5.0 Implementation Program

The goals set forth in Section 4.0, Resource Management Goals and Strategies will require an integrated set of programs and projects oriented toward the conservation and improvement of water resources within the watershed.   The following sections describe generally the activities that will be undertaken by various parties and identifies parties responsible for each activity. Table 17 in Section 5.9 provides a cost estimate and schedule for the District’s responsibilities for new activities in the implementation program.

5.1 Regulatory Program

As discussed in Section 3.6 above, future development is expected to contribute additional stormwater volume and phosphorus loads to Dutch Lake, further degrading water quality.  The current regulatory program will not be sufficient to control these impacts.  To mitigate these future impacts and to address other goals such as increased infiltration, wetland management, and improved ecological integrity, additional regulation may be necessary.  A decision on rulemaking needs/standards can only be made after the formal rulemaking process.  In addition, further amendments to the rules should not be precluded by the content of the plan.

Additional regulatory controls on permitted development and redevelopment will be considered for this subwatershed to increase phosphorus load reduction requirements, add volume management and infiltration requirements, implement wetland management in accordance with management classification, and increase scrutiny of development that may impact groundwater or key conservation resources.  Regulations providing an incentive such as a volume reduction credit to developers to maintain undisturbed areas, reforest, or plant native vegetation may be considered.

The following are revised or additional regulatory controls in this subwatershed that would be necessary to assist the District in meeting the goals of this Plan:

  1. Amend existing or establish new District rules requiring abstraction of the first one inch of rainfall on new permitted development and redevelopment.
  2. Provide regulatory constraints and incentives for the conservation of undisturbed native vegetation as sites develop.
  3. 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.
  4. Require submittal of a Natural Resources Inventory and Conservation Plan as a condition of permit approval.
  5. Amend existing or establish new District rules requiring greater than 50 percent phosphorus removal on new permitted developments within the Dutch Lake subwatershed
  6. Amend District rules to incorporate a requirement for stormwater management plan approval prior to submittal of a preliminary plat.
  7. Amend existing or establish new District rules requiring submittal of a functions and values assessment for all proposed wetland impacts requiring a permit; mitigation of all fill in Preserve category wetlands; and specifying by management classification stormwater discharge pretreatment, buffer, hydroperiod, and other wetland standards.
  8. Establish new District rule requiring an additional level of analysis and review of permitted development and redevelopment where there is a potential to adversely impact groundwater connected to a surface water feature.
  9. Require pretreatment of stormwater discharged to wetlands or infiltration areas in the in the areas of high aquifer sensitivity.
  10. Require developers to identify existing drain tile lines on property proposed for development.

5.2 Land Conservation Program

Prior to the encroachment of additional development, the opportunity exists to create connections between ecosystems within the Painter Creek, Langdon Lake and Lake Minnetonka Subwatersheds to improve water quality, preserve natural conveyances, and facilitate the movement and proliferation of native species as well as enhance recreational opportunities.  Figure 19 identifies priority areas, the conservation of which will improve the characteristics of the aquatic ecosystem and the water quality within the subwatershed as well as areas downstream.  

The District operates a Land Conservation Program that undertakes conservation activities ranging from assisting property owners in enrolling property in conservation programs to acquiring easements or fee title over high value resources.   Key conservation areas identified on Figure 19 are located within the current Land Conservation Program target area or have been proposed for addition to the target area.  The District will continue to proactively investigate opportunities to conserve key resources in these areas and work cooperatively with other agencies and groups to accomplish this subwatershed’s conservation goals.  The District will provide technical assistance to the LGUs to identify and implement strategies for local conservation efforts in support of program goals.

5.3 Education Program

The District operates a watershed-wide Strategic Education and Communications program that provides general information of wider interest as well as targeted information.  The targeted education and public involvement activities identified in this plan, including promotion of a Dutch Lake Association, will be implemented to assist in the reduction of existing pollutant loading to Dutch Lake and other water resources in the subwatershed as well as to minimize the impacts of future development.  The specific targeted messages will emphasize conservation of the wide range of high-value resources in the subwatershed and developer education targeting Better Site Design, infiltration, and conservation of undisturbed native vegetation as sites develop.

