Lake Zurich hires engineer for Mionske Pond study
Lake Zurich village officials Monday night hired an engineering firm to perform a hydraulic study on Mionske Pond to determine its capacity.
Silt runoff from the Illinois Department of Transportation's Route 22 bypass construction site and an on-site detention basin over several months starting in March 2006 compounded an existing sediment problem in Mionske Pond, the U.S. Environmental Protection Agency has determined.
Water leaving Mionske Pond enters the village storm sewer system and discharges directly into the village's namesake lake.
The EPA has separately cited IDOT for the runoff, and ordered Lake Zurich to stop allowing sediment from Mionske Pond to flow into the lake. The village has until April 30 to fix the problem, but officials are planning to request an extension.
The EPA would like to see Mionske Pond taken off the village's storm sewer system altogether, Lake Zurich public works director and village engineer Dave Heyden said.
The study commissioned Monday, costing $14,800, would evaluate the feasibility and costs of four proposals for resolving the sediment discharge issues with Mionske Pond. It includes the possibility of building a bypass storm sewer pipe around the pond, which would take it off the village's storm sewer system.
Other options would look at how the bypass sewer and the pond would be affected by leaving the lake at its current elevation or by dropping it one or two feet. Village officials also decided to look at the cost of dredging the pond as an alternative. The study would include an analysis of the entire watershed and determine the volume of water going in and out of Mionske Pond and the village's storm sewer system itself.
Lake Zurich and IDOT have already spent significant amounts of money on corrective measures to stop the sediment from flowing into the lake.
Lake Zurich found IDOT's on-site detention pond was severely undersized, which the state later redesigned.
Last month, village officials discussed improvements to the village's storm sewer system that could eventually run up the bill for the village and IDOT to roughly $2 million. Village officials had initially estimated it would cost roughly $205,000 to dredge and restore Mionske Pond and clean up sediment from the village's storm sewer system.
The village has been negotiating with IDOT on the cleanup/restoration of Mionske Pond for nearly a year.
"IDOT has agreed to fund $119,000 toward the final remediation for the Mionske Pond effort," Heyden said. "A share of that funding would go to pay for this study."
Village officials said Monday they intend to renegotiate with IDOT after cost estimates for all six options for Mionske Pond are determined.
"I want to make IDOT pay as much as we can on that," said Lake Zurich Village Mayor John Tolomei. "We're forging new ground here and that's what makes me nervous. We'll see what this (study) shows."
Mionske Pond was built in 1954 as an aesthetic wetland feature for a residential development. It sits southeast of the lake. It was never meant to be a detention basin. The pond was modified over the years to allow it to filter storm water runoff from nearby land through wetland plantings before emptying into the lake.
"It looks to be flooding at a two-month storm event instead of a 10-year storm event for which it was designed," Heyden said.
Heyden said the capacity problem may be due to the sediment that has settled in the pipes, a problem that may be alleviated if it is cleared.
"The pond has historically had a lower quality than the lake of Lake Zurich," Heyden said. "There is no historical information available on what the historic release of sediment from the pond has been."