By Dave Fidlin
Correspondent
It’s an all-too-common sight at Cravath and Trippe lakes — noxious, invasive aquatic plant life that has overtaken native greenery and choked a portion of the fish population.
A large-scale, multiyear project set to kick off this fall will eradicate the decades-old problem if all goes according to Whitewater officials’ plans.
Eric Boettcher, parks and recreation director, discussed the project at a recent neighborhood meeting. Depending on the full scope of the project, preliminary estimates have pegged the work at slightly under $782,000 to nearly $1.3 million.
Regardless of the path chosen, Boettcher said residents should brace themselves for a prolonged period of lower-than-normal conditions at both of the lakes. The entire project is expected to span 16 to 20 months.
Two specific options are on the table, Boettcher said at the Dec. 12 meeting, and both would start the clock on the project after this year’s warmest temperatures have come to pass.
Option No. 1, which is on the lower end of the cost estimate scale, entails carving out a 50-foot path through each lake and, in the process, creating navigation channels that would assist with dredging the bottom of the lake.
If the option were pursued, Boettcher said 42,000 cubic yards of unwanted plant material and sediment would be removed as city staffers and contractors work to try bringing the bodies of water back to their original pristine condition.
Option No. 2, which has more depth to it and carries a higher cost estimate, would carve a greater path in the water and entail removing a greater amount of sediment. Nearly double the amount of unwanted plant material — 81,000 cubic yards — would be removed in this option.
In his meeting with residents, Boettcher indicated the Common Council has shown more favor toward the first option.
Residents offered up a litany of comments, concerns and questions during a q-and-a session with Boettcher.
One speaker, for example, questioned why the timeline is so long.
“The DNR (Wisconsin Department of Natural Resources) is the one that determines when we drawdown and how fast,” Boettcher said. “It’s a very slow process.”
There are a number of reasons for the gradual drawdown, Boettcher said, including giving existing fish the opportunity to leave the lake and swim to adjacent creeks.
Another reason for the prolonged time period, Boettcher said, is the cleansing process. By leaving Cravath and Trippe lakes with minimal water over two winters, seeds for invasive and unwanted vegetation will die out after the first winter, giving workers the ability to undertake some of the heavy lifting, including dredging, in the second winter.
The timeline in motion calls for refilling both lakes in spring 2021, Boettcher said, and restocking the bodies of water with new additional fish about a year later. New plant life native to the area also would be installed once the lakes are back up to optimal water levels.
Boettcher said the city also is considering a study to determine how Cravath and Trippe lakes got to be in their current condition and what can be done in the future to prevent it from occurring again.
“When you invest this kind of money into a project, you want it to last as long as possible,” Boettcher said.
