5.9 Summary

The following tables summarize the proposed implementation action items and their relationship to the problems and issues identified in Section 3.0 above, the metrics by which the District will be evaluating progress toward resolving those issues and problems, the estimated District cost of implementing these actions, and anticipated implementation schedule.

Table 18.  Problems and issues identified in the Lake Minnetonka subwatershed and actions proposed to address them.

 

Problem or Issue

Actions in Implementation Plan

Degree of Improvement

Water Quality

Many of the bays of Lake Minnetonka are near or better than their water quality goal, but three bays in particular have significant water quality problems: Halsteds Bay, Jennings Bay, and Stubbs Bay.   West Arm and Priest Bay also do not meet their goal and are influenced by the water quality in the upstream bays.

  • Phosphorus load reduction plans for Halsteds, Jennings, and Stubbs Bays that set forth actions to reduce loading to meet in-lake P concentration goals.  For all waterbodies actions include an enhanced regulatory program and LGU requirements to reduce phosphorus from existing development.
  • Continue monitoring program to track changes

Implementation of all the actions in the phosphorus load reduction plan would theoretically reduce in-lake P concentrations, improve water clarity, and meet District water quality goals.

 

A whole lake model is necessary to fully understand the complex mixing that occurs within the lake and between the bays and to better forecast water quality

  • Develop a whole-lake model as part of the Hydrologic Data Program

Completion of this model would help improve understanding of water quality in Lake Minnetonka, improving accuracy of predictions of future water quality

No or limited data is available for smaller lakes in the subwatershed, including Peavey, Marion, Louise, Shavers, Forest, Galpin, and Lost Lake

  • Obtain baseline data were none is available and update every three years

Would fill a data gap and assist in tracking progress toward meeting water quality goals

Classen Creek conveys a significant phosphorus and sediment load to Stubbs Bay.


 

Development, redevelopment, and reconstruction in the subwatershed are predicted to increase nutrient and TSS loads from the watershed as well as increasing the volume of stormwater runoff, potentially further degrading water quality downstream.

 

  • Rules will be amended to require more stringent pollutant load reduction on new development and redevelopment, including adding a volume management requirement.
  • Would depend on ability of developers to incorporate adequate BMPs on their projects and properly maintain them to sustain removal efficiencies.
  • Cooperatively construct regional infiltration improvements to mitigate impact of new runoff from development.
  • Depends on ability to develop cooperative or collaborative improvements.
 
   

Water Quantity

The HHPLS identified a few locations that are predicted to overtop during the 100 year event, as well as others with a minimal amount of freeboard.

LGUs directed to evaluate these locations as part of their local water management planning.

Completed as LGUs complete their local plans.

Development is predicted to increase the volume of stormwater runoff from the subwatershed, conveying greater nutrient and sediment loads to Lake Minnetonka. 

  • Rules will be amended to require more stringent pollutant load reduction on new development and redevelopment, including adding a volume management requirement.
  • Would depend on ability of developers to incorporate adequate BMPs on their projects and properly maintain them to sustain removal efficiencies.
  • Cooperatively construct regional infiltration improvements to mitigate impact of new runoff from development.
  • Depends on extent of problem and ability to develop cooperative or collaborative improvements.
 
   

The HHPLS identified several locations where for both existing and future conditions higher velocities than desired may result in erosive velocities at outlets or culverts.   These include several road and railroad.  Erosion control or energy dissipation measures may be required in those locations.

  • Rules will be amended to require more stringent pollutant load reduction on new development and redevelopment, including adding a volume management requirement.
  • Would depend on ability of developers to incorporate adequate BMPs on their projects and properly maintain them to sustain removal efficiencies.
  • Cooperatively construct regional infiltration improvements to mitigate impact of new runoff from development.
  • Depends on extent of problem and ability to develop cooperative or collaborative improvements.
  • LGUs directed to evaluate these locations as part of their local water management planning.
  • Completed as LGUs complete their local plans.
 
   
   

Several landlocked basins are present in the subwatershed.  Within these landlocked basins, any future development or redevelopment should minimize creation of new stormwater volumes

LGUs prohibited from outletting these landlocked areas and directed to evaluate strategies for managing water volumes as part of their local water management planning.

Completed as LGUs complete their local plans.

Wetlands

The subwatershed includes numerous wetlands with high to exceptional vegetative diversity fish and wildlife habitat and aesthetic values that should be protected.

  • Key Conservation Areas identified that include high-value wetlands.  Some of these areas are identified as District priorities for continued implementation of the Land Conservation Program, and thus the District would proactively look for opportunities to conserve these resources. The Capital Improvement Program includes funds for Land Conservation Activities.   In all key areas, LGUs are required to include in their local plans strategies for conserving these values.
  • Ongoing effort that is dependant on property owner willingness to pursue conservation, District budget and staff capacity, and LGU plan completion.
  • Rules will be amended to establish management standards based on management classification for impacts to wetlands from development and redevelopment.
  • Implementation of revised rules would help minimize future impacts to the highest-value wetlands while still providing a measure of protection to those that provide mainly downstream resource protection.
 
