The Walnut Gulch Rainfall Simulator: A Computer-Controlled Variable Intensity Rainfall Simulator

This is the authors' abstract. We don't add key points for this paper.

The Walnut Gulch Rainfall Simulator (WGRS) is a portable, computer-controlled, variable intensity rainfallsimulator for rainfall-runoff-erosion research on rangelands. The WGRS was developed with the objective to quantify therelationship between rainfall intensity and steady state infiltration rate and to determine how that relationship affectssediment transport by overland flow. The simulator has a single central oscillating boom and applies water over a 2- . 6.1-marea. Two important improvements have been made to the oscillating boom simulator design. First, a computer-controlledstepper motor is used to control the oscillations and minimize the variability of the water application across the plot. Second,the spray time and sequence of nozzle operation are controlled by three-way solenoids to minimize the delay time betweenoscillations at low application rates. The simulator applies rainfall rates between 13 and 178 mm/h, in 13-mm/h increments,with a coefficient of variability of 11% across the plot. Water use is minimized by recycling the water that is not sprayeddirectly on the plot. The simulator has been tested in both laboratory and field applications.