(2 of 2) If the Asian carp do take over, it would most likely be
through the Chicago Sanitary and Ship Canal, the only connection
between the Mississippi River system and the Great Lakes. The
canal is the Thermopylae in the war against the carp, and the
Army Corps of Engineers has done its best to close off the pass,
installing underwater electrical barriers about 30 miles (48 km)
downstream from Chicago. The barriers send a small jolt of juice
across the water, enough to repel any approaching carp while
allowing free passage to ships and sewage. (The canal carries
Chicago's treated waste.) The corps is also looking into backup
measures, like an additional barrier that uses acoustics and
bubbles to dissuade incoming carp, as well as longer-term
strategies, so officials believe they can defend the Great
Lakes. "I feel confident that working together with other
agencies, we can do this," says Colonel Vincent Quarles, the
commander of the Chicago district of the corps. But some
environmentalists and politicians