5.4 Monitoring and Data Collection

Hydrologic Data Program

To monitor progress toward meeting water quality and quantity goals, routine monitoring of water quality in Dutch Lake and water quality and volume in Dutch Creek will continue to be a part of the District’s annual Hydrologic Data program.

Aquatic Vegetation

Lake aquatic plant monitoring provides information needed to manage aquatic plants, evaluate control measures, and plan for future actions.   This monitoring is especially useful as water quality management activities are implemented and plant communities change in response to changing water quality.  A baseline aquatic vegetation survey will be conducted as part of a proposed internal load project feasibility study.  The survey will be updated by staff/contractor after five years at an estimated cost of $7,000.  Interim monitoring could be conducted by trained volunteers.

Wetland Monitoring

Wetlands with exceptional value vegetation are present in the subwatershed.  Because of the importance to overall subwatershed ecological integrity of preserving these values, these wetlands will be regularly monitored for invasive species by staff or trained volunteers. 

5.5 Operations and Maintenance

Activities detailed in this implementation plan will require both ongoing and new operations and maintenance activities in this subwatershed.  These include:

Table 11.  Ongoing District operations and maintenance tasks for the Dutch Lake subwatershed.

Task

Spring

Summer

Fall

Routine Inspection Dutch Lake Creek

As needed

Annually and as needed

As needed

Inspect High Vegetative Diversity Wetlands

Regularly

Regularly

Regularly

Table 12.  Potential ongoing operations and maintenance tasks for proposed Dutch Lake subwatershed improvement projects.

Task

Treatment Pond

Wetland Restoration

Spring

Summer

Fall

Routine Inspection

a

a

Early and After Storm

After Storm

Late and After Storm

Vegetation Management

 

a

As needed

As needed

Periodic burns, mowing, or herbicide as needed

General Upkeep

a

a

Regularly

Regularly

Regularly

Debris and Trash Removal

a

 

As needed

As needed

As needed

Inlet/Outlet Cleaning

a

a

As needed

As needed

As needed

Minor Erosion Repair

a

a

As needed

As needed

As needed

Note: Responsible parties would be determined by negotiation at the time of project proposal.

5.6 LGU Requirements

5.6.1 Local Government Unit Subwatershed Phosphorus Load Reductions

Part of the phosphorus load reduction plan for Dutch Lake is a required reduction by the LGUs in the subwatershed of the phosphorus load contributed by existing land uses.  The requirement is a 15 percent reduction in loading from existing residential land use; 25 percent from agricultural land use; and 10 percent from other developed land use.  This reduction can be accomplished through application of BMPs such as additional street sweeping, local water quality ponds, rain gardens and infiltration swales, and agricultural BMPs that reduce erosion or treat runoff or drain tile discharge; prevention of future load increases through the conservation of lands previously identified for development; or achieving load removals in excess of  the minimum required.  The LGUs identified below must identify in their local water management plans specific steps to accomplish these minimum reductions.  The LGUs must also annually report to the District their progress toward accomplishing this requirement. 

Table 13.  Allocation of Dutch Lake subwatershed LGU phosphorus load reductions (lbs/yr).

Subwatershed Unit

Minnetrista

Mound

Total

DL-1

3

0

3

DL-2

1

0

1

DL-3

8

0

8

DL-4

2

0

2

DL-5

7

4

11

DL-6

3

0

3

DL-7

0

0

0

TOTAL

24

4

28

5.6.2 Land Conservation

A key element in achieving overall ecological integrity goals in the Dutch Lake subwatershed is the conservation of key ecological areas, including high-value wetlands and connecting uplands.  LGUs must identify in their local water management plans the areas shown on Figure 18.  The local plan must also identify strategies the LGU will undertake to protect the ecological values of those areas.  These may include such strategies as land use regulation; acquisition and management; conservation easements; ecological restoration; and property owner education regarding land management strategies to maintain ecological integrity.

