[ back ]
State says there's no time to wait on failing dam
(by Joan Demirjian - July 14, 2010)
State says there's no time to wait on failing dam
By JOAN DEMIRJIAN
Kenston Lake dam in Bainbridge is failing rapidly and needs to be drained as soon as possible, according to the Ohio Department of Natural Resources, Division of Soil and Water.
The division has sent letters to the owners of the dam that it needs immediate attention. A sinkhole has developed that is threatening the dam structure in the subdivision off of Bainbridge Road.
Sudden failure would result in flooding of residential structures and high-value property downstream and damage or disruption to the road along the crest of the dam, which provides the only access to several homes, according to David Hanselmann, chief of the division of soil and water resources, in a letter sent July 1 to owners of the private dam.
The Bainbrook and Laurel Springs subdivisions are downstream from the lake and dam.
At Monday's Bainbridge Township Trustees meeting, Trustee Jeff Markley said they must start draining the lake. "This is overwhelming news," he said.
The township's responsibility is to obtain bids now on the culvert project, in which the box culvert will be placed through the dam, he said. "It's the only road access for the homes," Mr. Markley said of the township road.
Trustees moved forward Monday to advertise for bids on the new culvert to be installed under the road. The culvert will drain the lake, which was installed in the late 1950s.
They will also seek proposals for the restoration work in the lake and stream bank after it's drained.
The dam's pipe and riser spillway are not functioning properly. Significant internal erosion is occurring along the principal spillway pipe, a large sinkhole has developed on the upstream slope of the dam, and the dam is actively failing, according to the state.
"Because of the imminent failure of the dam, you must implement your approved plans and specifications to decommission the dam immediately," Mr. Hanselmann said.
Draining of the lake had been in the planning stages. A study had been under way to determine how the lake's removal would affect underground natural gas in the area. However, based on what is happening, there is no time to wait for the study, according to the division.
While the dam is privately owned, Bainbridge has been involved with the project, because a township road is built over the dam. The road provides access to 12 homes.
Rodney Tornes, manager of the division's dam safety program, said there is active seepage along the spillway pipe, and the interior of the dam is eroding.
A sinkhole has developed, he said. When a dam is eroding interiorly, it is collapsing on itself, and it is unpredictable, Mr. Tornes said.
In the interest of public safety, and based on the conditions, there is no time for the hydrological study, Mr. Tornes said. "It's a serious matter."
There is an administrative order to move forward with plans already approved to put in the culvert and drain the lake, Mr. Tornes said.
The project to drain the lake because of the failing dam has been under discussion for several years.
The Ohio Environmental Protection Agency is providing a grant for restoration of the lake bed when it is drained. The township agreed to put in the new culvert under the township road, as a match to the grant.
The earthen dam, on which the township road is built, is fed by Linton Creek.
The division of soil and water resources staff responded to an emergency June 29 at the dam. The dam's pipe and spillway are not functioning properly, according to the division.
In an inspection, members of the division's dam safety engineering program observed a sinkhole measuring 25 feet across. Two of the owners, Rick and Donna Patz, had staked the area and had been taking measurements of the sinkhole since June 9.
The sinkhole has dropped 20 inches in the past 20 days, according to the measurements.
Internal erosion is occurring along the principal spillway pipe, resulting in the sinkhole. Continued internal erosion will lead to failure of the dam, Tina Griffin, an inspector said.
Amy Brennan, director of the Chagrin River Watershed Partners, said there were plans a year ago to bid out the work to replace the culvert which will drain the lake.
Then the EPA ordered the project to wait while the hydrogeology study was being done.
Now that the Ohio Department of Natural Resources has found the dam to be failing, the culvert project must move forward. "ODNR is saying it must be done now," she said.
The watershed partners organization has been working with the township on the project.
A stream restoration grant of $491,500 has been obtained from the EPA for stream restoration and other work.
The township will provide a 40 percent match by replacing the culvert under the roadway, thereby draining the lake. By putting in the culvert, the former dam will be a road embankment.
[ back ]
