Road residue tested in Eau Claire
By Joe Knight
EAU CLAIRE (AP) — UW-Eau Claire geology majors Tim Molitor and Katy Grant dipped a plastic bottle attached to a long plastic handle into Little Niagara Creek, where it flowed behind Phillips Science Hall, and removed a water sample.
The campus was quiet on a recent Friday afternoon — semester break still was in progress — but Molitor and Grant were among five students being trained as part of a statewide study of road salt in urban creeks.
The project started last year in Madison and Milwaukee after a researcher with the U.S. Geological Survey became concerned road salt running into creeks in some Milwaukee streams was killing aquatic organisms, said Christina Anderson of the state Department of Natural Resources. The DNR and UW-Extension have trained volunteers to monitor creeks in Madison and Milwaukee.
This year the agencies are expanding the project to other urban areas, including Eau Claire.
Volunteers agree to sample the creeks every two weeks during the winter and after big snowstorms, when streets likely would get a big dose of salt.
The volunteers also monitor in the summer, but less frequently.
“I’m pretty excited about it,” Molitor said. “It will be good field experience.”
Grant said a lake in Madison was showing some effects from road salt, and she was crossing her fingers that Eau Claire wasn’t having similar problems.
Anderson said although their recent sampling on Little Niagara Creek was for practice — the creek happened to flow right behind the building where they were conducting the training session — Little Niagara is one of the urban creeks they plan to monitor in Eau Claire.
Volunteers plan to monitor Lowes Creek, a trout stream, at the Highway II bridge a rural setting south of Eau Claire, and at Highway 37, below where the creek has passed through more developed portions of Eau Claire and the town of Washington.
They had hoped to monitor Otter Creek in Altoona, another trout stream and at the Spooner Avenue bridge, but Anderson said the banks were too steep. The snowy and icy conditions could have created a hazard for the volunteers, Anderson said, so she sought a flatter access point.
They also plan to monitor Sherman Creek, on the city’s western edge, for salt, she said.
The student stream monitors use two techniques to measure salt. A conductivity meter measures electrical conductivity ó basically the higher the conductivity, the higher the salt concentration.
Students will need to measure in the summer also to get natural conductivity for each creek.
Periodically they also will collect a water sample and send it to a state lab to be measured for chloride.
Anderson said the length of the study would depend on financing, but she wants it to continue for several winters because snowfalls and salt applications vary from winter to winter.
Using trained volunteers allows the DNR to monitor more creeks and rivers for a variety of things than if the agency solely had to rely on its staff, Anderson said.
And the volunteers usually have fun. She and her husband were volunteer monitors on Madison streams.
“It’s a nice way to get out,” she said. “Last year we had some people say they really enjoyed getting out because they could snowshoe down.”
In the Eau Claire area, much of the volunteer monitoring year-round is coordinated through the Citizen Science Center at Beaver Creek Reserve, a nature preserve and education center north of Fall Creek.
Anna Mares of Beaver Creek Reserve said the organizations had volunteers involved in monitoring 26 area streams, although one person is handling 11 creeks by himself.
Brian Amundson, Eau Claire public works director and acting city manager, said the city was keeping an eye on its use of road salt, both for environmental and budgetary reasons.
“We think about that all the time,” he said. The city tries to follow a “sensible salting” policy that involves not applying more salt than is needed.
“This year we bought some additional equipment to calibrate salters, so when we say we’re putting down 100 pounds per lane mile, we know were applying 100 pounds per lane mile,” he said. The trucks have the ability to vary the application rate, based on conditions.
At temperatures below 10 degrees, normal rock salt does not work well — it tends to bounce off the road — so if salt needs to be spread when it’s 15 degrees or colder, city trucks “prewet” the salt with calcium chloride, which makes it more active in cold conditions, Amundson said.
“We’re looking at the potential for using precoated salt, which is coated with an agricultural by-product that is not as aggressive on the environment and keeps the salt in place,” he said.
Salt still is the least expensive substance for keeping roads clear, Amundson said, but it has doubled in price during the past 10 years. It now costs the city about $65 a ton. The city has 86 miles of “ice control” route that regularly are salted. The rest of the streets, 65 miles classified as secondary plow routes and 193 miles of residential roads, receive plowing and sand, but no salt.
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