SOUTHEASTERN, N.C. — Six “Neptune’s forks” pulled 1,283,000,000 gallons of water out of the Cape Fear River last month.
The ‘forks’ sit at the front end of a massive, multi-partner system which provides water for over 350,000 people. The system starts with the Lower Cape Fear Water and Sewer Authority (LCFWASA), which delivers untreated water to regional providers like CFPUA and county-run utilities in Brunswick and Pender.
In May, this system – starting with LCFWASA – pulled more water than it had ever sourced from the river in a single month since its inception in 1983, and nearly 20% more than its previous record, set in June 2010. May’s demand also ever-so-slightly exceeded the regional delivery system’s output capacity for four days, peaking at 100.8% on May 29, the Wednesday after Memorial Day.
It was an apparent close call for the region’s water providers, but that’s not the end of the story. Demand is only increasing as development continues at some of the most rapid rates in the state. And, while several regional water providers have plans to increase capacity, new facilities and infrastructure are in some cases years away from completion.
Though automated triggers exist within the system, it heavily relies on human discretion and educated decision-making. With multiple partners pulling from the same line, it takes coordination to balance flow to reach over 350,000 people and five hospitals.
What follows is an in-depth look at how and why water demand maxed out the system, and some of the steps being taken to help plan for the future.
(Author’s note: This is part one of a two-part series. Stay tuned for part two Monday)
Behind the curtain
Gravity pulls freshwater at Kings Bluff through the Neptune’s forks, which are capped with ultra-fine stainless steel intake screens — each valued at $130,000 — that filter out debris. After pumping pressure is applied, the region’s water supply is fed through a 22-mile-long, 48-inch pipe. Each 20-foot section weighs 15,000 pounds.
“It’s pre-stressed steel concrete,” Don Betz, LCFWASA’s executive director said. “It is a monster.”
LCFWASA’s delivery pipe runs down N.C. 87, then Highway 74 where it feeds Brunswick County’s Northwest Water Treatment Plant. It carries on to cross the river to deliver raw water to Pender County’s Water Treatment Plant; and after a trip under U.S. 421, serves Cape Fear Public Utility Authority’s (CFPUA) Sweeney Water Treatment Plant in Wilmington.
Plans are in place to double delivery output from LCFWASA’s Kings Bluff station. But it’ll take at least three years until that parallel line is in the ground.
“We have the whole summer of ’20, the summer of ’21, and summer of ’22 before we get that parallel main,” Betz said.
A close call in May
A confluence of conditions triggered a close call in May. From the supply side, LCFWASA broke its all-time record.
The region had received just 14% of the rainfall it’s used to — just .63 inches of rain. Lawns, typically lush this time of year, were scorched. Thousands of people were irrigating their yards, all around the same time, as tourists rolled into the region’s beach towns.
Kings Bluff is more than capable of pulling in mass quantities of raw water from the river. In fact, its intake system is sized to pull in more than double of what it’s currently capable of sending out to its partners. This delivery system — the 48-inch pipe — is what exceeded 100% of its design capacity for four days in May.
What happens when a system reaches or exceeds 100%? Nothing — immediately. Exceeding 100% simply means the infrastructure is being used above and beyond what an engineer vouched for when they placed their seal on design documents. It increases the likelihood of equipment failure, and almost always means it’s time to expand.
Most of the year, increased capacity won’t be needed. But in summer months, when an unexpected drought hits, the extra room doesn’t hurt.
The pipe delivered as much as 27.7 millions-of-gallons-a-day (mgd) from LCFWASA to its first stop at the Northwest Water Treatment Plant, situated 13-miles downstream. That’s about 15% higher than the current allocation Brunswick County is contracted to pull from LCFWASA, and represents 66% of the total amount of water delivered to all partners that day, May 25.
This was the highest-volume 24-hour period — the Saturday before Memorial Day. The county’s system demand peaked 9% higher than its previous daily demand record set on June 10, 2015, at 95.7% of system capacity.
In total, May’s water demands broke the county’s previous record nine separate times. About one-fourth of the county’s raw water supply is sourced from its 211 Water Treatment Plant, which can treat a maximum of 6MGD pulled from the Castle Hayne Aquifer.
Donald Dixon, Brunswick County Utilities (BCU) deputy director, said complaints about low pressure in May could be attributed to drought conditions. “The majority of calls received for pressure issues were centered around our peak demand time between 5 and 8 a.m.,” Dixon wrote in an email.
