MINNEAPOLIS -- A proposal to close the Upper St. Anthony Falls Lock and Dam as a way of fending off invasive Asian carp, is picking up steam on Capitol Hill.

It's one of the provisions of a Water Infrastructure bill approved by a committee on Thursday in the U.S. House. Several members of the Minnesota delegation support the idea.

The idea has progressed even further in the Senate, after Sen. Amy Klobuchar inserted it as an amendment to the Water Resources Development Act that passed in May.

"It's the most effective way to keep Asian carp from moving upstream," Steve Frohnauer, of the Minnesota Department of Natural Resources, told KARE.

The DNR has hired a company to design an electrical barrier downstream at the Lock and Dam Number 1 near the Ford plant in St. Paul. The Coon Rapids Dam upstream is also being renovated, in part, to create another line of defense.

But closing the Minneapolis lock is viewed as more of a sure thing, according to Frohnauer.

"The St. Anthony Falls historically provided a natural barrier to invasive species, but the lock and dam system gives them away around the falls."

Lock and Dam function

The falls also created a natural barrier to boats, which is why the U.S. Army Corps of Engineers built the lock and dam system, to aid with navigation in the upper Mississippi River.

"A lot of times the locks and dams are known as the stairway of the Mississippi." Michael DeRusha, the lockmaster for the Corps of Engineers St. Paul District, told KARE.

"If we were to shut down, they would no longer have any vessels going through here."

Vessels at lower elevations, below the dam, enter the lock, which is an enormous concrete enclosure. Huge steel doors close behind them, allowing the chamber to slowly fill with water from above the dam.

As the lock fills the water lifts the boats up to the level of the water above the falls, at the higher elevation. While any size craft can go through the lock, the commercial value is derived from the huge barges that pass through it.

"Every loaded barge is equal to 56 semi truck loads of material, which, if they're not going through here, they're on our roadways," DeRusha explained.

If the Upper St. Anthony Falls lock and dam were to be closed to barge traffic, Northern Metal Recycling in Minneapolis would have to make other plans for shipping scrap iron it now sends downstream on the river.

A neighboring business, Aggregate Industries, would need to find other ways to bring in rock, gravel, sand and cement it now receives on barges in the Minneapolis upper harbor.

Representatives of those companies did not return calls to KARE on Friday. The legislation pending in Washington has no provisions to compensate them for the cost of a move or the added expense of trucking material.

Looming Carp Risk

Advocates of closing the facility say the cost to the Minnesota economy would be much more far reaching if the Asian carp were to establish a foothold in the recreational fisheries in central and northern Minnesota.

"Tourism and recreation industry in the upper Mississippi water shed is vast," Whitney Clark, executive director of Friends of the Mississippi River, told KARE.

"There's a lot of jobs. There's a lot of business associated with that."

Those species are prevalent through much of the Mississippi River south of Minnesota, and the discovery of an Asian carp carcass in Winona created more of a sense of urgency for sport fishing industry, regulators and environmentalists.

Clark said that silver carp and the three other species known as Asian carp don't just into the boats of shocked fisherman. They also wreak havoc on the ecology of the river.

"The reason that they're feared from an ecological perspective is that they out compete our native fish. When they do that, they disrupt the whole balance of our ecosystem," Clark explained.

"The health of our lakes and our rivers and the ecology of our rivers is worth something too, beyond just the economic value and the tourist value."

Metropolitan Council Study

A study commissioned in 2012 by the Metropolitan Council found that 765,000 tons of goods were shipped through the upper lock the preceding year. The report estimated that closing that part of the navigable channel would result in an additional 21,316 truck trips.

The report estimated the Minnesota economy would lose $21 million over the next 28 years as a result of shifting that traffic from the river to the roadways. But, the report concluded, that's relatively insignificant for a state that has $494 billion in economic output each year.

The report did predict, however, that the impact would be significant on the Minneapolis businesses that rely on the barge traffic currently and their employees.

It also said the loss of space currently used for storage of fertilizer and coal in the Upper Harbor may create supply chain problems in some sectors of the state's economy.

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