Gulf of the Farallones Disposal Issues

The Gulf of the Farallones region, including the Gulf of the Farallones National Marine Sanctuary, lies offshore of San Francisco. The region's varied habitats--from coastal wetlands to deep ocean water--support a rich diversity of marine life and provide nurseries and spawning grounds for commercially valuable fish and crab.

Proximity to a major population center makes the Gulf of the Farallones region vulnerable to environmental pressures. One such pressure--disposal of waste--was the subject of a recent study by the U.S. Geological Survey, which sought to answer two questions:

• What is the fate of more than 47,800 containers of low-level radioactive waste--many of which now lie within the Sanctuary boundary--that were dumped in the ocean between 1946 and 1970?
• What geological processes characterize deep-ocean areas that may be used as disposal sites for material dredged from San Francisco Bay?

To investigate these questions, the USGS cooperated with the U.S. Environmental Protection Agency, the NOAA Gulf of the Farallones National Marine Sanctuary, the U.S. Army Corps of Engineers, and the U.S. Navy.

Some results of the Study

Sophisticated computer techniques developed by the USGS to enhance sidescan-sonar images enabled the researchers to locate many of the drums of low-level radioactive waste. These techniques can be used to locate containers of hazardous waste in other ocean areas and also have utility for fisheries management. Results so far have been summarized in a fact sheet.

The sites considered for disposal of dredged material (41 Kb) were found to be areas of slow accumulation and erosion of sediment that is unlikely to slide downslope except during extreme earthquakes. Ocean currents (61 Kb) will, in general, be stronger at the shallower sites. Partly on the basis of these findings, Federal agencies chose a disposal site west of the Sanctuary at a water depth of about 2,800 m. The USGS results can serve as a baseline for subsequent studies to monitor the fate of the dredged sediment and its effect on the environment.

Many publications are available as a result of this study.

Atlas

The atlas provides information on the physical setting and living resources of the Gulf of the Farallones and adjacent ocean waters.

This atlas illustrates the value of seafloor mapping and oceanographic measurements offshore of the San Francisco Bay area, where the environmental and ecological concerns of the Gulf of the Farallones National Marine Sanctuary must be reconciled with the human, economic, and industrial demands of a major urban population center.

For additional information, contact Herman Karl -- Project Coordinator

Phone: (650) 329-5280