Minnesota DNR-Approved Shorelines
The Minnesota Department of Natural Resources (DNR) has set forth a series of guidelines that they believe should be followed when constructing a proper “DNR-approved” riprap shoreline.
What are the DNR criteria?
- Riprap should not cover existing vegetation, such as cattails or bull rushes.
- Riprap should be made of natural rock, 6 to 30 inches in diameter.
- Crushed rock, gravel or filter fabric should be placed underneath the riprap.
- Riprap is not more than 6-feet waterward of the Ordinary High-Water Level.
- Riprap conforms to the natural shape of the shoreline and does not obstruct navigation or water flow.
- Minimum finished slope of riprap is no steeper than 3:1 (horizontal to vertical) whenever possible.
- Area adjacent to the shoreline is not a posted fish-spawning area, or designated trout stream.
A DNR-approved shoreline is not a single row of large boulders placed along the shoreline.
A DNR-approved shoreline is not several stacked rows of boulders along the shoreline. This would be considered a retaining wall, and would be strongly discouraged (and would require a permit prior to construction, as well).
It is possible to have a quality shoreline that’s not DNR-compliant, but in most cases ours are DNR-compliant, and they are always of the highest quality money can buy.