Grand Marais Creek Cut Channel Stabilization
In the early 1900s, a joint State and County drainage project constructed a 1 mile outlet channel to Grand Marais Creek to provide a shorter outlet to the Red River and effectively abandoned the lower 6 miles of the natural channel. In recent times, the ditch has eroded from its original shape to a channel of steep gradients and unstable banks. This has resulted in head cutting of the channel and nearly continuous channel erosion and bank sloughing with the effect of depositing up to an estimated annual average of 700 tons of sediment into the Red River.
With a grant from the Clean Water Fund, the Red Lake Watershed District proposes to construct a project to stabilize the outlet channel. Drop structures/spillways will be used to flatten the channel profile to non-erosive velocities thereby eliminating the head cutting, bank sloughing and transport of sediments to the Red River. The cross section of the channel will be reestablished and critical areas will be armored to prevent future bank cutting. These repairs should reduce the turbidity impairments in the Red River.
This project is a component of a larger plan for the Grand Marais watershed that also includes restoration of the original Grand Marais Channel. This larger plan would divert flows from the outlet channel, further reducing the potential for erosion. Re-establishing flows to the original Grand Marais channel will enhance wildlife and aquatic habitats for an approximate 6 mile stretch of natural channel.
(b) $2,800,000 the first year and $3,124,000 the second year are for grants to watershed districts and watershed management organizations for: (i) structural or vegetative management practices that reduce storm water runoff from developed or disturbed lands to reduce the movement of sediment, nutrients, and pollutants or to leverage federal funds for restoration, protection, or enhancement of water quality in lakes, rivers, and streams and to protect groundwater and drinking water; and (ii) the installation of proven and effective water retention practices including, but not limited to, rain gardens and other vegetated infiltration basins and sediment control basins in order to keep water on the land. The projects must be of long-lasting public benefit, include a local match, and be consistent with TMDL implementation plans or local water management plans. Watershed district and watershed management organization staff and administration may be used for local match. Priority may be given to school projects that can be used to demonstrate water retention practices. Up to five percent may be used for administering the grants. (2011 - Runoff Reduction)
This project has yielded an estimated phosphorus reduction of 998 lbs/yr and sediment (TSS) reduction of 1699 tons/yr.