5.6.3 Other Issues

Modeled High Water Locations

The HHPLS identified a number of locations where modeling predicts that public roads, private roads, or private drives might overtop during infrequent events, or where there may be minimal freeboard above the flood level.   Local plans should identify observed or these potential locations and assess whether the risk of occasional flooding is acceptable or should be addressed.

Flow Velocity or Erosion Issues

The HHPLS identified a number of locations where modeling predicts that under existing or future development conditions higher velocities than desired ay result in erosion at outlets or culverts, potentially warranting erosion control or energy dissipation.  Local plans should identify observed or these potential locations, assess the need for such measures, and set forth a plan for preventing future erosion.

5.7 Phosphorus Load Reduction

One of the water quality goals for this subwatershed is the achievement of the Dutch Lake in-lake phosphorus concentration goal of 40 μg/L.  Reduction of phosphorus loads from the subwatershed to achieve that goal will require the combined efforts of the regulatory program, operational programs, LGU load reductions, and capital projects.  Table 14 below sets forth a summary plan for how this could be accomplished.

The table breaks down modeled phosphorus loading in the subwatershed by source: atmospheric deposition, external sources, and internal sources.  Atmospheric deposition is a regional issue and is not dealt with here.  The primary means of addressing external loading are through the regulation of new loads generated by development and the reduction of existing loads.  Application of the current regulatory program to new development would also reduce the expected load from ultimate development conditions.  As Table 9 above indicates, more stringent regulation of new development could reduce the need for or size of capital projects. 

It is important to note that a significant share of the modeled phosphorus load to Dutch Lake is from sources that have not been specifically identified.  The phosphorus load contributed by wash off from land within the subwatershed is not sufficient to explain the current in-lake phosphorus concentration.  The most likely sources for this discrepancy are internal loading from lake sediments or export of phosphorus from the wetlands upstream.  Quantification of those sources will require more detailed diagnostic study.  On completion of further diagnostic work, a feasibility study could more accurately identify specific improvements and their likely load reduction efficiencies.

Table 14.  Phosphorus load reduction plan for Dutch Lake.

Source 

Reduction

Ultimate Phosphorus Load [lb/yr]

Planned Reductions [lb/yr]

Final Loading [lb/yr]

 

Atmospheric

Atmospheric deposition

NA

38

NA

38

 

External Loads

External load determined from modeling land use

 

351

 

 

 

 

LGU load reduction (Table 13)

 

 28

 

 

 

Existing regulations

 

71

 

 

 

Additional regulation

 

36

 

 

 

Wetland detention pond

 

65

 

50%Removal at Outlet from DL-4

Total After Reductions

 

 

 

151

 

Internal / "Unknown" Loads

Internal /"unknown" loads determined from modeling land use

 

335

 

 

 

 

Internal load management project

 

235

 

70% reduction of internal loading

Total After Reductions

 

 

 

100

 

Total Load

 TOTAL

 

724

435

289

 

 LOAD GOAL

 

 

 

306

 

 DIFFERENCE

 

 

 

(-17)

 

5.8 Capital Improvement Program

The capital improvement program identified below includes projects that will progress the District toward achieving its various goals for the subwatershed.  This program is not a comprehensive list of all capital needs or potential projects within the subwatershed, and is limited by available financial resources and staff capacity to manage projects.  These priority projects are intended to:

  • Achieve nutrient load reductions in Dutch Lake to prevent future listing as an Impaired Water that would require a TMDL study.
  • Begin addressing the historic loss of wetlands in the subwatershed through restoration of degraded or drained wetlands.
  • Mitigate the impacts of future development on downstream resources.

These proposed projects emphasize the achievement of multiple objectives.  For example, wetland restorations would not only restore degraded or drained wetlands, they would provide an opportunity to increase infiltration, improve habitat, and conserve existing high-value resources.

