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What is a Buffer?

A buffer, also known as a riparian filter strip, is vegetated land adjacent to a stream, river, lake, or wetland.

Buffers help filter out phosphorus, nitrogen, and sediment and are an important conservation practice for helping keep water clean. Buffers are critical to protecting and restoring water quality and aquatic life, natural stream functions, and aquatic habitat.

aerial image of buffer in field

MN Buffer Law

Buffers are required on public waters with shoreline classifications and public ditches. These have been mapped by the DNR and can be found at If it is not on the map, a buffer is not required under this law.

How to Measure Buffer

Public waters: 50 foot average, 30 foot minimum, measured from top/crown of the bank or where there is no definable bank, measurement from the edge of the normal water level.       

Public Ditches: 16.5 feet in width measured outward from the top edge of the constructed channel.

aerial image of buffer along County Ditch 30

County Ditch 30

public water buffer

Public water buffer

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