   

The subwatershed includes numerous wetlands with high to moderate restoration potential that could be considered for protection and restoration

  • Wetlands identified as being of high to moderate wetland potential would be managed according to a Manage 1 wetland classification if they have been assessed as a Manage 2 or 3.   This would minimize further degradation that might make future restoration more difficult or costly.

Minimize further impacts to restorable wetlands until such time as projects are developed

Ecological Integrity

The subwatershed includes several sites identified as having biodiversity significance or that are Regionally Significant Ecological Areas.  Wetlands with high ecological and habitat value are present and those wetlands and associated upland areas should be conserved to preserve their values, create larger areas of ecological value, and connect existing resources.

 

Key Conservation Areas identified that include high-value wetlands.  Some of these areas are identified as District priorities for continued implementation of the Land Conservation Program, and thus the District would proactively look for opportunities to conserve these resources. The Capital Improvement Program includes funds for Land Conservation Activities.   In all key areas, LGUs are required to include in their local plans strategies for conserving these values.

Ongoing effort that is dependant on property owner willingness to pursue conservation, District budget and staff capacity, and LGU plan completion.

The Lake Minnetonka fishery is an exceptional regional resource and is regularly surveyed and actively managed by the DNR

  • Support the fishery through improvement of water quality, management of aquatic vegetation where internal load management is required, and the promotion of shoreline restoration.
  • Work cooperatively with the DNR to manage fisheries

Depends on response of natural system to improved water quality

Eurasian water milfoil is present in most of the bays of Lake Minnetonka

  • Manage aquatic vegetation where internal load management is required
  • Update aquatic vegetation surveys and develop aquatic vegetation management plans.

Completion of these plans would provide a plan for future activities by the District, LGUs, DNR, and other interested parties.

No systematic aquatic plant survey data is available for these lakes

  • Manage aquatic vegetation where internal load management is required
  • Update aquatic vegetation surveys and develop aquatic vegetation management plans.

Completion of these plans would provide a plan for future activities by the District, LGUs, DNR, and other interested parties.

Groundwater

Many of the major wetlands in the subwatershed were identified in the FAW as discharge or combination recharge-discharge wetlands.  Several recharge wetlands are located in the two areas of the subwatershed north where depth to bedrock is lower than in other parts of the subwatershed.  As development occurs it will be critical to maintain runoff and infiltration rates to help maintain hydrology to these wetlands

  • Amend rules to require pretreatment of stormwater discharged to wetlands or infiltration areas in the areas of high aquifer sensitivity.
  • Establish a new District rule that requires an additional level of analysis and review of permitted development and redevelopment where there is a potential for development to adversely impact groundwater connected to a surface water feature.

Will help minimize future impacts to groundwater and provide for proactive management rather than reactive

There are a number of areas in the subwatershed that are very highly or highly sensitive to aquifer impacts.

  • Amend rules to require pretreatment of stormwater discharged to wetlands or infiltration areas in the areas of high aquifer sensitivity.
  • Establish a new District rule that requires an additional level of analysis and review of permitted development and redevelopment where there is a potential for development to adversely impact groundwater connected to a surface water feature.

Will help minimize future impacts to groundwater and provide for proactive management rather than reactive

Stormwater management within wellhead Protection Areas should be coordinated with wellhead protection plans.

Stormwater and groundwater management within those areas will be coordinated with wellhead protection plans.

Will help minimize future impacts to drinking water and provide for proactive management rather than reactive

Table 19.  Summary of metrics to be used in evaluating progress toward Lake Minnetonka subwatershed goals.

Objective

Metric

Existing

Desired

Location

Water Quality

Phosphorus Loading (lbs annually)

5,208

(2000)

1,900

Jennings Bay

Phosphorus Loading (lbs annually)

891

(Ultimate)

554

Stubbs Bay

Phosphorus Loading (lbs annually)

7,818

(Ultimate)

2,027

Halsteds Bay

Water Quantity

Volume Reduction (Acre-feet)

 

112

Watershed-wide

1.5 year discharge (cfs)

See Table 4 for metrics by subwatershed

100 year discharge (cfs)

See Table 4 for metrics by subwatershed

Ecological Integrity

Index of Biotic Integrity

N/A

Above MPCA impairment threshold

Classen Creek Reach 4

4.83

(F-IBI)

Above MPCA impairment threshold

Classen Creek Reach 3

N/A

Above MPCA impairment threshold

Classen Creek Reach 2

6.0

(F-IBI)

Above MPCA impairment threshold

Classen Creek Reach 1

Stream Visual Assessment Protocol

N/A

5.0 or 1+ existing

Classen Creek Reach 4

N/A

5.0 or 1+ existing

Classen Creek Reach 3

N/A

5.0 or 1+ existing

Classen Creek Reach 2

N/A

5.0 or 1+ existing

Classen Creek Reach 1

Key Conservation Areas conserved (acres)

 

212

Watershed-wide

Wetlands

Wetland Acreage

3,197.9

3,197.9 or greater

Watershed-wide

1,682.1

1,682.1 or greater

Preserve

375.5

375.5 or greater

Manage 1

625.5

625.5 or greater

Manage 2

366.4

366.4 or greater

Manage 3

Table 20.  Summary of Lake Minnetonka subwatershed implementation program.

