| Abstract: | Multiple rainfall intensities were used in rainfall-simulation experiments designed to investigate the infiltration and runoff from 1-square-meter plots on burned hillslopes covered by an ash layer of varying thickness. The 1-square-meter plots were on north- and south-facing hillslopes in an area burned by the Overland fire northwest of Boulder near Jamestown on the Front Range of Colorado. A single-nozzle, wide-angle, multi-intensity rain simulator was developed to investigate the infiltration and runoff on steep (30- to 40-percent gradient) burned hillslopes covered with ash. The simulated rainfall was evaluated for spatial variability, drop size, and kinetic energy. Fourteen rainfall simulations, at three intensities (about 20 millimeters per hour [mm/h], 35 mm/h, and 50 mm/h), were conducted on four plots. Measurements during and after the simulations included runoff, rainfall, suspended-sediment concentrations, surface ash layer thickness, soil moisture, soil grain size, soil lost on ignition, and plot topography.
Runoff discharge reached a steady state within 7 to 26 minutes. Steady infiltration rates with the 50-mm/h application rainfall intensity approached 20?35 mm/h. If these rates are projected to rainfall application intensities used in many studies of burned area runoff production (about 80 mm/h), the steady discharge rates are on the lower end of measurements from other studies. Experiments using multiple rainfall intensities (three) suggest that runoff begins at rainfall intensities around 20 mm/h at the 1-square-meter scale, an observation consistent with a 10-mm/h rainfall intensity threshold needed for runoff initiation that has been reported in the literature. |
| Genre: | USGS Numbered Series |
| ProdID: | 80999 |
| Citation Author: | Kinner, David A.; Moody, John A. |
| Citation Contributing Office: | Geological Survey (U.S.) |
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| Citation Edition: | Version 1.0 |
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| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | 0401000 |
| Citation LatS: | 0400500 |
| Citation LonE: | -1051500 |
| Citation LonW: | -1052500 |
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| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | viii, 64 p. |
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| Citation Publisher: | Geological Survey (U.S.) |
| Citation Series: | Scientific Investigations Report |
| Citation Series Code: | SIR |
| Citation Series Number: | 2007-5211 |
| Citation Search Results Text: | Infiltration and Runoff Measurements on Steep Burned Hillslopes Using a Rainfall Simulator with Variable Rain Intensities; 2008; SIR; 2007-5211; Kinner, David A.; Moody, John A. |
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| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Infiltration and Runoff Measurements on Steep Burned Hillslopes Using a Rainfall Simulator with Variable Rain Intensities; 2008; SIR; 2007-5211; Kinner, David A.; Moody, John A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/sir/2007/5211/ |
| Date Other: | Sat, 8 Mar 2008 00:00 -0600 |
| Publisher: | Geological Survey (U.S.) |
