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Abstract Extreme precipitation during Hurricane Florence, which made landfall in North Carolina in September 2018, led to breaches of hog waste lagoons, coal ash pits, and wastewater facilities. In the weeks following the storm, freshwater discharge carried pollutants, sediment, organic matter, and debris to the coastal ocean, contributing to beach closures, algae blooms, hypoxia, and other ecosystem impacts. Here, the ocean pathways of land‐sourced contaminants following Hurricane Florence are investigated using the Regional Ocean Modeling System (ROMS) with a river point source with fixed water properties from a hydrologic model (WRF‐Hydro) of the Cape Fear River Basin, North Carolina's largest watershed. Patterns of contaminant transport in the coastal ocean are quantified with a finite duration tracer release based on observed flooding of agricultural and industrial facilities. A suite of synthetic events also was simulated to investigate the sensitivity of the river plume transport pathways to river discharge and wind direction. The simulated Hurricane Florence discharge event led to westward (downcoast) transport of contaminants in a coastal current, along with intermittent storage and release of material in an offshore (bulge) or eastward (upcoast) region near the river mouth, modulated by alternating upwelling and downwelling winds. The river plume patterns led to a delayed onset and long duration of contaminants affecting beaches 100 km to the west, days to weeks after the storm. Maps of the onset and duration of hypothetical water quality hazards for a range of weather conditions may provide guidance to managers on the timing of swimming/shellfishing advisories and water quality sampling. 

Existing codes spanning 2009-2012 for working with Surface Wave Instrument Floats with Tracking (SWIFT) data. Codes for both telemetry and post-processed data. Buoy versions v3, v3, and microSWIFTs supported. 

Exchange of material across the nearshore region, extending from the shoreline to a few kilometers offshore, determines the concentrations of pathogens and nutrients near the coast and the transport of larvae, whose cross-shore positions influence dispersal and recruitment. Here, we describe a framework for estimating the relative importance of cross-shore exchange mechanisms, including winds, Stokes drift, rip currents, internal waves, and diurnal heating and cooling. For each mechanism, we define an exchange velocity as a function of environmental conditions. The exchange velocity applies for organisms that keep a particular depth due to swimming or buoyancy. A related exchange diffusivity quantifies horizontal spreading of particles without enough vertical swimming speed or buoyancy to counteract turbulent velocities. This framework provides a way to determinewhich processes are important for cross-shore exchange for a particular study site, time period, and particle behavior. 

This archive contains COAWST model input, grids and initial conditions, and output used to produce the results in a submitted manuscript. The files are:</p> model_input.zip: input files for simulations presented in this paper   ocean_rip_current.in: ROMS ocean model input file   swan_rip_current.in: SWAN wave model input file (example with Hs=1m)   coupling_rip_current.in: model coupling file   rip_current.h: model header file    model_grids_forcing.zip: bathymetry and initial condition files      hbeach_grid_isbathy_2m.nc: ROMS bathymetry input file      hbeach_grid_isbathy_2m.bot: SWAN bathymetry input file      hbeach_grid_isbathy_2m.grd: SWAN grid input file      hbeach_init_isbathy_14_18_17.nc: Initial temperature, cool surf zone dT=-1C case      hbeach_init_isbathy_14_18_19.nc: Initial temperature, warm surf zone dT=+1C case      hbeach_init_isbathy_14_18_16.nc: Initial temperature, cool surf zone dT=-2C case      hbeach_init_isbathy_14_18_20.nc: Initial temperature, warm surf zone dT=+2C case      hbeach_init_isbathy_14_18_17p5.nc: Initial temperature, cool surf zone dT=-0.5C case      hbeach_init_isbathy_14_18_18p5.nc: Initial temperature, warm surf zone dT=+0.5C case</p> model_output files: model output used to produce the figures      netcdf files, zipped      variables included:           x_rho (cross-shore coordinate, m)           y_rho (alongshore coordinate, m)           z_rho (vertical coordinate, m)           ocean_time (time since initialization, s, output every 5 mins)           h (bathymetry, m)           temp (temperature, Celsius)           dye_02 (surfzone-released dye)           Hwave (wave height, m)           Dissip_break (wave dissipation W/m2)            ubar (cross-shore depth-average velocity, m/s, interpolated to rho-points)      Case_141817.nc: cool surf zone dT=-1C Hs=1m      Case_141819.nc: warm surf zone dT=+1C Hs=1m      Case_141816.nc: cool surf zone dT=-2C Hs=1m      Case_141820.nc: warm surf zone dT=-2C Hs=1m      Case_141817p5.nc: cool surf zone dT=-0.5C Hs=1m      Case_141818p5.nc: warm surf zone dT=+0.5C Hs=1m      Case_141817_Hp5.nc: cool surf zone dT=-1C Hs=0.5m      Case_141819_Hp5.nc: warm surf zone dT=+1C Hs=0.5m      Case_141817_Hp75.nc: cool surf zone dT=-1C Hs=0.75m      Case_141819_Hp75.nc: warm surf zone dT=+1C Hs=0.75m</p> COAWST is an open source code and can be download at https://coawstmodel-trac.sourcerepo.com/coawstmodel_COAWST/. Descriptions of the input and output files can be found in the manual distributed with the model code and in the glossary at the end of the ocean.in file.</p> Corresponding author: Melissa Moulton, mmoulton@uw.edu</p>