5.8.1 Dutch Lake Wetland Detention Pond

ProjectDutch Lake Wetland Detention Pond
DescriptionConstruction of a stormwater treatment pond at the main tributary to Dutch Lake
NeedThe phosphorus reduction plan for Dutch Lake requires a reduction of pounds of phosphorus per year from the subwatershed. A wet detention ponproposed for consideration at the main tributary to Dutch Lake, which drasubwatersheds DL-1 through DL-4. It would be sized to remove 50 percenthe incoming load.
OutcomeThis pond could remove an estimated 65 pounds of phosphorus annually, along with other pollutants such as sediment.
Estimated Cost and FundingInvestigation, permitting, construction, and project management. Funding source is the District capital levy.
$202,000 Design
$1,754,100 Constr, easmnt
$1,956,100 Total
Schedule

2014 Design, easement acquisition

2015 Construction

5.8.2 Wetland Restoration

ProjectDutch Lake Wetland Restoration
DescriptionRestoration of drained or degraded wetlands in the Dutch Lake subwatershed
Need

Two wetland projects in the subwatershed would be considered for restoration to restore hydrology, improve habitat, increase infiltration, expand wildlife corridors or connect other high-value resources. Prioritization and selection of specific restoration projects would be based on criteria including:

  • Potential to achieve multiple objectives such as improving downstream water quality, increasing infiltration, increasing stormwater storage, improving habitat, or connecting other resources
  • Opportunity to increase wetland acreage through restoration of drained wetlands

One wetland in the subwatershed would be considered for restoration to restore hydrology, improve habitat, increase infiltration, expand wildlife corridors or connect other high-value resources. Prioritization andselection of specific restoration projects would be based on criteria including:

  • Potential to achieve multiple objectives such as improving downstreamwater quality, increasing infiltration, increasing stormwater storage,improving habitat, or connecting other resources
  • Opportunity to increase wetland acreage through restoration of drained wetlands

The following are some of the potential restoration locations that mightmeet those criteria, although other locations may also be considered.Game Farm Road Wetland. One wetland in the subwatershed wasidentified as having a high restoration potential. It is an approximately 20acre Type 2 wet meadow adjacent to the central wetland complex andconservation corridor. Restoration of this wetland could be part of another future corridor linkage to the Painter Creek subwatershed corridors.

OutcomeRestored and improved wetland functions and values, enhanced habitat,increased infiltration, expanded and connected wildlife corridors, protection of downstream resources
Estimated Cost and Funding
Design, easement acquisition,permitting,
construction, constructionmanagement,
vegetation managementcontract. Funding
source is the Districtcapital levy.
$51,700 Design
$678,400 Constr, easmnt
$730,100 Total
Schedule

2012 Wetland identification, design, easement acquisition

2013 Construction

5.8.3 Regional Infiltration

ProjectDutch Lake Regional Infiltration
DescriptionImplementation of opportunities to increase infiltration, including but not limited to construction of infiltration basins and devices, wetlandrestoration, reforestation, revegetation
Need

The proposed rule requiring new development and redevelopment toinfiltrate one inch of rainfall would capture approximately 70 percent ofnew runoff volume from the watershed. The remaining 30 percent wouldcontinue to convey pollutants to Dutch Lake and other resources in the watershed. To minimize this pollutant loading and to minimize new stormwater volumes generated from the subwatershed, regional infiltration opportunities such as wetland restoration, underground storage and infiltration, or native vegetation restoration and reforestation may be necessary.

Prior to implementing any of these options, opportunities in the subwatershed should be investigated for the most cost-effective and suitable locations. Regional infiltration will be focused on those subwatershed unitsthat are expected to see significant new runoff volumes between 2000 and ultimate development.

OutcomeMinimized new pollutant loads conveyed by runoff; minimized newvolumes generated by new development; protection of wetland and surficialgroundwater hydrology; wetland restorations; conservation of high-value native vegetation and habitat
Estimated

Project 1: Improvements in DL-3. Funding source is District capital levy.

Project 2: Improvements in DL-5 at Camp Christmas Tree, including channel restoration, bioretention area,shoreline restoration, and other project elements.Funding source is District capital levy.

Project 3: Improvements in DL-7. Funding source is District capital levy.

