Building N.C. 540 across southern Wake County would not threaten the existence of two endangered species of mussels that live in Swift Creek, according to the U.S. Fish and Wildlife Service.
That opinion, published last week, greatly reduces the chance that the Federal Highway Administration will seek to stop or alter construction of the final legs of the Triangle Expressway because of the endangered mussels — the dwarf wedgemussel and the yellow lance.
The two types of thumb-size mussels have for years threatened to alter or derail the $2.24 billion final leg of the 540 loop around Raleigh. The endangered dwarf wedgemussel was the reason the N.C. Department of Transportation considered an alternative path for the road known as the Red Route, which would have largely avoided the mussels while plowing through subdivisions, businesses and churches in Garner.
Instead, NCDOT consulted the U.S. Fish and Wildlife Service on other ways it could minimize the highway’s impact on the mussels. These include steps to prevent sediment from washing into the creek during construction and to eliminate runoff from the highway going directly into the water.
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NCDOT has also pledged $5 million to establish and operate a laboratory to study the mussels and raise young ones to be released into the wild in Eastern North Carolina. The lab, at Historic Yates Mill County Park south of Raleigh, would be used by researchers at N.C. State University.
The Fish and Wildlife Service says the mussel hatchery "fulfills an urgent need in the conservation and recovery" of dwarf wedgemussels in the Swift Creek watershed.
At the same time, the agency also concluded that building the road would likely have little effect on the mussels, if NCDOT and its contractors take care not to harm the creek during construction.
The agency also noted that more homes and businesses will be built in southern Wake County regardless of whether the highway comes through, and that the road will cause "a relatively small incremental increase in this development." It concludes that the impact of the additional development would likely not be "discernible or measurable."
A spokeswoman for NCDOT called the Fish and Wildlife Service's opinion an important step.
"We have collaborated with the U.S. Fish and Wildlife Service the last several years to work through any issues or concerns so both parties' expectations are met," Carly Olexik wrote in an email. "We will continue to collaborate with them as we apply for permits and work on the mitigation facility."
Environmental groups that oppose building the six-lane toll road are still reviewing the Fish and Wildlife Service's opinion, said Kym Hunter, a staff attorney for the Southern Environmental Law Center. The law center represents Sound Rivers and Clean Air Carolina, which say the benefits of building the highway don't outweigh the damage it will do to the environment in Wake and Johnston counties.
Hunter said the groups don't think the steps NCDOT plans to take, including the hatchery, are enough to conclude that the Triangle Expressway won't threaten the existence of the mussels. She notes that NCDOT's support for the hatchery would keep it running for only five years.
"Under this proposal, NCDOT's responsibilities to the mussels will have ended before 540 has even been constructed," she wrote in an email. "All NCDOT is doing is throwing $5 million at the issue without any ongoing responsibility to ensure the funds result in effective conservation."
NCDOT describes the proposed mussel hatchery in the Final Environmental Impact Statement, a report that spells out the possible effects of the final 28.4 miles of the Triangle Expressway on the natural and human environment. The state expects final approval of the environmental report by the Federal Highway Administration this summer, which would put it on schedule for contractors to begin construction next year.
The environmental law center could file suit to try to stop or modify the project. In December 2016, the center sued on behalf of the Sierra Club to try to stop a 10.3-mile highway that would carry U.S. 70 around Havelock and through a portion of the Croatan National Forest. The suit came after the Fish and Wildlife Service and the Federal Highway Administration had signed off on the bypass.
NCDOT and the law center announced Monday that they had settled the lawsuit, after state and federal agencies agreed to steps to protect stands of longleaf pine in the Croatan forest. NCDOT now expects to begin construction on the $221 million bypass in 2019, two years later than planned before the lawsuit.