Runoff and hillslope erosion resulting from a high-intensity thunderstorm near Mack, western Colorado.

Data on hydrologic and geomorphic processes from single storm events are rare. The opportunity to make such measurements occurred on August 12, 1964. The runoff and hillslope erosion resulting from a high-intensity thunderstorm were measured in a small basin of 12 acres in western Colorado. The maximum intensity of rainfall for a 10-minute period was 1.98 inches per hour. The total runoff as measured in a reservoir was 0.508 inch over the basin, and 0.90 inch of precipitation had been recorded when runoff stopped. Data from measurements of erosion pins along 6 hillslope profiles indicate that approximately 0.11 acre-foot was eroded from the basin during the storm; survey of the reservoir shows that 0.090 acre-foot was delivered to the lower end of the basin. Estimates of soil loss using measurements of erosion pin exposure are considered to be good in basins where sediment transport from hillslopes to the measuring point is not complicated by diverse topography or intermediate areas where deposition may occur. [ABSTRACT FROM AUTHOR]