$118,200

$294,280

$40,000
Schedule

2010: Identify and construct improvements in DL-3

2011: Identify and construct improvements in DL-5

2014: Identify and construct improvements in DL-7

5.8.4 Land Conservation

ProjectDutch Lake Subwatershed Land Conservation Activities
DescriptionImplementation of Land Conservation program activities in the Dutch Lake subwatershed, including but not limited to acquisition of conservationeasements or fee title to land as well as facilitating partnerships, encouragingconservation planning and activities, providing technical assistance, and education and outreach.
NeedThe Land Conservation Program is an integral strategy to achieving the goals in this subwatershed plan. Land conservation activities help to maintain and improve ecologic integrity, surface and groundwater quantity and quality, wetlands integrity, and streambank stability. High priority areasare located in this subwatershed, including areas with high ecological values.Conservation of key land cover types may be beneficial to reducing runoff and associated pollutant transport, preserving high-infiltration areas,conserving native vegetation, conserving habitat and natural resource corridors, and improving ecologic integrity.
OutcomeMinimized new pollutant loads conveyed by runoff; protection of wetlandand surficial groundwater hydrology; wetland restorations; conservation ofhigh-value native vegetation and habitat.
Estimated Cost and Funding
Estimated cost to achieve conservation goals in the
Dutch Lake subwatershed 2007-2017
$2,575,000
District capital levy
ScheduleImplement both proactively and as opportunities arise during the period 2007-2017

5.8.5 Other

This Plan identified the need to consider an internal load management project in Dutch Lake, but that project was not included in the 2007-2016 prioritized CIP. The Board may consider such a project during the time frame of this Plan if funds are available.

ProjectDutch Lake Internal Load Management Project
DescriptionDesign and implementation of strategies to reduce internal phosphorus loading, including: feasibility study; aquatic vegetation survey update and management plan; fishery survey update and management plan; biomanipulation strategies that may include aquatic vegetation management, zooplankton community and fishery manipulation, and chemical treatment
Need

The modeled watershed phosphorus wash-off load to Dutch Lake is not sufficient to explain the in-lake concentration of total phosphorus that exceeds the lake’s total phosphorus goal. An “unknown load” to Dutch Lake is attributed to internal loading, and is likely a combination of bottom sediments, aquatic vegetation, and model accuracy. A watershed and lake diagnostic / feasibility study will be required to confirm the internal and external phosphorous loading to Dutch Lake, as well as the necessary load reductions. In particular, the “unknown load” must be identified as either an external or internal load before specific strategies can be selected. A variety of strategies would be investigated in the diagnostic and treatment study proposed in this plan.

This project would identify and implement a suite of strategies to manage aquatic vegetation, the fishery, and zooplankton community to achieve water quality and clarity goals. The project includes an ongoing vegetation and fishery management plan.

OutcomeReduction in phosphorus load from internal sources estimated at 235 pounds annually; improved water clarity; more diverse aquatic vegetation community; improved aesthetics
Estimated Cost and Funding
Investigation, permitting, fish, vegetation, and
zooplankton surveys, and implementation of
strategies. Funding source is the District capital
levy.
$18,700 Design, surveys
$234,600 Construction
$253,300 Total
Schedule

One Year Prior to Implementation: Fish, vegetation, and zooplankton surveys, development of management plans

No Year Assigned: Implementation of strategies

5.9 Summary

Following tables summarize the proposed implementation action items, 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.

 

Problem or Issue

Actions in Implementation Plan

Degree of Improvement

Water Quality

The water quality in Langdon Lake is in the D-F grade range.  Based on this monitoring history, Langdon Lake’s water quality is not supportive of swimming.

  • A phosphorus load reduction plan for Langdon Lake that sets forth actions to reduce loading to meet in-lake P concentration goals.  These actions include an enhanced regulatory program, LGU requirements to reduce phosphorus form existing development, and capital projects to reduce internal and external loads.
  • Continue monitoring Langdon. 

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.

Phosphorus loading reductions would be necessary to achieve any of these desired in-lake phosphorus concentrations.  The HHPLS and modeling performed for this plan also noted that internal loading and possibly phosphorus export from wetlands in the subwatershed were likely significant sources of excess phosphorus in the lake

A diagnostic and feasibility study assessing sources of pollutant loading, and capital projects to reduce internal and external load sources.

Would depend on outcome of diagnostic and feasibility of implementing improvements.

