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1. Quantifying Coastal Storm Impacts Using a New Cumulative Storm Impact Index (CSII) Model: Application Along the Virginia Coast, USA

   https://doi.org/10.1029/2022JF006641  

   Fenster, M. S.; Dominguez, R. (September 2022, Journal of Geophysical Research: Earth Surface)

   Abstract This paper presents a new empirical model, called the cumulative storm impact index (CSII), that quantifies the impact of coastal storms on sandy beaches. The new model utilizes user‐defined storm data to incorporate both individual storm magnitude and the cumulative effect of successive storms into an index, which is a proxy for beach erosion at a given time. Applying this model to long‐term water‐level data from a Virginia tide gauge showed that the greatest storm impact resulted not from the larger individual storms, such as the Ash Wednesday nor'easter of 1962, the “Perfect Storm” of 1991, or Hurricane Sandy of 2012, but rather from especially stormy winter seasons that occurred during the twenty‐first century. Additionally, the CSII model uncovered a trend—not detectable by single storm impact analyses—toward greater storm impacts, which began c. 1980 and continued to the present day. Finally, comparative analyses using wave power as a storm index shows CSII can capture decadal or seasonal scale storminess. We expect this model to have utility in many areas of the coastal sciences and engineering, including developing holistic response models, quantifying erosion potential at other locations, and managing coastal ecosystems. 

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2. Factors controlling longshore variations of beach changes induced by Tropical Storm Eta (2020) along Pinellas County beaches, west-central Florida

   https://doi.org/10.34237/1008929  

   Cheng, Jun; Toledo Cossu, Francesca; Wang, Ping (January 2021, Shore & Beach)

   Tropical Storm Eta impacted the coast of west-central Florida from 11 November to 12 November 2020 and generated high waves over elevated water levels for over 20 hours. A total of 148 beach and nearshore profiles, spaced about 300 m (984 ft) apart, were surveyed one to two weeks before and one to eight days after the storm to examine the beach changes along four barrier islands, including Sand Key, Treasure Island, Long Key, and Mullet Key. The high storm waves superimposed on elevated water level reached the toe of dunes or seawalls and caused dune erosion and overwash at various places. Throughout most of the coast, the dune, dry beach, and nearshore area was eroded and most of the sediment was deposited on the seaward slope of the nearshore bar, resulting in a roughly conserved sand volume above closure depth. The longshore variation of beach-profile volume loss demonstrates an overall southward decreasing trend, mainly due to a southward decreasing nearshore wave height as controlled by offshore bathymetry and shoreline configurations. The Storm Erosion Index (SEI) developed by Miller and Livermont (2008) captured the longshore variation of beach-profile volume loss reasonably well. The longshore variation of breaking wave height is the dominant factor controlling the longshore changes of SEI and beach erosion. Temporal variation of water level also played a significant role, while beach berm elevation was a minor factor. Although wider beaches tended to experience more volume loss from TS Eta due to the availability of sediment, they were effective in protecting the back beach and dune area from erosion. On the other hand, smaller profile-volume loss from narrow beach did not necessarily relate to less dune/ structure damage. The opposite is often true. Accurate evaluation of a storm’s severity in terms of erosion potential would benefit beach management especially under the circumstance of increasing storm activities due to climate change. 

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3. Impact of Hurricane Maria on Beach Erosion in Puerto Rico: Remote Sensing and Causal Inference

   https://doi.org/10.1029/2020GL087306  

   Pérez Valentín, Jaynise M.; Müller, Marc F. (March 2020, Geophysical Research Letters)

   Abstract Beach erosion due to large storms critically affects coastal vulnerability, but is challenging to monitor and quantify. Attributing erosion to a specific storm requires a reliable counterfactual scenario: hypothetical beach conditions, absent the storm. Calibrating models to construct counterfactuals requires numerous observations that are rarely available. Storm paths are unpredictable, making long‐term instrumentation of specific beaches costly. Optical remote sensing is hampered by persistent cloud cover. We use Sentinel‐1 satellite radar imagery to monitor shoreline changes through clouds and propose regression discontinuity as a strategy to estimate the causal effect of large storms on beach erosion. Applied to 75 beaches across Puerto Rico, the approach detects shoreline changes with a root‐mean‐square error comparable to the resolution of the imagery. Hurricane Maria caused an erosion of 3 to 5 m along its path, up to 40 m at particular beaches. Results reveal strong local disparities that are consistent with simulated nearshore hydrodynamic conditions. 

