(50’ avg. buffer standard)
Purpose and Considerations
This document is for the use of MN NRCS 393 (pdf) (Filter Strip) or 391 (pdf) (Riparian Forest Buffer) Conservation Practice Standards to comply with the Minnesota Buffer Law. MN NRCS 393 (pdf) & 391 (pdf) Standards may be used as standalone conservation practices as long as practice criteria is being met for the defined purpose. For the purposes of this common alternative practice, the definition of a filter strip is: “A strip or area of herbaceous vegetation that removes contaminants from overland flow.”
Note: Alternative practices installed per this document within shoreland zoning districts should be coordinated with county or municipal officials responsible for shoreland ordinance provisions.
Additional information on using RUSLE2 for Design and Predicted Effectiveness can be found at: https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=18578.wba (pdf)
NOTE: : These standards are not directly related to the Conservation Reserve Program (CRP) criteria.
The NRCS 393 (pdf) Practice standard calls for overland flow entering the filter strip to be uniform sheet flow and any concentrated flow will be dispersed before it enters the filter strip or addressed by an additional conservation practice. It also calls for more specific seeding mixes and the maintenance standards are more prescriptive as it calls for a 10-year life expectancy and after up to 6” of sediment accumulation the strip is to be re-shaped, graded as needed and vegetation re-established. Therefore, implementation of a properly sited, designed and maintained filter strip following NRCS 393 (pdf) or 391 (pdf) practice standards will provide comparable water quality benefit.