4.6 Shorelines and Streambanks

Goal 6 - Shorelines and Streambanks

Preserve the natural appearance of shoreline areas and minimize degradation of surface water quality which can result from dredging operations.

Discussion

Eroding shorelines and streambanks contribute to the degradation of water quality.  Native vegetation can effectively stabilize these areas, filter runoff for sediment and other pollutants, and provide habitat.

The key areas identified in this plan for conservation activities include buffer zones adjacent to Minnehaha Creek.  In some cases these buffer zones are riparian or flow-through wetlands, and those wetlands have been identified as key conservation areas.  Where streams and channels flow through upland areas, conservation of native vegetation within these zones would also increase or maintain infiltration rates; decrease or maintain runoff rates and pollutant conveyance to water resources; and help minimize erosion.   Restoration of lakeshore would have the same benefits.  Sustaining or improving water quality and ecological integrity is necessary to meet District goals as well as to meet state and federal nondegradation, water quality and biological integrity requirements and to prevent the need for future TMDLs. 

The District recognizes that many areas along the creek have historically been held within the public domain for public use.  Public use can be defined in a number of ways including stormwater conveyance, recreational features and amenities as well as ecosystem functions.  The Minnehaha Creek Visioning Partnership was convened to provide recommendations on achieving balance between these various, sometimes competing, functions.  Due to the desire to have multifunctional landscapes throughout the Creek corridor, the District is committed to working with collaborative partners to achieve mutual goals.  Stable streambanks and shorelines adjacent to public resources are assumed to be in the interest of all parties who own and manage public resources throughout the subwatershed.

Restoration of streambanks on Minnehaha Creek is a key strategy for meeting this plan’s goals.  The Minnehaha Creek Stream Assessment identified locations where restoration and the creation of buffer zones may be desirable and feasible.  This restoration would be accomplished through cooperative projects to restore high-priority stream reaches and to perform spot repairs of eroded locations.

Desired Outcomes:  Stable streambanks and shorelines to supplement other goals.

Metrics:

  • Stream Visual Assessment Protocol (SVAP) in Minnehaha Creek
  • Linear feet of stabilized eroded shoreline and streambank
  • Linear feet of shoreline protected in Key Conservation areas
  • Linear feet and width of riparian areas protected in Key Conservation Areas

Goal 6.1 - Minnehaha Creek

Where appropriate, collaboratively work to stabilize and/or restore degraded streambanks and riparian zones on Minnehaha Creek to help meet pollutant loading reduction and ecological integrity goals.

Actions

  1. In collaboration with riparian cities and property owners, agencies, and infrastructure owners construct priority streambank and buffer improvements to stabilize streambanks and riparian zones and to repair existing erosion and reduce the risk of future erosion.  The highest priority for stabilization are those non-impounded reaches identified in the Minnehaha Creek Stream Assessment where the Pfankuch stability rating relative to Rosgen stream type is “Fair” or “”Poor” or where the Stream Visual Assessment Protocol (SVAP) mean score is less than 5.0.  Construct improvements in other reaches as opportunities arise. Figure 20 illustrates areas of high priority for improvement based on the Stream Assessment.
  2. Use the results of the Minnehaha Creek Biotic Integrity TMDL/Diagnostic Study to refine the identification and prioritization of potential streambank and riparian zone improvements to improve streambank stability, reduce pollutant loading, and increase habitat and incorporate those findings into the Capital Improvement Program.
  3. In collaboration with riparian cities, agencies, property owners and infrastructure owners spot repair identified erosion locations in Minnehaha Creek and develop strategies to prevent future erosion and sediment transport.
  4. Promote native vegetation over structural stabilization where practical and effective in District policies, regulations, and programs.
    1. Provide education and training opportunities, technical and planning assistance, and demonstration project funding to LGUs to assist them in restoring streambanks and buffers on public property such as parks and open spaces.
    2. Develop and distribute written material to riparian property owners explaining the benefits of streambank restoration and buffer creation to the reduction of pollutant loads and creation of shoreline habitat and providing design, plant selection, installation, and maintenance advice.
    3. Develop a small grant program to provide financial assistance to property owners desiring to restore their shoreline or plant a buffer.
  5. Work cooperatively with the National Park Service and Minneapolis Park Board to identify necessary streambank restoration and structure improvements in Minnehaha Park from Minnehaha Falls to the Mississippi River and incorporate those findings into the Capital Improvement Program.