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Abstract Interactions between surface flows and groundwater in beaches can influence erosion and accretion, wave overtopping, groundwater levels and salinization, and transport of nutrients and pollutants. Laboratory experiments using transparent crushed quartz and optically matched mineral oil as proxies for sand and water allow the degree of saturation to be computed at pore‐scale (0.7 mm resolution) enabling detailed investigations of the wave runup driven infiltration into a beach in a wave flume for a range of slopes and flow boundary conditions. The evolution of the wetting front resulting from wave runup on an initially unsaturated beach is described in detail, including the formation of an infiltration wedge in the subsurface of the swash zone and the wave‐driven rise in fluid elevation inside the beach. The elevation of the runup for each event is found to be related closely to the saturation of the beach face, reaching an equilibrium state once the subsurface in the swash zone reaches capacity. The back wall boundary condition in the flume has a significant role in how subsurface flows increase saturation within the beach, especially with boundary head elevations greater than the initial phreatic surface. The results of these novel experimental observations are used to develop dimensionless relationships between the surface wave runup and the subsurface saturation rates. To improve monitoring and interpretation of future coastal groundwater studies, three distinct cross‐shore regimes are defined for assessing change in subsurface fluid elevation in the beach. 

Wave-orbital velocities are estimated with particle image velocimetry (PIV) applied to rapid sequences of images of the surfzone surface obtained with a low-cost camera mounted on an amphibious tripod. Time series and spectra of the remotely sensed cross-shore wave-orbital velocities are converted to the depth of colocated acoustic Doppler velocimeters (ADVs), using linear finite depth theory. These converted velocities are similar to the velocities measured in situ (mean nRMSE for time series =16% and for spectra =10%). Small discrepancies between depth-attenuated surface and in situ currents may be owing to errors in the surface velocity measurements, uncertainties in the water depth, the vertical elevation of the ADVs, and the neglect of nonlinear effects when using linear finite depth theory. These results show the potential to obtain spatially dense estimates of wave velocities 

Waves running up and down the beach (‘swash’) at the landward edge of the ocean can cause changes to the beach topology, can erode dunes, and can result in inland flooding. Despite the importance of swash, field observations are difficult to obtain in the thin, bubbly, and potentially sediment laden fluid layers. Here, swash excursions along an Atlantic Ocean beach are estimated with a new framework, V-BeachNet, that uses a fully convolutional network to distinguish between sand and the moving edge of the wave in rapid sequences of images. V-BeachNet is trained with 16 randomly selected and manually segmented images of the swash zone, and is used to estimate swash excursions along 200 m of the shoreline by automatically segmenting four 1-h sequences of images that span a range of incident wave conditions. Data from a scanning lidar system are used to validate the swash estimates along a cross-shore transect within the camera field of view. V-BeachNet estimates of swash spectra, significant wave heights, and wave-driven setup (increases in the mean water level) agree with those estimated from the lidar data. 

Abstract Currents transport sediment, larvae, pollutants, and people across and along the surfzone, creating a dynamic interface between the coastal ocean and shore. Previous field studies of nearshore flows primarily have relied on relatively low spatial resolution deployments of in situ sensors, but the development of remote sensing techniques using optical imagery and naturally occurring foam as a flow tracer has allowed for high spatial resolution observations (on the order of a few meters) across the surfzone. Here, algorithms optical current meter (OCM) and particle image velocimetry (PIV) are extended from previous surfzone applications and used to estimate both cross-shore and alongshore 2-, 10-, and 60-min mean surface currents in the nearshore using imagery from both oblique and nadir viewing angles. Results are compared with in situ current meters throughout the surfzone for a wide range of incident wave heights, directions, and directional spreads. Differences between remotely sensed flows and in situ current meters are smallest for nadir viewing angles, where georectification is simplified. Comparisons of 10-min mean flow estimates from a nadir viewing angle with in situ estimates of alongshore and cross-shore currents had correlationsr²= 0.94 and 0.51 with root-mean-square differences (RMSDs) = 0.07 and 0.16 m s⁻¹for PIV andr²= 0.88 and 0.44 with RMSDs = 0.08 and 0.22 m s⁻¹for OCM. Differences between remotely sensed and in situ cross-shore current estimates are at least partially owing to the difference between onshore-directed mass flux on the surface and offshore-directed undertow in the mid–water column. 

