Introduction
The $4 billion Tunnel and Reservoir Plan (TARP), better known as “The Deep Tunnel,” is the Metropolitan Water Reclamation District of Greater Chicago's answer to water pollution and sewer backup problems in 52 municipalities in Cook County. Begun in 1975, and at one time the nation's largest municipal water pollution control project, it involves the construction of 109 miles (174 kilometers) of tunnels 9 to 33 feet (3 to 10 meters) in diameter excavated in dolomitic limestone bedrock as much as 350 feet (107 meters) below the surface. These tunnels will collect combined sanitary and storm sewer flows and convey them to surface reservoirs, such as quarries, for storage until the area's water reclamation plants can treat and safely discharge the effluent.
Reason to Be Selected
The success of the TARP is evident by the dramatic improvements in the water quality of the Chicago River, the Calumet River and other waterways. Game fish have returned, marinas and riverside restaurants abound, river recreation and tourism are booming, and waterfront real estate values have skyrocketed as Chicago area residents see the river system as a major asset rather than an embarrassment.
Highlights:
Majewski Reservoir: The 350-million-gallon Majewski Reservoir was completed by the USACE in 1998 at a cost of $45 million. Since its completion, the Majewski Reservoir has yielded over $500 million in flood damage reduction benefits to the three communities it serves.Details
Thornton Composite Reservoir: The Thornton Composite Reservoir was constructed in two stages. The first stage, a temporary 3.1 BG Natural Resources Conservation Service (NRCS) flood control reservoir called the Thornton Transitional Reservoir, was completed in March 2003 in the West Lobe of the Thornton Quarry. This reservoir provides Thorn Creek overbank flood relief for nine communities and has captured over 42 BG of flood water during 61 fill events (as of July 2019).
Recommended
McCook Reservoir: McCook Reservoir Stage 1 was completed in 2017 and provides 3.5 billion gallons of storage. Stage 2 will be completed in 2029 and provide 6.5 billion gallons of storage. The McCook Reservoir will provide more than $143 million per year in flood damage reduction benefits to 3,100,000 people in 37 communities, along with a total capacity of 10 BG.
The second stage is a permanent combined NRCS/CUP reservoir, called the Thornton Composite Reservoir, constructed in the North Lobe of the Thornton Quarry. The Thornton Composite Reservoir currently provides 7.9 BG of CSO storage. In operation since the fall of 2015, the reservoir provides benefits to 556,000 people in 14 communities.
Conclusions
In its first year of operation, it captured more than 4.5 BG of polluted water. At the end of 2020, the temporary 3.1 BG Thornton Transitional Reservoir will be returned to the quarry and all of the flow will be held in the Thornton Composite Reservoir.
| Lat: | 41.39 |
| Lng: | 87.34 |
| Type: | |
| Region: | NorthAmerica |
| Scale: | Region |
| Field: | Infrastructure |
| City: | Chicago |