It is unclear how wildlife might be affected by removing the Fourth Street Dam without knowing future water levels and quality, a DNR specialist told a city committee Monday, June 15.
If a water level drop were to narrow the Yahara River channel north of the dam, it would change the habitats of waterfowl, but whether that change is positive or negative is difficult to predict, Andy Paulios, an area wildlife supervisor with the Wisconsin Department of Natural Resources told the Whitewater Park ad hoc steering committee. He also said the Yahara River chain is not considered a critical habitat for water birds.
The city brought in Paulios to answer concerns from Town of Pleasant Springs residents and recreational users that if the dam is removed, water levels would drop in an already shallow waterway. Some have speculated a drop in water levels would harm waterfowl and recreational uses and reduce property values.
City officials have said the dam removal is imperative for safety of the proposed whitewater park south of the dam, near Mandt Park, and studies the Whitewater Park steering committee commissioned show little effect on the water surface level. Kenneth Potter, professor emeritus of hydrology at the University of Wisconsin-Madison who saw preliminary plans for the Whitewater Park, previously told the Hub the removal of any dam is likely to be beneficial to fish and water quality.
Paulios noted he is a wildlife specialist and therefore could not speak for how the dam removal would affect water levels. And it is difficult to know how wildlife would be affected without knowing how the wetland and marshland change, he said.
“How (waterfowl) would change – it might not change at all depending on the water levels – it could get better, it could get worse,” Paulious told the committee. “It is really hard to say without knowing the future hydrology.”
The most recent hydrology study done by Recreation Engineering and Planning, the company that is designing the park and likely would build it, shows nearly no impact on the river north of Cooper’s Causeway, which is near the Forton Street bridge.
REP’s study used a hydraulic model with the river’s average flow of 380 cubic feet per second. It shows a .1 foot change from Cooper’s Causeway to County Hwy. B and zero change from County Hwy. B to Lake Kegonsa Dam, according to an email from city parks and recreation director Dan Glynn, who has been spearheading the whitewater project for about three years.
But most of the 30 people who attended the meeting on Monday appeared to be skeptical of the dam removal.
A 350 member Facebook group, called Friends of Yahara Bay, was created for people who have hunted, kayaked or lived on the Yahara River for long periods of time and are unhappy with the possible dam removal. Members of that group who attended said they are skeptical of the studies they’ve seen because throughout the year they witness large fluctuations in water levels.
David Pfeiffer, chair of the Town of Pleasant Springs board, told the Hub that the people he has talked to are getting mixed messages; he has heard that the water levels won’t drop significantly enough to harm the bay, and he has heard the water levels will drop but it won’t negatively affect the environment.
“My sense is that the ad hoc committee’s perspective seems to be full steam ahead with the dam removal / river lowering after doing their ‘due diligence’ to hear and dismiss objections to their plan, and that they now plan to use the rationalization that the area of the river north of Stoughton isn’t sufficiently significant as a wildlife habitat,” Pfeiffer wrote to the Hub in an email.
Paulios said what he looks at when a dam removal is considered is whether there are any rare or endangered species in the waterway, and he did not list any. He noted that in the spring, waterfowl like pelicans and swans often use the Yahara Bay, which is east of Williams Drive, but he said it is not considered a statewide priority for statewide critical habitat.
A critical habitat, as the DNR defines it, is an area considered the most important to the overall health of aquatic plants and animals. The areas are mapped and recognized so people know which areas are most vulnerable to human impact. A local example is the Koshkonong water system, and a well known one is the Horicon Marsh, Paulios said.
A public commenter wanted to know what would happen to waterfowl if the water levels in the Yahara reduced, and the bay turned into a narrow channel. Paulios said certain birds would leave and others would come.
“If it did decrease the amount of open water it would be replaced with a lot of emergent vegetation so you’d shift the system from a flat water, open water pelicans, swans, geese to more emergent marsh critters black birds.… not good or bad per se for a wildlife system, but just different. It would be different for the people obviously, but not for the critters as much,” Paulios said.