The Metropolitan Sewer District says a mass of tree roots, grease and "flushable" wipes caused a sewer line to overflow in Winton Woods. The agency is also investigating a second sewage spill elsewhere in the park.
The sewage was discovered flowing into a retention pond and then into Winton Lake Monday, forcing Great Parks to close the lake.
MSD used a camera attached to a hose to identify the blockage. Spokeswoman Deb Leonard says pressurized water jets were used to clear the mass. The district also checked for other possible overflows upstream of the blockage.
Great Parks' Jennifer Sivak says there may be a second problem elsewhere in the park.
"There is a presence of sewage in a small stream but we haven't actually found the source yet," she says. "We know it is near where Lakeview and Sharon Road meet."
She says a staff member noticed a smell near Sharon Road and Lakeview Drive on Tuesday. MSD and Great Parks are investigating. As of noon on Tuesday it was uncertain if it was an overflow, and if so, the source, destination, and whether it may be sewage.
By 3 p.m., MSD's Deb Leonard confirmed the source as an overflowing manhole. However, she points out it is from a separate sewer line than the one discovered Monday.
"This area is about a mile from Winton Woods Lake. At this point in the investigation, MSD does not believe any of the sewage has entered the lake," Leondard says.
Despite signs stating the lake is closed, people could be seen fishing Monday evening and Tuesday morning.
Gregory Mancill and his grandson were casting their lines near where the retention pond feeds into the lake. (The culvert is blocked with plywood and sandbags, though some contaminated water continues to flow through.)
"We don't eat anything that we catch here and we've been handling things, if we do catch them, with rags, so we're pretty confident that we'll be alright," he says. "Not a problem, I don't think."
He says they'll both be sure to wash their hands afterward, too.
Others fishing Tuesday morning had similar sentiments, saying they intended to just catch and release, not eat anything.
Anthony Lewis says a knee injury means Winton Lake is the only place he can get to right now to enjoy some fishing.
"Does [the sewage spill] bother me?" he asks. "No, because I'm not going to eat this fish."
The overflow was discovered Monday afternoon, though it's unclear how long it had been going on. MSD's Deb Leonard says it's unclear how much sewage spilled from the manhole and she's not certain MSD will be able to come up with an amount.
Crews continued pumping water out of the contaminated pond Tuesday and working to clear the obstruction. Water from the pond is piped into the sewer system, downstream of the blockage. The line was cleared by Tuesday afternoon.
"MSD will then follow protocol to clean up and monitor the area to protect public health and the environment. This includes washing and disinfecting the impacted ground," the agency said Monday.
The Ohio EPA and Hamilton County Public Health are both on scene.
"Ohio EPA staff has been on-scene today offering technical assistance and observing cleanup efforts and will remain engaged during the cleanup process," the agency says in a statement.
The sewer district maintains 3,000 miles of sewers. There are approximately 200 people in the Waste Water Collection Division, including Assessment and Cleaning teams dedicated to determining the condition of the sewer lines and cleaning them. Leonard explains the teams use cameras and assessment tools that can tell if a line is blocked.
She says those teams work year round inspecting the lines.
The sewer that overflowed into the retention pond was last inspected in August 2015, Leonard says. It was scheduled to be cleaned and lined this year. That work, she says, will still be done because it is contracted out. The liner is an epoxy coating inside the sewer that prevents roots from getting through.
As WVXU reported in 2018, a lot of stuff gets flushed that shouldn't, leading to problems such as this. Despite being marketed as "flushable," wet wipes do not break down in water the way toilet paper does. They can become tangled around equipment or get combined with grease and other refuse items to form "fatbergs," - congealed masses that clog sewer lines and cause backups and overflows.
MSD's "Love Your Loo" program asks people to only flush human waste and toilet paper.
This story has been updated.