Posted: June 25, 2009

Thiensville — construction of a fish ladder to help fish get up and over the Mequon Thiensville Dam will allow the city and village to correct several problems with the dam at a reduced cost to local taxpayers.

The money to be used, grants totaling $250,000, expires at the end of the year. In addition to the grants, Thiensville will pay $37,000 and Mequon $105,000 toward the total cost of the project.

Part of the Mill Race, the mill pond on the Thiensville side of the dam that once powered a local mill, would be filled in order to create the ladder. That plan caused concern among property owners abutting the pond.

Beth Shully, who with her husband, Scott, runs their business, Shully's Catering, on a lot that reaches out to the Mill Race. The Shullys were among a group of 47 people who addressed the Village Board last week.

"(Mequon Engineer) Bill Hoppe discussed options but there is no option to say no," Beth said last week.

Safety concerns at dam

The Army Corp of Engineers in 2004 and the Wisconsin Department of Natural Resources and Giles Engineering in 2002 found structural and safety concerns at the dam and Mill Race.

After some research, Hoppe determined that there were few grants available for dam repair but there were grants for fish ladders, which the DNR wanted to see built at the dam.

The city, with the support of the village, applied for and received three grants toward the construction of the fish ladder and then in both 2008 and 2009, Marquette University students worked on the design as a senior design project.

By building the fish ladder, the city and village would remove the leaking earthen embankment along the Mill Race and make repairs to the spillway and fill in a hole at the base of the dam caused by the flow of the river. The water control gate that allows water to flow from the river into the Mill Race would be removed as part of the project.

A portion of the Riverwalk would be modified and a pedestrian bridge built to allow its continued use once the fish ladder is in place.

Helping fish migrate, spawn

Hoppe said the fish ladder will be a 10-foot-wide meandering stream with deeper pools and riffles where migrating fish can rest as they swim upstream.

"This is a really neat project that has a slew of benefits from both an environmental and economic perspective," Hoppe said.

Not only will the fish be aided in their trip upstream to spawn, but there will be no changes to existing wetlands along the river, nor to the impoundment behind the dam that is widely used for recreation.

"People may also come to watch the fish migration in the park," Hoppe said. "And it will correct the structural deficiencies."

Staff to talk with residents

Village Manager Dianne Robertson said the board approved the plan for the fish ladder but asked Hoppe to talk with the owners on the west end of the Mill Race about their concerns.

The stream would fall short of those properties, including Shully's Catering and the building that was the former mill.

Shully said her husband in the past purchased additional land so that weddings could be held on the Mill Race. That would not be possible with the current plan for the fish ladder, she said. The water would be gone.

Hoppe said he is working on revisions to the plans, hoping to keep water in the western end of the Mill Race if possible.

"I want to see if we can do it without it becoming a stagnant pond," he said. "We are putting our heads together to see what we can do, but we have to be able to do it within the current budget."

Hoppe said once the gate to the Mill Race is closed, likely this week, he will be able to check the conditions in the pond to see if there are any natural springs.

He plans to put the project out for bid in the middle of July with work starting in September, when the river is historically at a low flow.