Swannanoa Floodbench and Constructed Wetlands Project SRP-SW-ARP-0026
In February 2023, the Town of Black Mountain received $5 million in ARPA LASII funding for the Swannanoa Floodplain Project identified in the Stormwater Master Plan Update. The LASH grant funding pays all costs associated with developing and constructing this project. The original project location included the North Bank of the Swannanoa River from Hwy 9 to 1-40 near the Community Gardens. In August 2023, the town solicited requests for qualifications for engineering firms to assist with the project scope and design. During the process, firms expressed varying concerns regarding the project scope and proposed time lines. Timelines are beyond the control of the town and all LASII construction projects in this grant must be completed and closed by the end of 2026. Failing to meet the required federal deadlines creates financial risk for the Town.
Due to the timeframe of the funding and project deadlines required by the federal government, the granting authority and Town determined pursuing this project at the original location was unachievable. In September 2023, both agreed to pursue an alternate project that is similar in nature which is also identified in the Stormwater Master Plan. The new project area will encompass two sites which are both located on town owned property and may be viewed in the Project Area tab below. The entire Project Area Map may also be viewed in the Documents section below.
Mandatory Pre-Response Conference
We will meet in the board room at Town Hall located at 160 Midland Ave., Black Mountain NC 28711
Deadline for Questions (written)
Town will Provide Final Response to Question(s) via Addendum(s) by this date.
Response Submissions DUE
Deadline for Town Approval of Design-Build Contract
Execution of Design Build Contract
Within 7 days after Town approval of design-build contract.
Engineering Report Submittal to NCDEQ
The Engineering Report must be developed using the guidance found on NCDEQ Website: (https://deq.nc.gov/about/divisions/water-infrastructure/i-have-funding/engineering-reportenvironmental-information).
ASAP after execution of design-build contract
Design Package Submittal due to NCDEQ
ASAP after award
Firm must be able to complete all the work and close the grant by the end of 2026.
December 31, 2026
*No reimbursements will be made after this date
The proposed Project area encompasses two (2) sites along an approximate 3,300 linear-foot reach of the Swannanoa River as further described below. The sites were identified in the Town’s Stormwater Master Plan Update (2022) as providing opportunities to mitigate flooding and improve water quality in the watershed. Projects on private property will require landowner participation which will be considered in the next steps to determine overall project viability.
A Project Area Map and Stormwater Master Plan Update (2022) may be viewed in the Documents section in the tab to the right.
Map Legend: Yellow= Stormwater Control Measure ; Blue= Floodway; Purple=Floodplain; Light Purple= 500 Year Floodplain
Site #1 Swannanoa River near Confluence with Flat Creek
Description: Approximately 7.25 acres lie in the regulatory (1%) floodplain along the south bank of the Swannanoa River west of Hemphill Road continuing along the railroad and to the trestle south of the Rivendale Apartments. Grading this area to establish a floodplain bench would reduce the erosive forces along the north bank and provide for water quality treatment during more frequent storms. The Project would reduce the requirement for “hard” bank stabilization measures on the north bank. Water quality benefits will be gained from establishing a floodplain bench and those benefits can be increased by incorporating off-channel pocket wetlands into the design.
Site #2 South Bank of Swannanoa East of Dog Park Between Norfolk Southern Railroad and Interstate 40
Description: The 2009 Stormwater Master Plan recommended a project that would involve floodplain benching and the construction of a roughly 6.5-acre wetland in the area along the south bank of the Swannanoa south of the railroad and north of I-40. The Project would improve the connection between the river and its floodplain and result in diverting flows from more frequent storm events into the constructed wetland for water quality treatment.
This State Water Infrastructure Authority (SWIA) has approved this project to receive nonmatching grant funds through the Local Assistance for Stormwater Infrastructure Investments (LASII) grant from the American Rescue Plan Act (ARPA). Grant funds will be one hundred percent of eligible project costs up to a maximum of $5,000,000. Projects funded by ARPA must meet applicable federal law and guidelines. The funding letter may be viewed in the Documents section.