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4. Coastal Typology: An Analysis of the Spatiotemporal Relationship between Socioeconomic Development and Shoreline Change

   https://doi.org/10.3390/land9070218  

   Mack, Elizabeth A.; Theuerkauf, Ethan; Bunting, Erin (July 2020, Land)

   null (Ed.)

   Globally, coastal communities are impacted by hazards including storm events, rising water levels, and associated coastal erosion. These hazards destroy homes and infrastructure causing human and financial risks for communities. At the same time, the economic and governance capacity of these communities varies widely, impacting their ability to plan and adapt to hazards. In order to identify locations vulnerable to coastal hazards, knowledge of the physical coastal changes must be integrated with the socio-economic profiles of communities. To do this, we couple information about coastal erosion rates and economic data in communities along the Great Lakes to develop a typology that summarizes physical and economic vulnerability to coastal erosion. This typology classifies communities into one of four categories: (1) High physical and economic vulnerability to coastal erosion, (2) High physical but low economic vulnerability to coastal erosion, (3) Low physical and low economic vulnerability to coastal erosion, and (4) High economic but low physical vulnerability to coastal erosion. An analysis of this typology over three time periods (2005–2010), (2010–2014), and (2014–2018) reveals the dynamic nature of vulnerability over this fourteen year time span. Given this complexity, it can be difficult for managers and decision-makers to decide where to direct limited resources for coastal protection. Our typology provides an analytical tool to proactively address this challenge. Further, it advances existing work on coastal change and associated vulnerability in three ways. One, it implements a regional, analytical approach that moves beyond case study-oriented work and facilitates community analyses in a comparative context. Two, the typology provides an integrated assessment of vulnerability that considers economic vulnerability to coastal erosion, which is a contextual variable that compounds or helps mitigate vulnerability. Three, the typology facilitates community comparisons over time, which is important to identifying drivers of change in Great Lakes coastal communities over time and community efforts to mitigate and adapt to these hazards. 

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5. Post-Hurricane Michael damage assessment using ADCIRC storm surge hindcast, image classification, and LiDAR

   https://doi.org/10.34237/1008741  

   Davis, Joshua; Mitsova, Diana; Briggs, Tynon; Briggs, Tiffany (January 2019, Shore & Beach)

   null (Ed.)

   Wave forcing from hurricanes, nor’easters, and energetic storms can cause erosion of the berm and beach face resulting in increased vulnerability of dunes and coastal infrastructure. LIDAR or other surveying techniques have quantified post-event morphology, but there is a lack of in situ hydrodynamic and morphodynamic measurements during extreme storm events. Two field studies were conducted in March 2018 and April 2019 at Bethany Beach, Delaware, where in situ hydrodynamic and morphodynamic measurements were made during a nor’easter (Nor’easter Riley) and an energetic storm (Easter Eve Storm). An array of sensors to measure water velocity, water depth, water elevation and bed elevation were mounted to scaffold pipes and deployed in a single cross-shore transect. Water velocity was measured using an electro-magnetic current meter while water and bed elevations were measured using an acoustic distance meter along with an algorithm to differentiate between the water and bed during swash processes. GPS profiles of the beach face were measured during every day-time low tide throughout the storm events. Both accretion and erosion were measured at different cross-shore positions and at different times during the storm events. Morphodynamic change along the back-beach was found to be related to berm erosion, suggesting an important morphologic feedback mechanism. Accumulated wave energy and wave energy flux per unit area between Nor’easter Riley and a recent mid-Atlantic hurricane (Hurricane Dorian) were calculated and compared. Coastal Observations: JALBTCX/NCMP emergency-response airborne Lidar coastal mapping & quick response data products for 2016/2017/2018 hurricane impact assessments 

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