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  • FINAL REPORT

    US Army Corps of Engineers St. Paul District Mississippi Valley Division

    Feasibility Report and Environmental Assessment

    Marsh Lake Ecosystem Restoration Project

    Minnesota River

    Big Stone, Lac qui Parle, and Swift Counties, Minnesota

    Photo by Ron Bolduan

    Completed in conjunction with the Minnesota Department of Natural Resources

    July 2011

  • FINAL REPORT

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  • FINAL REPORT

    1

    Summary Introduction This report was prepared in response to the study authorization contained in a

    Resolution of the Committee on Public Works of the U.S. House of Representatives,

    May 10, 1962. The resolution reads as follows:

    Resolved by the Committee on Public Works of the House of Representatives, United

    States, that the Board of Engineers for Rivers and Harbors be, and is hereby, requested

    to review the report of the Chief of Engineers on the Minnesota River, Minnesota,

    published as House Document 230, 74th Congress, First Session and other pertinent

    reports, with a view to determining the advisability of further improvements in the

    Minnesota River Basin for navigation, flood control, recreation, low flow augmentation,

    and other related water and land resources.

    In response to the study authority the reconnaissance phase of the study was

    completed in December 2004 (USACE 2004) and approved in January 2005. The

    reconnaissance study resulted in the finding of Federal interest in and potential solutions

    to several existing water resources problems that warrant feasibility studies, including

    ecosystem restoration at Marsh Lake.

    The Minnesota Department of Natural Resources (DNR) as the non-Federal

    sponsor, and the U.S. Army Corps of Engineers, St. Paul District (Corps) initiated the

    feasibility phase of the study on February 2, 2006. The feasibility phase study cost was

    shared equally between the Corps and the sponsor.

    This summary is intended to describe the major factors which were considered in

    the investigation and influenced the decisions and recommendations documented in this

    report.

    Planning Process and NEPA Starting in November 2000 through 2002, the DNR conducted a planning

    process with interagency coordination and public participation to identify ways to restore

    the Marsh Lake ecosystem.

  • FINAL REPORT

    2

    In collaboration with the DNR and making use of the information generated from

    the DNR's earlier planning for Marsh Lake, we identified the problems and opportunities,

    set project objectives, identified and evaluated a number of alternative measures for

    Marsh Lake ecosystem restoration, formulated alternative plans, assessed the costs,

    benefits, environmental and social impacts of the alternative plans, coordinated with

    agencies and the public, recommended a plan and documented this planning process in

    this draft integrated Feasibility Report and Environmental Assessment (FR/EA).

    This FR/EA has been prepared to meet Corps of Engineers planning guidance

    and National Environmental Policy Act (NEPA) requirements. Following agency and

    public review, a final FR/EA will be prepared. The St. Paul District Commander will

    consider signing a Finding of No Significant Impact for the Marsh Lake Ecosystem

    Restoration Project to conclude the National Environmental Policy Act (NEPA) process.

    This planning process has been subject to Value Engineering Review, Agency

    Technical Review; review by interested agencies and the public, and review by the

    Corps of Engineers Mississippi Valley Division and by Corps Headquarters.

    Major Conclusions and Findings Planning Objectives The investigation of the problems and opportunities led to the establishment of

    the following planning goals and objectives for ecosystem restoration in the Marsh Lake

    study area.

    Goal: A return of the Marsh Lake area ecosystem to a less degraded and more natural

    and functional condition

    Objectives:

    1. Reduced sediment loading to Marsh Lake over the 50-year period of analysis

    2. Restored natural fluctuations to the hydrologic regime of Marsh Lake over the 50-year

    period of analysis

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    3. Restored geomorphic and floodplain processes to the Pomme de Terre River over the

