Asheville’s North Fork Reservoir will get another turbidity-reducing mineral treatment next week, as the lake’s murkiness continues to decline.

At Friday’s daily Tropical Storm Helene briefing, Asheville Water Resources spokesperson Clay Chandler said the key turbidity level dropped again since Wednesday, falling below 17 Nephelometric Turbidity Units (NTUs) by Friday morning, about a 1 point drop from Wednesday. Also, the amount of lake water the city is able to push into the system for filtration rose from 17 million gallons to 19 million, also a good sign as the city slowly heads toward providing potable water again.

The ultimate goal is to get turbidity down to 1.5-2.0 NTU, which would allow for optimal filtration.

Helene devastated the city’s water system Sept. 27, knocking out transmission lines from North Fork, which provides 80 percent of the city’s drinking water, and leaving the 350-acre lake a murky mess. Chandler said North Fork’s output capacity hovered between 17 million and 19 million gallons Thursday, until a 16-inch water line on Patton Avenue broke in the afternoon.

“And if you were anywhere in the area of Patton Avenue yesterday afternoon, you saw water on the street, but that’s been fixed,” Chandler said. “So that’s a good example that our ability to push treated water into the system is going to depend, obviously, on turbidity continuing to fall and no major breaks in the system.”

The city is pursuing a two-pronged approach to restoring potable water: reducing the reservoir’s turbidity through the installation of turbidity curtains to still the water, coupled with a four-day application next week of aluminum sulfate and caustic soda; and pursuing the installation of an Army Corps of Engineers mobile treatment facility at North Fork to treat high-turbidity water.

“They have verbally awarded the contract to a contractor for that project,” Chandler said of the Army Corps of Engineers. “That contractor will be on site early next week for a site visit, and the build-out will begin shortly after that.”

The timeline for that project’s completion remains late November or early December. Chandler explained that while the equipment, which allows filtration of high-turbidity water, will come in on trucks and is considered mobile, it still requires some construction, as well as determinations on what size of equipment is most appropriate.

“There is a lot of piping that’s going to have to be installed,” Chandler said. “Just right now, our estimate is that the piping is probably going to take up most of the build-out time. It’s not just a few feet — it could be as much as a couple of thousand feet.”

Additionally, the units have to be laser-leveled when set into place, as even a small amount of unevenness could cause problems or even damage. 

Asheville Watchdog asked Chandler why the city initially said it could not process North Fork water until the turbidity level had dropped to 1.5 to 2 NTU but is now filtering 19 million gallons a day of water with 17 NTUs.

“We’re able to push treated water into the system due to the change not only in the overall level of turbidity, but also in the density of the turbidity-causing material,” Chandler said after the briefing. “Initially, the turbidity was thick mud, which would obviously wreak havoc on our filters. Since then, the overall level has lowered and the particles have ‘slimmed up,’ so to speak, so they can be washed out of the filters.”

By comparison, the water in the city’s Bee Tree Reservoir in Swannanoa remains a thick mud with a turbidity in the 140 NTUs range, down from more than 200 initially, he said.

The city needs North Fork to reach 27 million gallons of water per day being treated and sent out to fully pressurize and flush the system. That flushing and repressuring could take two to three weeks, Chandler has said previously, so a return to potable water could still not come until mid-December.

Chandler also noted that North Fork’s 20,000-plus acre watershed sustained “significant tree loss” during Helene, including from a possible tornado that twisted off trees half-way up. 

“We don’t expect the quality of the water to decline,” Chandler said. “The tributaries that are pushing water into the North Fork Reservoir now are crystal clear.”

Starting next week, a contractor will begin the city’s third application of aluminum sulfate and caustic soda at North Fork. The materials help clay particles coagulate and sink, leaving clearer water to filter. 

