GOVERNMENT
By Adam Powell
Correspondent
As the Town of Chapel Hill moves forward with long-term planning for a well-situated area for residential development along Legion Road, one concern for town leaders and neighbors alike is the ongoing maintenance of Legion Pond.
The three-acre, man-made Legion Pond, constructed in the 1960s, sits within a 13-acre watershed. The pond was originally part of a 36.2-acre tract of land owned by American Legion Post 6, which had its meeting hall at 1714 Legion Road for decades.
Originally a stock-watering pond, it is fed by a spring or alternate water source that must be identified before residential construction takes place on the adjoining property.
In 2017, American Legion Post 6 sold the 36.2 acres to the Town of Chapel Hill. Over the ensuing seven years, the town has sought to figure out the best way to utilize the land, while also mitigating any potential issues with the pond.
The town is seeking to establish affordable housing in the area as part of its long-term strategy to increase Chapel Hill’s housing supply through an increase in so-called ‘missing middle’ and affordable housing starts.
A report conducted by engineering firm Garrett & Moore in the spring of 2023 and presented to the Chapel Hill Town Council in May 2023 indicated that a failure of the Legion Pond dam would cause substantial damage to surrounding areas.
“The dam is considered ‘high risk,’ and it is not safe to leave it in its current condition,” said former Chapel Hill Mayor Pam Hemminger.
Garrett & Moore’s analysis also indicated that Legion Pond will also have to be completely drained before any construction work can be completed.
“A necessary step to help us determine how to move forward will be to drain the pond and keep it empty through one growing season,” the former mayor added.
Another assessment of the pond—this one undertaken in 2024 by environmental engineering firm Tetra Tech—included hydrologic and hydraulic model dam analyses.
The firm expressed in its opening statements that maintaining the status quo for the dam—or conducting rehabilitation that would keep the pond in its current form—was not feasible over the long term.
“The ‘do nothing’ approach, rehabilitating the pond and keeping it the same size, was quickly ruled out in group discussion,” Tetra Tech explained in its memo to town leaders. “Factors considered by the group included downstream impacts, flooding, operation and maintenance, dam failure, and future affordable housing plans.”
Tetra Tech recommended two possible options to mitigate the dam’s structural integrity, One is the construction of a structured wetland on the Legion Pond space, while another option was to reduce the size of the pond.
“Rehabilitating the pond dam, lowering the pond dam, and reducing the pond size was deemed possible,” Tetra Tech explained.
“The Town has been working with an engineering consultant to determine the next steps for the Legion Property pond. Based on their professional assessment, we will replace the pond and dam with a constructed wetland,” the Town stated on its website earlier this summer.
In detailing the new wetland space, Tetra Tech indicated that ‘the dam and pond are removed and replaced with a constructed wetland which increases space available to accommodate the future affordable housing draining area (for the proposed affordable housing community to be built).”
Along with a smaller surface area, plans call for a shallow open water space, fluctuating between six inches and three feet in depth. According to the engineer, non-invasive local plants that could potentially be introduced to such a constructed wetland include marshmallows, cardinal flowers, and black-eyed susans, among other types of fauna.
In addition to the constructed wetland concept for the pond as a whole, Tetra Tech recommended a wide range of proposed fixes to the Legion Pond dam, including removal of all trees and improper vegetation along the dam, the installation of a 25-foot-wide articulated concrete block spillway, replacement of the existing spillway pipe with a permanent self-priming 8-inch PVC siphoning system, and the construction of a new rip rap plunge pool to go along with the establishment of new grass and ground cover around the perimeter of the wetland.
The town provided four bullet points as to why they elected to go with the structured wetland option.
“A constructed wetland is a vibrant and biodiverse water feature that is well-suited for the property’s future,” the town explained. “It will meet both the water containment and stormwater management needs on the property. It will allow for the development or affordable housing along the front of the property. It will provide numerous walking, environmental education, and engagement opportunities.”
Nearby neighbors don’t necessarily agree with the town’s position on the constructed wetland. They share concerns that it could become a breeding ground for mosquitoes and other invasive species.
There is also a debate surrounding the hydrologic report, which indicated that rainfall runoff would be the primary source of water for the structured wetland, even though the current Legion Pond is fed by an additional water source that must be identified during the initial stages of construction following the pond’s draining.
Mosquitoes require stagnant water, with their eggs floating in so-called ‘rafts’ on the water’s surface, to thrive. A well-constructed and maintained stormwater pond will keep the water flowing effectively through the space, forcing the mosquito egg rafts out of the space relatively quickly, in a matter of days.
The structured pond planned by town staff will ensure that there are not large supplies of animal waste products and other nutrients essential for mosquitoes and other invasive species to thrive in and around the pond water, hopefully reducing the risk of mosquito breeding throughout the pond.
The process is still in its relatively early stages, as the town still must design a structured wetland apparatus before applying for the necessary environmental regulatory permits. Construction can begin on the damaged dam and surrounding landscape only after the permits are obtained. The town will also assess potential wildlife impacts in the local area while making final preparations for construction.
The work on the structured wetland will realistically begin in early-to-mid 2025 at the earliest. The first phase of construction will include draining the pond, demolishing the original pond, and building the new structured wetland, which will run into 2026.
From there, the town plans to apply for low-income housing tax credits (LIHTC) for affordable housing funds that would allow for the completion of an affordable housing development on the property surrounding the new structured wetland. Assuming the LITHC process goes through successfully, construction could feasibly begin sometime in 2027.
Adam Powell is a reporter on local news and sports and an education communications professional. A 2001 graduate of UNC-Chapel Hill, Powell has served as managing editor of multiple local publications, including the Mebane Enterprise, News of Orange County and TarHeelIllustrated.com. The public information officer for Rockingham County Schools in Eden, N.C., Powell is the author of four books and lives in Mebane with his wife and two children. This reporter can be reached at Info@TheLocal Reporter.press
Has anyone noticed that the Legion pond never goes away? During drought, the pond is there and full of water. It does not dry up. During rain, the pond is there and draining through the pipe system on one side of the dam. That means that the pond is fed heartily through underground streams. Those streams will not go away. The pond cannot just be removed. It is currently its own balanced system – receiving and moving water safely through that area. Supporting wildlife in a way that even controls mosquitoes. Its an ecosystem that works incredibly well. Why change it?