Modeled surface waves from winds in South San Francisco Bay

A nested, stand-alone SWAN model application was constructed using Delft3D modeling system to simulate wind waves in South San Francisco Bay between May 30, 2021, and May 19, 2022. The model application included two domains that were 1-way coupled. The coarse overall model domain (wsfb_g1.grd) included the coastal ocean across the entire San Francisco Sacramento/San Joaquin Bay-Delta region was forced along the oceanic boundaries with measured time-varying, spatially uniform wave parameters derived from CDIP station 029 (Point Reyes). The nested detailed model (wsfb_g2.grd) covered south San Francisco Bay and was forced with simulated wind data from the High Resolution Rapid Refresh (HRRR) atmospheric model produced by NOAA with a spatial resolution of 3 km and temporal resolution of 1 hour. Water level data provided from NOAA station 9414523 (Redwood City, California) were used throughout the model domains to simulate tidal variations. Bathymetry data were compiled from Fregoso and others, 2017 and Fregoso and others, 2020. Water density was fixed at 1023 kg/m3 to reflect brackish conditions; a Collins bottom-friction formulation was used with coefficient 0.02; Van der Westhuysen whitecapping was used for better performance in wind-dominated systems. The model inputs were split into 4 time intervals (summer, fall, winter, spring) and run sequentially to simulate approximately 1 year.

Stationary model output were produced hourly in four separate seasons. Simulated wave metrics, specifically significant wave height and mean wave period, were compared against observed timeseries measurements collected in the mudflats near Eden Landing (station BMV in Ferreira and others, 2023).