STORM PATTERN EFFECT ON INFILTRATION, RUNOFF, AND EROSION.

A programmable rainfall simulator was used to study the effects of variable intensity storm patterns on infiltration, runoff, and erosion. When rain was applied to an initially dry soil, peak runoff rates were four to 20 times greater from storms having maximum intensities occurring near the end of the storm than peak rates from storms of uniform intensity or storms having their maximum intensities occurring early in the storm. Soil loss from late peaking storms was two to eight times that from early peaking storms. Runoff and soil loss from a storm of a given pattern occurring on a wet soil was greatest when preceding storms had maximum intensities occurring very early in the storm. Apparent infiltration rate varied with rainfall intensity, which was likely caused by spatial variability of infiltration rates.