Millions of gallons of waste water spilled into several Raleigh creeks and streams after heavy rain this week.
“The severity of this rain event was not predicted,” according to a city news release. “The amount of localized flooding was the result of the four inches of rainfall within a twelve-hour period, overwhelming the sanitary sewer system.”
In total, 7,083,958 gallons of untreated waste water spilled into Big Branch Creek, Marsh Creek, Walnut Creek, Crabtree Creek or unnamed creeks that lead to them.
Waste water or sewage spills can be caused by a number of factors including when heavy rain leaks into old pipes. When those pipes are full, they can push the waste water up through manholes or the pipes can crack, both causing spills.
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The largest spill came when nearly 5 million gallons of sewage spilled into Marsh Creek at 3204 Yonkers Road. Raleigh-based Moffat Pipe was repairing “aging infrastructure” and had set up an 18-inch bypass pipe. The area flooded and an equipment trailer at the construction area struck the bypass pipe, causing the break.
“The pumps were wide open at this point, so they were going like crazy,” said Ed Buchan, Raleigh’s senior utilities analyst. “So they had no way to get there to turn them off. They couldn’t control it until the water receded a bit.”
Many times, he said, these incidents are considered “acts of God” and there’s no way to prevent them with so much water during a short amount of time. Moffat will likely have to file an insurance claim to cover the damage to the flooded vehicles, Buchan said.
The city’s largest sewage spill occurred during Hurricane Matthew in 2016 when more than 33 million gallons spilled at the flooded Crabtree Creek Lift Station, which pulls wastewater from points of low elevation to higher elevation.
Here are the locations of the other spills this week:
- 1.04 million gallons spilled into Crabtree Creek at 3308 Holston Lane, Raleigh: A manhole and sewer siphon box, which helps correct the flow of the wastewater, were both overflowing at 10:45 a.m. Tuesday and stopped by 5 p.m. the same day.
- 220,000 gallons spilled into Big Branch Creek at 3265 Anderson Drive, Raleigh: A manhole began overflowing at 9 p.m. Monday and was stopped by 3:20 p.m. Tuesday.
- 207,000 gallons spilled into Crabtree Creek at 3316 Alleghany Drive, Raleigh: Two sewer manholes were found overflowing at 11 p.m. Monday and stopped at 2:20 p.m. Tuesday.
- 198,000 gallons spilled into an unnamed creek that leads to Walnut Creek at 1712 Mayridge Lane, Raleigh: A 54-inch sewer above-ground sewer pipe broke at 8:45 a.m. Tuesday and was stopped by 5 p.m. the same day. The sewer main was already planned to be replaced “due to its poor condition,” according to a city news release.
- 138,000 gallons spilled into an unnamed creek that leads to Walnut Creek at 1551 Rock Quarry Road, Raleigh: A sewer manhole began overflowing at 11:30 p.m. Monday and was stopped by 11 a.m. Tuesday.
- 138,000 gallons spilled into Crabtree Creek at 3409 Lassiter Falls Circle, Raleigh: A sewer manhole began overflowing at 11:30 p.m Monday and was stopped by 2:20 p.m. Tuesday.
- 128,000 gallons spilled into Walnut Creek at 1201 Sunnybrook Road, Raleigh: A sewer manhole was overflowing at 11:30 p.m. Monday and stopped by 10:10 a.m. Tuesday.
- 18,000 gallons spilled into Big Branch Creek at 800 Hardimont Road, Raleigh: A sewer manhole was overflowing at 2 a.m. Tuesday and stopped by 4 a.m. the same day.
- 291 gallons spilled into Walnut Creek at 556 Dacian Road, Raleigh: Three sewer manholes were found overflowing around 11:30 p.m. and were stopped by 4 p.m. Tuesday. The small spill amount is due to the small number of sewer connections in the area.
No fish have been found dead due to the spills. The N.C. Department of Environmental Quality, Division of Water Resources has been notified.
The Neuse River Resource Recovery Facility, formerly called the Neuse River Wastewater Treatment Plant, normally treats 48 million gallons of wastewater per day but the facility received nearly 130 million gallons during Tuesday’s heavy rain.
“This substantial increase of flow to the facility was due to stormwater leaking into old or submerged sections of the sewer collection system,” according to the news release.