The suggested method has changed but the goal to drain a hidden lake in the Ethel's Woods Forest Preserve near Antioch, and open the area to public access, is moving ahead.
"On the surface, it looks like a beautiful lake. But you look beyond that and there are some real problems," said Randy Seebach, interim director of planning, conservation and development for the Lake County Forest Preserve District.
The district bought the property east of Route 45 and south of Route 173 in 2001. One of the main features was Rasmussen Lake, created in the mid-1950s by a private landowner who built a 600-foot long dam across North Mill Creek.
But the water quality is second worst of the 162 lakes monitored by the Lake County Health Department and nearly the entire shoreline of the milelong, 57-acre lake is severely eroded, with some slopes of five feet or greater.
The poor condition of the dam, spillway and overflow outlet were also among the reasons district officials in 2007 determined that draining the lake and allowing the creek to resume its original meandering would be the best option to improve water and wildlife quality and allow for public access.
Rasmussen is ranked 161 of 162 lakes monitored by the county health department in terms of quality, with low oxygen levels and 10 times the median concentration of phosphorous. The lake bed is 19 feet but the water is only nine feet deep because it is filled with 10 feet of pollutant-trapping sediment that would cost $10 million to remove, according to the district.
A plan was assembled and permits applied for to breach the dam, but regulators had questions about the construction methods.
"We had to change our approach," Seebach said. "There were issues with the management of the sediment. It kicked into a different level of review."
The revised plan involves lowering the water level at a slower pace by notching the earthen dam at a higher elevation so the sediment wouldn't be released downstream. This would allow for about 4,500 feet of the original channel to be reestablished and a 14-acre lake created to catch the sediment.
"It's still a very viable project. We're just changing how we'll construct it," said Leslie Berns, project manager for the forest district.
In the second part of the project, the smaller lake would be drained, the erosion addressed and the floodplain seeded. The entire project would cost an estimated $4.5 million. There currently is only about $2.7 million earmarked, and district officials need to determine how to fund the plan if they want to proceed.
Berns presented the plan last week to two district committees. Both recommended awarding a $78,500 contract for engineering plans and documents that would be submitted to regulatory agencies for approval. The full board will vote on the contract Sept. 10.
If the contract is approved and the permits secured, construction could start in the summer of 2014, although Berns said that may be optimistic.
The North Mill Creek restoration will be coordinated with plans to build a parking lot at Miller Road and a trail to the lake that would include overlooks and exhibits explaining the project and process, Seebach said. That work probably wouldn't begin until 2015, he said.
Work also continues on the Dutch Gap area master plan, a coordinated plan outlining recreation improvements, educational planning and habitat restoration for five forest preserves in the northern part of Lake County, including Ethel's Woods.