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. John Boyle has been covering Asheville and surrounding communities since the 20th century. You can reach him at (828) 337-0941, or via email at jboyle@avlwatchdog.org. The Watchdog’s local reporting during this crisis is made possible by donations from the community.  To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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Tropical Storm Helene damaged or destroyed as much as 40 percent of the trees in  Buncombe County, not counting the tree cover in Asheville, appraisers for the North Carolina Forest Service concluded in a new assessment of timberlands released Thursday. 

In all, nearly 822,000 acres of forestland were damaged, and in some cases flattened entirely, throughout the 17 counties in western North Carolina impacted by the most powerful storm to hit the region in 35 years. 

“The heaviest damage was confined to a six-county area with Buncombe and McDowell counties being at the center of this area,” the N.C. Forest Service report noted. An estimated 89,440 combined public and private acres of Buncombe’s 223,600 total tree acreage were damaged by the storm. Appraisers put the value of the lost timber at $19.3 million for Buncombe alone.

McDowell forests saw 130,805 acres of damage. Yancey County had the most expensive losses, $27.5 million. According to a heat map of the damage, the worst damage occurred just east of Buncombe in McDowell County.

The estimates do not include an assessment of urban settings like Asheville, according to the report. 

“No attempt was made to assess urban or landscape trees during this survey,” the report said. “Storm impacts related to urban trees are difficult to quantify by aerial survey and determining values of urban trees involves a complex process.” 

The Forest Service is urging homeowners to contact a qualified arborist to assess and provide guidance with urban and landscape trees.

The loss of such a large portion of the ecosystem can have several negative effects, such as the threat of wildfires due to increased fuel levels, loss of vital wildlife habitat, impacts on watershed health, and the higher potential for invasive species to thrive, the U.S. Forest Service remarked in another report last week. 

It will grow back

Overall, Helene’s devastation ransacked 17 western North Carolina counties and crippled 821,906 acres, with timber losses estimated to be $213.7 million, according to the report.

“Our damage estimate indicated that over 27% of the forestland in the affected counties received some level of damage,” the report found, noting that the damage was not evenly distributed.

“This is probably the most severe that we’ve had in the state since Hurricane Hugo in ‘89 and Fran and ‘96 as far as wind damage,” said James Slye,  head of N.C. Forest Service’s forest health branch.

Areas damaged are not total losses, Slye said. Though some were devastated, with hundreds of contiguous acres flattened, others had more moderate damage, like loss of leaves and top limb breakage.

“The individual that has a stand of trees that they potentially would harvest at some time, is looking at that and saying, ‘Okay, my timber is now on the ground, so I’ve got a loss here,’” Slye said. “We don’t view it that way.” 

Although people who owned forested land and intended to sell their timber certainly lost something, the acres aren’t lost as forest land.

“They’re going to regenerate,” Slye said. “If you want to look at it from an ecological standpoint, it’s a forest disturbance. And forest disturbances happen all the time on large scales or small scales.” 

Events like Helen are constantly altering the shape of forests, but they’ve come back. All that’s changed is the age structure of the forests, Slye said.

Even areas that lost every single tree will grow back.

“If you got an area that was relatively lightly damaged and has some trees down, some trees standing … you might end up with a multi-aged forest stand right there that you know 50, 60, years from now you’re looking at two or three different age classes in that forest.” 

Regeneration could be obvious as soon as next year, Slye said. 

“Think about an agricultural field that just gets abandoned,” he said by way of example. “If you look at that site five years down the road, you’ve got tree cover on it, all kinds of stuff starting to come up.”

N.C. Forest Service will be monitoring the damage yearly. Slye said the department tries to conduct aerial surveys of 20 percent of the state to survey the forests each year.

It also has offices in every county, equipped to help manage tree loss on an individual scale. 

“The people in the public that have concerns about their trees or their forest stand or individual trees, they can reach out to our county office, and [agents] will come out, take a look and give them some management advice,” Slye said.

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. Andrew R. Jones is a Watchdog investigative reporter. Email arjones@avlwatchdog.org. The Watchdog’s local reporting during this crisis is made possible by donations from the community. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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