Though the county’s water system was pushed to its max, BCU’s director John Nichols said low-pressure issues weren’t tied to a lack of water. “There have been no low-pressure issues within the County water system or in any wholesale water systems served by Brunswick County due to a lack of raw water,” Nichols wrote in an email.
Plans to double production capacity at the Northwest Water Treatment Plant, which has treated a maximum of 24 MGD since it was first built in 1985, are still in the design phase.
A $179.4 million overhaul to expand and add reverse osmosis treatment technology is underway and expected to reach completion by December 2022.
Pender County, LCFWASA’s least-intensive municipal partner, is the next stop on the line. Though Pender County’s plant is capable and sized to treat 4MGD, due to a lack of personnel, it can only usually treat up to 2MGD. LCFWASA delivered over 2.6MGD — record amounts — to Pender County on May 18 and May 29, according to data provided by Kings Bluff Pump Station.
Water systems generally aim to operate on a 24-hour schedule. A treatment system’s delivery capacity can be offset through storage tanks that fill at night when demand dips. Operating during off-hours can reduce regional stress that kicks in when people start taking showers, and sprinkler heads rise.
“We thought we had another year before we needed to add more personnel and go to a 24-hour operation, but these last couple of months have taxed us beyond what we thought,” Kenny Keel, Pender County Utilities (PCU) director, said Wednesday.
Normally, Pender’s 1-to-2MGD pull wouldn’t phase LCFWASA’s 45MGD delivery capacity. But in May, Pender’s peaking demands and half-day operations became a blip in the regional equation.
“When they’re trying to run at a very high rate of speed trying to get those tanks filled at only 10 hours, that interferes with normal operations,” Betz said.
Pender County does not have plans in place to hire two more water operators – the personnel needed to get the water plant to a 24-hour schedule.
“Where it would help more than anything is the other partners that are getting water from [LCFWASA],” Keel said. “Instead of us compressing our need for raw water into 12-13 hour period, we’d be able to stretch it out over the entire 24 [hours].”
“So we would be pulling at a rate that’s half the rate we’re pulling out of that pipeline now for half a day,” he added.
Keel said PCU’s half-day operations have never impacted its water neighbors until last month, when drought conditions triggered higher-than-anticipated demands.
“This was exacerbated by some maintenance that was being completed to [CFPUA’s] raw water pump station, making raw water even more scarce,” Keel said. “We are looking at ways now to stretch out our operations to be a better neighbor to our fellow water systems that use the same source.”
Still, Jack Hogan, superintendent at Kings Bluff, said LCFWASA’s small customers — Pender County, Invista, and Praxis — don’t put a large dent in supply. Contracted to deliver 23MGD and 24MGD, CFPUA and Brunswick County are the authority’s most impactful players. Both utilities are good at coordinating with one another, Hogan said.
“It’s them that gives the heavy draw time,” Hogan said. “So they coordinate with each other and they back off a little to help us out.”
An offline pump station
On May 9, before LCFWASA reached 100% of its delivery capacity, CFPUA asked BCU for a run-of-the-mill request: turn on the LCFWASA booster pump. CFPUA’s Sweeney Water Treatment Plant was receiving 18MGD, but needed 21 to 22MGD to meet demand, according to its spokesperson.
Located just after BCU’s intake at the Northwest Water Treatment Plant, the booster pump isn’t always online. It’s initiated as needed, fulfilling its namesake, to boost pressure near the halfway point of the 22-mile-long line.
Under normal conditions, CFPUA is less reliant on LCFWASA’s 48-inch main. That’s because it has its own 30-inch raw water delivery pipe. CFPUA owns a pump station, which directly neighbors the LCFWASA’s Kings Bluff Pump Station.
CFPUA’s direct tie-in to the river typically helps offset regional demands. Prior to late-May upgrades, the station was capable of delivering 6.7MGD to 9.2MGD to the Sweeney Water Treatment Plant. About 20% of CFPUA’s raw water comes from its own pump station, according to its spokesperson, and 80% is sourced from LCFWASA’s station.
May’s conditions prompted a new long-term solution for CFPUA: consider increasing Sweeney Treatment Plant’s current 35MGD capacity to 44MGD, discussed on June 27. With new pumps installed late last month, CFPUA can deliver up to 10MGD on its own to Sweeney, leaving breathing room for the utility, whose demands peaked at 19.39MGD in May — 55% of its total treatment capacity.
But, beginning in late November 2018, CFPUA had to turn its own Kings Bluff pump station offline. This meant the authority was fully reliant on LCFWASA’s 48-inch pipe for raw water (CFPUA also has two groundwater systems — Richardson Water Treatment Plant; a 6 MGD plant, and Monterrey Heights; which treats less than 1 MGD).
