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Rising Kinnickinnic temperature may negatively impact wildlife

April 2, 2009

The upper and lower dams on the Kinnickinnic River have long been the subject of debate over whether they provide vital power to the city or damage the River’s water quality.

The Kinnickinnic, or Kinni, as it is locally known, is regarded nationwide as one Wisconsin’s, and even one of the nation’s premier trout waters. 

Members of the local Kiap-TU-Wish Chapter of Trout Unlimited question the ability of the city to keep the dams along with a healthy lower river.

“As the city grows, the impact on water temperature will continue to increase, on top of the temperature pressures the dam currently puts on the system,” Gary Horvath, secretary of the Kiap-TU-Wish Chapter, said.

The dams retain the flowing water, allowing it to warm in summer, and cool in winter. Brown trout, the dominant species in the Kinni, have a maximum sustained temperature tolerance of between 65 and 68 degrees Fahrenheit.

Kent Johnson, a Kiap-TU-Wish member, does extensive temperature monitoring on the River. Monitoring stations are set above the first dam at the Division Street Bridge, as well as just off of Quarry Road on the northern edge of town. On the lower River, below the dams, the stations are located near the mouth of Rocky Branch and underneath the County Road F Bridge, Johnson said.

“During the warmest months, there is typically a five degree increase from Quarry Road to the Rocky Branch site. The lower River trout usually begin to sweat for a little while,” Johnson said.

The winter water temperatures may also affect the reproduction of the trout below the city. 

“They’re fall spawners. Once the eggs are in the redds, they’re completely vulnerable,” Johnson said.  “In winter, the upper River is typically three to four degrees warmer.”

The first dam was installed on the Kinni in 1865. The upriver power plant was built in 1900.  This plant currently produces up to 250 kilowatts per hour, while the lower plant produces 125 kilowatts per hour when operating at peak efficiency, according to the River Falls Municipal Utilities Web site.

That is enough energy to power nearly 260 households, according to U.S. Department of Energy data.

The amount of revenue generated by those who come to River Falls to use the Kinni is something often overlooked. 

“The economics of keeping the dam running when compared with what the River provides the city is something I’d like to see,” Horvath said.

Data regarding the percentage of power the plants produce for River Falls is currently unavailable. 

Representatives from RFMU were unavailable for comment. 

Former UWRF student and avid trout angler Brian Swenson said he sees a difference in the upper and lower River trout populations.

“Upstream the fish are everywhere. Below the dams, there are definitely fish, but the numbers are noticeably fewer,” Swenson said.

The upstream portion of the Kinni harbors 8,000 to 9,000 trout per mile, whereas the lower River has a population of roughly 3,000 trout per mile, less than half that of the upper River.

The City of River Falls, along with Trout Unlimited, the Wisconsin DNR and UWRF began studying ways to improve the upper, Lake George impoundment several years ago.

According to the City, in 2002, a DNR grant was awarded to the City to fund studies determining what action should be taken regarding the lake and its dam.

Total removal of the dam would take three to six years, so other options were sought. 

“A wetland improvement was decided upon where the channel would be separated from storm water ponds. It would’ve sped up the flow of water through the dam. But the City had a grant killed two years ago from the EPA,” Horvath said.

Though the Kinni currently boasts a healthy trout population in its lower portion, Horvath noted it is a unique situation. 

“River Falls is the only city in Wisconsin with a population of 10,000 or more where below the City the water is still trout water,” Horvath said.  “Is [the dam] sustainable if you also want to sustain the lower River?”