Drought won`t affect Chicago River much after all - Boston News, Weather, Sports | FOX 25 | MyFoxBoston

After months of severe drought, the water level of Lake Michigan has fallen slightly below that of the Chicago River.

There were rumors that the drought could create problems in the Chicago River. In fact, some said it could reverse the flow. But, as FOX 32's Mike Flannery found out, though the low levels are unusual, it isn't unheard of and it's happened before.

The surface of the big lake is normally about 200 higher than the river, which is why a lock was built to lift or lower boats passing from one to the other. Now, the seawall plays an unusual role: keeping dirtier Chicago River water from leaking into the much cleaner lake--the source of drinking water for millions.

In an operations center where Water Reclamation District engineers monitor and control flows between Lake Michigan and three local waterways, computer screens told an unusual story. The surface of the Chicago River was a tiny bit higher than the surface of Lake Michigan: 6/100ths of an inch, to be exact.

But, they said, very little water from the polluted river would end up in the lake, thanks largely to a network of recently modernized seawalls and gates.

The U.S. Army Corps of Engineers operates the huge lock near Navy Pier. The Corps said it was prepared to limit lock operations, in order to reduce any flow of river water into the lake. Engineers are not expecting problems. The Corps' hydrological forecasters expect the level Lake Michigan to rise several inches by summer, restoring a more normal balance to the local ecosystem.

The lake's level was even lower in 1964 than it is now, according to the operations manager for the water reclamation district. It does put a spotlight on how dependent this part of the country is on Lake Michigan.