San Francisco Bight Coastal Processes Study

Field Methods

Real-time Monitoring

A camera system, installed for a period of time at the top of the Cliff House Restaurant at the northern end of Ocean Beach, looking south, was used to monitor beach and nearshore morphology and processes in real-time. The system was comprised of an analog video camera and a digital still camera, housed in a single pan tilt unit, linked to a computer and DSL connection such that the camera can be controlled remotely from our office in Santa Cruz. Monitoring Ocean Beach in real-time and archiving all images allowed us to track short-term shoreline changes, beach evolution, sand bar migration, wave direction, storm effects, beach response, and nearshore circulation.  

The web camera unit looks south from atop the roof of the Cliff House Restaurant at Ocean Beach

Another view of the web camera unit on the roof of the Cliff House

Grain Size Analysis

Using a digital bed sediment camera (a.k.a "eyeball"), grain size surveys are conducted periodically at Ocean Beach as a proxy for tracking changes in the physical energy along the beach. The grain size parameters can be extracted from a digital image by an analysis of the variation and offset of the pixel intensities. This allows us to process over 300 sediment samples in less than a day, whereas traditional sieving could take several months of work. A standard digital camera is housed in a custom waterproof casing for use in the coastal environment.
 

Student surveys the surface of Ocean Beach using the "eyeball" camera

A digital image of the beach surface at Ocean Beach allows grain size to be determined in minutes. The image is 1 cm across.