An update on repairs to the water system in Asheville - AVLtoday

A treatment of aluminum sulfate and caustic soda continues for North Fork reservoir.

Photo via City of Asheville

The Water Resources Department has continued to outline the progress made in restoring potable water to the thousands of locals and businesses left without after the storm, sharing updates on treating the North Fork reservoir, and keeping the public up to date on the water system in Asheville.

The City of Asheville has not provided an exact timeline for complete restoration and treatment, still stressing that “water restoration will occur slowly and incrementally.” Public Information Officer Clay Chandler reiterated, “I’d love to be able to tell you, but I just can’t.”

However, in the Monday, Nov. 4 briefing, the community got the first taste of a potential timeline.

Before we dive into all those details, here’s what we do know about the progress.

Asheville is served by three water treatment plants — North Fork in Black Mountain, Mills River near the airport, and William DeBruhl in Swannanoa — which together operate thousands of miles of pipes.

The Mills River plant, which primarily serves South Asheville, is fully operational. The city is asking those with water to conserve, and the boil water advisory remains in effect. The William DeBruhl plant (usually referred to as Bee Tree) had waterlines demolished in the storm and is currently inaccessible until roads are repaired. According to the county, a lot of debris has been removed and road repair is beginning — but assessment is still underway as of Monday, Oct. 14.

North Fork, the principal water treatment plant for the area, is responsible for 80% of our water. North Fork’s 36-in bypass waterline experienced significant damage after the storm washed away almost 25 feet of ground. This bypass line was a redundant installation meant to mitigate any damage to the 36-in and 24-in main and transmission lines and was originally built to withstand a typical hurricane event — but Helene exceeded the typical. With these other lines gone, repair of the bypass line became a top priority.

Helene shifted the waterway entirely and it now flows over the lines, so crews had to construct dams as they went to make the repairs. The crew also had to run the repaired line further than the original because the original line was clogged by boulders.

The rebuild, which will be installed deeper and will be armored, has been reconnected. At a recent news briefing, Assistant City Manager Ben Woody shared some context for the speed of those repairs: When the line was originally installed, it was a three-year project. If they were operating under normal conditions to do these repairs, it would be a two-year project.

To address the turbidity (amount of sediment) of the water in the North Fork reservoir, the local team and the EPA created a pilot plant (which is a small version of the plant, kind of like a lab) to test treatment options and developed an in-reservoir treatment plant. These measures are meant to address the turbidity of the water and allow for coagulation, which removes the charge from the particles in the water and allows them to settle.

Water Resources Department Specialist Clay Chandler said that fixing the city’s pipes is like “playing a game of whack-a-mole.”

Photo via City of Asheville

On Thursday, Oct. 10, water resources staff began pressurizing and filling the North Fork Bypass line. They are currently feeding ~12 million gallons per day into the line to support flushing the water system and expanding the restoration of water service.

The North Fork Water Treatment Plant can’t be used right now, so crews are pressurizing the distribution system directly from reservoir water instead of going through the treatment plant. As such, the water is highly chlorinated to ensure it is safe to use.

Restoration began in Swannanoa — which Woody called “ground zero” of the water system destruction — and started moving incrementally west from North Fork to Asheville. On Sunday, Oct. 13, crews began supplying water to areas west of Swannanoa, and as of Monday, Oct. 21, Chandler said that ~95% of service has been restored.

On Tuesday, Oct. 15, large batches of aluminum sulfate and caustic soda arrived at the North Fork reservoir, and on Wednesday, they were joined by an applicator boat. These chemicals will aid coagulation and PH balance, respectively, and initially they cleared the water from the bottom up, then began clearing from the top down. Note: These materials are used by the Water Resources Department as part of their normal treatment process.

As a reminder, coagulation is the process of reducing the electric charge of the particles in the water so that they can gravitate toward each other, become heavier, and sink to the bottom. This process is ongoing.

Crews continue to pressurize and fill the system with this sediment-heavy water, which allows them to repair smaller leaks, fill tanks, remove airlocks, and flush the system without waiting for the reservoir treatment to be completed — thus speeding up restoration.

The totes of aluminum sulfate and caustic soda, which are deposited in the outer zones shown here, hold 300 gallons each.

Graphic via City of Asheville

The treatment plan has other pieces, though. The long-awaited curtain — which works as a shield to block sediment from flowing into other application zones of the water and to allow water treatment to be completed in stages, rather than having to treat the whole reservoir at once — was anchored in place on Wednesday, Oct. 30. A mama bear and cub showed up to supervise, and Chandler noted that they seemed pleased, “I hope we can share some good news with them.”

