Dynamics and scaling of a small river discharging into the surf zone

We use an idealized numerical model to investigate the dynamics and fate of a small river discharging into the surf zone. Our study reveals that the plume reaches a steady state, at which point the combined advective and diffusive freshwater fluxes from the surf zone to the inner shelf balance the river discharge. At a steady state, the surf zone is well-mixed vertically due to wave-enhanced vertical turbulent diffusion and has a strong cross-shore salinity gradient. The horizontal gradient drives a cross-shore buoyancy-driven circulation, directed offshore at the surface and onshore near the bottom, which opposes the wave-driven circulation. Using a scaling analysis based on momentum and freshwater budgets, we determine that the steady-state alongshore plume extent (Lp) and the fraction of river water trapped in the surf zone depend on the ratio of the near-field plume length to the surf zone width (Lnf/Lsz) across a wide range of discharge and wave conditions, and a limited set of tid..., , , # Data from: Dynamics and scaling of a small river discharging into the surf zone

[https://doi.org/10.5061/dryad.2280gb608](https://doi.org/10.5061/dryad.2280gb608)

The present dataset includes the [COAWST model](https://www.usgs.gov/centers/whcmsc/science/coawst-a-coupled-ocean-atmosphere-wave-sediment-transport-modeling-system) outputs used to describe the dynamics and scaling of a small river discharging into the surf zone.

## File structure

The data are structured as follows:

1. plume_scale.mat - Data of plume scales of all the cases, where
* Hs: significant wave height [m]
* Q: river discharge [m^3 s^-1]
* L_nf: near-field plume length [m]
* L_p: alongshore plume extent [m]
* h_sz: water depth at the surf zone edge [m]
* x_sz: surf zone width [m]
* S_in: inflow salinity [PSU]
* g_p: reduced gravity at the river mouth [m s^-2]
* g_p*_*0: reduced gravity at the river mouth calculated using the density difference between river inflow and ambient ocean w...,