Shell Rock River Watershed District leaders and other officials from the city ceremonially flipped the switch Tuesday to turn on what is the first of a potential series of electric fish barriers planned throughout the district.

The barriers are part of a project to limit carp in local lakes and to improve water quality, said watershed technician Andy Henschel.

On Tuesday, district leaders focused on the fish barrier at the outlet of Mud Lake along Freeborn County Road 46. The barrier at this outlet — which is Shoff Creek flowing east through Shoff Park and entering Dane Bay — will begin to directly impact water quality in Pickerel and Mud lakes farther downstream, Henschel said.

The district also hopes to move forward with placing barriers at three places along Fountain Lake: Wedge Creek, the creek connecting to Lake Chapeau (sometimes called White Lake) and the channel outlet underneath Bridge Avenue, he said. However, the funding for those barriers is pending in the Legislature.

Henschel said the ultimate goal of the district is to have clean lake water. An initial step to achieve that is through treating rough fish.

According to the Watershed District’s Web site, in the last four years Pickerel Lake has had water clarity less than 6 inches by mid-June. Carp contributes in large part to this problem, as they uproot the aquatic vegetation and stir bottom sediment.

“This re-suspends phosphorous into the water column where the algae uses [sic] this phosophorous to explode into large algae blooms, thus making the lake look like pea soup,” the Web site states.

The Minnesota Department of Natural Resources estimates there are between 1,000 and 1,500 pounds of carp per acre of Pickerel Lake.

Henschel said the Watershed District officials think that Pickerel and Mud lakes are acting like carp nurseries that transport carp to the other lakes in the district.

To help begin solving some of these problems, the district replaced three culverts at the Mud Lake outlet with 62- and 42-inch culverts that have four three-inch metal bands. The barriers feature electric pulsators, which create an electric field for when the fish are going through.

The farther the fish swim through the culvert, the more of a shock they receive. The shock can be so severe that it can paralyze the fish and send it downstream.

A second step to getting clean water will come later this fall or winter with a chemical treatment, Henschel said. This will kill the rough fish. The lakes will be restocked with game fish.

After the fish kill happens, that’s when people will start noticing a larger difference in water quality, he said.

Though a major difference will not be noticed with the initial Mud Lake barrier, it is one step of several to completely turn around the water quality of the district’s lakes.

The total cost of the Mud Lake fish barriers was $265,000, Henschel said. Out of that total, $19,000 came from a DNR grant, and the district has applied for another $100,000 grant.

Henschel said someone from the Shell Rock River Watershed District will check the computer system that controls the barriers probably once every two weeks. Because the barrier is on DNR-owned property, DNR officials will probably check on it as well.