Developing best management practices for coastal engineering projects that benefit Atlantic Coast shoreline-dependent species

Abstract

(ERDC-EL), to summarize known impacts on seasonal habitats used by migratory shoreline-dependent birds (primarily shorebirds and seabirds) and nesting sea turtles along the Atlantic Coast by U.S. Army Corps of Engineers (USACE) coastal engineering activities. The USACE is responsible for maintaining coastal infrastructure including ports, harbors, shoreline stabilization, and maintenance of the Intracoastal Waterway System (ICWW) along the Atlantic Coast. This infrastructure is essential to the long-term sustainability of national and economic prosperity by ensuring navigation through ports and harbors that transport goods necessary for national and international commerce. Coastal shoreline stabilization and sediment management can also provide opportunities for reductions in storm surge, flood control, residential growth, recreational activities, coastal habitat restoration, and fisheries management. Routine engineering actions by the USACE includes maintenance dredging and dredged material deposition, beach nourishment, inlet realignment and shoreline stabilization, and dike, sea wall, terminal groin and revetment construction. These actions can alter the shape, structure and function of coastal habitats, and have the potential for both positive and negative seasonal effects on shoreline-dependent organisms. The objectives of this technical note include the following: (1) introducing issues concerning coastal engineering impacts on shorelinedependent birds and sea turtles, (2) providing suggestions on specific management approaches that can be used to minimize these impacts, and (3) developing insights for future research and monitoring that should be undertaken to ensure that management actions are having the desired effect on target populations. BACKGROUND: The U.S. Atlantic coast supports more than 35 shorebird species and an additional 13 tern and skimmer species (Sibley 2016). Five species of sea turtles are known to nest on beaches along the U.S. Atlantic or Gulf Coasts. Many North American birds and sea turtles are highly dependent upon coastal, sediment-based habitats, including beaches, inlets, marshes, bays, and estuaries. Maintenance and enhancement of navigation infrastructure often requires large expenditures in equipment, and the design and implementation of engineering projects to build, maintain, or enhance existing coastal infrastructure. Harbors, ports, approach channels, and the ICWW require sufficient depths to permit navigation of large oceanic cargo vessels used for the

Benefits of engineered habitats to seasonal bird communities on the Savannah Harbor Navigation Project, Dredged Material Containment Areas, 1994-2012

“…The complexity of migratory bird life-history traits requires that habitat be available during the entire life cycle, both breeding and non-breeding seasons, including the availability of high-quality stopover habitat during migration (Newton 2004, Mehlman et al 2005, Kirby et al 2008. The USACE has a disproportionate role influencing coastal habitats along the Atlantic Coast due to its mission in the creation, enhancement and maintenance of coastal infrastructure (Guilfoyle et al 2019). Maintenance dredging, beach nourishment, shoreline stabilization (Gittman et al 2015), and other coastal engineering activities are likely to affect the availability and quality of seasonal habitats for waterbirds and other floral or faunal wildlife species.…”

“…Maintenance dredging, beach nourishment, shoreline stabilization (Gittman et al 2015), and other coastal engineering activities are likely to affect the availability and quality of seasonal habitats for waterbirds and other floral or faunal wildlife species. Efforts to mitigate or restore habitats lost or degraded during coastal engineering is often required through legal mitigation processes or through USACE habitat restoration efforts (Guilfoyle et al 2019).…”

“…Trend results for non-waterbird species are also presented. (Guilfoyle et al 2019). Dredging operations are used regularly to maintain port and harbor depths sufficient to support international and national commerce.…”

“…Dredging operations are used regularly to maintain port and harbor depths sufficient to support international and national commerce. Natural coastal sedimentation processes are altered by maintenance dredging and shoreline armoring, both of which may reduce natural formation of coastal habitats, including beaches, sand spits, mud flats, marshes, and other wetland habitats (Guilfoyle et al 2019). These changes can reduce or degrade important coastal habitat for local and regional floral and faunal species.…”

Use of Engineering With Nature® concepts on the Savannah Harbor Navigation Project, Dredged Material Containment Areas, Savannah, GA

“…Waterway systems in and around ports and harbors require regular maintenance, typically through annual maintenance dredging operations that support sufficient depths for passage of large oceanic vessels. The process of deepening ports and harbors, in combination with associated shoreline stabilization efforts, often results in modification of existing current patterns that shift sediments away from navigation channels, and reduces or eliminates the natural meandering processes typical of coastal environments (Guilfoyle et al 2019). These efforts often result in the reduction or degradation of sediment-based features including beaches, sandy shoals, sand spits, wetlands, islands, and inlets.…”