Environmental Quality Commission: October 21, 2026
To: Members of the Environmental Quality Commission
From: James McDermott, Water Quality Technician
Title
Consider Motion of Support for Ames Mill Dam removal timeline and next steps.
Body
Action Requested:
The Environmental Quality Commission is asked to approve a motion to support the Ames Mill Dam removal timeline and next steps.
Summary Report:
EQC members are asked to discuss considering a motion that would support the proposed Ames Mill Dam removal timeline and next steps.
Background Summary:
James McDermott, City of Northfield Water Quality Technician and Jennifer Tonko, Executive Director for Clean River Partners will provide a presentation at the meeting and welcome questions and input from the EQC.
Background
Post Consumer Brands owns the Ames Mill Dam. The aging structure no longer serves its original milling purpose. The first dam dates to 1855, the year Northfield was founded. The existing concrete dam was constructed in 1919. According to the accompanying project presentation, a 1997 inspection recommended studying potential removal. Malt-O-Meal explored a replacement option in 2007, but cost and limited funding for privately owned dams prevented the project from advancing.
On November 21, 2023, the City Council adopted the Ames Mill Dam Feasibility Report’s recommended Option 3, removal of the dam with installation of long rock rapids. Council also authorized staff to explore ownership transfer and funding. The current work follows that direction by examining whether the City can proceed under acceptable environmental, financial, and ownership conditions.
The long rock rapids concept would replace the dam’s abrupt drop with a more gradual series of rock features intended to allow fish passage and improve river safety. Final engineering would determine the configuration, water levels, river appearance, and recreational conditions. The feasibility concept provides a direction for further study rather than a completed construction design.
On November 21, 2023 Northfield City Council adopted the Ames Mill Dam Feasibility Report Recommendation Option 3 - Removal of the Dam and installation of long rock rapids, and authorized staff to explore phase 2 - dam ownership transfer and exploration of funding opportunities. The replacement of the Ames Mill Dam is also identified as a priority in the current City Council approved Strategic Plan along with the Riverfront Enhancement Action Plan and the City of Northfield 2045 Comprehensive Plan. The Northfield Climate Action Plan also lists evaluation of the upstream and downstream impact on the Cannon River of the Ames Mill Dam removal as a recommended action.
The next step is an option agreement with Post Consumer Brands and preliminary engineering and environmental studies to inform later decisions about ownership, project design, and funding.
Why City involvement matters
An option agreement would give the City a conditional path to future ownership while allowing studies and funding work to proceed. Public involvement provides an opportunity to shape the project and coordinate it with broader riverfront improvements. The proposed option contemplates a future transfer at no purchase price, but ownership and removal would still carry costs and responsibilities. Entering the option agreement would authorize the next phase of exploration; transfer and construction would require later decisions.
Environmental and public benefits
The vision and plan for Ames Mill Dam removal provides an opportunity to proactively address an existing river hazard while restoring habitat connections through downtown Northfield. The
• Fish passage and habitat. Removing the barrier could allow native fish to reach additional habitat and spawning areas and improve connections among river populations. The 2023 preferred alternative was developed to meet Minnesota Department of Natural Resources fish passage expectations.
• Native mussels. Many native mussels depend on fish as hosts during part of their life cycle. Restoring fish movement can also help restore mussel distribution and reproduction. The presentation draws on DNR research documenting the effects of dams on native fish and mussels.
• River connectivity. The presentation identifies a potential 33-mile connected reach if both Ames Mill Dam and Faribault Woolen Mill Dam are removed. This broader benefit depends on both projects and should not be attributed to Ames Mill Dam removal alone.
Public safety and recreation. Low-head dams can create dangerous recirculating currents. Removing the existing dam could reduce that hazard and improve fishing and paddling opportunities. Rock rapids would still require careful design, and river conditions would continue to pose risks.
Improved river access and recreation may also support downtown businesses, visitor activity, and residents’ quality of life. These are potential benefits to evaluate as the project develops. Specific economic returns and recreational outcomes have not been established.
