Assessing shoreline erosion and sediment deposition as contrasting influences on the sustainability of natural marshes and living shorelines: Plant communities in created marshes are usually similar to those in natural marshes after a few growing seasons, but other characteristics may take decades to approach equivalency. This study examines whether tools and metrics developed for natural marshes are applicable to living shorelines from installation onward, or if refinements are necessary as the created marsh ages. Insights from this project are critical for assessing potential vulnerability of living shorelines to environmental changes over time to prioritize them for action.
Dr. Cindy Palinkas
Beach Berms: The Missing Link To Predicting Decadal-Scale Barrier Island Evolution will develop and test a model for the coupled beach-dune system at Masonboro Island, NC to predict barrier island evolution over annual to decadal timescales. By monitoring island topography, aeolian sediment transport, offshore wave characteristics, storm-induced water levels, and meteorological conditions, we will assess the ability of the model to represent these processes. Project outcomes aim to benefit the NC National Estuarine Research Reserve that manages the island and other coastal stakeholders and agencies that rely on predictions of island evolution to make management decisions.
Dr. Joseph Long and Dr. Andrea Hawkes
Image: Open-ocean coastline of the Masonboro Island National Estuarine Research Reserve, Feb 2019. Credit: UNCW Coastal Hazards Lab.
Hydrologic dynamics influence the physical and chemical environment of coastal wetlands by controlling water levels and transporting materials. Trajectories of groundwater, surface water, and land elevations in managed settings with sea-level rise tests how feedbacks between surface and subsurface hydrology can alter hydro-ecologic zones, wetland carbon cycling, and soil elevation trajectories. This project will provide stakeholders with an improved understanding of how diked coastal systems can be managed or rehabilitated to protect coastal environments while maintaining beneficial habitats.
Dr. Kevin Befus
Dr. Michelle Hummel
Image: Herring River Estuary in the Cape Cod National Seashore, Jun 2019. Credit: Alexander Kurnizki
Long term morphodynamic stability at a bar-built estuary with implications for breach management combines in-situ observations and morphodynamic modeling to look at processes during beach breaching and closure. This study leverages several years of morphological observations at the Carmel River State Beach and will use numerical models to determine long-term trends in breach characteristics and morphological evolution. Project outcomes will benefit and inform management breaching and closure practices at bar-built estuaries along the entire California coast by providing a data-driven model that can be used to assess breach conditions for future events.
Dr. Mara M Orescanin
Dr. Liliana Velasquez-Montoya
Image: Carmel River State Beach under closed (top) and breached (bottom) conditions.
When forces collide: Developing a scalable framework for compound flood risk assessment investigates the spatial variation and extent of transition zones, where joint river and ocean processes combine to exacerbate flooding along coastal river systems. Using multivariate statistical models, hydrodynamic numerical models, and machine learning algorithms, this project develops an efficient and scalable hybrid modeling framework for quantifying graduated compound flood risk. The hybrid framework will be employed at locations around the U.S. to advance the understanding of along-river compounding effects for different local characteristics, supporting ongoing efforts to increase resiliency in coastal communities susceptible to compound flooding.
Dr. Thomas Wahl and Dr. Katy Serafin
Image: Framework for the hybrid statistical-numerical modelling framework to assess compound flooding in coastal river systems.
Natural and nature-based features, such as oyster breakwaters, are being proposed as viable alternatives to gray approaches for reducing shoreline erosion and attenuating boat-wakes along narrow, heavily trafficked waterways. Evaluating the Coastal Protection and Ecological Co-Benefits of Novel Marsh-Oyster Restoration Approaches evaluates the performance of oyster breakwaters in attenuating boat-wake induced wave energy, protecting and restoring marsh shorelines, and restoring oyster habitat.
Dr. Rachel Gittman
Image: High-relief Oyster Catcher reef constructed in July 2020 in coordination with the NC Coastal Reserve and Sandbar Oyster Co.
Natural and Anthropogenic Influences on National Beach Nourishment Activities and the Impact on Regional Sediment Budgets assesses historical trends in beach nourishment events over the last century at national and regional scales, evaluates possible natural and anthropogenic drivers of nourishment events, and explores the impacts on sediment budgets over time. Project outcomes aim to benefit coastal stakeholders, agencies, and managers by providing information to help better plan for future sediment resource needs and a methodological template to implement similar analyses at various scales of interest.
Dr. Tiffany Roberts Briggs
Image: Reshaping renourished sand at Jupiter-Carlin Beach in southeast FL. Credit FAU Coastal Studies L
Processes that Cause Long-term Nearshore Morphological Evolution is a collaborative effort with USGS partners to use a wide range of existing field observations to evaluate and improve numerical models, which can be used to examine the long-term evolution of nearshore regions, including beaches, inlets, and coastal bays and sounds. The models can also simulate future scenarios, such as more intense and long-lived storms and sea-level rise. The observations encompass extreme events (hurricanes and strong nor'easters), more moderate, but longer-acting stormy periods, and calmer conditions, allowing investigations into storm-induced changes to the shoreline, and the slower post-storm recovery important to long-term resiliency and sustainability.
Drs. Steve Elgar and Britt Raubenheimer
Image: A 1994 field campaign at the USACE Field Research Facility that collected one of the study datasets
Structures restricting tidal flow to coastal marshes are common and often have negative consequences for ecosystem functioning and the delivery of valuable services. Hydrological management of a tidally restricted coastal wetland: Characterizing biogeochemical responses over multiple time scales is a collaborative effort with USGS scientists to quantify the long-term impacts of tidal restriction on soil carbon accretion rates and evaluate the impact of restoration on ecosystem functioning related to the installation of box culverts. A key deliverable will be dissemination of data products and results to end users and restoration practitioners at government and non-governmental agencies to support their decision making processes.
Dr. Amanda Spivak
Image: Tidal restriction in Gulf Shores, AL converted salt- to freshwater marsh w ponding and dead trees.
Innovations in acoustic remote sensing of sediment transport for improving short-to-long-term models is studying how waves transport sand on open coastlines, and how this process varies from the shoreline to offshore of the wave break point. Studying wave-driven transport requires detailed observations very near to the seabed, without causing disturbances to the near-bed flow. For this reason, the project is developing acoustic sonar methods to remotely probe near-bed sediment load and flow velocity. This and related instrumentation will be installed on an amphibious vehicle (see figure), allowing measurements to be collected in a variety of water depths and wave conditions. The resulting data will be used to validate sediment transport theories used in numerical models.
Dr. Greg Wilson
Image: The Coastal Research Amphibious Buggy, a unique vehicle of the Field Research Facility in Duck NC.
Bridging the gap between process-based marsh evolution models and data-driven metrics of marsh health partners with USGS to improve models for marsh evolution and their comparison with real sites. A new model and geospatial analysis better interpret geomorphological metrics commonly used to characterize marsh sites, and quantify the contribution of different mechanisms – ponding, drowning, channel widening, and edge erosion – to the total marsh loss. The model is used to hindcast marsh evolution at selected sites, applying the improved metrics to calibrate and validate the model. A key deliverable is the fully documented, open source, numerically-efficient marsh evolution model, which can be used to hindcast and forecast marsh changes, as well as to simulate marsh restoration techniques.
Dr. Giulio Mariotti