    50-year period of analysis

    4. Reduced sediment resuspension within Marsh Lake over the 50-year period of

    analysis

    5. Increased extent, diversity and abundance of emergent and submersed aquatic plants

    within Marsh Lake over the 50-year period of analysis

    6. Increased availability of waterfowl habitat within Marsh Lake over the 50-year period

    of analysis

    7. Restored aquatic habitat connectivity between Marsh Lake, the Pomme de Terre

    River and Lac Qui Parle over the 50-year period of analysis

    8. Reduced abundance of aquatic invasive fish species within Marsh Lake over the 50-

    year period of analysis

    9. Increased diversity and abundance of native fish within Marsh Lake and the Pomme

    de Terre River over the 50-year period of analysis

    Alternatives A wide range of alternative measures were identified to address the planning

    objectives. Alternative plans were formulated. Alternative measures evaluated as a part

    of this study are as follows:

    Modifications to the Marsh Lake Dam to enable passive and active water level

    management.

    Provide for fish passage between Lac qui Parle Lake and Marsh Lake and the

    Pomme de Terre River. Restore the Pomme de Terre River to its former channel

    near its confluence with the Minnesota River. Construct a bridge over the

    Pomme de Terre River to maintain access to the Marsh Lake Dam.

    Construct rock wave-break islands in Marsh Lake to reduce wind fetch, wave

    action, and sediment resuspension to restore aquatic vegetation.

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    4

    Reconnect the abandoned fish rearing pond next to the Marsh Lake Dam with

    the upper end of Lac qui Parle.

    Install gated culverts in the Louisburg Grade Road to enable water level

    management in upper Marsh Lake.

    Modify the Reservoir Regulation Plan for the Lac qui Parle Flood Control Project

    to include growing season drawdowns of Marsh Lake as needed to restore

    aquatic vegetation in years when river discharge allows.

    Construct recreational and educational features including a trail bridge over

    Marsh Lake Dam to connect with the Minnesota State Trail, fishing access on

    Marsh Lake, canoe access on the Pomme de Terre River, and an improved

    recreation area at Marsh Lake Dam.

    Monitor the ecological effectiveness of the Marsh Lake ecosystem restoration

    features to provide information for future adaptive ecosystem management.

    Local Support The non-Federal sponsor, the Minnesota Department of Natural Resources, has

    expressed the desire for implementing ecosystem restoration and sponsoring project

    construction in accordance with the items of local cooperation that are set forth in this

    report. The financial analysis indicates that the non-Federal sponsor is financially

    capable of participating in the project.

    Recommended Plan

    The Recommended Plan recommended for implementation is Alternative Plan 4

    which consists of the following:

    Restore the Pomme de Terre River to its historic channel

    Breach dike at abandoned fish pond

    Construct drawdown structure

    Construct Louisburg Grade Road gated culverts

    Modify the Marsh Lake Dam, construct fishway

    Through the planning process outlined in this report, it was determined that Alternative

    Plan 4, consisting of the measures noted above, provided the greatest increase in

    benefits, addressing each planning objective, at the least cost. The Recommended Plan

    will provide an increase of approximately 8400 Habitat Units at an average annual cost

  • FINAL REPORT

    5

    of $474,000. In addition, a number of recreation features will be constructed (highlighted

    in Section 7.2) that will provide approximately $225,000 of economic benefit at an 8.6

    benefit-cost ratio with an average annual cost of $26,000. The total project costs of the

    ecosystem and recreation features equals $9,967,000 with an annualized cost of

    $500,000. The costs and benefits of the Recommended Plan are summarized below:

    EcosystemRestoration

    9,967,000$ 214,000$

    10,181,000$

    500,000$ 35,000$

    8400225,000$ Total Annual Benefits (Recreation)

    Breakout of Total Project Costs and BenefitsMarsh Lake Ecosystem Restoration - Recommended Plan

    Total Project First CostsInterest During Construction (4.125%)Present Worth of Investment

    Annualized Total Project CostsAnnual Operations and Maintenance Costs

    Total Annual Benefits (Habitat Units)

    Rounded to nearest $1000

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    Ecosystem Restoration Features of the Recommended Plan

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    Recreation Features of the Recommended Plan

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    Table of Contents

    Summary ..........................................................................................................

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