At its latest meeting on Monday, the Burlington, Vermont Board of Finance heard a report from the Department of Public Works on an underwater sewer main break that is releasing hundreds of thousands of gallons of raw sewage into the Winooski River and Lake Champlain.
On July 12th Burlington’s Department of Public Works was alerted to a broken sewer mainunder the Winooski River, which carries untreated wastewater to the city’s North Treatment Plant. Hundreds of thousands of gallons of sewage were flowing into the river and downstream into Lake Champlain. DPW Director Chapin Spencer explained the situation.
“We quickly jumped into action and identified the problem and have been working ever since on a three-pronged response: reducing the flows, rerouting the flows and repairing the infrastructure. But we are also contracting with a company with pumper trucks to work 24/7 to remove as many flows from that sewer shed as possible. The fourteen-day cost for that work is estimated to be around $210,000.”
In addition to the pumper trucks, Spencer said a temporary, mile-long overland bypass pipe is being constructed.
“Running largely through the city's right-of-way and along the right-of-way to North Plant, it’s around 5000 feet. We are expecting that this project is going to cost approximately a half a million dollars. Until that work is done, we will be continuing to run the pumper trucks 24/7. And together, these two projects will cost approximately $700,000.”
Department of Public Works Water Division Director Megan Moir says while pumper trucks are able to haul hundreds of thousands of gallons daily, untreated wastewater is still flowing into the river.
“At this point we still estimate that it's about 350 to 400,000 (gallons) during dry weather conditions that is going into the river. The overall volume is going to be more during a storm event because this is a combined sewer system. Right now, we're not getting it all with the pumper trucks. We're doing sort of the best that we can. Obviously, the Winooski (River) is still flowing high. There's still a ton of things in the Winooski. We absolutely want to make sure that by the time flows sort of return to normal and the system’s kind of flushed itself and now we're one of the only things that is now adding pollution that we have that emergency bypass in place which would be capturing all of the flows during a dry weather condition.”
Moir hopes that soon after the bypass is activated divers will be able to physically inspect the underwater pipe.
“The other piece that we’re doing: we've already dye tested from the section close to the plant. What we're hoping to determine if we put in dye over here is if we see dye in that same location, then we'll believe that it's more of a spot break. Versus if we see dye further out in the middle of the river or on the other bank then we're going to have a bigger situation on our hands letting us know that there's either multiple breaks or potentially that a whole section of the pipe has been washed away. We're hoping that's not the case. We're hoping it's just a small break on one side.”
The department believes the break is due to “intense and powerful storm flows” causing “heavy scouring leading to erosion around the pipe.” Spencer says they are working with the city administration, consultants and in-house FEMA experts to collect documentation for potential federal reimbursement.
“There are two very fortuitous things. One is the council just approved two months ago a hazard mitigation plan for the city. That helps the reimbursement rate through FEMA. So that's positive. And the second thing was that we inspected the sewer main underneath the river with divers just last month and found no major findings.”
The Department of Public Works is asking residents and businesses in the eastern part of the New North End to conserve water. There is no estimate on when the underwater pipe may be repaired. The temporary bypass is expected to be completed by early August.
