Tuesday, July 23, 2024

‘Most degraded watershed in the county’ to be restored with green infrastructure

Of the 12 watersheds in New Hanover County, the more-than 5,000-acre Pages Creek is “the most degraded in the county,” according to New Hanover Soil and Water Conservation District Director Dru Harrison. The county is working to preserve it by installing living shorelines. (Port City Daliy/File)

WILMINGTON — Development surrounding the Pages Creek watershed has caused poor water quality, more contaminated stormwater runoff, and high levels of pollution. New Hanover County is preparing to solve these problems with green infrastructure. 

READ MORE: Pages Creek pollution isn’t a new phenomenon 

Starting with a preliminary site visit on Thursday, Pages Creek will see the installation of living shorelines, or barriers made of natural elements like sand, rocks, and plants. 

Of the 12 watersheds in New Hanover County, the more-than 5,000-acre Pages Creek is “the most degraded in the county,” New Hanover Soil and Water Conservation District Director Dru Harrison said at an informational presentation during the Feb. 19 New Hanover County commissioner meeting.

The creek is a crooked pitchfork of a waterway, with the tines beginning inland at Bayshore, and flowing past residential neighborhoods, marinas, and a medical supply store before feeding into Goodman’s Channel, through which the water runs out to the Atlantic Ocean. 

According to Harrison, the installation of living shorelines will cost $250 per square foot and will likely be made of recycled materials. 

Living shorelines are used to stabilize coastal areas by diffusing the damaging effects of severe weather like hurricanes, and furnish local wildlife with suitable habitats. Some of these effects reinforce each other, like oyster reefs blunting dangerous waves. 

There is no price tag attached to the entire restoration yet and costs will vary depending on the area. A company will be selected in a future bidding process if the project’s cost exceeds $30,000 with the job awarded to the lowest bidder. 

Its restoration is part of a plan conceived in partnership between the New Hanover Soil and Water Conservation District, Cape Fear Resource Conservation and Development, and Raleigh-based civil engineers Moffatt and Nichols.  

To lessen the threat of flooding and improve water quality, Harrison said streets and lots near Pages Creek would be retrofitted with permeable pavement. The watershed is now around 17.8% impermeable surfaces. 

According to the Environmental Protection Agency, permeable pavement absorbs water into the soil below rather than diverting precipitation into runoff. This form of pavement may also require less upkeep and therefore have lower maintenance costs and filter pollutants from the water. 

A plan to address the issues of the Pages Creek watershed was commissioned by the county two years ago. The official Pages Creek Watershed Restoration Plan was adopted at a January board of commissioners meeting.

Its primary goal is to improve water quality by preventing contamination from stormwater runoff caused by development, which will bring both economic and environmental benefits.

Environmentally, the plan increases the tree canopy, adding greater numbers of native plants as cover, and soil amendments. According to the NC State Extension, they are items used to beneficially alter the properties of soil, which in this case will also serve to decrease runoff and mitigate pollutants. 

Harrison told commissioners the main source of contamination is stormwater runoff, which has increased around 20% since 2001. The plan’s goal is to return the levels to the measurements of two decades ago, when the average runoff was 97 cubic feet per second. For comparison, the average runoff in 2023 is 172 cubic feet per second. 

In turn, the main source of stormwater runoff is development and the non-natural surfaces that accompany build-outs. 

The residential areas around the creek were constructed throughout the last decade. Not coincidentally, Pages Creek has received a poor rating based on the high levels of fecal contamination in the previous 12 years. According to Larry Cahoon — a UNC Wilmington oceanographer — the level of contaminated water is measured with two bacteria as metrics: fecal coliforms and fecal enterococcus.

“Humans also bring new sources of fecal pollution with them, dogs especially, and stimulate the presence of wildlife that associate with humans, such as geese, raccoons, etc.,” Cahoon said.

He added other sources can contribute to high levels of fecal contamination, such as pollution being introduced to an environment through rain and groundwater. 

“The central sewer system in that watershed is old, dating back as far as the 1980s,” Cahoon said, “and was poorly constructed and maintained for many years. There are various vehicles and vessels that may have onboard waste systems that are not properly managed as well.”

The plants in Pages Creek are unhealthy as gauged by their low levels of essential chlorophyll. Unhealthy vegetation leads to more flooding because healthy vegetation serves as a bioregulator. 

“Bioretention — think of it as a garden that is a sponge,” Harrison said. “It holds that rainwater between the point at which it originates and where it would go into the creek. A living shoreline not only absorbs bacteria, it helps reduce erosion.”

“It has a double effect,” Commissioner Rob Zapple said at the February meeting. “One, it works in our environment, but also it demonstrates to all of our community, all our citizens who come by and look at it and say, ‘Oh, I could make that happen in my yard.’ Bioretention, it sounds like it’s a fancy term, but it’s actually pretty darn simple and is incredibly effective.”

Cahoon stated it’s the county’s responsibility under the Clean Water Act to improve the water quality so it matches the North Carolina Department of Environmental Quality’s rating. 

The NCDEQ currently classifies the surface waters of Pages Creek as Class SA, which means the water in that area could be used for commercial shellfishing. The suitability of an area for shellfish harvesting is decided by the NCDEQ by using a variety of metrics, including the impact of rainwater and stormwater runoff.

“There was a small shellfish lease there years ago, in addition to natural oyster and clam populations open to harvest,” Cahoon said. 

Harrison said at the meeting half of Pages Creek is closed to shellfishing because it’s unsafe.

“[It’s] miserable to close so much of Pages Creek to shellfishing,” Zapple said at the meeting. 

Shellfishing is a major industry on the North Carolina coast. Much of this activity is conducted in Pender County; Pages Creek is just south of the New Hanover and Pender county borders. 

Oyster harvesting as a whole in 2022 brought $31.66 million into the state’s economy. That same year there were 283 North Carolinians working in oyster mariculture, according to data from NC State.

The DEQ limits the quantity of shellfish that can be harvested regardless of the pollution. According to the department, oysters’ immobility makes them far more vulnerable to the effects of pollutants and destruction of their environment. 

Pages Creek’s pollution has become more noticeable in the last decade and not all of the pollution is anthropogenic. In 2015, roots growing into a manhole by the intersection of Scorpion Drive and Bayshore Drive caused a sewer overflow that spilled 4,500 gallons of wastewater into Pages Creek. 

In 2022, measurements of the creek also registered high levels of fecal bacteria and was heavily polluted by runoff, an increase attributed then to the development around Pages Creek. 

Harrison explained the next steps toward cleaning up Pages Creek are to hold meetings with communities and stakeholders and look into obtaining an EPA 319 Grant. These are distributed to states and territories to cover a variety of expenses. 

The plan is set to unfold over the next decade and will continue to track fecal contamination and stormwater runoff levels on a yearly basis. The plan will be updated yearly if required and final evaluation is projected for year 20, when, if deemed necessary, the plan will be extended. 

Harrison said the Pages Creek watershed has the potential to be pristine. 

“Do I think the county’s project will restore shellfishing to Pages Creek? I’ll believe it when I see it, but we have to try,” Cahoon said.

[Editor’s Note: This article has been updated to correctly attribute Cape Fear Resource Conservation and Development as a partner, remove an incorrectly attributed statement, and clarify the project’s final evaluation process. Port City Daily regrets these errors.]

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