Cal-Sag Channel Watershed
The Calumet-Saganashkee (Cal-Sag) Channel Watershed is located in southwestern Cook County and drains an area of 151 square miles that includes 27 communities. The area north of the Cal-Sag Channel is drained primarily by the East and West branches of Stony Creek, which both discharge into the Cal-Sag Channel. Several smaller streams discharge westward into the Illinois & Michigan (I&M) Canal or southward into the Cal-Sag Channel. The area south of the Cal-Sag Channel has various tributaries, such as Tinley Creek and Mill Creek, that flow north to the Cal-Sag Channel. Other tributaries flow west to the I&M Canal, and south west into Will County.
The MWRD has more than 240 active and complete stormwater projects throughout Cook County. These improvements include regional and local stormwater projects, green infrastructure, Space to Grow, and voluntary flood-prone property acquisitions. To see what projects are active and complete in your watershed, see the map below.
In conjunction with local municipalities, the MWRD operates three regional reservoirs located in this watershed, providing 377 acre-feet (122.8 million gallons) of stormwater detention.
- Bedford Park Reservoir - Bedford Park, IL - 188 acre-feet
- Melvina Ditch Reservoir - Burbank, IL - 165 acre-feet
- Oak Lawn Reservoir - Oak Lawn, IL - 24 acre-feet
The following MWRD infrastructure are also located within this watershed. Below, you can download a map of these facilities located throughout Cook County.
Tunnel and Reservoir Plan
The northernmost tip of this watershed is served by the Mainstream tunnel system and McCook reservoir, while the easternmost side of the watershed is serviced by the Calumet tunnel system and Thornton composite reservoir. The tunnels and reservoirs were constructed as part of the Tunnel and Reservoir Plan (TARP).
Wastewater in this watershed is primarily treated by the Calumet Water Reclamation Plant, which can treat up to 430 million gallons of wastewater per day. The northern tip of the watershed is served by the Stickney Water Reclamation Plant, while the western most edge of the watershed is served by the Lemont Water Reclamation Plant.
Chicago Area Waterways
The Cal-Sag Channel was constructed in 1922 and is the primary receiving waterway for this watershed. It connects with the Little Calumet River in Calumet Park and flows to the Chicago Sanitary and Ship Canal in Lemont.
These rivers and canals make up a part of the Chicago Area Waterway System (CAWS). The CAWS provides drainage for much of the Chicago region and connects the Great Lakes with the Gulf of Mexico. The MWRD controls the flow and water level in the CAWS using control structures to both prevent discharges into Lake Michigan and reduce the risk of overbank flooding. These structures are located along Lake Michigan and at the southernmost point of the CAWS, the Lockport Powerhouse.
The MWRD also monitors the water quality of these waterways. In this watershed, three Sidestream Elevated Pool Aeration (SEPA) stations were installed along the CAWS to improve the water quality and support natural habitats for fish and other aquatic life.