Coon Rapids, MN Fence Regulations: Retaining Walls (2026)

Section 11-1001.10(3), part of the MRCCA overlay district's Land Alteration Standards and Stormwater Management provisions, treats retaining walls together with rock riprap and other erosion control structures. Work located at or below the ordinary high water level (OHWL) must comply with Minnesota Rules parts 6115.0215, subpart 4, item E, and 6115.0216, subpart 2, and cannot proceed until approved by the state commissioner. Construction or replacement within the bluff impact zone or water quality impact zone is allowed by City permit, but only to correct an established erosion problem confirmed by the City of Coon Rapids or the Coon Creek Watershed District, and the structure must be sized at the minimum necessary to fix that problem.

Absent a professional engineer's determination that a larger structure is needed, replacement retaining walls in these zones cannot exceed five feet in height and must be spaced a minimum horizontal distance of ten feet apart, while riprap is capped at the regulatory flood protection elevation. The code's 'retaining wall' definition in Section 11-1001.2(6) covers mortar and rubble masonry, rock or stone regardless of size, timber pilings, timber planks with piling supports, sheet pilings, poured concrete and concrete block walls. Repair of an existing wall above the OHWL does not need a permit as long as it involves no land alteration under Section 11-1001.10(2).

These standards apply specifically within the MRCCA overlay along the Mississippi River corridor; they are not a general, citywide retaining wall permit rule for yards outside that overlay district.