Updated 04/18/13 – 12:26 p.m.
CHICAGO (CBS) — The huge amount of rain over the past 24 hours has filled the large underground flood control system known as Deep Tunnel.
The Metropolitan Water Reclamation District’s Tunnel and Reservoir Project (TARP), better known as “Deep Tunnel,” was designed to absorb and store 2.3 billion gallons of excess storm water before it reaches local waterways.
While the Tunnel has been filled to capacity before, it is rare. It’s happened only three or four times in the past four years. The last time was in 2011.