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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #124131
Title: A PORTABLE RAINFALL SIMULATOR FOR PLOT-SCALE RUNOFF STUDIES

Author
item HUMPHRY, J - UNIVERSITY OF ARKANSAS
item DANIEL, TOMMY - UNIVERSITY OF ARKANSAS
item EDWARDS, DWAYNE - UNIVERSITY OF KENTUCKY
item Sharpley, Andrew

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2001
Publication Date: 1/20/2002
Citation: HUMPHRY, J.B., DANIEL, T.C., EDWARDS, D.R., SHARPLEY, A.N. A PORTABLE RAINFALL SIMULATOR FOR PLOT-SCALE RUNOFF STUDIES. TRANSACTIONS OF THE AMERICAN SOCIETY OF AGRICULTURAL ENGINEERS. 2002. V. 18. P. 199-204.

Interpretive Summary: Rainfall simulators have been used with much success throughout the last 75 years to conduct research on infiltration, surface water runoff, and soil erosion. While natural rainfall is desirable, as it represents natural conditions at a given place, data acquisition is very slow and the spatial and temporal distribution of rainfall intensity, duration, and kinetic energy cannot be controlled. Rainfall simulators have the ability to create controlled and reproducible artificial rainfall, which in turn expedites data collection and allows comparison of soils and management variables among locations. This paper describes the construction and use of a lightweight (aluminum frame) and portable rainfall simulator that is part of the National Phosphorus Research Project. The design of the simulator allows two researchers to conduct runoff studies in locations that lack access to water and electricity. In locations where there is no access to water or electricity, a trailer outfitted with a water tank, gas generator, and hose reels is required to operate the simulator. When traveling from site to site, two people can disassemble/assemble the simulator within 10 minutes.

Technical Abstract: Rainfall simulators have a long history of successful use in both laboratory and field investigations. Many plot-scale simulators, however, have been difficult to operate and transport in the field, especially in remote locations where water or electricity is unavailable. This paper describes a new rainfall simulator that is relatively easy to operate and transport to and from the field, while maintaining critical intensity, distribution and energy characteristics of natural rainfall. The simulator frame is constructed from lightweight aluminum pipe with a single 50 WSQ nozzle centered at a height of 3 m. An operating nozzle pressure of 28 kPa yields continuous flow at an intensity of 70 mm/h over a 1.5- by 2-m plot area with a coefficient of uniformity of 93%. Kinetic energy of the rainfall is about 25 J/m2/mm, approximately 87% of natural rainfall. The simulator can be easily transported by two field personnel and completely assembled or disassembled in approximately 10 minutes. Water usage is at minimum as the simulator utilizes only one nozzle.