The 275-acre Deer River marsh system, one of the largest intact marsh complexes along Mobile Bay's western shore, provides vital habitat for fish, shellfish, birds, and wildlife while buffering nearby industrial and residential areas from storm surge and wave energy.  In 2018, the Mobile Bay National Estuary Program (MBNEP) received funding from the National Fish and Wildlife Foundation's Gulf Environmental Benefit Fund and  National Coastal Resilience Fund to design and implement restoration measures addressing decades of shoreline erosion, marsh degradation, and impaired hydrology in the Deer River Watershed.

Overall project goals include stabilizing eroding shorelines, re-establishing tidal exchange and hydrologic connectivity, elevating marsh elevation to enhance resilience, and demonstrating the beneficial use of dredged material to create habitat.  Following years of design and coordination with the U.S. Army Corps of Engineers, Phase I construction began in fall 2023.  Work included dredging the Middle and South Forks of Deer River to improve circulation and recreational access and using thin layer placement techniques to keep river derived dredged material on site to raise adjacent marsh elevations.  Offshore, an island complex was constructed using containment dikes built from in-situ material and filled with approximately 250,000 cubic yards of dredged material from the Mobile Harbor Deepening Project.  Segmented rubble-mound breakwaters were also installed as permanent wave attenuators and to encourage natural pocket beach formation along the bay shoreline.

Post-construction evaluations revealed that the fill material was predominantly fine-grained.  Consequently, the final marsh platform consolidated to an average elevation of +1.0 ft NAVD88 rather than the minimum design target elevation of +2.5 ft.  This outcome triggered adaptive management during winter  2025-2026.  Planned corrective actions include excavating a tidal creek through the 19-acre island to improve drainage, re-stacking dredged material to achieve the desired elevations, and placing 20,000-25,000 cubic yards of supplemental sand along the bay side to facilitate pocket beach formation and shoreline stability.

This adaptive management phase represents an important learning opportunity for optimizing the use of fine-grained sediments in coastal restoration.  While coarse-grained material is preferred, it is important that coastal resource managers navigate design and construction activities using finer sediments.  By documenting performance and sediment response, MBNEP and its partners aim to develop transferable guidance for maximizing ecological value and cost efficiency when coarse-grained material is limited, advancing resilient, nature-based shoreline management across coastal Alabama.