San Francisco Bight Coastal Processes Study

Introduction

The USGS is conducting a study that documents and analyzes the processes that control the sand transport and sedimentation patterns of Ocean Beach, a National Park site within the Golden Gate National Recreation Area. This area encompasses a complicated coastal setting that is impacted by the tidal influence of San Francisco Bay, as well as the southwest and northwest Pacific swell. High-energy conditions at this site have restricted comprehensive field surveys in the past, but recent innovations in field techniques now make it possible to perform detailed analysis of the physical processes operating on high energy coastlines, such as Ocean Beach.

The USGS has employed a multi-faceted research approach at Ocean Beach that links wave and tide data with numerical modeling, periodic three-dimensional topographic beach surveys, cross-shore bathymetric surveys using personal watercraft, and onshore grain-size analysis using a bed sediment camera. The objective is to assess the cause of the erosion hot spot at the south end of Ocean Beach by quantifying the physical processes, determining the dominant sediment transport pathways, identifying seasonal trends, and evaluating the efficacy of potential coastal management solutions.