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Facility Name:
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Newport City
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Donald Grondin
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City of Newport
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460-529 Main Street force main
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09/16/2020
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09/29/2020
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08:00 pm to 04:00 pm
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Discharged untreated sewage
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>1,000 to 10,000 gallons
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Crack/Hole in Pipe
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rags , roots FOG
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Other
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Dig Safe was called at 5am on Wednesday for an emergency dig.
On Wednesday morning excavation began, and red dye was put into the Lake Road pump station. This red dye was pumped into the force main and the sewage leak was observed. No red dye exited the bank and it was determined that the force main does not leak. The leaking sewage smelled different and looked different from sewage in the pump station.
Excavation revealed a culvert located near the lakeshore that was exposed due to low water levels. A clay pipe was found attached to that culvert, and this appeared to be the source of the sewage leak. However, this clay pipe and the culvert are not part of the current sewer system and are likely the remains of the sewer system that was replaced ~1962. The straight pipe (culvert) and old clay pipe were replaced by a gravity line and force main that are both located within the roadway on Main Street.
An electronic trace was placed into the pipe, and it appeared to indicate that the pipe may be connected to an apartment building (Governor Prouty Apartments, unit closest to Main Street). Red dye was flushed in 2 separate apartment’s toilets. This dye was observed flowing out of the bank a short time later. Camera work indicated that the suspected old clay pipe connection to the apartment building was previously sealed with brick.
A blockage was found in the gravity line composed of wet wipes, roots and grease. A sump was created to collect sewage, and pumping/trucking continues. No breaks have been found in the gravity line yet. The culvert discharging to the lake was bricked up.
Additional excavation and camera work is underway to try to identify the source of the sewage. The City will monitor the system daily until an exact location of the sewerage leak is determined. Then the City will excavate the roadway to correct the problem.
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Lake Memphremagog
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Thomas Bernier Public Works Director City of Newport
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nForms
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Y
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On Tuesday morning (9/22/2020) Pedro was called by DPW to go turn on the Lake Rd pump station. DPW staff was called to Main St (~529-460) to regarding a strong septage odor. DPW wanted to check to see if running the pump would help locate the leak. Pedro ran the pump, then went to where the leak was reported. He was able to locate where sewage was leaking into the lake from the bank.
Assuming a forcemain leak, Pedro examined the road for surfacing sewage. DPW maps were retrieved and additional investigation was conducted. Tom B called Pedro to get an update on the situation. At ~3:30 Pedro called John Merrifield at VT DEC to report the leak. He instructed Pedro to stop the flow to the lake and to pump/truck per the City’s OMERP. The pump station was shut down from Tuesday ~4 pm to Wednesday at 10 am.
The initial Incident Report was based upon the information available at the time (Assumed forcemain leaking for up to 1 week). The 1 week duration is assumed due to noticeable odor and proximity to residences.
Initial volume estimates were based upon measured flow rates of ~ 400 gpm and recorded pump run times. Volumes through that pump station are ~75,000 to 100,000 gpd. The initial reported volume of 100k-500k gal. was selected based upon flows corresponding to assumed conditions. .5 x 100,000 x 7 = 350,000 gallons.
After reviewing plant flow records, observing the discharge to the lake, and discussing the matter with EEO Smith, Pedro determined that the actual quantity of spilled sewage was probably closer to 7000 gallons than to the initial estimate of 100,000-500,000. This new number is based upon the changes in assumptions: there is a small leak in the gravity line which serves a small number of residences vs a leak in a pressurized force main, and a review of flow records that indicates that no sizable change in flow at the WWTF or at the pump station was detected. Pump station run times were reviewed and are very consistent from day to day.
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HP2-Z4R0-JVQGA
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