A Low Intensity Rainfall Simulator and Runoff Collection System
Presented at the American Geophysical Union, 2001 Fall Meeting, San Francisco, California, December 10-14.
In the past, rainfall simulators have been designed for high intensity events; however there is a lack of studies on the simulation of low rainfall intensities. This research presents a system capable of performing rainfall simulations over large areas with intensities as low as 15.5mm/h (0.6in/h) and a Coefficient of Variation greater than 0.8. The system consists of towers distributed spatially in the corners of hypothetical equilateral triangles with varying sizes. The simulation area should be inside the triangles to ensure adequate coverage and minimize wind effects. Thus, the minimum configuration for the system is three towers. Each tower consists of three aluminum legs that are 2.5m (8ft) high and support a 1/4 GG - SS 10 nozzle, manufactured by Spraying Systems Corporation. A pressure gauge is incorporated in each tower to monitor the flow. The water supply is pumped from a tank into a main hose that has a flow control and pressure gauge. The water is subdivided into individual hoses that supply water to each tower. The hose diameters vary according to the number of towers used in each simulation. This configuration is capable of simulating a wide range of rainfall intensities over small and large regions. The collection of the runoff is accomplished with a 1 1/2 in semicircular PVC Pipe. This system is applied to a research project that evaluates the impacts of dust suppressants on disturbed lands.