The Arrowhead Lake Flood Control project increased floodwater storage in Arrowhead Lake, 7016 W. 135th St., in the Forest Preserves of Cook County (FPCC) by replacing an existing dam and raising an existing bicycle trail on the north and east sides of the lake in unincorporated Cook County near Palos Heights. In addition to removing structures from the 100-year floodplain, this collaborative effort between the MWRD, FPCC, City of Palos Heights and Cal-Sag Watershed Planning Council worked to restore and improve forest preserve amenities at Arrowhead Lake.
As part of the $1.6-million project, the existing dam and outlet culvert were demolished and replaced with a new concrete dam, outlet culvert and spillway. The additional stormwater storage is 40 acre-feet or 13,034,057 gallons. Approximately 2,675 feet of a multi-use pedestrian path was also resurfaced with new asphalt. An eroded bank at the south side of Arrowhead Lake was regraded and restored with native seed, plant plugs and trees.
The Arrowhead Lake Flood Control project increases flood storage and removes 70 structures from the FEMA Zone A flood plain in Palos Heights, where flood insurance was mandatory due to the area being inundated by a 1-percent-annual-chance of a flood event. The impacted residential area is located approximately between Harlem Avenue to the west, Edgewood Road to the north, Forestview Road to the east, and 131st Street to the south. The project also provides new trails and recreational benefits for Forest Preserve users. Long-term maintenance responsibilities for the site were defined through an intergovernmental agreement between the MWRD, FPCC and City of Palos Heights.
Officials from the MWRD, City of Palos Heights and Forest Preserves of Cook County (FPCC) gathered in the Forest Preserves to formally kick off the Arrowhead Lake project on April 30, 2019. Work and trail upgrades were completed in late 2019. On March 11, 2022, the FEMA Flood Insurance Rate Map was officially revised, removing the 70 homes from the FEMA Zone A floodplain in the City of Palos Heights. Officials plan to commemorate this achievement during a ribbon cutting event planned for May 3, 2022.