11 a.m. Storm Update: MWRD’s TARP systems manages heavy rainfall

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) has been working around the clock to capture billions of gallons of stormwater that have fallen across Cook County during recent storm events.  According to the National Weather Service, the latest storm event had rainfall amounts that ranged from 0.7 inches at O’Hare International Airport, 1.7 inches at Midway International Airport, and nearly 2 inches in southern Cook County. Due to recent rain events, the MWRD TARP systems are holding nearly 9 Billion Gallons of stormwater, which is enough water to fill 13,600 Olympic-Size swimming pools. 

The massive TARP infrastructure protects the region’s water environment and mitigates sewer overflows and basement backups for more than 3.71 million people served by combined sewer systems in the Chicago area. TARP consists of three reservoirs and four tunnel systems. As of 11 a.m., there had been no combined sewer overflows in Chicago area waterways. Here is the breakdown:

• The McCook TARP system is approximately 92 percent full, holding 4.7 billion gallons. The McCook Reservoir has 3.5 billion gallons of capacity and serves central Chicago and 36 municipalities covering 252 square miles on the Des Plaines and Mainstream Tunnel Systems. 
• The Calumet TARP system is approximately 48 percent full, holding 4.1 billion gallons. The Thornton Composite Reservoir has 7.9 billion gallons of total capacity, including 4.8 billion gallons of combined sewer capacity, serving 91 square miles on the Calumet Tunnel System, covering the South Side of Chicago and 13 south suburban municipalities.
• Majewski Reservoir is empty. The Majewski Reservoir has 350 million gallons of total capacity, serving 11 square miles on the Upper Des Plaines Tunnel System, covering Arlington Heights, Des Plaines and Mount Prospect. 

Before storms, the MWRD lowers the levels of the Chicago Area Waterway System by diverting more water at its Lockport Powerhouse to provide added capacity in local waterways. The MWRD called for an overflow action alert Sunday, urging area residents to conserve water to provide more capacity in sewers and local infrastructure to take on the influx of rain.

“Our staff is managing billions of gallons of water at our seven water reclamation plants and through our Tunnel and Reservoir Plan which is operating to protect our water environment and mitigate flooding,” said MWRD President Kari K. Steele. “During rain events, we encourage everyone to conserve water, when possible, to create more capacity in our systems.” 

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Applications are now open for municipalities and local government entities to partner with the MWRD on four stormwater management programs designed to mitigate community flooding throughout Cook County. More information can be found at mwrd.org/stormwater/partnerships.

Visit these links for more information about the MWRD, Stormwater Management, TARP and how to help reduce flooding and protect water quality.

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