The Arrowhead Lake Flood Control project will increase 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 restores and improves forest preserve amenities at Arrowhead Lake.
As part of the project, the existing dam and outlet culvert will be 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 will be resurfaced with new asphalt. An eroded bank at the south side of Arrowhead Lake will be regraded and restored with native seed, plant plugs and trees.
The Arrowhead Lake Flood Control project will increase flood storage and remove 70 structures from the FEMA Zone A flood plain in Palos Heights, where flood insurance is mandatory due to the area being inundated by a 1-percent-annual-chance of a flood event. The project will also provide new trails and recreational benefits for Forest Preserve users. Long-term maintenance responsibilities for the site have been 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 in April 2019. Pedestrian access to the FPCC trail system was being maintained during construction through a series of temporary bypass trails. Work was completed in late 2019.