Corps delays turning on fish barrier
Electrified system to stop Asian carp
Posted on St. Paul Pioneer Press online on May 10, 2006
CHICAGO — The Army Corps of Engineers has postponed turning on an electrified barrier designed to keep pesky Asian carp out of Lake Michigan.
The barrier was scheduled to be activated Monday, but tests show the electric field has extended beyond its half-mile boundaries. Out of safety concerns, the Corps wants to fix the barrier before switching it on.
Chuck Shea, barrier project manager for the Corps, said the goal is to have the problem corrected next week.
Asian carp, which can grow to 100 pounds, can eat up to 40 percent of their body weight each day. Biologists worry that they could rob Lake Michigan's popular sporting fish of their food supply. That could create a problem for the commercial and sport fishing industry, which is worth an estimated $4.5 billion annually to the Great Lakes region.
The electric barriers are strung along the bottom of the Chicago Sanitary and Ship Canal.
While the new $9.1 million barriers are being fixed, a temporary barrier set up four years ago is being used. Shea said legislation is pending in Congress that would make the temporary barrier a permanent backup.
At their maximum power, the new barriers emit one volt of electricity per inch, and in the area where the electricity has overflowed, the voltage is about 100 times weaker.
Tests show that the voltage in the water beyond the barrier's boundaries isn't strong enough to electrocute a human being, but workers have to wear special life vests that keep their heads above water.
To keep sparks from flying between vessels in the electrified water, the U.S. Coast Guard has set up a barrier safety zone in which barges can't pass each other and must be tied together.
Fish farmers first used Asian carp to help keep their ponds clean, but flooding allowed them to get into the Mississippi River and eventually into the Illinois River.
In some areas of the Illinois River, carp account for 75 percent of the fish population.