This archive contains field data used to investigate swash velocities by Britt Raubenheimer, Steve Elgar, and Alexandra Muscalus. The quality controlled cross-shore velocity time series are in the .zip folder "u", and the quality-controlled alongshore velocity time series are in the .zip folder "v". Details about the files and data are provided in README.txt. For further questions, please contact Britt Raubenheimer at braubenheimer@whoi.edu, Steve Elgar at elgar@whoi.edu, or Alexandra Muscalus at alexandra.muscalus@whoi.edu Support was provided by the National Science Foundation, the US Coastal Research Program, and the WHOI Build the Base Program. 

This archive contains 2-min mean remotely sensed surface currents generated using optical imagery and PIV (Dooley et al., 2024) from field experiments (2013, 2018, 2021, 2022) occurring at the U.S. Army Corps of Engineers Field Research Facility, in Duck, NC. The README.txt file contains information regarding variables found in the MATLAB (PVLAB_PIV_SurfaceFlows.mat) file, including estimate locations, units, and timestamps. Estimates were generated at times with appropriate conditions for remote sensing (e.g., sufficient foam tracer) that were within 1-day of measured bathymetry at the field site. Additional data for the field site (obtained by the USACE Field Research Facility or by NOAA) including the measured bathymetry and wave conditions can be found at: https://chlthredds.erdc.dren.mil/thredds/catalog/frf/catalog.html Remote sensing estimates are not perfect and errors in filtering out bad data are possible. Please reach out to Ciara Dooley at cdooley@whoi.edu, Steve Elgar at selgar@mac.com, and Britt Raubenheimer at braubenheimer@whoi.edu if you have any questions. Additionally, the optical imagery (large dataset, many TBs) used to generate flow estimates can be accessed by contacting the authors. 

Model results from a double barred system in the surfzone 

Abstract In the surfzone, breaking‐wave generated eddies and vortices transport material along the coast and offshore to the continental shelf, providing a pathway from land to the ocean. Here, surfzone vorticity is investigated with unique field observations obtained during a wide range of wave and bathymetric conditions on an Atlantic Ocean beach. Small spatial‐scale [O(10 m)] vorticity estimated with a 5 m diameter ring of 14 current meters deployed in ∼2 m water depth increased as the directional spread of the wave field increased. Large spatial‐scale [O(100 m)] vorticity calculated from remote sensing estimates of currents across the surfzone along 200 m of the shoreline increased as alongshore bathymetric variability (channels, bars, bumps, holes) increased. For all bathymetric conditions, large‐scale vorticity in the inner surfzone was more energetic than in the outer surfzone. 

In Fall of 2024, central Florida was impacted by Hurricane Helene (landfall in Perry, FL as a Cat 4 hurricane on Sept 27) and by Hurricane Milton (landfall in Siesta Key, FL as Cat 3 on Oct 9). The hurricanes led to damages of an estimated value > $200billion. The Nearshore Extreme Events Reconnaissance Association (NEER) and the Geotechnical Extreme Events Reconnaissance Association (GEER) represented by their members from more than 10 academic institutions, federal agencies, and industry and supported by technical staff from the NHERI RAPID facility and the UF Center for Coastal Solutions initiated on Sept 23 a data collection effort that included pre-, during-, and post-storm multi-disciplinary data collections efforts. The field data collection effort was concluded on Nov 22. Data includes hydraulic information on storm surge, waves, and currents, topographic and bathymetric data sets, terrestrial and seabed mapping, and geotechnical site characterization including in-situ testing, sediment sampling, and seismic testing. Data was collected in four focus areas in Florida (Cedar Key; Horseshoe Beach; Midnight Pass and Milton Pass, both near Venice) and observational data and limited data products were collected in other areas in Florida including Orchid, Ponte Vedra, Suwannee, Panama City, and others. Data is organized by site (four primary sites and others); data collection phase with respect to the two hurricanes; and instruments or data collection method. This work included support from both the UF Center for Coastal Solutions and the NHERI RAPID facility.