After winning a fight to close the uppermost lock on the Mississippi River by next June, advocates are now pressing the U.S. Army Corps of Engineers to further limit operations at the next two locks downstream to block invasive carp from spreading upstream.

The corps has proposed reducing hours at the two Twin Cities locks from the current 19 hours a day during the navigation season to 10. The two locks are Lock and Dam No. 1, or the Ford dam, and the Lower St. Anthony Falls Lock and Dam.

The corps is planning to reduce hours because the congressionally mandated closure of the Upper St. Anthony Falls lock is expected to eliminate shipping traffic at the next two locks downstream. But restrictions at those two locks will hamper recreational boaters and tour operators.

“I fear we will lose the opportunity to protect a unique reach of the river for this and future generations,” John Anfinson, superintendent of the National Park Service unit for the Mississippi in the Twin Cities area, wrote in a public comment period that ended this week.

The Stop Carp Coalition of 10 environmental and conservation groups is pushing for the Ford lock to be open to commercial vessels by appointment only. It wants the lower St. Anthony lock limited to opening only at set times.

Besides blocking carp from migrating into the Mississippi’s northern waters, advocates for stricter hours say keeping the carp out of the Mississippi gorge above the Ford dam is critical to boater safety. Rowers practice out of college or recreational boathouses in the gorge between the locks. Schoolchildren paddle voyageur canoes there, but that program has stopped using the locks due to the threat of the jumping carp, known for their ability to leap several feet into the air.

“If one child is hit by a silver carp in this pool, the entire program will end,” Anfinson wrote. He called the issue “of paramount concern” to his agency.

But further lock restrictions are opposed by tour operators.

Dan Dickinson, who pilots the Magnolia Blossom from the Watergate Marina in St. Paul, said he’d prefer at least a day shift opening for the Ford lock, with hours until 10 or 11 p.m. for evening cruises.

If the locks are cut to an appointment-only basis, Dickinson said, “People aren’t ever going to use the locks again. You might as well close them.”

Another excursion company operates from Bohemian Flats between the two locks.

The issue arises even as it’s uncertain when the Upper St. Anthony Lock will close for good. Some want it to remain closed when the ice melts next spring, but barge shippers hope to keep operating as long as possible before the June 10 federal closure deadline.

The corps hours reduction proposal caught some public officials and advocates off guard. Minneapolis Mayor Betsy Hodges asked the corps to extend its comment period and hold a public hearing. The corps denied both requests.

Concern over the northern carp migration rose in July after a bighead and a silver carp were netted in Cottage Grove, their furthest confirmed sighting near the Twin Cities area. They were netted between the Hastings and Ford lock and dams.

Anfinson said that limiting Ford to appointment-only stet would make the use of chemical or other carp barriers more feasible than more frequent locking.


Twitter: @brandtstrib