Pump motors and electrical components at CFPUA’s pump station at Kings Bluff had reached the end of their useful lives, according to CFPUA spokesperson Vaughn Hagerty. While the station was offline, CFPUA had two temporary diesel pumps on site, available to be used as needed, according to Hagerty. These pumps could pull as much as 7.5 MGD from the river to Sweeney.
Per CFPUA’s request, BCU personnel turned on LCFWASA’s booster pump at around 10:30 a.m. Thursday, May 9. Soon, “it became obvious that the booster station was out pulling Kings Bluff,” according to Glenn Walker, BCU’s water resources manager. In an email to Betz, Walker wrote the move meant Brunswick County couldn’t reach its desired flow rate.
A raw storage tank — owned by LCFWASA but on-site at the Northwest Water Treatment Plant — had reached uncomfortably low levels. According to Dixon, the tank reached as low as 5.3 feet that day (below the 7-foot level at which an alert is issued, and well below the usual ‘comfortable’ level of 21 to 34 feet).
Dixon said the one-day event did not result in low-pressure issues in Brunswick County or in any of its wholesale systems.
After 5 p.m., Walker wrote: “The Raw Tank has continued to drop and I alerted CFPUA to that fact and they are asking us to run the tank until empty or to an uncomfortable level that may result in sludge being pulled from the raw tank into the system.”
CFPUA told Walker their station — still undergoing repairs — would not be up and running until the next week. “In my opinion, the current method of operation is not sustainable and there is a distinct possibility that demand may exceed capacity or operational issues may be exacerbated (air or sludge into the system),” Walker’s email states. Walker asked LCFWASA to provide guidance and included recommendations that Pender County extend its operational hours and CFPUA run its station using temporary diesel pumps.
So, the next day, CFPUA engaged its diesel pumps. CFPUA ran the temporary solution for 10 days in May. As might be expected, data provided by Kings Bluff shows LCFWASA delivered less water to the Sweeney Water Treatment Plant on the days the pumps were running, compared to days when CFPUA’s station was completely offline.
According to Hagerty, CFPUA stipulated that construction to replace the old pumps at its Kings Bluff station be completed by May 23.
Why stipulate construction be completed that close to the holiday weekend?
“The construction schedule was the best possible given the time needed to complete the work and desire to mitigate risks such as periods of peak demand (based on past experience) and events such as hurricanes,” Hagerty wrote in an email. “To expedite the work, CFPUA purchased the necessary equipment ahead of time, rather than leave that to the contractor. In addition, we had temporary diesel pumps on hand to provide additional capacity if needed.”
Though LCFWASA’s tank was drained that day, sludge and air did not end up entering the system, according to Betz.
From Hogan’s seat, tank levels are just one thing to keep track of. “We sit here and watch it,” Hogan said, pointing to the Kings Bluff monitoring station. “If we get too low, we start calling our customers and tell them, ‘Hey this is the tank level, y’all need to kind of coordinate with each other.'”
Hogan said a positive aspect about the regional system, is that all parties have access to river, tank, delivery, and pumping levels at all times. “If we’ve got a major mess up, it ain’t only just Brunswick County that knows it,” Hogan said. “We’ve got three counties and two private industries that know it.”
New water emergency protocol
LCFWASA met for its regular board meeting four days after Walker’s email. According to Betz, the group did not discuss the booster pump request at the meeting. The topic did, however, come up at a regional meeting at LCFWASA headquarters on May 22, where staff from all partners attended.
According to Betz, CFPUA’s temporary offline pump station status, Pender County’s limited personnel, seasonal drought conditions, the region’s growth rate, and pending capacity expansions all prompted the authority’s solution to May: update its Water Emergency Plan.
McKim & Creed was hired on June 10 to review partner’s Water Shortage Response Plans and create a new Water Emergency Plan for the authority. “There are days when there’s operating challenges,” Betz said.
Partners are developing a common set of triggers and actions in order to balance system withdrawals during critical water shortage periods. Water Shortage Response Plans help inform water providers when to begin asking the public to engage in water conservation measures. In this case, a new plan could help LCFWASA come up with new system-specific protocols that balance each partner’s needs.
The new plan, due in August, will be a long-range document.
“How do we disseminate the information? Do we disseminate it collectively? Individually?” Betz asked, hoping the new plan offers recommendations on these questions.
(Author’s note: This is part one of a two-part series. Stay tuned for part two Monday)
Send tips and comments to Johanna Ferebee at firstname.lastname@example.org