Environmental study and preliminary engineering
Sediment accumulates upstream of dams over time. Understanding its volume, composition, and potential contaminants is a necessary part of evaluating removal. Barr Engineering’s proposed preliminary scope in the presentation includes:
• Phase I and Phase II Environmental Site Assessments to review site history and investigate environmental conditions.
• Geotechnical and hydrogeologic investigation, along with a vibration study, to inform design and evaluate site and nearby structural considerations.
• Environmental Assessment Worksheet preparation, permitting preparation, and preliminary design.
The work will include what sediment sampling and management are needed, identify potential environmental responsibilities, and clarify costs before the City considers ownership. Sampling results and agency review would guide whether sediment can remain, requires management during construction, or must be removed and disposed of at an approved facility.
The available information does not establish that the impounded sediment is toxic, and it does not establish that it is free of contamination. Testing is intended to resolve those questions. The City has experience testing sediment during stormwater pond dredging, but results from those ponds do not establish conditions at Ames Mill Dam.
Historic character and community input
The dam and mill setting are familiar parts of downtown. Residents may have concerns about changes to the river’s appearance, sound, water levels, and historic character. Further design and applicable historic review that is required and will include public input and local Heritage Preservation Commission review. This process will provide an opportunity to address those concerns and explore ways to recognize the site’s milling history.
Ownership and responsibilities
Post would remain the owner unless and until a transfer occurs under a separately approved agreement. The proposed agreement would establish the terms for due diligence, cost sharing, and a possible later transfer. Staff and legal counsel will need to evaluate the allocation of environmental and other responsibilities before recommending that the City accept ownership.
If the City were to take ownership before construction funding is available, Council would also need to understand the costs of inspections, maintenance, insurance, and any necessary repairs during that period. The future Council presentation will identify a cost-sharing approach for preliminary Barr Engineering work and subsequent design due diligence. Any commitments beyond the initial phase need to be defined in the agreement and future authorizations.
Questions for Commission discussion
Does the Commission support advancing the long rock rapids alternative based on its potential environmental and safety benefits?
City Plans & Policies Relevance:
The replacement of the Ames Mill Dam is also identified as a priority in the current City Council approved Strategic Plan along with the Riverfront Enhancement Action Plan and the City of Northfield 2045 Comprehensive Plan. The Northfield Climate Action Plan also lists evaluation of the upstream and downstream impact on the Cannon River of the Ames Mill Dam removal as a recommended action.
Alternative Options:
Take no action at this time.
Financial Impacts:
The proposed initial Barr Engineering environmental exploration costs estimated at $500,000 would be shared equally by the City and Post Consumer Brands. Staff has identified existing stormwater funds for the City’s early work, with no current stormwater rate change associated with that phase. Council consideration will include information forthcoming at their November 10th meeting that outlines scope, contract amount, and each party’s obligation.
Staff is exploring state and federal funding to reduce the local cost of future removal and restoration. Public ownership requires eligibility for significant funding opportunities identified in the presentation, including dam safety and habitat restoration programs. Eligibility varies by program, and ownership is not a universal prerequisite for every grant. Staff will need to confirm the ownership requirements and timing for each funding source before recommending a transfer. Additionally, this initial environmental work being proposed is being completed prior to Council consideration of transfer of ownership.
Future decisions will need to address total project cost, grant availability, local matching funds, sediment management costs, and ongoing responsibilities. Staff’s approach is to gather enough information for Council to assess the potential benefits alongside the City’s financial exposure.
Included is consideration of a motion to support the Ames Mill Dam removal timeline and next steps.
Tentative Timelines:
The current schedule anticipates a City Council work session on November 10, 2026, followed by consideration and possible action on November 17, 2026. These dates are tentative. The presentation identifies the ownership transfer option agreement and Barr Engineering contract authorization as upcoming Council items.
If Council authorizes the next phase, staff would proceed with the approved studies and funding exploration. Study findings, refined design, and funding information would support later Council decisions on whether and when to accept ownership and proceed toward construction. The EQC recommendation would become part of the information Council considers as it evaluates the next phase.
See attached presentation for future phased tentative timelines.