Attenuation of Runoff and Chemical Loads in Grass Filter Strips at Two Cattle Feedlots, Minnesota, 1995-98

Water-Resources Investigations Report 03-4036


By S.C. Komor and D.S. Hansen


Prepared in cooperation with the Minnesota Pollution Control Agency

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Attenuation of cattle feedlot runoff in two grass-covered filter strips in Minnesota was estimated by measuring chemical loads into and out of the strips. Filter strips of the Bock and Sanborn sites were 60-m long and 20-m wide and received runoff from cattle feedlots that supported 35 and 225 cattle, respectively. Feedlot and filter-strip runoff were measured using flumes with stage sensors. Water samples were collected using automated samplers. Attenuation values were calculated from four storm-runoff events. Ground water sampled beneath and outside the filter strips indicated some infiltration losses of sulfate, chloride, and nitrogen at the Bock site where soil permeability was greater than at the Sanborn site. Chemical constituents in filter-strip runoff, and their corresponding ranges of attenuation were as follows: chemical oxygen demand, 30–81 percent; dissolved chloride, 6–79 percent; dissolved sulfate, -3–82 percent; dissolved ammonia nitrogen, 33–80 percent; suspended ammonia plus organic nitrogen, 29–85 percent; dissolved organic nitrogen, 14–75 percent; suspended phosphorus, 24–82 percent; dissolved phosphorus, 14–72 percent; and fecal coliform bacteria, 18–79 percent. The ranges seem to be affected by barriers of direct contact of the runoff water with the soil. This varies seasonally by coverage of the soil by ice in winter and vegetation in summer months. Greater attenuation values occurred in October and May when mats of wilted, flat-lying grass covered the filter strips; attenuation values were less during the summer when tall growing grass covered the filter strip





Purpose and scope

Previous studies

Description of study area

Bock site

Sanborn site


Quality of water

Bock site

Sanborn site

Attenuation of runoff and chemical loads



For additional information write to:


U.S. Geological Survey
District chief

2280 Woodale Drive

Mounds View, MN 55112


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U.S. Geological Survey

Branch of Information Services

Box 25286, MS 517

Federal Center

Denver, CO 80225


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Last modified: Thursday, September 01 2005, 02:19:49 PM
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