Construction at UConn's Mirror Lake in Storrs will replace a spillway and dam, addressing water quality and safety concerns. The project will manage stormwater runoff with temporary impacts expected during construction.
UConn photo
Initial drafts of the improvement noted that hydraulic dredging would be one action in addressing safety concerns regarding the lake’s water quality and flooding concerns.
Spillway replacement and dam reconstruction on Mirror Lake got under way at the University of Connecticut in Storrs over spring break with workers fencing the project site.
The work is expected to last approximately one year and is starting eight months later than predicted, the Daily Campus, the school's student newspaper, reported April 4, 2025.
Initial drafts of the improvement noted that hydraulic dredging would be one action in addressing safety concerns regarding the lake's water quality and flooding concerns.
According to the federal National Oceanic and Atmospheric Administration (NOAA), dredging increases water capacity by removing sediment and debris from the bottom of a body of water. However, challenges in the university's budget required a redesign of the plan that held off on the dredging and delayed construction, noted an article in UConn Today.
Stephanie Reitz, a university spokesperson, said that this redesigned plan, due to financial considerations, does not detract from the demand for dredging in the lake.
"The project was delayed as UConn reviewed its financial constraints and determined that the proposal involving [a full dredge of] Mirror Lake was cost prohibitive at this time," Reitz said in an email to the Daily Campus. "While we agree on its benefits, the resources were needed elsewhere as we prioritize our academic and research missions and our student services amid budget challenges."
Turner Construction Co. in Shelton, Conn. is the contractor making the improvements at Mirror Lake.
The revised construction plan focuses on repairing the lake's dam and spillway rather than dredging. Repairs will occur as a response to the safety concerns brought up in a 2019 Connecticut Department of Energy and Environmental Protection (DEEP) survey that classified the lake as a hazard, the Hartford Courant has reported.
In addition, UConn Today noted that sediment runoff contributed to the hazardous conditions by reducing the capacity of Mirror Lake. As a result, water was overflowing near the spillway and pooling within drainage pipes downstream. A spillway is defined as a part of a dam designed for water to flow freely over the dam during floods.
An ArcGIS StoryMap created by UConn faculty for an environmental storytelling course said that the hazardous conditions of the lake can be explained by the history of development around Storrs.
"Runoff increases with development because while rainwater can be absorbed by natural groundcover like trees, grasses and shrubs, [it] cannot be absorbed by impervious surfaces like buildings, streets, parking lots and other paved surfaces," the StoryMap said.
In her email to the Daily Campus, Reitz said that only some of the sediment causing this overflow can be characterized by human development.
"The material that has built up on the lake's bottom is a deep layer of muck containing sediment [made up of dirt and sand] that has flowed into the river over time along with leaves and other vegetation, [plus] waste from the ducks and birds that frequent the lake and other runoff," she said.
While wildlife sources are a naturally-occurring source of sediment in the water, the dirt and sand creating the lake's layer of muck likely flows into feeder streams from nearby roads, according to the U.S. Forest Service.
Mirror Lake Critical to Managing UConn's Stormwater Runoff
While the dam construction is designed to improve Mirror Lake's ecosystem, the process that UConn must go through to make these changes will not come without its downsides, noted the Record of Decision for the lake's improvements, which said, "Limited unavoidable temporary impacts are anticipated during the construction phase, including construction-related impacts to traffic, air quality, noise, hazardous materials, solid waste, aesthetics, turbidity and stormwater."
Reitz explained that UConn will manage some of these obstacles for its students, such as keeping Connecticut Highway 195/Storrs Avenue, which runs along the east side of Mirror Lake, open during the construction.
The work will be paused during the busiest high-traffic periods on campus over the next several months, including commencement activities, the days when students move out of their dormitories at the end of the current term and when they move-in again next fall, she said.
Students may see workers near the dam, spillway or in the water as they set up temporary dams and other equipment, but Reitz noted that there will be no reason for concern.
Mirror Lake is a key component of the Roberts Brook watershed, according to the UConn StoryMap.
While not technically a "lake," the approximately 5-acre stormwater basin serves a crucial role in the management of campus runoff and is within the Roberts Brook watershed. Rainfall runoff and snow melt flows off hard surfaces at the university into Mirror Lake and on to Roberts Brook before flowing into the larger Fenton River. Each of these watersheds are located within drinking water supply areas.
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