Cube requests change to 401 certificate

Published 10:10 am Tuesday, July 23, 2019

Cube Hydro Carolinas plans to request a change be made to its 401 Water Quality Certificate to incorporate new technology into its High Rock and Tuckertown sites.

The certificate currently demands the use of a Howell-Bunger valve, but Cube wants the language changed to allow for the use of a linear cone valve.

Jody Smet, director of the Federal Energy Regulatory Commission (FERC) licensing and compliance for Cube, said Wednesday evening the Howell-Bunger valve is “proven technology.” However, she and Neal Simmons, vice president of research and development and optimization, said even still, the Howell-Bunger valve has several disadvantages.

The Howell-Bunger valve shoots water out in a cone, with part of the water immediately going back into the body of water below while the rest shoots outward longer. The water that is almost immediately deposited downward has less chance to become oxygenated than the water that is shot out farther.

The Howell-Bunger valve takes months to install, Simmons said.

Adding it requires a hole be made in the dam, which Cube would rather avoid, Smet said.

Smet said other issues include its effect on the dam as a National Register of Historic Places-eligible site.

The linear cone valve developed by Cube fixes those issues, according to the company.

Because the water is sent out in a sheet rather than a cone, the water as a whole goes up and out, letting more of the water become aerated, Simmons said. No hole is required in the dam and installation only takes about a week. It does not affect the look of the dam, can be set to “self-regulate flow or vary oxygenation,” and is “safer for downstream recreation,” Cube claimed in the presentation.

The only two issues Cube notes with the technology are it is a “new solution with limited field experience” and it is “limited to facilities with spillways, such as the facilities on the Yadkin River.”

While it is new, the linear cone valve has been tested and data shows the dissolved oxygen level is higher when the valve is opened.
Cube’s analysis compared the percentages of times the water quality was over the standard set by the state. The numbers show an increase from 2018 to 2019 numbers at High Rock, Narrows and Falls.

At Falls, the average went from 88.6 to 100 percent. At High Rock, it was more drastic, increasing from 51.4 to 98.6 percent.
Cube compared the information from May and June 2018 and May and June 2019.

The dissolved oxygen levels at High Rock and Tuckertown “periodically fall” below state standards from May through November, according to the presentation. But “Cube Yadkin understands the importance of meeting water quality standards, including DO,” it noted in its presentation.

This new valve was created in part to help reach that goal.

Ann Brownlee, president and founder of Trading Ford Historic District Preservation Association in Salisbury, said she has no issue with the use of the valve.

Smet said she plans to send a letter to the North Carolina Department of Environmental Quality requesting the change by the end of August, but the deadline for the request is Sept. 15.

According to Smet, Cube will not ask for any other details of the certificate to be changed.

Imari Scarbrough is a freelance contributor for The Stanly News and Press.