 

Runoff from developed areas in the eastern subwatershed receives little if any treatment prior to discharge to receiving waters

Requirements for LGUs to reduce phosphorus load from existing land uses through retrofit or  redevelopment.

Plans completed as LGUs complete their local plans, and implemented as opportunities arise.

No monitoring data are available for Saunders Lake or Black Lake.

Utilize satellite-estimated measure of water clarity to monitor water quality

Would provide a cost-effective means of monitoring these wetlands.

The HHPLS identified several locations where outlets and culverts require maintenance.

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

Completed as LGUs complete their local plans.

Water Quantity

Development, redevelopment, and reconstruction in the subwatershed is predicted to increase volume of stormwater runoff from the watershed as well as increased nutrient and TSS loads. 

  • 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.
 
 
 

Future development could increase the volume and velocity of discharges conveyed by the channel from Saunders Lake to Langdon Lake.

  • 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 two locations where the minimum 2 foot freeboard requirement was not met for the 100-year event: the outlet of Saunders Lake and at County Road 110 between Langdon Lake and Lost Lake.

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

Completed as LGUs complete their local plans.

Wetlands

The subwatershed includes several Preserve classification 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
 

Wetlands with high to moderate restoration potential in the Regional Park

  • Work cooperatively with Three Rivers Park District to identify potential restorations.
  • 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.

An initial effort that identifies for restoration those wetlands that would technically be easiest to restore, and those in Key Conservation Areas that may benefit most from restoration.   This would begin to mitigate wetland losses from past development and help to increase the quantity and quality of wetlands present.

Ecological Integrity

  • Areas both in and outside the Park have been designated as Regionally Significant Ecological Areas.  Wetlands with high ecological 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.  An ecological corridor through the subwatershed should be conserved to span several subwatersheds.

 

  • 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 railroad berm that bisects the subwatershed is a barrier to ecological connectivity.

Work cooperatively with Hennepin County to identify opportunities to improve ecological connectivity

Depends on opportunities and ability to collaborate on improvements.

The Langdon Lake fishery was last surveyed in 1993 and there is no current fish data.

  • Support the fisheries 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 obtain fishery data.

Depends on response of natural system to improved water quality

No detailed information is available on aquatic vegetation in Langdon Lake.

  • Conduct aquatic plant surveys as part of internal load management diagnostic and feasibility studies for Langdon Lake.
  • Completion of this survey would fill this data gap.
 

Groundwater

There are areas in the subwatershed that are 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
 

The FAW identified several large recharge wetlands in the subwatershed.  As development occurs it will be important to maintain hydrology to them to preserve groundwater recharge.

  • Amend rules to require infiltration or abstraction of the first one inch of rainfall on new permitted development and redevelopment.
  • Identify a network of surficial aquifer monitoring wells across the watershed, monitor groundwater levels and quality.
  • Promote Better Site Design (Low Impact Development) principles for new development that mimic predevelopment hydrologic regime.

Infiltration on site will assist in preventing further modification of surficial groundwater recharge and help to maintain wetland hydrologic regimes.

Wellhead Protection Areas and associated Drinking Water Sensitivity Management Areas have been identified within this subwatershed. 

 

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

Objective

Metric

Existing

Desired

Location

Water Quality

Phosphorus Loading (lbs annually)

610 (Ultimate)

258

Langdon Lake

Water Quantity

Volume Reduction (Acre-feet)

 

45

Watershed-wide

1.5 year discharge (cfs)

4.9

4.9

Watershed-wide

100 year discharge (cfs)

14.0

14.0

Watershed-wide

Ecologic Integrity

Key Conservation Areas conserved (acres)

 

51

Watershed-wide

Wetlands

Wetland Acreage

203.1

203.1 or greater

Watershed-wide

157.5

157.5 or greater

Preserve

11.3

11.3 or greater

Manage 1

12.0

12.0 or greater

Manage 2

8.7

8.7 or greater

Manage 3

 

Item

 

Description

 

Estimated Cost

 

