Construction has started on the much-anticipated flood relief project in Carol Stream's Armstrong Park.
Crews have cleared vegetation and installed a fabric fence for sediment and erosion control in preparation for coming earthwork, officials said.
Workers also have removed baseball backstops, basketball poles and other items in the park.
The reservoir project is expected to cost $12.5 million and is a joint endeavor among DuPage County, the village and Carol Stream Park District.
Officials hope to relieve flooding in the area by building two reservoirs. When water rises in Klein Creek, it will first spill into the smaller reservoir and then be pumped into the larger one.
Water from the larger reservoir will be released through an outlet pipe back into the creek in an area south of Armstrong Park.
The next step is to remove water from part of the park's Lake George, officials said.
That will involve essentially placing a dam in the middle of the lake and pumping water out of one part so the larger reservoir can be built on the south part of the lake, officials said.
That process is expected to start later this week or next.
The entire project will consist of three phases: building the reservoirs, constructing the pump station and installing pipes.
Work should be completed by next spring.