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 Six Mile Marsh subwatershed is notable for its ecological resources and large tracts of park reserve and minimally developed area, including wetlands, forests, and grasslands.  Some areas within the subwatershed are located in an MCWD, local or regional conservation corridor.  There is potential to create ecological corridors through the watershed centered on the streams and wetland complexes through which they flow, connecting to high-value resources in the Carver Park Reserve.

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 preservation 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 prevent the need for future TMDLs.

The Six Mile Marsh subwatershed includes numerous wetlands with exceptional or high fish or wildlife habitat value as well as wetlands with exceptional or high vegetative diversity.  The Key Conservation Areas identified in this plan (see Figure 19) include those wetlands as well as associated upland areas of high ecological value such as maple-basswood forest.  Conservation of those associated upland areas not only provides additional habitat type, but also helps preserve local runoff and infiltration rates.  The plan also identifies areas within the Carver Park Reserve as high-value resources, and coordination between the Three Rivers Park District, DNR, the MCWD, and other interested parties will be essential to protecting and improving those resources.   

The fisheries in the subwatershed are generally actively managed by the DNR and Three Rivers Park District.  There is little information on aquatic vegetation communities in the lakes, although it is known that Eurasian watermilfoil is present in most of the lakes.  The ecological community in Six Mile Creek is limited by its hydrology, lack of habitat and large riparian wetlands.  The primary strategies for improving aquatic communities are the acquisition of new data such as vegetation surveys and management plans, and improvement of water quality.  The several wetlands in the subwatershed with exceptional or high vegetative diversity 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 Six Mile Creek
  • Stream Visual Assessment Protocol (SVAP) in Six Mile 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 - Six Mile Marsh

Maintain and improve overall ecological integrity within the subwatershed.


  1. Continue Land Conservation Program efforts to proactively seek out conservation opportunities in areas identified in this plan as priority areas.
  2. 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).
    1. 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.
    2. Restore areas of degradation within key conservation areas.
    3. Provide education and training opportunities, technical and planning assistance, and financial incentives to LGUs to actively conserve key ecological areas.
  3. Work cooperatively with other agencies and organizations to improve upon existing conservation corridors and where practical, develop new conservation corridors connecting wetlands within the Six Mile Marsh subwatershed of exceptional or high wetland functions and values and subwatershed stream corridors with areas that have been identified by others as having high local, county, regional, or national ecological significance.
  4. 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.
  5. Provide regulatory incentives for the preservation of undisturbed native vegetation as sites develop.
  6. Require MCWD review of preliminary plats and vegetation surveys so the District may comment on proposals and how they relate to District ecological integrity goals.
  7. Require submittal of a Natural Resources Inventory and Conservation Plan as a condition of permit approval.

Goal 2.2 - Six Mile Marsh

Maintain conditions suitable for healthy and varied sport fish communities within the lakes.


  1. Work cooperatively with the DNR and Three Rivers Park District in lake fishery management efforts, and request that fish surveys be conducted regularly.
  2. Achieve lake water quality and clarity goals to maintain or improve habitat conditions.
  3. Manage aquatic vegetation in accordance with vegetation management plans that take into account fishery habitat requirements.

Goal 2.3 - Six Mile Marsh

Maintain healthy aquatic vegetation communities.


  1. Perform a baseline survey of aquatic vegetation in the lakes and update those surveys every five years.
  2. Develop and implement aquatic vegetation management plans for the lakes that evaluate and implement options for the management of internal phosphorus loads as well as maintenance of a desirable aquatic vegetation community.
  3. Recruit and train volunteers to monitor aquatic vegetation in the lakes on an ongoing basis, and work cooperatively with Three Rivers Park District on lakes within the park reserve.
  4. Develop and implement a plan to monitor wetlands with exceptional or high vegetative diversity for presence of exotic vegetative species.

Goal 2.4 - Six Mile Marsh

Maintain conditions suitable for a healthy and varied biologic community in Six Mile Creek, given its natural limitations.


  1. Reduce phosphorus and sediment in Six Mile Creek and minimize periods of low dissolved oxygen.
    1. Implement the water quality improvement actions of this plan to reduce load discharged into the creek from the lakes and washed off from the watershed.
    2. Work cooperatively with riparian property owners to repair eroded streambanks.
    3. Implement the water quantity improvement actions of this plan to limit periods of erosive velocities in the creek.
  2. Increase macroinvertebrate and fish habitat where feasible in Six Mile Creek to achieve M-IBI scores above the MPCA threshold for impairment and to achieve a Stream Visual Assessment Protocol mean score above 5.0.
    1. Increase the variety of habitat features such as improved substrate, cobble and boulders, vegetated streambanks, root wads, and large woody debris.
  3. Periodically update the Six Mile Creek stream assessment to assess current stream condition and ecological integrity.
  4. Monitor macroinvertebrate community every 3 years.
  5. Improve degraded stream reaches for the purposes of bank stabilization, reducing sediment loads, preserving existing stream courses, improving habitat, and enhancing biotic integrity.
  6. Woody debris that falls in Six Mile Creek or other streams shall only be removed if it causes an obstruction to 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.