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FAQ - Sewer Break & Temporary On-Ground Bypass Pipe Project
What Happened?
Around 6AM on July 12, Burlington Department of Public Works (DPW) Water Resources staff discovered that there was a break in a wastewater pipe that crosses underneath the Winooski River which brings untreated wastewater into North Plant for treatment. Crews were quickly mobilized to respond. 
What Caused This Break?
This pipe undergoes biannual inspections and the last inspection was actually in June 2023. This break is very likely a result of the intense and powerful storm flows currently affecting the Winooski River. With rapid water flows, we expect there was heavy scouring, leading to erosion around the pipe which led to this breakage.
What's Being Done to Fix This?
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By 8:45AM on the morning of the break, Water Resources staff was able to cap the sewer main at the Plant to limit untreated wastewater flows into the River. This has helped us capture 50% of the normal flows to the plant. By July 14th, we had a contractor mobilizing to build a bypass pipe which will capture just about 100% of all flows from the broken pipe for full treatment at North Plant.
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We are quickly working on a multi-pronged approach and evaluating the feasibility of quick, effective solutions along with a longer term repair plan. More details on the repair plan to come. It will entail:
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- Reducing untreated flows to the river
- Rerouting to get these flows through the Plant
- Repairing the pipe: First, temporarily to bring flows back through and then permanently to ensure more resilient infrastructure
How often does this pipe get inspected? Is it possible that this pipe can be broken for months in between inspections?
The pipe undergoes dye-based inspections twice a year with periodic checks by divers. The last dive inspection was actually completed in June 2023.
We have flow monitors that track incoming and outgoing sewer flows which we monitor to discover anomalies. This is what helped us to become aware of the July 12th break.
What kind of repair will be made to ensure this doesn't happen again?
While most of our efforts right now are on completing the temporary bypass piping project, we will be evaluating a range of options for the permanent fix. We will need more time to evaluate a range of design, permitting, resiliency, and financial considerations as we plan the post-emergency work. More information to come.
I'm being asked to conserve wastewater. What can I do?
This is extremely important for users who are in the area that flows to the river crossing (see map above). This includes but is not limited to:
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Limit toilet flushing, when possible.
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Running dishwashers and washers only with full loads.
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Taking short showers and limiting bath tub use.
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Turn off faucet when brushing teeth or washing hands.
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Disconnecting sump pumps from discharging to the sewer system and running the discharge pipe onto your lawn (this is a best practice always)
As this conservation notice is driven by limitations on the wastewater system and NOT the water system, using City water for irrigation or other activities which involve water soaking into the ground is acceptable.
How long will it take to construct the temporary bypass wastewater pipe?
Our contractor will be building a mile long temporary on-ground piping network. It is currently anticipated that this work will take 10-14 days (ending around early August), and will start at both North Plant and the “interception location” near the 127/Winooski Bridge, and working toward the middle. See the possible route at burlingtonvt.gov/water/winooskibreakjuly12. This route may change in some locations.
Is this safe? Will wastewater leak from the temporary pipe?
We are using high density plastic which can withstand the moderate force of intermittent wastewater and stormwater flows. We will also be taking precautions and burying the pipe below grade at road crossings and driveways. This kind of work has been done elsewhere successfully.
When will the underground pipe be fixed?
We need to wait for river levels to recede and for the water to become less murky, at which point we will have a diver inspect the pipe to help determine the proper fix. We don’t have an estimate on timing yet.
I’m seeing some street puddling and/or material blocking catch basins. Is this related to the sewer break?
We have made the decision to plug any catch basin that is connected to our combined sewer network that directly impacts the North Plant siphon break where we are currently hauling wastewater via tanker trucks. This is in an effort to focus our bypass operation on wastewater collection instead of being inundated by stormwater. Please note that the puddles will be stormwater only and will not be sewage reaching the surface. Please do not remove any of the items that we are using to plug the catch basins, see attached pictures for examples of what these plugged basins look like.
**Why is there a sewer pipe under the Winooski River?**
The sewer line crosses under the Winooski River in 2 places (see map at the URL above) and was first installed in the 1950's, around the same time as when North Plant was built. This chosen path at the time allowed the most efficient, feasible route for wastewater from this area of the New North End to reach North Plant for treatment.
In the 1950's, it was probably not feasible to have a cast iron pipe directionally drilled, so this pipe is at or near the river bed surface. Modern sewer system design would likely avoid a river crossing entirely.
**Reasons for installing a river crossing:**
-It provided a direct sewer route, reducing the length of pipe needed and relies on gravity (via an inverted siphon design), rather than pumps to direct wastewater to North Plant.
-The river crossing is ~3500 feet; a forcemain along the road would need approximately one mile (5300') and require multiple private easements
-While our current temporary bypass operation is, in effect, a force main, a permanent installation would require private easements, additional controls, excavation, tankage, and potentially other things like generators.
**Why not just bury this temporary bypass pipe, and make it permanent?**
The design and construction of a new, buried sewer line over-land would require a mile long excavation, and would need to be carefully designed to avoid other utility conflicts (gas lines, water lines, etc). It would also require the above mentioned private easements, and a permanent force-main. It couldn't be built as quickly as this temporary on-ground system. This temporary bypass pipe will soon allow us to capture just about 100% of untreated flows under most circumstances.
**So, what's going to happen with the damaged pipe?**
We are moving with all deliberate speed to continue reducing any untreated flows to the Winooski River and are capturing upwards of 75% of normal flows to North Plant for treatment. At the same time, we are evaluating a range of options for the permanent fix.
Once water levels safely recede and the water is less murky, we will inspect the damage on the pipe to determine a) what short term fixes can be employed AND b) what long term repairs or designs can be implemented for a more climate resilient pipe.
**A note on inspection:**
Residents have asked how we know if this pipe is damaged. We conduct 2x/year dye testing to ensure there are no leaks and have periodic checks by a diver to inspect the condition of the pipe. The last dive inspection was actually in June 2023. We also have flow monitoring technology at the Plants which we monitor to determine if an anomaly is ever present in the amount of wastewater coming into our Plants. This is what helped us to discover the July 12th break, and then mobilize quickly.
