Broken Stream Banks: Too Many Rivers and Streams Go Unprotected

Tuesday, April 29, 2014


Although Minnesota has a unique policy designed to curb agricultural water pollution by requiring a 50-foot buffer zone between farmland and the state’s river and stream banks, less than a fifth of the waterways in the southern part of the state are fully protected, an Environmental Working Group report shows.

In the report released yesterday (April 28), titled Broken Stream Banks, EWG analyzed aerial photography and other spatial data sets to grade more than 8,000 miles of public waterways based on the presence or absence of permanent vegetation in the required 50-foot buffer zones.

The report found that overall, about 72 percent of the required buffering acres were in place in agricultural areas. But that overall average is misleading, because there are large differences among waterways. Only 18 percent (87 waterways) earned a grade of A, meaning 100 percent of the required buffer zones was maintained. In contrast, 21 percent (101 waterways) got a failing grade – meaning that less than 60 percent of the buffer acreage was in place.

Southern Minnesota and the Minnesota River basin in particular have serious problems with pollution by sediment and nutrients. These problems cannot be solved unless polluted runoff from cropland and stream bank erosion is dramatically reduced. In 30 counties, row crops occupy more than 50 percent of the total land area, and in 13 counties row crops account for 75 percent or more.

Maintaining a buffer of permanent vegetation between row crops and waterways will not solve all of the pollution problems. But science and professional experience show that such buffers make an important contribution to cleaner water and stronger stream banks.

All the EWG data has been published on an interactive map allowing you see areas where missing buffers exist and how well public waters scored. See for yourself by clicking on the map below.


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