Chicago's Deep Tunnel Near Capacity After Historic Rainfall

After a soggy start to summer, Chicago's Deep Tunnel is nearly full as the Thornton Reservoir hits 94% capacity (7.4 billion gallons)—the fullest it's ever been—while the McCook Reservoir is also full at 3.6 million gallons, signaling potential river flooding in the south suburbs if capacity is exceeded; the McCook expansion will add 6.5 billion gallons by 2032, and rainfall totals across the region have been record-setting (Midway 11.43 inches since June 1; O’Hare 8.56 inches), with a drier stretch forecast before more storms later in the week.