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Edenville Dam

The Edenville Dam is located on the Tittabawassee and Tobacco Rivers near Edenville, Michigan. The Edenville Dam was built to provide water level control for the purpose of hydro-electric power generation and received its original license from FERC in 1998. On May 19, 2020, an extreme rain event caused the Tittabawassee and Tobacco rivers to swell and resulted in the breach of the Edenville Dam. 
Source: Four Lakes Lake Level Study by Spicer Group

Edenville Dam interim Repair Measures

Phase I Interim Stabilization Measures at Tobacco Spillway
  1. Lowering and filling existing concrete spillway.
  2. Restoring base flow in the Tobacco River.
  3. Lowering water level upstream of dam.
  4. Stabilizing River immediately downstream of dam.
  5. Spillway designed to convey approximately 11,300 cfs – approximately 200-year flood flow.
  6. MDOT constructing temporary M-30 causeway.
  7. Embankment stabilization adjacent to concrete.
Phase II Interim Stabilization Measures at Edenville Spillway
  1. Remove Edenville spillway to it’s base.
  2. Install low dike across the breach channel.
  3. Install sheet pile cut off wall across breach channel.
  4. Restore base flow to original river channel.
  5. Convey 200 storm year inflow without overtopping into breach channel.
  6. Exploring options for the powerhouse – either demolish or re-use water passages as a low level outlet. Hydro generation is not an option.
  7. Stabilize and restore downstream portions of the Tittabawassee River channel.
  8. Exploring embankment stabilization options along upstream face of dike from spillway to M-30.
  9. Installing boom on Tobacco River for safety.

Quick Facts

$96.5 million
2,875
2026
$115 - $460*
Cost to Repair
Waterfront Properties
Estimated Lake Return Date
Estimated Annual Capital Assessment Range
*Capital Assessment estimates are subject to variation of +/- 30% because of cost sensitivities such as construction costs, the financing term and interest rates.
​
Edenville Dam will require demolition of damaged structures - the spillway and powerhouse - and construction of new primary and auxiliary spillways.
Tobacco River spillway repairs
Tobacco River Proposed Plan View of Permanent Repairs
Tittabawassee River Repairs
Tittabawassee River Proposed Plan View of Permanent Repairs
Edenville Proposed Embankment at Breach Channel
Edenville Proposed Embankment at Breach Channel
Tobacco Proposed Embankment Stabilization
Proposed Tittabawassee Spillway
Proposed Tittabawassee Spillway
crest gate
Example crest gate with gate closed on the far/left side and the gate open on the right side
 

Wixom Lake Recovery and REstoration Timeline

Picture
Last update: November 12, 2021

Long-Term Restoration

Critical items
Spillway Adequacy
  • Edenville is classified a high hazard dam. Prior to May 2020 flood, the total spillway capacity (Edenville + Tobacco) was approximately 20,670 cubic feet per second (cfs) before water would begin overtopping embankments
  • Prior State of Michigan 1/2 PMF was 25,000 cfs
    • Based on current on-going studies and recent flood, this will increase
  • FLTF study currently estimating future spillway requirement being 52,275 cfs
  • Spillway requirements still being finalized based on
    • PMP and PMF studies
    • Inflow Design Flood Study
    • State of Michigan Dam Safety Task Force
    • EGLE approval 
Water Retaining Structures
  • The left embankment completely breached. Portions of the remaining embankments were damaged due to rapid reservoir drawdown and scour
  • Remaining embankment slopes are steep and don’t meet stability criteria
  • Embankments leak excessively. No seepage cutoff and no internal filter zones to protect against seepage-induced internal erosion
  • Total spillway capacity is significantly lacking
  • Geotechnical investigations and structural analyses are required to support design of new embankments and repair of existing embankments
  • All water retaining structures will need to be thoroughly evaluated and designed to meet State and federal dam safety standards
Risk-based design approach
  • The IDF/risk-based approach aligns with FEMA guidelines and recommendations of the Michigan Dam Safety Task Force guidelines for Michigan dams
  • Inflow Design Flood that requires these steps:
  1. Site-specific Regional Probable Maximum Precipitation (PMP) studies which are underway.
  2. Perform downstream Inundation mapping assuming dam failure for a range of flows starting from the 100-year flood up to the PMF
  3. Determine the incremental hazard increase and consequences of failure for a range of flood flows up to the PMF
  4. Use risk-based, IDF approach to inform the design spillway capacity – no less than 200-year but possibly less than the ½ PMF

Resources

Edenville/Wixom Documents
Contacts
  • Wixom Lake Association: Facebook • website • email • Larry Woodard, President
  • ​FLTF Board Representatives: 
    • ​Don Zakett, Wixom Lake, 2020-2022
    • Dave Rothman, Wixom Lake, 2020-2023
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©2021 | Four Lakes Task Force is a US 501 (c)(3) public charity, EIN 27-4698447. 
Four Lakes Task Force
  • About
    • Get Involved
    • History
    • Who We Are >
      • Team Bios
    • Operations
    • Secord Dam
    • Smallwood Dam
    • Edenville Dam
    • Sanford Dam
  • Restoration Plan
  • Donate
    • Why Donate?
    • Our Donors >
      • Corporate Sponsors
      • Individual Donors
    • Four Lakes Legacy Society
  • Events
  • Documents
    • Annual Reports
    • Audited Financials
    • County Documents
    • Edenville/Wixom
    • Engineering Reports & Studies
    • Flyers & Brochures
    • Meeting Presentations
    • News Flashes
    • Newsletters
    • Published Statements
    • Regulatory Correspondence
    • Restoration Plan
    • Sanford
    • Secord
    • Smallwood
    • Tax Filings & Governance
  • Resources
    • Erosion Control >
      • Appeal NRCS Ineligibility
      • Project Financing/NRCS Program
      • Project Map
      • Project Permitting
      • What You Can Do
    • FOIA Request
    • Frequently Asked Questions
    • Lakebottom Access & Use Rules
    • Subscribe
    • Updates
    • Volunteer Portal
  • Special Assessment District
    • Assessment Map
    • FAQs
  • Contact