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.

Discussion

The Lake Minnetonka subwatershed is dominated by Lake Minnetonka and its riparian wetlands.  There are other high-value resources in the subwatershed, including other wetlands and tracts of high-value upland.  Some areas within the subwatershed are located in an MCWD, local or regional conservation corridor.  There is potential to connect ecological resources in the subwatershed to corridors in other subwatersheds.

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 prevent the need for future TMDLs. 

The 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 Lake Minnetonka fishery is in excellent condition and is a premier regional resource.  It is actively managed and monitored by the DNR.  There is no comprehensive data on aquatic vegetation communities in Lake Minnetonka, although Eurasian watermilfoil is a known nuisance in many of the bays and channels.  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.  There are several wetlands in the subwatershed with exception or high vegetative diversity.  These would be inspected at least annually for invasive vegetative species.

Lake Minnetonka contains a large and productive littoral zone--the shallow transition zone between dry land and the open water area of the lake. In Minnesota waters, the littoral zone extends from the shore to a depth of about 15 feet, depending on water clarity. The littoral zone is highly productive. The shallow water, abundant light, and nutrient-rich sediment provide ideal conditions for plant growth. Aquatic plants, in turn, provide food and habitat for many animals such as fish, frogs, birds, muskrats, turtles, insects, and snails. Protection the littoral zone is important for the health of the lake ecosystem as well as the overall quality although such protection may sometimes conflict with desires for navigational access.  It is District policy that in such cases, the District will show preference to alternatives which first avoid and then minimize impacts to the littoral zone.

Desired Outcomes: Functional and healthy ecological corridors and waters throughout the subwatershed.

Metrics:

  • Macroinvertebrate Index of Biotic Integrity (M-IBI) in Classen Creek
  • Stream Visual Assessment Protocol (SVAP) in Classen Creek
  • Acres of land conserved in Key Conservation Areas
  • Acres of restored/created wetland within Key Conservation Areas

Goal 2.1 - Lake Minnetonka

Maintain and improve overall ecological integrity within the subwatershed.

Actions

  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 Conservation Areas (see Figure 19).
    1. Require LGUs to recognize 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 Conservation 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 Lake Minnetonka 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 conservation 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.

Goal 2.2 - Lake Minnetonka

Maintain conditions suitable for healthy and varied fish communities within Lake Minnetonka and the other lakes.

Actions

  1. Work cooperatively with the DNR in lake fishery management efforts.
  2. Achieve 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.
  4. Manage, protect, enhance, and preserve the littoral zone of Lake Minnetonka and other lakes.

Goal 2.3 - Lake Minnetonka

Maintain healthy aquatic vegetation communities.

Actions

  1. Perform baseline surveys of aquatic and shoreline vegetation in the bays of Lake Minnetonka and update them every five years.
  2. Develop and implement aquatic vegetation management plans for the bays of Lake Minnetonka that include 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 Lake Minnetonka on an ongoing basis.
  4. Develop and implement a plan to monitor wetlands with exceptional or high vegetative diversity for presence of exotic vegetative species.

Goal 2.4 - Lake Minnetonka

Maintain conditions suitable for a healthy and varied biologic community in Classen Creek.

Actions

  1. Reduce phosphorus and sediment in Classen Creek and minimize periods when dissolved oxygen falls below the level necessary to sustain aquatic life.
    1. Implement the water quality improvement actions of this Plan to reduce load discharged into the creek from the watershed.
    2. Work cooperatively with the City of Orono to repair eroded streambanks identified in the Stream Assessment and through other inspections.
    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 in Classen Creek.
    1. As opportunities arise identify potential locations and install habitat features such as improved substrate, cobble and boulders, vegetated streambanks, root wads, and large woody debris.
  3. Monitor the macroinvertebrate community every 2-3 years.
  4. Woody debris that falls in Classen 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.