ABSTRACT:
There are approximately 8,340 mapped sinkholes in karst terrain of southeast Minnesota. Most sinkholes are adjacent to row crops that likely contribute pollutants to surface waters and aquifers. Vegetated buffers can improve water quality by reducing sediment, fertilizers, pesticides, and other potential contaminants from runoff, and may benefit water quality when placed around sinkholes. We evaluated sediment, nitrogen, phosphorus, and runoff for buffers from 2.5 to 30 m (8.3 to 98 ft) wide with a spreadsheet model. We found buffers 30 m (98 ft) wide may reduce pollution by 80 percent, although buffers 15 m (49 ft) wide may be most cost effective. Buffers could contribute to goals of reducing sediment, nitrogen, and phosphorus loads in Minnesota waters. Buffers 15 m (49 ft) wide around all sinkholes would retire approximately 436 ha (1,077 ac) of land from production and cost approximately $260,000 yr−1 based on Conservation Reserve Program payments, while requiring <14 percent of the budgetof the program for groundwater protection in southeast Minnesota.
Footnotes
Adam Petersen is a grayling technician III for the Montana Fish, Wildlife, and Parks in Bozeman, Montana. Bruce Vondracek is a unit leader with the U.S. Geological Survey, Minnesota Cooperative Fish and Wildlife Research Unit at the University of Minnesota in St. Paul, Minnesota.
- Copyright 2006 by the Soil and Water Conservation Society
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