Martin Marietta Materials hopes to increase the size of its limestone pit near Castle Hayne by 358 acres to meet the continued building demands of the Wilmington area. This expansion will affect 143 acres of medium- to high-quality wetlands.
The current Martin Marietta facility is located north of Holly Shelter Road in the northern part of New Hanover County, an area with several industrial facilities. The expansion would push the quarry north and east, bringing it closer to the Northeast Cape Fear River and Island Creek watersheds.
Below: Map of the proposed expansion.
Laura Oleniacz, public information officer for the North Carolina Department of Environmental Quality’s Division of Water Resources, explains, “The North Carolina Wetland Assessment Method is used in North Carolina to identify wetland types and their ecological function, and to assign a ‘high,’ ‘medium,’ or ‘low’ rating based on their hydrology, water quality, and habitat.”
She added, “High-quality wetlands are not fragmented or disturbed, they are connected to other hydrologic features, and provide robust habitat.” High quality wetlands provide excellent filtration for pollutants, help with storm water retention, regulate waterflow, and provide habitat for wildlife.
Medium-quality wetlands are typically smaller, with fewer connections to other wetlands or waters. Though they’ve been disturbed or altered, they still benefit the environment, Oleniacz said.
“Martin Marietta’s consultant did an assessment of the wetlands proposed to be impacted by the proposed mine expansion, and determined that most wetlands that would be impacted were of high quality, while the others were of medium quality,” said Oleniacz.
The project will also affect 9.7 acres of open water.
Roger Shew, retired geologist, told WHQR, “The lowland areas along Island Creek will be most impacted with quarry expansion/deepening. These lowlands/wetlands are part of what the NC Natural Heritage Program has deemed this the Northeast Cape Fear River Floodplain and recognized it as a nationally significant Tidal Cypress-Gum Swamp plant community.”
Shew continued, “If mining occurs, we should minimize removal of these wetlands and we should require a large buffer between mine site and the floodplain. The 50-foot vegetative buffer is not enough.” Shew proposed a 100-foot buffer at minimum, but thinks a 200-foot buffer would be most protective.
Shew added, “Modeling should be done to determine how large of a cone of depression will form [to] analyze the possibility of some sinkhole development [and] how much of a reversed hydraulic flow may occur from Island Creek.”
Even though the Cape Fear River would be impacted by this project, said Shew, “the smaller, lower flow of Island Creek would be more impacted as two of the Alternatives that Martin Marietta has proposed for expansion come very close to Island Creek and certainly its floodplain.”
“For mined areas, it will be extremely difficult, if not impossible, to restore a disturbed wetland area. And even with mining directly adjacent to the floodplain, without adequate buffers, the lowering of the water table [caused by] mining could negatively impact wetland species.” Shew said that when companies attempt wetland restoration, “it is rarely successful, certainly not restoring the area to its former uses/health.”
Martin Marietta proposed a 2:1 wetland mitigation meaning they would pay for credits in an existing site creating mitigation for a different project or they would buy into a fund that purchases wetland areas.
Shew said, “Loss or damage to a nationally significant floodplain, as identified by NC Heritage, is [not] adequately mitigated by a 2:1 ratio.” He continued, “Wetland loss can [not] be compensated; particularly if it is in another watershed or far removed from the area of interest.” Even though this is a standard process, Shew feels that “these significant wetlands should have a much higher compensation value.”
In Shew’s view, removing surface material for mining activities “effectively degrades the topsoil and surficial materials leaving them unable to continue to provide their ecosystem services of forage and habitat for wildlife, sediment and nutrient storage, carbon sequestration, etc.”
Martin Marietta Materials traces its origins back to Raleigh in the late 1930s, and later expanded through a series of mergers and acquisitions. The American-based company has been very successful; it’s listed on the S&P 500 and has operations in over two dozens states, Canada, and The Bahamas. The company is not related to the Martin Marietta Corporation, an aerospace firm which merged to form Lockheed Martin in the 1990s.
In 2001, Martin Marietta built a new plant on Grand Bahama Island. According to The Tribune, residents have complained continuously about the noise and cracks appearing in their foundations and walls caused by the company’s blasting since at least 2016. This year, a decade into the issues on Grand Bahama Island, the company, according to its website, rolled out new blasting rules to prioritize “being a good neighbor” across all its sites. Residents near the Castle Hayne mine continue to complain about disruptive noise from blasting and heavy equipment.
Many residents express concern about the overdevelopment of the Wilmington area, and its impact on flooding and stormwater.
Shew put it this way, “Northern New Hanover County is one of the last slightly undeveloped areas in New Hanover County…These areas have lots of wetlands and developments are more and more building on these wetter soils. Wetter soils are most often poorly drained leading to stormwater management issues. And of course removal of trees/natural areas reduces connectivity for wildlife biodiversity as well as aesthetic properties that are important for humans, too.” The more we develop these rural areas, the less space wildlife (both plants and animals) will have to live.
Experts like Shew say developing in wetlands harms our ability to survive floods that inevitably come with storms and hurricanes. Shew said that an important concern is “flooding that may occur from local and/or upstream large rain events. An example is Hurricane Florence. Florence inundated the Castle Hayne mine site, and in fact, the mine was shut down for months until the water could be drained from the mines. Almost all of the mine site is within the 100-year floodplain and is subject to flooding.”
If mining is allowed to expand, Shew recommends a measured approach because “giving a large area of approval does not allow for retraction of that approval if unintended consequences occur. I would advocate for monitoring during extraction and if no unintended consequences occur, to then allow them to come back for another expansion. Once harm occurs, it is difficult to correct.”
Given that Martin Marietta’s currently mined sites, as viewed from aerial maps, “have not been fully restored to even near pre-existing conditions [and] mine spoil areas are present at this mine and at their Rocky Point mine,” Shew believes, “there should be a few more requirements for restoration of the sites such as tree planting and natural area restoration.”
Note: WHQR reached out to Martin Marietta for comment, but has not heard back. We will update this article if we receive a response.
A public hearing will be held Tuesday, July 14 at 6 p.m. at Heide Trask Senior High School auditorium, 14328 N.C. 210, Rocky Point, N.C., 28457.
Written comments can be given at the hearing, online, or through the mail by August 13, at 5 p.m. Online comments can be sent through this link with the project No 20260387, version 1 and the project name listed as “Castle Hayne.”
Written comments may also be submitted via mail to Stephanie Goss, 401 Permitting, 1617 Mail Service Center, Raleigh, NC, 27699-1617. All comments received on the permit will be considered as part of the decision on this application.
