Pumps Start Removing Water From Chicago Tunnel System

Workers on Monday began slowly pumping water out of tunnels under the downtown business district that had been flooded a week ago, when the Chicago River gushed through a hole in a tunnel wall.

Pumping had to proceed carefully--at about 4,800 gallons per minute--to prevent risking further damage to the tunnel walls and basements as the pressure and weight of the water was removed from waterlogged structures.

Two downtown landmarks--City Hall and Marshall Field’s department store--were open Monday for the first time in a week. Both still had water in their sub-basements.

Taking silent notice of the flood, the mannequins in the department store’s windows held mops.

The Chicago Board of Trade, in one of the hardest-hit buildings, ran its futures and options markets on an abbreviated schedule, but said it would return to its normal schedule today.

The immediate danger of further flooding was over since crews during the weekend stopped up the riverbed hole. The flood brought the Loop to a standstill because the tunnels, once used for freight deliveries, house major electrical equipment and telephone cables.

The University of Illinois and the Federal Reserve Bank, in a joint report, estimated that the city lost $1.5 billion in business because of the flooding.

Experts said there was no way yet to determine tunnel damage. The risk of any part of the tunnel collapsing is a “small risk, but it’s a risk we don’t want to chance,” Army Corps of Engineers Lt. Col. Randall Inouye said. “We’re going to continue this drawdown at a very slow rate.”

Engineers said the draining process could take 12 days.

The water was being pumped to street level--about 40 feet above the tunnels--and dumped into access shafts leading to the vast Deep Tunnel storm drain system.

Engineers began checking major intersections in the Loop for shifting and settling, which also is a danger to many of the city’s historic buildings, erected before modern construction techniques were adopted.

Police allowed deliveries to resume in the Loop, and a Commonwealth Edison Co. spokesman said some building owners were asking to have their power cut as new problems were discovered.