The Universal Soil Loss Equation (USLE) was developed at the USDA National Runoff and Soil Loss Data Center at Purdue University in a national effort led by Walter H. Wischmeier and Dwight D. Smith. The USLE was published in 1965 in USDA Agriculture Handbook 282.
Soil
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Image Caption: The Universal Soil Loss Equation for estimating average annual soil erosion.2003
A = average annual soil loss (in tons/acre)
R = rainfall erosivity index
K = soil erodibility factor
LS = topographic factor
C = cropping factor
P = conservation practice factor
The Fresno scraper established the basis for the modern earthmoving scraper, being able to scrape and move a load of soil, then discharge it at a controlled depth. It quadrupled the productivity of manual labor, replacing hand shoveling of earth into horse carts.
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Image Credit: Courtesy Flickr/Alisha Vargas (CC BY 2.0)Image Caption: Fresno ScraperEra_date_from: 1883
1991
The largest rolled-earth fill dam in the world at the time of its completion, Denison Dam eventually served as a prototype for dam construction in future U.S. Army Corps of Engineers projects throughout the arid plains of the American Southwest. Procedures and equipment developed during its construction are now commonplace in the sampling and testing of soils.
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Image Credit: Courtesy Flickr/Robert Nunnally (CC BY 2.0)Image Caption: Denison DamEra_date_from: 1943
1993