This summer, drivers along Governors Highway have seen stacks of stone at the staging area for the $4.1 million Cherry Creek flood control project, which the Metropolitan Water Reclamation District (MWRD) expects to complete this fall. The stones are being used to rebuild Cherry Creek as it meanders north from Homewood-Flossmoor High School.
For starters, let’s talk about the big slabs of limestone — they are officially known as J-hook pieces — that are being used to rebuild Cherry Creek as it meanders north from Homewood-Flossmoor High School.
This summer, drivers along Governors Highway have seen stacks of stone at the staging area for the $4.1 million Cherry Creek flood control project, which the Metropolitan Water Reclamation District (MWRD) expects to complete this fall.
Different types of stone were stored at the staging area next to H-F’s north parking lot along Governors Highway. Rip-rap is used to line the entrances to new culverts that were constructed this summer. “Riffle stones” are also being used to rebuild Cherry Creek north of the high school. They have two main sizes and can be as big as a soccer ball or as small as your fist.
J-hook pieces need to be a minimum of one foot high by two feet wide by three feet long and weigh upwards of 800 pounds each. As Cherry Creek is rebuilt, the boulder-sized J-hook stones will play an important role in forming new contours for the stream. They will also help create pools for aquatic life on the creek, perhaps even fish.
Adel Awad, an MWRD senior engineer, said 12 dump truck loads of stone are being used to rebuild the creek. Eight loads of riffle stone are going in place along with four loads of J-hook pieces.
Most of the major work at the Cherry Creek project is already finished. Governors Highway was closed as a through road for eight weeks this summer. During that time, new culverts were built under H-F’s two entrances at Governors Highway, and also at the school’s pond at the South Building. Another culvert was built under Governors Highway at the north parking lot.
A 48-inch pipe was constructed between the pond and Governors Highway. It replaces a 12-inch pipe that was not capable of handling water from the pond following heavy rains. That led to repeated flooding, especially to homes lying just south of the high school’s North Building.
MWRD engineer Justin Kirk led a Friday tour of the Cherry Creek project area. He said MWRD — which oversees the treatment of wastewater in much of the Chicago area — included Cherry Creek in a detailed watershed plan that, in part, focused on areas that were prone to chronic flooding.
Planning for the project began in earnest after a cost-benefit study showed that work along Cherry Creek would eliminate flooding in nearby homes, Kirk said. In early 2016, the MWRD entered into an intergovernmental agreement with the village of Flossmoor and H-F High School District 233.
Cherry Creek enters H-F property after crossing Kedzie Avenue from Coyote Run Golf Course. It travels underground to the pond and then enters the pipe to Governors Highway, which in the past has been a significant choke point. The creek continues in a pipe underneath Governors Highway, where water continues north in a culvert on the east side of the road.
The water then travels back across Governors Highway through the culvert at H-F’s north parking lot. After that, the water continues along the creek in the area just behind Calvary Assembly of God Church. That’s where the creek is being rebuilt with the J-hook and riffle stone, and the MWRD project area ends just to the north.
Construction crews this summer also built a swale between H-F’s North Building and Governors Highway. Following heavy rains, overflow water from the new 48-inch pipe will be diverted into the swale, Kirk said.
“Most of the time we expect that it will be dry,” he said.
Landscaping on both H-F property and in the area behind the church will begin this year. MWRD purchased 3.7 acres from the church and that area will be used for both the creek and water storage, Kirk said. MWRD will plant vegetation — trees, shrubs and grasses — in the rebuilt creek area that is best suited for effective water storage.
Flossmoor will eventually take over the land behind the church, Kirk said. The village and high school district will be responsible for maintaining the project area once MWRD and its intergovernmental partners sign off on the work.
After the project is completed, 16 homes in Flossmoor can be taken off federal flood plain maps. When that happens, the owners of those properties will no longer have to purchase costly flood plain insurance.
Awad said MWRD agreed with the high school district to perform the bulk of the Cherry Creek work after H-F’s regular academic year ended. Still, he said, a number of students were attending summer school during construction and other programs were being conducted at H-F.
“It was a challenge,” he said. “We knew we would have just eight weeks when Governors Highway would be closed. But we got it done.”