BRUNSWICK COUNTY — Brunswick County Public Utilities reported its tenth sewer spill of the year late Wednesday evening, after an estimated 32,000 gallons of untreated wastewater leaked through a cracked pipe, reaching the Shallotte River Basin.
Tuesday morning’s spill brings the county’s total amount of publicly reported untreated wastewater discharges to approximately 405,750 gallons in 2020.
Related: Brunswick reports sixth sewer spill in four months, 360,000 gallons spilled since April
This year’s pattern of spills marks an anomaly for the public utility, which has previously reported far lower spill totals over the last several years. According to the utility, the increase is not related to any specific cause, other than possibly rainfall amounts associated with overflow events.
417,750 gallons spilled this year
The public learns of sewer spills because of a state law that mandates utilities to publicize overflow events when at least 1,000 gallons of untreated wastewater reaches public surface water. The same rule doesn’t apply when sewage doesn’t reach public surface waters; in early January, the county didn’t inform the public when 12,000 gallons of sewage pooled in a field off Mt. Misery Road.
Including the Mt. Misery spill, this year’s known total climbs to an estimated 417,750 gallons of sewage spilled.
Public utilities annually log reportable spills in a state-mandated report by fiscal rather than calendar years. Halfway through the current fiscal year, the county has nearly tripled its next-highest spill total reported over the last seven fiscal periods, with an estimated 203,000 gallons spilled since July 1.
In fiscal years 2018-19 and 2014-15, the county had no reportable spills. In fiscal years 2017-18 and 2015-16 it reported two spills, totaling 5,300 and 36,994 gallons, respectively. Besides the current fiscal year, which began July 1, the county’s next-highest spill total among publicly available data occurred in fiscal year 2016-17, with 73,900 gallons discharged among nine overflow events.
Brunswick County isn’t alone in its recent high discharge amounts. In December 2019, Cape Fear Public Utility Authority reported its second-highest spill ever, when 2.4 million gallons of wastewater gushed out of a broken ’70s-era pipe into Smith Creek. The 40-hour spill caused fecal coliform levels in the creek to surge. When this happens, excess bacteria can choke out organisms, reducing dissolved oxygen levels in the waterway. It also presents a public health concern, especially if the waters are used recreationally by swimmers.
CFPUA’s largest spill occurred during Hurricane Florence when the utility released 5.25 million gallons of partially treated wastewater from its Southside Wastewater Treatment Plant after two generator failures.
What causes spills?
As the sixth-largest county in N.C. by landmass, Brunswick County runs one of the largest utilities in the state. It manages six wastewater treatment plants, 158 major pump stations, 4,000,000 feet of sewer lines, hundreds of acres of effluent re-use facilities, and over 8,000 grinder pump stations, according to public utilities director John Nichols.
Nichols pointed out the county merged with two town’s utility systems this year — Navassa and Northwest.
Spills aren’t always the fault of the utility. Sometimes they can be caused by contractors that inadvertently strike underground pipes. That was the case with the county’s May 20 spill, when a contractor struck a force main, causing 30,000 gallons of wastewater to reach a tributary of Persimmon Swamp and a golf-course pond in Carolina Shores.
It was also the case with the Jan. 16 inland spill, after a small hole initially created by a cable contractor that ran a boring machine along the top of the county’s 8-inch force main eventually grew into a larger split.
However, eight of the 10 spills this year have been caused by mechanical or physical failures tied to county sewer infrastructure. Failures can occur due to aging pipes, heavy rainfall events, roots growing into a piping system, or blockages in pipes. Non-biodegradable materials (PSA: flushable wipes aren’t actually flushable) can contribute to blockages that can exacerbate damages.
Continuous monitoring and upgrades of public infrastructure can help reduce the prevalence of spills, which inevitably occur in all systems. Still, any number of unplanned events can contribute to a spill, according to Nichols.
“Despite ongoing preventive maintenance procedures and 24/7 monitoring, facilities could be damaged by construction, disaster, or the mechanical components could occasionally fail and contribute to a sewer overflow into the many nearby surface waters in the county,” Nichols wrote in an email. “When this occurs, County staff notify the appropriate regulatory agencies and take remedial action to minimize and mitigate the effects. Component damage and failure may occur due to nearby construction, lightning strikes, rainfall, shifting soils due to wet conditions, inundation, material defects, and normal usage.”
Asked to reflect on the increase in spills this year compared to previous years, Nichols said there’s no clear-cut cause.
“A review of past annual reports indicates that the number of sanitary sewer overflows may vary significantly from year to year,” according to Nichols. “Other than the amount of rainfall associated with a number of the sanitary sewer overflows reported this year, there is little correlation with any specific cause.”
Summary of known spills in 2020:
- Dec. 2 — 32,000 gallons reached the Shallotte River Basin
- Nov. 12 — Between 6,000 and 7,000 gallons were discharged into a tributary of the Lockwood Folly River
- July 31 — 4,500 gallons reached a tributary of Persimmon Swamp
- July 8 — Between 150,000 and 170,000 gallons spilled, reaching Shallotte River
- June 12 — Between 10,000 and 15,000 gallons spilled, reaching the Calabash River
- June 12 — Between 5,500 and 7,000 gallons spilled, reaching a tributary of Williams Branch
- May 25 — 125,000 gallons spilled, a portion of which reached a tributary of Jinny’s Branch
- May 20 — 30,000 gallons spilled, reaching a tributary of Persimmon Swamp and a Carolina Shores golf course pond
- April 2 — 29,000 gallons spilled, reaching the Calabash River
- Jan. 16 — 12,000 gallons spilled off Mt. Misery Road. Note: This spill did not reach public surface waters.
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