Route 366 by the Indian Lake spillway will not be closed during replacement of the spillway this fall. The announcement was made by Rob Kirkbride, consulting engineer for the Ohio Department of Natural Resources (ODNR), to 100 residents attending an information meeting at the IL Community Church Lighthouse.
“We will completely remove the existing spillway and replace it with a new one using a labyrinth design,” Kirkbride said about the more than 100-year-old spillway. Final design will be completed and presented to ODNR by the end of June with construction presently scheduled to begin in September. The project will take approximately a year to complete.
Instead of the current 10-foot-high and 700-foot-long wedge of concrete, the new spillway, also made of concrete, will have 18-inch thick walls arranged in an accordion fold configuration for 700 feet. “The new spillway will be 16 percent more efficient,” Kirkbridge said, meaning that water flowing over the walls will move faster. A 160-foot midsection will be 18 inches lower than the rest of the wall, but it will not alter the lake level in existence now. The labyrinth design will be the first used in Ohio, though it has been used in western states like Arizona and Texas.
During a question and answer period, residents asked about flooding below the spillway. “This is not a flood control dam, said Jim Wisse, of the ODNR office of communications. The flood plain of the new spillway will nearly match the current one for a 100-flood. By definition, a 100-year flood is one that will occur one per cent of the time and is the standard used by the U.S. Army Corps of Engineers.
When asked why improvements are being made now, Kirkbridge said that there have been too many years of repairs and rehabilitation efforts. During large rains, ground water is seeping under the levy to the other side and the spillway is deteriorating. Most notable seepage is the helioport pad and parking lot just north of the levy. The levy mound, upon which State Route 366 runs, will be built up in some sections on the downside to alleviate this problem.
A temporary dam will block one-half of the spillway at a time, allowing water to continue flowing over the spillway during construction. Wissse said residents can follow the progress of the spillway project by going to the website OhioDNR.gov, clicking on the engineering tab and then on the dam rehabilitation projects tab to find the Indian Lake spillway.
Judy Wherry is a regular contributor to this newspaper.