Exceptional test of restoration project a success
Twelve Mile Creek in Mobile, Alabama had been experiencing significant degradation and instability, excess sediment, and the expansion of invasive species. The Mobile Bay National Estuary Program (MBNEP) engaged Stantec to restore a segment of Twelve Mile Creek, including restoring ecological function to the existing streams, floodplains, and riparian corridors. The project withstood Hurricane Ida after being completed just days prior.
Hurricane Ida, a Category 4 storm with winds of over 150 miles per hour upon landfall, overwhelmed the Gulf Coast with multiple tornadoes and flooding rains of up to 11 inches over several days shortly after completion of the project. Despite the severe test of the design improvements so closely following construction completion, the Twelve Mile Creek restoration of over 1,700 feet of stream remains intact.
“This headwaters restoration was a priority project identified in the Three Mile Creek Watershed Management Plan and is the first phase of a comprehensive restoration of Twelve Mile Creek, in partnership with the City of Mobile, with an objective of reducing stormwater volume and sediment being delivered downstream into Langan Park Lake,” according to Christian Miller, Watershed Management Coordinator at MBNEP.
The MBNEP, one of 28 federally authorized NEPs administered and funded by the EPA, works collaboratively with landowners, local governments, agencies, and contractors to implement effective watershed restoration projects in Coastal Alabama. To restore the headwaters of Twelve Mile Creek, the MBNEP applied for and received RESTORE Act funding under the US Environmental Protection Agency Gulf National Estuary Program Comprehensive Plan Implementation Program.
“While you never anticipate a hurricane or tropical storm to immediately test a newly constructed restoration project, this is exactly the type of significant challenge that we need to demonstrate the strength and importance of working with nature rather than against it,” said Stephanie Coffman, River System & Basin Management Program Lead and Senior Principal at Stantec. “We are so fortunate to have had the opportunity to work with such a collaborative project team where our efforts were focused on making this restoration successful not only for the local area, but for the watershed.”
The Stantec team developed a design that reestablished a more natural channel and valley form, provided floodplain connectivity, and restored the riparian corridor. These goals were achieved while maintaining proper stormwater conveyance and protecting critical infrastructure. The stream design incorporated mostly wood-based structures and restoration efforts also included bank stabilization, floodplain grading, and the reestablishing of native vegetation in the area.
For more than 30 years, Stantec has been a national leader in river restoration, fluvial geomorphology, channel assessment and stability design, sediment transport analysis, fish passage, the restoration of native riparian systems, and recreational access amenities. Stantec has completed over 2,000 miles of stream restoration and assessment projects across the US with successful projects implemented from coast to coast.