NORTH RIDGEVILLE — Two pending sewer projects are designed to reduce the devastating impact of future flooding.
One improvement is a nearly $500,000 sewer line change that should boost the speed with which sewage and water enters the city’s French Creek Wastewater Plant.
The other is an alteration in a weir, or low concrete, that regulates the flow of stormwater held behind a dam.
The planned changes ideally will lower stormwater by up to six inches for residents of the Gina-Pitts-Gail Drive area, which has sustained some of the worst flood damage in the city over the past 20-plus years.
Both projects are to be done this year, said Mayor David Gillock.
The smaller project calls for an $18,300 modification of an opening at the top of a 60-foot-wide concrete dam that runs parallel to Root Road north of the Ohio Turnpike.
The dam, which is 12 to 13 feet tall, was built in 1998, and retains stormwater before releasing it into a detention basin off West Point Drive, which runs parallel to Bainbridge Road. The detention basin releases stormwater into a nearby ditch that carries it north out of the city, said Assistant City Engineer Cathy Becker.
The change in the dam was recommended by an engineering study and would dovetail with recent work to dig the detention basin substantially deeper to hold more stormwater, Gillock said.
Plans call for a small opening at the top of the weir to be altered to retain more water behind the dam.
City officials are checking calculations to determine whether putting more water behind the dam can be achieved without putting too much pressure on the dam, Becker said. If the dam was to shift or begin to give way due to extreme pressure, it could lead to serious flooding upstream, or south of the dam.
If needed, the area of the dam around the altered opening could be reinforced with steel to prevent it from possible collapse, Becker said.
Stormwater is generally held for up to 12 hours behind such dams before being released into drainage ditches, she said.
“If water comes across (residential) yards in a big storm, and you have two inches in front of your door, lowering that by six inches should prevent flooding,” Gillock said. “We’re not saying this is a cure-all, but it will certainly help.”
The French Creek Wastewater Treatment Plant project is a $470,000 enlargement of sanitary sewer lines at the entrance to the plant on North Abbe Road.
Plans call for the removal of a 90-degree, T-shaped sewer line connection that links south and northbound lines into a single pipe that moves into the plant.
The T-shaped line would be replaced by 42-inch pipe containing two 45-degree bends to move water and sewage more quickly into the plant through a much bigger 60-inch line, Gillock said.
Over time, the T-shaped connection has deteriorated, Gillock said.