The Metropolitan Water Reclamation District of Greater Chicago reported two separate stormwater storage developments this week.

MWRD and the Chicago Department of Water Management showcased a completed underground storage tank on Maypole Street July 7 and marked the start of construction on a second tank on LeMoyne Street. The two tanks, part of a project called Wing Storage, will provide nearly 1.7 million gallons of combined stormwater storage across the 28th, 29th and 37th wards, protecting more than 2,900 homes, businesses and other buildings. DWM and MWRD are sharing the cost of the $12 million project, with MWRD contributing up to $6 million.

Separately, MWRD's Tunnel and Reservoir Plan, known as the Deep Tunnel, neared capacity after storms brought 8 to 10 inches of rain to parts of the region between July 2 and July 4. The McCook Reservoir, located in Bedford Park, which serves central Chicago and 36 municipalities, reached 98% full and 3.4 billion gallons of water as of 9 a.m. Monday, MWRD reported. It hit full capacity  onJuly 3, the sixth time this year, compared with five times total between 2021 and 2025.

The Thornton Reservoir, located near South Holland, serving the South Side and 13 south suburban municipalities, reached 94% full and 7.3 billion gallons the same morning, the fullest it has been since opening in 2015, MWRD said. It warned that if Thornton reaches capacity, south suburban communities could face a higher risk of overbank flooding.

The district is dewatering the reservoirs to prepare for rain forecast for Thursday, and that if the Deep Tunnel reaches capacity, sewers will overflow into surrounding rivers, MWRD spokesperson Patrick Thomas said, according to a report by Block Club Chicago.

MWRD is currently excavating a second stage of the McCook Reservoir that will add 6.5 billion gallons of storage capacity, bringing the reservoir's total to 10 billion gallons. The district said the project's completion date is now estimated at Dec. 31, 2032, delayed from earlier projections due to a slowdown in demand for the stone being mined during construction, according to MWRD.