UConn Working to Clean Mirror Lake

By John Kennedy

STORRS – Mirror Lake, a symbol of the University of Connecticut’s flagship campus since 1922, will be dredged next summer in order to improve the lake’s health and make it more aesthetically pleasing, said Dave Lotreck, the manager of Building Services, landscaping and elevators.
Lotreck estimated the cost of the dredging project to be between $1.5 million and $4 million, though he said he was more inclined to lean toward the $1.5 million range.
“The broad range [of costs] would be dependent on the amount of material and the composition of the material,” Lotreck said. “On a project like this, the final costs will not be known until the project is pretty much complete.”
Lotreck added that if the composition of the material is hazardous, the price will rise, since it will cost more to decontaminate and dispose of it.
The money for the project will be taken from UConn’s Save the Lakes Fund, which has been collecting donations. If the fund does not have enough money to cover the cost of the endeavor, dredging will be postponed, Lotreck said.
So far, the main problem that has been addressed has been the goose population. The geese, which saturate the lake and surrounding area with waste, have become a huge problem in recent years.
Not only is their excrement a hazard to students walking the shoreline, but the excess nitrogen it adds to the water can cause large algae blooms that can kill other life in the lake.
At the moment, a grid of wires stretches across the lake, invisible to the human eye from a distance, but visible to the geese when they try to land. According to Lotreck, geese don’t like anything strange in their landing area, so the wires throw them off, forcing them to land elsewhere.
Lotreck also said that the vegetation surrounding the lake has been left unmowed, another attempt to keep geese from flocking to the water. Even though it may look unkempt, geese like to have a clear path from land to water, and long grass prevents that.
In addition to the geese prevention measures, other landscaping work has been done. Lotreck said that the island was cleared of brush over the summer so it would be less overgrown, and some of the invasive species, such as phragmites, have been controlled.
The lake, which began as a boggy marsh, is being restored for aesthetic reasons and to improve the overall health of the lake.
The average depth of Mirror Lake is currently 1.5 feet, though it sinks to a depth of about seven to eight feet on one side of the island.
Because of the shallow depth, the lake tends to overheat in the summer, which causes large algae blooms that can starve fish and other aquatic creatures of oxygen, Lotreck said.
Lotreck said the dredging will increase the lake depth to an average of eight to 12 feet, so that little light will reach the bottom and vegetation won’t be as thick. Deeper water will also allow the lake to be healthier, with more movement of water, as opposed to the stagnation that is currently occurring.
In order to avoid sediment from building up again after the lake has been dredged, Lotreck said that the university is investigating more efficient methods of preventing material from draining into the lake from the roads.
Last winter, UConn dumped about 320 cubic yards of sand onto the streets of its campus to counteract ice. Most of that eventually ended up in the lake or clogged the catch basins. Over time, that sand has created a large sandbar between an island on the lake and the shore, where the water is only a few inches deep.
To eliminate this problem, Lotreck said the university is looking at different strategies that would cut back on or even eliminate the use of sand. One of these strategies is to use a brine solution that would melt the ice and result in less runoff than sand.
Another option that the university is looking at is the installation of vortex separators or “high-tech catch basins” as Lotreck calls them.
The current catch basins are designed so that when water and sediment fall into them, the sediment sinks and the water flows out through another pipe. However, most basins fill up before they can be cleaned, resulting in material entering the lake.
Vortex separators, on the other hand, are designed to create a vortex of water that improves their ability to remove sediment and other material from the water.
Lotreck said the plans call for three or four to be installed, at a cost of about $10,000 to $15,000 each. This money will come from the university’s expense budget, much like a bus stop or a road.
Another option – allowing the lake to revert back to its former landscape as a swamp – would save money, Lotreck said.
Lotreck disagrees with that choice, however, since nature will not fully reclaim the lake for about 80 years. During this time, the area will not be pleasant to look at and it could become a hazard.
A swampy setting makes it easier for mosquitoes to breed, increasing the chance of mosquito-borne diseases. It would also be harder to keep the area clean of litter.