Multi-scale Modeling of Coastal Evolution (USGS Project)

 

 
San Waves at SF Mouth (Barnard)
Recent NearCoM/Delft/Data Comparisons
Animation of Currents at SF Mouth
Ocean Beach Camera
CDIP
NearCoM
 
 
 

NearCoM Modeling of Sediment Transport in San Francisco Bight and its Open Coasts

The Nearshore Community Model - NearCoM is extended to include large-scale dynamic components such as tidal currents, wind-induced currents, river discharge, and wind wave generation. With a semi-implicit numerical scheme implemented in the circulation module - SHORECIRC, NearCoM is able to incorporate longer time scale and far field motions into the prediction of waves, nearshore circulations and sediment transport.n the present study, the modified NearCoM is applied to a process-based multi-scale modeling of waves, currents and sediment transport in San Francisco Bight and its accompanying open coast at Ocean Beach

 
FIELD MEASUREMENT
Field measurements were conducted in the summer of 2005 and the winter of 2006. Nortek AWAC and RD Instruments’ (RDI) ADCP current profilers were deployed at four different locations out of Ocean Beach (Figure 1) in 2005 summer. In the winter of 2006, several current profilers were deployed from January through February. Nortek Aquadopp current profilers were placed in the surf zone at eight different sites form January 23-27, 2006.

 
 
NEARCOM MODEL INTEGRATION

We integrated SWAN (non-stationary mode)-SHORECIRC for modeling of waves, tide- and wind-induced circulation in the large-scale SF domain and REFDIFS-SHORECIRC-HH for modeling of nearshore waves,circulation and sediment transport in the small-scale OB domain.  The shows computational grids for SF domain and OB domain, respectively.

 

TIDAL MODULATION OF WAVES

 

In the presence of strong tidal currents in the upper Ocean Beach region wave quantities such as frequency and energy are shown to fluctuate at the tidal period. The figure shows a strong tidal modulation of surface waves (middle panel) at a location in northern Ocean Beach.

 
CAN WE MODEL EROSIONAL HOT SPOTS?
 

Recent studies on beach evolution indicated that the variation of the tidal shoal directly links to the erosional hot spots on beaches. Model results from simulations of 2005 summer show wave focusing at the location of the erosion hot spot at the southern end of Ocean Beach. Figures below illustrate time-averaged results (Jun 20 ~Aug 1) of peak wave directions and significant wave heights, respectively. .

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