Schedule

Section 3.0

Problems Addressed

MCWD Capital Projects

1

Internal load management project

$620,500

2013

3.1.1, 3.1.2, 3.1.5

2

Wet detention pond

$801,700

2013

3.1.1, 3.1.2, 3.1.5

3

Regional infiltration

$18,600

2009

3.1.1, 3.1.2, 3.1.5, 3.2.2, 3.2.3, 3.5.2

$100,800

2012

$83,400

2016

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

3.1.5, 3.2.1-3.2.4, 3.3.1, 3.4.1, 3.5.1

2

Identify keystone, umbrella, and indicator species, evaluate habitat, and develop conservation strategies

Part of watershed-wide study

2010 and ongoing

3.3.1, 3.4.1, 3.4.2, 2.4.3, 3.4.4

MCWD Land Conservation Program

9

Undertake land conservation efforts in accordance with Figure 19

$602,000

Part of ongoing watershed-wide program

3.3.1, 3.3.2, 3.4.1, 3.4.2

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, 3.1.2, 3.1.3, 3.1.5

2

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

Part of watershed-wide effort

2007-2009

3.1.1, 3.1.2, 3.1.3, 3.2.2-3.2.4, 3.3.1, 3.5.1 – 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, 3.4.1, 3.5.1, 3.5.2

MCWD Hydrodata Program

13

Monitor Langdon Lake

Part of watershed-wide hydrologic data program

Part of ongoing watershed-wide program

3.1.1, 3.1.2, 3.1.3, 3.1.5, 3.2.2

14

Identify shallow wells to monitor groundwater levels

Part of watershed-wide study

2008 and ongoing

3.2.2, 3.3.1, 3.3.2, 3.4.1, 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

3.1.1 – 3.1.3, 3.2.4, 3.2.5, 3.3.1, 3.4.1, 3.5.1, 3.5.2

2

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

Part of ongoing watershed-wide education program

Part of ongoing watershed-wide program

3.1.1- 3.1.5, 3.2.2, 3.2.3, 3.3.1, 3.3.2, 3.4.1, 3.5.1, 3.5.2, 3.5.3

3

Develop and distribute model ordinances and design standards that incorporate low impact design principles

Part of watershed-wide education program

Part of ongoing watershed-wide program

3.1.1-3.1.3, 3.1.5, 3.2.2, 3.2.3, 3.4.1, 3.5.1, 3.5.2, 3.5.3

4

Promote the development of a Langdon Lake Association

Part of watershed-wide education program

Part of ongoing watershed-wide program

3.1.1, 3.1.2, 3.1.3, 3.1.5, 3.2.2, 3.3.1, 3.4.1, 3.4.3, 3.4.4

5

Recruit and train volunteers to monitor vegetation in Langdon Lake

Part of watershed-wide education program

Part of ongoing watershed-wide program

3.1.2, 3.1.2, 3.1.5, 3.4.3, 3.4.4

6

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, 3.1.2, 3.1.3, 3.2.2-3.2.4, 3.3.1, 3.5.1 – 3.5.3

MCWD Operations and Maintenance

1

Inspect channels and outlet structures every five years

Ongoing activity

Part of ongoing watershed-wide program

3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.2.1, 3.2.2, 3.2.3

2

Monitor high vegetative-diversity wetlands for exotic species

Part of watershed-wide program

Part of ongoing watershed-wide program

3.3.1, 3.4.1

3

Operate an internal load reduction system

$69,300

annually

Ongoing following construction

3.1.1, 3.1.2, 3.1.5

Collaborative Projects

1

Cooperative project with Hennepin County to identify ways to improve trail corridor connectivity

Part of watershed-wide cost-share program

2008 and ongoing

3.3.1, 3.4.1, 3.4.2

2

Cooperative project with Minnetrista to identify need to stabilize Saunders Lake outlet

Part of watershed-wide cost-share program

2008 and ongoing

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.1, 3.2.2, 3.2.3, 3.2.4

3

Cooperative project with Minnetrista and Three Rivers Park District to identify need to stabilize Black Lake outlet

Part of watershed-wide cost-share program

2008 and ongoing

3.1.1, 3.1.2, 3.1.4, 3.1.5, 3.2.1, 3.2.2, 3.2.3, 3.2.4, 3.3.2