Winter was rough, and summer isn’t starting out all that nice, either, for Chicago.
Last night’s wild storms dumped huge amounts of rain on the city and its primary means of drainage: The Chicago River.
One of our downtown spies sent in this photo taken this morning (July 1, 2014). You can see the construction pits at Wolf Point are flooded, the Chicago River has risen all the way up to the construction fencing, and at the eastern edge of the property, only a bit of sheet piling separates the risen river from the flooded footprint of the west tower. Whether that is rainwater in the pits, or river water is hard to tell. Zooming in shows that the water level in the construction zone is somewhat lower than the level of the river, but there’s no way we can tell what’s runoff and what’s seepage.
Right now, pump and their big hoses are trying to empty out the waterlogged area.
The Metropolitan Water Reclamation District’s gauges recorded 1.45 inches of rain in central Cook County, but 3.08 inches north, and 1.63 inches south. That’s enough water inland that the MRWD had to reverse the river’s reversed flow and let it all flow along its natural path, out into Lake Michigan.
When the Chicago area waterway levels are higher than Lake Michigan and certain elevations are reached, the MWRD opens control structures to move as much water as possible out of the system. This provides overbank flooding protection as well as more capacity for stormwater. The gates at Wilmette were opened at 11:23 p.m. and closed at 5:50 a.m. The gates on the Chicago River Controlling Works downtown were opened at 12:58 a.m. and closed at 7:10 a.m. The amount of water released to Lake Michigan will be estimated in the weeks following this storm event, after operational issues have been addressed.
The Tunnel and Reservoir Plan (TARP) system is operational and working as designed. TARP is comprised of 109 miles of tunnel and two reservoirs. The Mainstream Tunnel, which is 40.5 miles long and can hold 1.2 billion gallons, was full at 11 p.m. The Calumet Tunnel, which is 36.7 miles long and can hold 630 million gallons, was full at 2:30 a.m. The Des Plaines Tunnel, which is 25.6 miles long and can hold 405 million gallons, is currently full. The Kirie Tunnel is 6.6 miles long, can hold 70 million gallons and was filled by 1 a.m. The entire tunnel system holds 2.3 billion gallons. The Majewski Reservoir, which can hold 350 million gallons, is in operation and receiving flow.