A portable rainfall simulator for small paired-plot comparisons

TitleA portable rainfall simulator for small paired-plot comparisons
Publication TypeConference Paper
Year of Publication2001
AuthorsVan Zee JW, Herrick JE
Conference NameSoil Science Society of America Annual Meeting
Date PublishedOctober 15, 2001
ARIS Log Number129786
AbstractWe describe the design and calibration of an inexpensive rainfall simulator in which a manually operated pulley system is used to move a nozzle along a 3m track, uniformly covering an area of up to 1 x 2.5m. Nozzle heights can be set up to 3m from the ground surface. High or low intensity rainfall events can be simulated using a VeeJet and cone nozzle. The simulator, pump and 500-gallon water tank are transported in a pickup truck. Garden hoses transport water from the tank to the simulator, allowing plots to be located in remote sites. Using a VeeJet nozzle, water distribution within 0.5m2 (70.7 x 70.7cm) plots remained uniform in winds up to 40kph, as long as all sides of the simulator were protected with tarps: the average difference between the highest and lowest rates recorded by 5 gauges in each plot was just 11% of the mean (n = 23 runs). Cone nozzles produced only slightly less uniform distributions. Nearly 80% and 55% of drop sizes sfell between 1 and 3mm for the VeeJet and cone nozzle, respectively. We present equilibrium infiltration rates and sediment production data from experiments designed to quantify disturbance effects based on simultaneous measurements from paired plots.