Item

Description

Estimated Cost

Schedule

Problems Addressed

MCWD Capital Projects

1

Halsteds Bay internal load management

$538,400

2015

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.2, 3.4.2, 3.4.3, 3.4.4

2

Stubbs Bay internal load management

$519,900

2007

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.2, 3.4.2, 3.4.3, 3.4.4

3

Classen Lake Creek management

$93,600

2007

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.2, 3.4.2, 3.4.3, 3.4.4

4

Swan Lake Pond excavation

$104,000

2007

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.2, 3.4.2, 3.4.3, 3.4.4

5

Halsteds Bay wetland restoration

$588,900

2009

3.3.2, 3.4.1

6

Big Island wetland restoration

$108,900

2008

3.3.2, 3.4.1

7

Regional infiltration

$103,600

2014

3.1.1, 3.1.4, 3.1.5, 3.2.4, 3.3.1, 3.4.1, 3.5.1

$57,300

2009

$195,800

2011

$14,500

2012

$14,800

2013

8

Grays Bay Highway 101 causeway reconstruction

$1,656,100

2010

3.1.1

9

Lake Minnetonka shoreline restoration

$208,100

2007

3.1.1, 3,.4.1, 3.4.2, 3.4.3, 3.4.4

10

Lost Lake/Langdon Lake/Cooks Bay

$390,200

2007

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.2, 3.4.2, 3.4.3, 3.4.4

MCWD Data Acquisition/Study

1

Develop infiltration/filtration strategies appropriate to wellhead protection areas and areas of groundwater sensitivity

Part of watershed-wide study

2008

3.1.1, 3.1.4, 3.1.5,  3.2.4, 3.3.1, 3.4.1, 3.5.1

2

Identify key indicator species, evaluate habitat, and develop conservation strategies

Part of watershed-wide study

2010 and ongoing

3.3.1, 3.3.2, 3.4.1, 3.4.2

MCWD Land Conservation Program

1

Undertake land conservation efforts in accordance with Figure 19

$2,276,000

 

Part of ongoing watershed-wide program

3.1.1, 3.1.3, 3.1.4, 3.1.5, 3.2.2, 3.3.1, 3.3.2, 3.4.1

MCWD Regulatory Program

1

Amend District Rules to increase stormwater management requirements for new development

Part of watershed-wide effort

2007-2009

3.1.1, 3.1.3, 3.1.4, 3.1.5

 

2

Amend District Rules to require abstraction of 1” of runoff on new development and redevelopment

Part of watershed-wide effort

2007-2009

3.1.1, 3.1.3, 3.1.4, 3.1.5, 3.2.1, 3.2.2, 3.2.3, 3.2.4, 3.3.1, 3.3.2, 3.5.2, 3.5.3

3

Amend District Rules to adopt wetland management rules based on wetland management classification

Part of watershed-wide effort

2007-2009

3.3.1, 3.3.2

MCWD Hydrodata Program

1

Monitor bays and lakes in accordance with Hydrodata Program

Part of watershed-wide hydrologic data program

Part of ongoing watershed-wide program

3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.2.2, 3.2.4, 3.3.1, 3.3.2, 3.5.1

2

Identify shallow wells to monitor groundwater levels

Part of watershed-wide study

2008 and ongoing

3.1.2, 3.2.2, 3.3.1, 3.4.1, 3.5.1

3

Develop a whole-lake model for Lake Minnetonka

$30,000

2008

3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.2.2, 3.2.4, 3.3.1, 3.3.2, 3.5.1

MCWD Education/Communication Program

1

Provide targeted education materials to key stakeholder groups to meet objectives of plan

Part of watershed-wide education program

Part of ongoing watershed-wide program

All

2

Provide educational opportunities for LGU staff, developers, elected and appointed officials and other interested parties

Part of watershed-wide education program

Part of ongoing watershed-wide program

All

3

Develop a small grant program to provide financial assistance to property owners desiring to implement BMPs on their property or to install demonstration projects on public property

Part of watershed-wide program

2008 and ongoing

3.1.1, 3.1.4, 3.1.5, 3.2.1, 3.2.2, 3.2.3, 3.2.4, 3.3.2, 3.4.1, 3.5.1

MCWD Operations and Maintenance

1

Inspect Classen Creek erosion-prone areas annually

Ongoing activity

Part of ongoing watershed-wide program

3.1.3

2

Monitor high vegetative-diversity wetlands for exotic species

Part of watershed-wide program

Part of ongoing watershed-wide program

3.3.1, 3.3.2, 3.4.1

3

Operate Grays Bay outlet in accordance with the operation plan

Ongoing activity

Part of ongoing watershed-wide program

3.2.1, 3.2.2

Collaborative Projects

 

None identified