4.2 Ecological Integrity
Goal 2 - Ecological Integrity
Promote activities that maintain, support and enhance floral, faunal quantity and ecological integrity of upland and aquatic resources throughout the watershed.
The Minnehaha Creek subwatershed has few large tracts of minimally developed area save for some large wetland complexes in the upper subwatershed. There is potential to create an ecological corridor through the watershed centered on Minnehaha Creek and the wetland complexes through which it flows. Such a corridor along the Creek would connect Lake Minnetonka, the Chain of Lakes, and the Mississippi River.
Connected corridors are desirable as they provide a variety of habitats both aquatic and terrestrial as well as protected areas for passage. Within these conservation areas wherever possible the District would promote the conservation or establishment of native vegetation to increase or maintain infiltration rates; decrease or maintain runoff rates and pollutant conveyance to water resources; and minimize erosion of shorelines and streambanks. Sustaining or improving water quality and ecological integrity is necessary to meet the District goals in this plan as well as to meet state and federal nondegradation, water quality and biological integrity requirements and to comply with existing and prevent the need for future TMDLs.
The ecological community in Minnehaha Creek is impaired by its hydrology and lack of habitat as well as the existing water quality. A wide corridor that includes stream buffers maintained with native vegetation, vegetated streambanks, and in-stream habitat for fish and macroinvertebrates is desirable to help improve the ecological integrity of Minnehaha Creek and the area through which it flows. Strategies to achieve this long-term goal include conservation of land on which to create or conserve buffers; establishment or conservation of native vegetation; restoration of streambanks and creation of new in-stream habitat; and close management of streamflows in Minnehaha Creek to minimize extreme variations in streamflow and maintain baseflow sufficient to sustain aquatic life.
The primary strategies for improving aquatic communities within the lakes are the development and implementation of aquatic vegetation management plans, and improvement of water quality. There are a few wetlands in the subwatershed with exceptional or high vegetative diversity. These would be inspected at least annually for invasive vegetative species.
Desired Outcomes: Functional and healthy ecological corridors and waters throughout the subwatershed.
- Macroinvertebrate Index of Biotic Integrity (M-IBI) in Minnehaha Creek
- Stream Visual Assessment Protocol (SVAP) in Minnehaha Creek
- Acres of land conserved in Key Conservation Areas
- Linear feet and width of riparian areas protected in Key Conservation Areas
- Acres of restored/created wetland within Key Conservation Areas
Goal 2.1 - Minnehaha Creek
Maintain and improve overall ecological integrity within the subwatershed.
- Continue Land Conservation Program efforts to proactively seek out conservation opportunities in areas identified in this plan as District priority areas.
- Protect existing fish and wildlife habitat and promote the development of additional habitat areas and corridors by the conservation and restoration of key ecological areas (see Figure 19).
- Require LGUs to recognize District key conservation areas in their natural resources and land use planning and to identify in their Local Water Management plans how they intend to conserve their ecological values.
- Provide education and training opportunities, technical and planning assistance, and financial incentives to LGUs to actively conserve key ecological areas.
- Restore areas of degradation within key conservation areas.
- Work cooperatively with the LGUs, Minneapolis Park Board, DNR, National Park Service, other agencies and organizations to improve upon existing conservation corridors and where practical, develop new conservation corridors along Minnehaha Creek.
- Identify keystone, umbrella, and indicator species to serve as indicators of ecological integrity, evaluate existing habitat within the subwatershed, and develop strategies for the conservation of that habitat.
- Provide regulatory incentives for the conservation of undisturbed or creation of new native vegetation as sites develop.
Goal 2.2 - Minnehaha Creek
Maintain conditions suitable for healthy and varied sport fish communities within the primary lakes of the subwatershed.
- Work cooperatively with the DNR and the Minneapolis Park Board in fishery management efforts.
- Achieve lake water quality and clarity goals to maintain or improve habitat conditions.
- Manage aquatic vegetation in accordance with a vegetation management plan that takes into account fishery habitat requirements.
Goal 2.3 - Minnehaha Creek
Maintain a healthy aquatic vegetation community.
- Develop and implement a plan to monitor wetlands with exceptional or high vegetative diversity for presence of exotic vegetative species.
- Assist the MPRB in evaluating and implementing an Aquatic Plant Management Plan for the Minneapolis Chain of Lakes.
Goal 2.4 - Minnehaha Creek
Improve Minnehaha Creek riparian vegetation management.
- Promote native vegetation over structural streambank stabilization where practical and effective in District policies, regulations, and programs.
- Where compatible with other uses, promote restoration of riparian zone vegetation.
Goal 2.5 - Minnehaha Creek
Maintain conditions suitable for a healthy and varied biologic community in Minnehaha Creek.
- Complete a TMDL identifying stressors causing impaired biotic conditions in Minnehaha Creek, and develop and implement strategies for improvement.
- Reduce phosphorus and sediment in Minnehaha Creek and minimize periods of low dissolved oxygen.
- Prepare a Minnehaha Creek Diagnostic Study to identify sources of phosphorus and sediment in the creek, and develop and implement strategies for improvement, potentially incorporating specific watershed phosphorus load reductions assigned to LGUs in the subwatershed.
- In collaboration with riparian cities, agencies, and infrastructure owners repair identified erosion locations in Minnehaha Creek and develop strategies to prevent future erosion and sediment transport.
- Implement the water quantity improvement actions of this plan to limit periods of erosive velocities in the creek and maintain/stabilize base flows in the creek.
- In collaboration with riparian cities and property owners, other agencies, and infrastructure owners, construct priority stream restorations to improve in-stream fish and invertebrate habitat and near-stream conditions. The highest priority for restoration are those non-impounded reaches where the M-IBI score is below the Minnesota impairment threshold for streams of the Creek’s region, size, and type, or where the Stream Visual Assessment Protocol (SVAP) mean score is less than 5.0. Construct improvements in other reaches as opportunities arise.
- Monitor the fish and macroinvertebrate communities every 2-3 years.
- Use the results of the Minnehaha Creek Biotic Integrity TMDL and Minnehaha Creek Diagnostic Study to refine the identification and prioritization of potential in-stream, streambank and riparian zone improvements to increase macroinvertebrate and fish habitat and streambank and buffer conditions and incorporate those findings into the Capital Improvement Program.
- Periodically update the Minnehaha Creek stream assessment to assess current stream condition and ecological integrity.
- Woody debris that falls in Minnehaha Creek or other streams shall only be removed if it causes an obstruction to navigation or flow such that streambanks are destabilized or eroded or the Creek is caused to overtop its banks. Such debris shall be removed by the District or by cooperative arrangement with the LGU at the owner’s expense.