for studying sheet and rill erosion on long, steep slopes in a laboratory setting by using multiple box plots and a rainfall simulator. Devices were designed to collect runoff from the bottom of an erosion box, to transport the runoff and associated sediment to the top of another box, and to redistribute the runoff at the top of the second box in a fashion to simulate runoff conditions at the bottom of the first box. This simulates the effects of a slope twice the length of one box. Observations were made of the box plots and of a site where natural rainfall occurred on a continuous slope. These sites were compared visually to evaluate the ability of the sequential box plots to simulate conditions found on a single long slope in the field.

Based on these observations, the experimental system simulates combined sheet and rill erosion conditions very well. Channels of runoff were continued from one box to the next. Rills began forming in the lower third of the first box, and there was rill development throughout the second box. Visually, rill development in the boxes was similar to rill development on a slope of equal length in the field.

Recommendations for improving the experimental design were made, as were recommendations for future research.