53:171 Water Resources Engineering
Problem #25
Application of the Universal Soil Loss Equations

An site near Iowa City has a silt loam soil, with a typical slope of 5% and a slope length of 150 feet. The existing vegatation is grass with has no appreciable canopy and almost 100% ground cover. During construction, most of the site will be disturbed, leaving only 20% ground cover. One erosion control measure being considented is wood chips (a 7 ton/acre mulch rate).

1. Determine the cropping management factor C for before construction, after the cover is disturbed, and after wood chips are applied.
2. Estimate the average annual soil loss (in tons/acre) from this site for the three conditions.
3. Estimate the soil loss (in tons/acre) for a historical storm event (which is used for design in the area) for the three conditions [Use the hourly rainfall data for Station -2-].