With the curtain installed, another round of treatment began, then concluded on Thursday, Oct. 31. The treatment process involves depositing one tote of aluminum sulfate and one tote of caustic soda in each outer application zone.

“Turbidity” is probably Asheville’s word of the year — it’s been thrown around a lot, so let’s quantify it. Turbidity, which is the cloudiness of water caused by suspended particles, is measured in Nephelometric Turbidity units (NTUs). The Water Resources Department is aiming for 1.5-2 NTUs before putting potable water back into the system. To get a measurement of current levels, crews record the maximum turbidity over a 24-hour period.

As of the morning of Monday, Nov. 4, the North Fork reservoir’s turbidity was ~18.5 NTUs. Between Saturday afternoon and Sunday afternoon, the turbidity was 19.7 NTUs, meaning that the second round of treatment has greatly increased the rate at which the water is clearing.

A final decision has not yet been made, but according to Chandler, it is very likely that a third round of treatment will be applied early next week.

That treatment plan is still ongoing, but thanks to the US Army Corps of Engineers (USACE), our Water Resources Department has a second option at its disposal. The USACE is in the early stages of constructing mobile treatment units at the North Fork reservoir, situated in a clearing above the dam. It hasn’t yet been determined how many will be in place or what size the units will be, but the USACE has said that it will be able to treat 25 million gallons per day — which would be enough to keep the system pressurized and complete the flushing process (we’ll clarify that in a second).

In a very simplified way, these mobile treatment units contain sedimentation plates that are able to remove almost 100% of the sediment in the water. They take the water out of the reservoir, get its turbidity down to 1-2 NTUs, then plug it back into our treatment system.

Planning for this backup treatment started at the beginning of October, and after the USACE got the go-ahead from its chain of command on Oct. 30, crews began the procurement process for material and personnel. They will be working 24 hours a day until the system is operational.

The in-reservoir treatment will continue concurrently to maximize redundancy.

According to information from the USACE, Chandler said that the mobile treatment unit project could possibly be operational by very late November or very early December.

Because it is a construction project, there are a lot of variables outside the control of the crews, like weather, procurement schedules, and regulatory requirements. But, Chandler added, “We are very, very hopeful and optimistic that by early December — based on information we have right now — this system will be operational.”

Unlike our water, though, let’s be clear. That doesn’t mean that potable water will start flowing in early December; there are a few more steps in the process.

Regardless of which treatment works first, once the turbidity numbers are where they need to be, it will still be two and a half to three weeks before potable water is flowing in the system. Crews will submit a plan to the EPA, then kick off the flushing process, which will involve testing, draining nonpotable water from tanks, and then adding potable water to the system. When the potable water is ready, the two won’t be mixed.

According to Chandler, the department doesn’t expect an interruption in service when this happens.

This map looks full, but it is not meant to denote that everyone in the highlighted areas has service; restoration is just substantial in these areas.

Map via City of Asheville

Progress has been made, but don’t forget that the water coming out of our taps is still nonpotable and under a boil water notice. That notice will not be lifted until all water has been treated to ensure safety. As we move toward full service restoration, there are some steps you need to take before water returns and once you see it flowing.

Because this water will contain a lot of sediment, you want to ensure it doesn’t damage your appliances and home system.

When you begin receiving water, it’s crucial to flush your pipes. A lot of dirt and sediment have entered the system through damage or just while they were sitting unused, so you need to get all that out to help clear your water. To flush your private lines, simply run water in a bathtub faucet or outdoor faucet (essentially, any faucet that doesn’t run the water through a filter, screen, or aerator) for about 15 minutes. After flushing, you can turn your water heater and other appliances back on and flush your toilet.

Once the system has been flushed, the water will start looking clearer — but it still isn’t safe for consumption. It is safe for laundry, handwashing, washing dishes, and showering, but it is still under a boil water notice and there are some steps you need to take to use it safely for these purposes. Check out the City of Asheville’s frequently asked boil water notice questions for more details.

Woody also emphasized that water crews can use residents’ help. To restore water to the whole city, all pipe leaks have to be fixed, and you shouldn’t assume that crews know where the breaks are. If you see a leak, call the Water Resources Department customer service at 828-251-1122.

Drinking water as well as nonpotable water can be found at these city and county distribution sites:

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