Staff from Geosyntec and from ATM, a Geosyntec Company, presented at the 24th Annual Conference of the North Carolina Beach, Inlet, and Waterway Association at Aloft Wilmington, in Wilmington, N.C. Alessandra Braswell, Ph.D., P.E., (North Carolina), from Geosyntec, presented “Lake Mattamuskeet Watershed Active Water Management Project: One Year Later” at 1:40 EDT on Friday, November 5, 2021. Francis Way, P.E., (South Carolina) from ATM, presented “Seabird Nesting Habitat Restoration in Charleston Harbor” at 2:05 EDT on Friday, November 5, 2021.

Alessandra Braswell is a Water Resources Engineer who specializes in urban stormwater management, stormwater master planning, and sedimentation modeling. Her experience includes development of watershed-level water management strategies for coastal resiliency; planning, design, and permitting of stormwater control measures for public and private land development projects; National Pollutant Discharge Elimination System permitting compliance; hydrologic and hydraulic modeling for flood control; sedimentation analyses; green infrastructure and low impact development design; expert witness support to evaluate compliance with stormwater management regulations; erosion and sediment control design for linear construction projects; and development of stormwater ordinances and other technical documents.

Francis Way is a Senior Coastal Engineer with more than 19 years professional experience in coastal, environmental, and water resources engineering. He specializes in coastal and water resources analyses and permitting, modeling, beach nourishment, dredging and navigation studies, and shoreline stabilization projects. He completes hydrodynamic, water quality, flushing, watershed, sediment, and wave modeling as well as field data collection, data mining, and statistical and time series analyses. Francis has been with ATM for 18 years and provides services in Florida, Georgia, South Carolina, North Carolina, and the Caribbean.

The North Carolina Beach, Inlet, and Waterway Association is dedicated to preserving, protecting and enhancing North Carolina’s coast by merging science and public policy in order to create a sustainable and resilient coast. The association works on behalf of its members by encouraging government action and funding, educating and advocating for effective federal and state policy, and facilitating environmentally sound scientific and engineering solutions for threatened beaches, inlets, and waterways.

Lake Mattamuskeet Watershed Active Water Management Project: One Year Later 

Lake Mattamuskeet, the largest lake in North Carolina, occupies approximately 40,000 acres in flat-lying, generally agricultural Hyde County and anchors the Mattamuskeet National Wildlife Refuge. Flooding frequently occurs in the lake watershed due to an insufficient gravity drainage system, sea level rise, and extreme weather events. Additionally, the lake is listed under Clean Water Act Section 303(d) for impairment arising from elevated pH and chlorophyll-α, and the population of submerged aquatic vegetation has largely declined in the last several decades. To address these impairments, a coalition of county, state, and federal stakeholders collaborated to development a watershed restoration plan. In 2020, after securing funding through the Clean Water Management Trust Fund and North Carolina General Assembly, Hyde County contracted with the North Carolina Coastal Federation to implement its watershed restoration plan, key initial objective of which is the establishment of active water level management. The federation contracted with the team of Geosyntec and Coastal Protection Engineering to conduct a study of engineering active water management options.

This presentation provided an overview of the project, which began in early summer 2020 and is planned to be completed by October 2021. The presentation discussed the study outcomes, including the modeling approach and results; active water management alternatives considered; the selected alternative and its engineering design; and the efforts to foster robust public engagements focused on the specific goals of the plan. Future work planned, including additional data collection and modeling, were also discussed.

Seabird Nesting Habitat Restoration in Charleston Harbor

The US Army Corps of Engineers (USACE) plans to restore the Crab Bank Seabird Sanctuary, located at the mouth of Shem Creek in Charleston Harbor, using dredged material from the ongoing harbor deepening project (“Post 45” Deepening). This federal beneficial use of dredge material project will restore 32 acres of critical high nesting grounds through the one-time placement of roughly 660,000 cubic yards of compatible dredged material. While the USACE conducted an analysis on the placement and size of the nesting habitat, the Town of Mount Pleasant had some concerns that the proposed project would inadvertently and detrimentally impact Shem Creek. The town noted that the currently eroded Crab Bank had migrated about a quarter-mile since its creation in 1958, that the proposed 660,000 cubic yard project was about twice as large as the 1958 placement, and that Shem Creek is a vital component of the Town’s tourism, recreational boating, and commercial fishing. 

ATM began working with the Town of Mount Pleasant in 2019 to ensure that Shem Creek would not detrimentally impacted by the proposed project. Based on ATM’s review of USACE documents, the accretion/sedimentation effects of the proposed mitigation on the Shem Creek mouth area were not modeled, since the review indicated that the dredge material placed on Crab Bank would erode and this eroded material had the potential to significantly affect resources and sediment processes in the area. Given this finding, ATM advised that the fate of the placed material and the projected evolution of the restored bank warranted investigation. ATM conducted these analyses and worked with the Town to move the location of the proposed project. The Town/ATM team and the USACE had several meetings and negotiations over the last few years to come up with a revised placement location (known as ATM3) that satisfies the Town’s concerns while also restoring a much-needed seabird nesting habitat. The construction of Crab Bank is slated to occur this winter and the Town/ATM team will continue to monitor the project’s progress. 

More Information

About the event: www.ncbiwa.org/events/upcoming-events/ 

About North Carolina Beach, Inlet and Waterway Association: www.ncbiwa.org For consultation regarding water resources and coastal management and engineering, contact Alessandra at abraswell@geosyntec.com or Francis at fway@appliedtm.com.

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