Lake Nokomis Shoreline Habitat Enhancements
$444,000 in the first year is to the commissioner of natural resources for an agreement with the Minneapolis Park and Recreation Board to enhance aquatic habitat on Lake Nokomis. A list of proposed enhancements must be provided as part of the required accomplishment plan.
Improved aquatic habitat indicators - Increased diversity and quantity of native emergent and shoreline plants will be assessed through annual point-intercept plant surveys. Regular water sampling will provide nutrient loading information..
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MPRB requests $444,000 to improve aquatic habitat in Lake Nokomis through integrated lake management. This project will enhance 4580 linear feet of shoreline.
The enhancement activity included in this project will improve habitat for fish, birds, reptiles, amphibians, and aquatic invertebrates in the entirety of Lake Nokomis. The lake measures 200 acres; approximately half is less than 15 feet deep. The lake is owned entirely by MPRB. Its shoreline consists of a combination of Works Progress Administration stone wall in varying condition along with stretches of turfgrass with poor quality native shoreline buffer and little emergent vegetation along the eroding lake edge. It is an important stop-over for migratory waterfowl, songbirds, and shorebirds that use the Mississippi River Flyway, such as wood ducks, loons, grebes, coots, warblers, vireos, grosbeaks, herons, rails, and sandpipers.
Lake Nokomis is limited in its habitat potential due primarily to its lack of clarity and lack of aquatic vegetation. The poor water clarity is attributable to a negative feedback cycle centered on an imbalance in the fish population. Periodic fish surveys have found that small black bullheads and small panfish are overabundant in the lake. There is not enough aquatic vegetation in the lake for these species’ shelter and food needs (plants would serve as habitat to prey insects), so these species root in the substrate in search of food. Sediment re-suspension increases turbidity in the lake and also instigates algae blooms by releasing nutrients back into the water column. Sediment- and algae-based turbidity then further suppresses plant growth by preventing light penetration to the lakebed.
Aquatic and shoreline vegetation is critical to overall lake clarity and habitat. A study by Canfield and Hoyer (1992) has shown that lakes with at least 40% vegetative coverage function as high quality habitat lakes with good water clarity. Lake Nokomis currently has 11% vegetative coverage. Plants grow only to lake depths up to 8 feet and not in the entire littoral (15-foot maximum depth) zone—which constitutes about half the lake.
This project will enhance of 4580 linear feet of shoreline by regrading banks to stabilize erosion, removing invasive plants in the shoreline buffer, and installing appropriate native emergent and shoreline plants.
This activity is proposed based on extensive scientific study of the lake. A variety of other previous efforts that have improved the lake’s habitat. In 2001 MCWD and MPRB installed a weir between Lake Nokomis and Minnehaha Creek to reduce nutrient inflow to the lake from the creek, then modified that weir in 2012 to protect against zebra mussels. Also in in 2001, MPRB, MCWD, and the City of Minneapolis installed several native species-planted storm water treatment ponds near the lake to pre-treat urban runoff and provide habitat for various animal species. Nearby residents and groups such as Friends of Lake Nokomis, Blue Water Commission, the Nokomis East Neighborhood Association, and the Hale Page Diamond Lake Neighborhood Association have historically supported efforts to improve lake water quality and habitat through participation in planning and with volunteer efforts.
Lake Nokomis has excellent habitat potential. MPRB and MCWD have been studying this generally shallow lake for years and have implemented some critical habitat improvements already. LSOHC funding would leverage MPRB and MCWD’s efforts through each agency’s general operations and maintenance funding. It would allow the next phase of habitat enhancement to occur.