DNA testing could hint at Coon Rapids Dam’s status as Asian carp barrier
$16 million solution for dam has been proposed
by T.W. Budig
ECM Capitol Reporter
The importance of the Coon Rapids Dam in the state’s Asian carp prevention efforts should soon become clearer. Recently, a total of 50 water samples, half from above the century old dam, half below, were taken and are now being analyzed for the presence of Asian carp DNA.
Should Asian carp DNA be discovered above the dam, what happens then?
“That’s a good question,” said Department of Natural Resources specialist Tim Schlagenhaft, who has been deeply engaged in the state’s Asian carp efforts. “I think it’s in the back of people’s minds.”
First, Schlagenhaft cautions against overreacting to the DNA testing results, saying the technology is new and possibly even traveling birds can transport Asian carp DNA from place to place by means of their droppings.
The final determination of the presence of Asian carp is bringing one to the surface, he explained.
There are other physical barriers on the Mississippi River to the north that might serve to halt the invasive specie should the Coon Rapids Dam have been passed, Schlagenhaft said.
But the Rum River would be open to Asian carp infestation, he said, because the dam on the Rum River in downtown Anoka is not considered a viable fish barrier.
DNR officials talk of getting the results of the latest round of DNA water sampling analyze back in two to four weeks.
Currently, there is a $16 million proposal underway to upgrade the Coon Rapids Dam into a stouter fish barrier. The DNR this month is expected to send out a proposal for engineering services for the Coon Rapids Dam upgrade.
Engineering, dam gate selection and fabrication, the hiring of a contractor is expected to take place next year with construction in 2013-14.
The Coon Rapids Dam seeps water like all dams, explained Jason Boyle, a DNR dam specialist, but it’s unlikely Asian carp can go under it — turbidity at low water would likely betray such an opening.
It would be difficult to speed-up the dam upgrade, as materials have to be ordered and the project is extensive, involving the building of coffer dams to divert the river away from sections of the dam, Boyle explained.
It’s believed an upgraded Coon Rapids Dam would make for a highly effective fish barrier — not 100 percent effective, but close, DNR officials said. Its benefit could go beyond preventing the spread of Asian carp.
According to the DNR, for 10,000 years St. Anthony Falls in Minneapolis had served as a natural fish barrier for native fish on the Mississippi River, with 123 fish species known to have lived below the falls, only 64 species above.
Construction of a lock system at St. Anthony Falls in the 1960s for river traffic breached this churning barrier.
Recent DNA testing suggests that Asian carp — carp known for their massive size, big appetites, and with the silver Asian carp disturbing habit of leaping into the air when disturbed and smacking boaters — have likely penetrated the St. Croix River and perhaps come up the Mississippi River as far the Ford Dam in St. Paul.
Commercial fisherman, fishing below the Ford Dam in low water, failed to catch any Asian carp, suggesting that if the carp is present in that area, the numbers are very low, said DNR Invasive Species Specialist Luke Skinner in an email.
And, too, Asian carp simply are difficult to catch, the DNR notes.
Beyond upgrading the Coon Rapids Dam, a state action plan calls for the federal government to grant state officials emergency powers to close the locks at the Ford Dam and St. Anthony as a means of halting the spread of Asian carp.
Current federal law does not allow the Army Corps of Engineers authority to close the locks to serve as barriers to invasive species, only for reasons tied to navigation.
Not All Agree
Not everyone thinks closure is a thoughtful solution.
“In trying to solve a problem, you’re creating another,” Dick Lambert, director of the Minnesota Department of Transportation’s Ports and Waterways Section, of closing the locks. An enormous amount of material like gravel currently travels by barge to industrial sites in Minneapolis, Lambert said.
Closing the locks could result in as many as 500 additional trucks a day traveling Highway 61 and I-94, adding to congestion, adding exhaust to the air. “We don’t feel this makes a lot of sense,” Lambert said.
According to the U.S. Army Corps of Engineers, almost 1,500 commercial boats — a designation including tows, passenger, dry cargo, liquid cargo — went through the Upper St. Anthony Falls lock last year.
Some 2,450 recreational boats also went through the lock.
All told, some 71,471 excursion boat passengers and thousands more in recreational crafts passed through the lock last year.
So did about 1 million tons of shipping.
The reason few people know the extent of river-borne commerce, Lambert said, is because it takes place with minimal impact.
Still, the Minneapolis City Council recently indicated a willingness to see the St. Anthony locks closed, but also looks for funding for redeveloping its industrial riverfront.
State funding may be available for the eventual placement of a bubble barrier at the Ford Dam lock or at the mouth of the St. Croix River, Schlagenhaft explained.
These barriers, which use a curtain of bubbles to discourage the movement of fish, would serve to slow down the progress of Asian carp. But they’re not effective enough to halt it, he said.
As for the Minnesota River, the DNR is probably looking more at managing Asian carp in that river than preventing their entry, Schlagenhaft said.
With a broad floodplain and other characteristics, the Minnesota River is a difficult river to protect from Asian carp, he said.
Democratic Gov. Mark Dayton, other state and federal officials, met at the State Capitol on Nov. 18 to discuss and further hone the state’s response to Asian carp. Dayton at one point expressed frustration over talk of studies that may take months or years to complete, and urged a quicker, more immediate response to the Asian carp threat.
“By the time you prove these tests the carp will be in Canada,” he said.
The governor specifically pointed to the construction time line envisioned for the Coon Rapids Dam project as too long.