Hall Lake Dam modifications

Hall Lake Dam (ID# 765) was created in two parts. Hall Lake originated as a natural lake, approximately 8 acres in size and 6 feet deep, before the construction of the Gun Lake Road embankment. The development of Gun Lake Road initially raised the lake water levels to about 12 feet. A water-control structure was added in the mid-1960s that raised the lake’s elevation approximately 6 more feet to its current size and depth. The Michigan Department of Environment, Great Lakes, and Energy's Dam Safety Unit has classified the Hall Lake Dam as a significant hazard dam. This means that if the dam fails, loss of human life is unlikely, but economic damage, environmental harm or disruption to essential services downstream are probable. In this case the biggest risk would be washing out Gun Lake Road, although there are homes downstream which may be impacted by a dam failure.

The current road prism and earthen embankment are beginning to fail as water is penetrating through the area, causing the embankment to slough or cave in. The water control pipe running through the embankment has significantly deteriorated and reached the end of its useful life. The embankment was originally built over organic material, which likely contributes to the embankment’s instability. Additionally, the culvert and embankment were initially designed to support a county road. There is no clear evidence that it was intended to function as a long-term dam, which could explain why organic materials remained and were not replaced with more suitable and stable materials. In compliance with EGLE, the DNR Parks and Recreation Division has been monitoring the dam for 20 years. The continued sloughing, or erosion, of the downstream embankment indicates water is seeping through and destabilizing the embankment. Regular inspections by EGLE have identified structural deficiencies, leading to a “poor condition" designation, requiring corrective action.

In addition, the DNR has been assessing the infrastructure condition and feasibility of maintaining more than 200 dams in the DNR’s inventory. Many of these dams are near, or have exceeded, their useful life span. The age and condition of the DNR-owned dams have left DNR with a significant infrastructure liability and the DNR must begin to look for ways to lower this risk. As part of this effort PRD has carefully evaluated the balance between safety, long-term costs and recreational value. DNR does not have the financial means to continue to maintain all the dams in our system. 

While Hall Lake is appreciated by a dedicated group of users, it's one of many regional small lakes that provide similar recreational opportunities. After dam decommissioning, Hall Lake will be smaller in size and depth; however, the recreational trail attributes like the North County Trail and Hall Lake Trail will remain. Additionally, the DNR Parks and Recreation Division is exploring how to maintain a small vessel carry-down boating access site. Although the look and size of the lake might be changing, park visitors will still find similar recreation facilities and opportunities nearby at Deep, Long, Williams, Baker and Chief Noonday lakes.

In 2022, PRD initially engineered a project to replace the water control structure, culvert and a portion of the embankment. The competitive bid for this first phase of dam repairs exceeded the available budget of $500,000 by more than double. Since dam repair bids exceeded the originally allocated funds available for construction, the project was paused, and the funding was transferred to other shovel ready projects. If this Phase 1 dam repair project were be constructed in 2026, the cost estimate in today’s dollars PRD estimates a cost ranging between $1.1-1.3 million.

Furthermore, once this work would be finished, a second phase of work would need to occur to address additional embankment work to bring the dam back into compliance with EGLE's Dam Safety Unit requirements. This project phase was never scoped or engineered so PRD does not have a cost estimate for Phase 2.

Based on the high bid costs and thorough project re-evaluation, the DNR Parks and Recreation Division applied for and was awarded a $1.6 million EGLE Dam Risk Reduction Grant, with a scope to decommission the dam. Throughout this process, PRD collaborated with EGLE to determine an acceptable lower lake level that reduces risk, meets the decommissioning threshold and still maintains a water body to support recreational use. PRD’s goal is to ensure that Hall Lake and surrounds amenities remain a valuable natural resource that is both safe and sustainable. The EGLE grant cannot be converted to a scope that repairs the dam. If PRD does not decommission the dam within the given grant timeframe, the grant would be forfeited. PRD or DNR as a whole do not have funds available to invest in a dam repair.

Historical records indicate that the DNR Fisheries Division installed the water control structures in the 1960s. Since then, the DNR Parks and Recreation Division has maintained and operated the dam infrastructure to support recreational opportunities and habitat management.

To safely remove the dam while minimizing impacts to downstream resources and infrastructure, the lake will first be gradually lowered to a controlled level. A new culvert will be installed under the road to maintain water flow, and the road itself will be fully restored. The outdated water control structures will be removed, and PRD will conduct an ecological restoration to support a healthy lake and riparian transition. This includes monitoring the natural seed bank, managing invasive species, and potentially planting native vegetation to enhance habitat diversity.

The DNR is the owner and land administrator of the dam and will make the final recommendation for how it will be managed. As stewards of public lands, the DNR has a responsibility to balance safety, environmental sustainability and long-term costs. Given the dam’s aging infrastructure, high-repair costs, safety concerns and the availability of similar small lake recreational opportunities nearby, decommissioning the dam is the most responsible course of action; however, the Parks and Recreation Division remains open to discussions with stakeholders. If another public entity were to assume ownership and responsibility for repairs and future maintenance, this could be an alternative path forward.

If another public entity were to agree to dam ownership and finance the necessary repairs, including the ongoing monitoring and reporting of safety and maintenance concerns, a rapid commitment and funding plan is necessary to replace the expiring EGLE grant. This grant must be spent by October 2026, leaving minimal time to seek alternative funding commitment. PRD is working with our consultant to determine the milestones of this critical timeline while considering critical factors such as obtaining permits, drawdown, construction and environmental restrictions. The DNR Parks and Recreation Division anticipates completing this milestones timeline by April 15.

The most noticeable change will be a reduction in lake size, with shallow areas transitioning to wetland habitat. Over time, this will promote greater biodiversity, including aquatic plants like cattails and lily pads, which provide habitat for fish, amphibians, and birds. While boater water access may initially be more challenging, PRD will evaluate options for a new carry-down boating access site to support continued paddling recreation. Although temporary road closures will impact travels during a short construction season, this is better than an emergency of an uncontrolled and unplanned road closure. During construction the boat launch will be closed as we evaluate mitigation measures, however visitors can enjoy the seven other boating access sites in the Yankee Springs Recreational Area. Also, none of the recreational trails will be impacted during construction. PRD’s goal is to ensure Hall Lake remains a valuable natural and recreational resource, even as it returns a more natural condition similar to pre-water control structure and post-road development.

An estimated 100 people attended the open house, although only 60 signed in officially. Representatives from the DNR Parks and Recreation, Fisheries and Wildlife divisions, EGLE, the DNR Executive Office and Spicer Group were present. Multiple informational stations were set up to cover project necessity, park history, design details, regulations, stewardship and fisheries/wildlife. Staff and consultant experts were represented at each of these stations, engaging in conversations and answering questions throughout the evening. The open house format allowed visitors to come at a time convenient for them.

Additionally, 113 citizens submitted either a paper or online survey (some duplicates were noted). Seventeen respondents indicated acceptance or neutrality regarding dam decommissioning, while 96 expressed opposition, with 13 specifically advocating for alternative funding.

The DNR is currently reviewing these survey results.