Study shows how salt is harming fish in Mirror Lake

LAKE PLACID – A month after the village Board of Trustees voted to test a liquid de-icer on a stretch of Mirror Lake Drive sidewalk, the Mirror Lake Watershed Association is trying to gain support for more than $4,000 worth of extra tests, citing the latest research by the Ausable River Association.

With this season’s warm early winter weather, the rollout of the pilot program for the mixable liquid solution de-icer has been delayed. Meanwhile, the Ausable River Association issued a Mirror Lake Water Quality Monitoring Proposal outlining how 2015 sampling efforts and research in the lake show road salt pollution is negatively affecting the bottom waters of the lake.

The association says the results of the study show a higher salinity at the bottom of the lake than at the top due to road salt pollution, and that the bottom waters have a lack of oxygen for much of the summer season. The report adds that in the Adirondacks, this only occurs in lakes that have super-salty discharge during the spring runoff period, indicating water flowing from downtown through numerous stormwater drains is negatively affecting the lake. The association and the MLWA say the additional winter and spring testing is necessary to validate the preliminary 2015 results.

MLWA President Bill Billerman said Wednesday that of all 72 lakes analyzed by the Ausable River Association, Mirror Lake ranks in the 97th percentile for sodium and chloride concentration. Billerman overall described Mirror Lake as “pretty healthy and clean,” but the president did emphasize how road salt settling in the lake alters the oxygen level at the bottom, affecting fish negatively.

“We really think that’s one of the main impacts to the lake, is the amount of road salt that goes into the lake, because it is surrounded by a road all the way around,” Billerman said. I think the stormwater pollution that comes from road salt has the most impact to the lake, and second to that would be invasive species. But the lake doesn’t have many (invasive species), and they are in small quantities.”

The village plans to replace its old stormwater infrastructure beneath downtown, but it doesn’t yet have the millions of dollars that project will require. The state helped by awarding a $1.85 million grant recently, but Mayor Craig Randall estimates the project will cost between $6 million and $8 million.

Billerman said the increased testing the Ausable River Association is offering would focus more on the deep water of the lake. For $4,330, the testing will provide “a more sold database for renovating the stormwater system,” he said, one which will help Lake Placid and the MLWA further piece together the impact of road salt and other pollutants.

“It all ties together,” he said.

The already-approved liquid de-icing for this winter on Mirror Lake Drive will cover an estimated two-thirds of the perimeter of Mirror Lake. The Main Street portion of Mirror Lake will continue to have rock salt this winter to melt the ice and snow, as the state Department of Transportation maintains Main Street, but Billerman and others hope the MLWA and Ausable River Association’s research efforts may change the snow and ice-melting procedures on Main Street in the future.

“That’s one of the reasons for the testing,” Billerman said, “to gain a little more data when presenting to the Department of Transportation to do something to reduce the amount of salt.”

Billerman said the MLWA has received interest helping to fund the additional research.

The association’s report highlights how the road salt-related problems at the bottom of Mirror Lake may result in only two meters of the water column remaining suitable for healthy lake trout populations. The lake trout are forced into this zone due to the surface waters being too warm and bottom waters, lacking sufficient oxygen. At its deepest, Mirror Lake is 65 feet, and its average depth is 14 feet, according to the state Department of Environmental Conservation. Along with lake trout, rainbow trout, smallmouth bass, yellow perch, brown bullhead, rock bass and pumpkinseed inhabit the lake.

“The high sodium and chloride levels, chemical stratification, and early onset of anoxic conditions in the lake warrant further investigation,” the association wrote. “If these conditions continue to get worse Mirror Lake may not be able to support healthy fish populations, may lose its cold water fish species (lake trout and rainbow trout), experience algal blooms, and be more vulnerable to invasive species infestations.”