Janesville55.1°

Continual flooding on Rock River raises frustration levels

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NEIL W. JOHNSON
August 23, 2010
— When it comes to conditions along the Rock River in recent years, locals don’t need a yardstick and rubber boots to determine the obvious.

It has been flooding. A lot.


In fact, data from the U.S. Geological Survey show that the Rock River at Afton has crested at 10 feet or higher seven times since 2006. Compare that to river levels at Afton in the 17 years preceding 2006, when water topped 10 feet just four times.


There’s an obvious explanation for some of the flooding: In the last few years, the Rock River basin has gotten a lot of rain.


Rainfalls near Janesville have topped 40 inches every year since 2006, and rains this year already total around 30 inches, the USGS reports. That’s something of an anomaly, considering that from 1990 to 2005, annual rainfalls topped 40 inches just three times.


No one who’s seen swamped waterfronts and roiling waters beneath the bridges at Memorial Drive and Centerway and Milwaukee streets needs a hydrology lesson on how rain affects the Rock River.


They’ve seen the water beast. Janesville is in the belly of it.


Hard times on the Rock

“It just seems like the entire last half-decade, the river has either been high water or it’s flooding,” said Joel Shapiro, president of the Rock Aqua Jays, Janesville’s amateur ski club.


Shapiro and the Aqua Jays are acquainted with the Rock River’s volatility. The club’s stomping grounds are on the river, between two manmade hydrologic bookends: The Indianford Dam, a spillway dam 10 miles north of Janesville that controls flows from Lake Koshkonong, an impoundment of the Rock River; and the Centerway Dam in Janesville, which is just south of the Traxler Park riverfront, where the Aqua Jays practice and perform.


Floods from heavy rains in July and August submerged parts of Traxler Park this summer, prompting canceled shows and scrubbed practices for the Aqua Jays. But for the Aqua Jays, the letdown of the year came earlier this month with the washout of the National Show Ski Association nationals, which were scheduled Aug. 13-15 at Traxler Park.


NSSA officials were forced to move the tournament to Wisconsin Rapids because of high water at Traxler Park. The move meant a potential $2.5 million blow to Janesville’s local economy through lost food, gas and hospitality revenue, Janesville Area Convention & Visitors Bureau has estimated.


Big flows

Unfortunately, Wisconsin’s stretch of the Rock River doesn’t operate according to economic development principles. It simply drains the water that pours into its 3,800-square-mile basin. And in recent years, the river has had a mounting surplus of water.


An example: the Rock River at Newville, a few miles upstream from the Indianford Dam. Of the 10 highest crests ever recorded there, eight have occurred within the last decade, the USGS reports.


Also at Newville, the USGS reports the river has reached flood stage multiple times in each of the last four years. All of that water flows south, past the Indianford Dam and through Janesville.


The Indianford Dam is owned by the Rock-Koshkonong Lake District and regulated by the Wisconsin Department of Natural Resources. An operating order by the DNR requires the district to open flood control gates at the dam any time water upstream at Lake Koshkonong rises above 776.3 feet above sea level.


Kim Bothom, the contractor who operates the Indianford Dam, said rain and runoff have kept waters at Lake Koshkonong at least a foot above the dam’s operating limits for the last nine months.


During that time, Bothom has kept the dam’s flood control gates open constantly. He said it’s part of an ongoing trend in high water at the lake and along the Rock River.


“We haven’t been within the (DNR) operating range for two years,” Bothom said.


Shapiro said the Aqua Jays are concerned the constant volume of water coming from the Indianford Dam could be higher than the amount leaving through the Centerway Dam and that the difference could be causing the Rock River to pond up between the two dams.


Even during periods of less rain this summer, Shapiro claims the stretch of river between the two dams has been slow to recede.


“There were a couple of weeks prior to July (2010) with no rain. The river didn’t go down. Somebody needs to explain that,” Shapiro said.


What about Centerway?

The Centerway Dam is a hydroelectric spillway dam owned and operated by North American Hydro. The company operates dozens of hydro plants in Wisconsin and surrounding states, including dams at Beloit and at Rockton, Ill. It is regulated by the Federal Energy Regulatory Commission.


In 2009, North American Hydro replaced a system of interlocking wooden boards at the overflow spillway at the Centerway Dam. The system is designed to keep the river’s flow over the dam at a constant rate, but many of its boards were missing or damaged by debris from past floods, company officials said.


Shapiro said the Aqua Jays question whether repairs to the boards have changed or extended the spillway’s reach, causing more water above the dam to back up.


North American Hydro did not grant the Gazette’s repeated requests for a tour of the Centerway Dam, but company officials said the new spillway board system was engineered to match the original designs at the dam.


Scott Klabunde, an asset manager for North American Hydro, said the dam’s spillway does hold back more water that it did before repairs last year. He said that’s because water is no longer rushing through broken or missing boards.


Klabunde estimated the spillway now retains an additional 20 cubic feet of water per second. He said that increase allows the company to generate more power but that any boost it would cause in the height of water above the dam is “so insignificant it’s microscopic."


“That’s thousands of an inch in elevation,” Klabunde said. “It’s not even a factor. It’s not even a drop in the bucket.”


North American Hydro continues to run the Centerway Dam under an operating order written years ago by the Federal Energy Regulatory Commission.


According to the company, the agreement requires it to open all four of the dam’s flood control gates once water at the dam’s crest reaches 769.4 feet above sea level.


The requirement, like DNR mandates at the Indianford Dam, is designed to keep the river flowing at a natural pace, regardless of manmade barriers.


Early last week, the river’s flow rate near the crest of the Centerway dam was at 5,600 cubic feet per second, said Greg Brzozowski, a regional manager for North American Hydro.


During the same period, a USGS gaging station upstream at the Indianford Dam measured a nearly equal flow rate of 5,490 cubic feet per second, while a gaging station downstream at Afton measured flows of 6,600 cubic feet per second.


“That’s an indication the Janesville (Centerway) Dam is passing more water than what’s coming in. It shows the river’s flow is not being restricted,” Brzozowski said.


Still, waters on the river remain above normal. Brzozowski said recent floods put waters at the Centerway Dam’s crest about 2 feet above operating limits. He said a cycle of repeated high water along the Rock River has forced the company to leave the dam’s flood gates open almost constantly during “the last four or five years.”


“All we can do is open up the gates and let both (power generator) units run and let Mother Nature run its course,” Brzozowski said.


Analysis, please

Shapiro said the Aqua Jays are considering putting a monitoring station at the Rock River between the Indianford and Centerway dams and have considered asking the city of Janesville to assist with the cost.


“It (a monitoring station) wouldn’t solve the problem, but it could give everybody data to decide what’s going on with high water,” Shapiro said.


Shapiro said the Aqua Jays also would like to learn more about how water is managed at the Centerway Dam, although he specified the ski club isn’t accusing any of the river’s dam operators of wrongdoing.


“We’re not interested in stirring up the pot. We just want answers. We’re trying to take a leadership role in starting to ask these questions. Maybe we get an indication that it is simply an extraordinary weather circumstance, and we can live with that,” Shapiro said.


Shapiro said the Aqua Jays also plan to publicly support the Rock-Koshkonong Lake District in the district’s ongoing court battle against the Wisconsin DNR.


The lake district seeks to raise summer levels at Lake Koshkonong by 7.2 inches, in an effort to improve boat access, while at the same time eliminating DNR-mandated winter drawdowns at the lake, which send an influx of water south along the Rock River.


“If there’s anything that can be done to better manage and control the water levels, it needs to be done,” Shapiro said. “That’s not just for water skiing. It’s for residents and all user groups along the river.”



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