It is important that currents do not carry dredged material from the site into the nearby Gulf of the Farallones or Monterey Bay National Marine Sanctuaries, either during dumping or after the material has settled on the sea floor. Some answers Almost no measurements of currents or sediment movement exist for the region. Hence, we conducted a year-long measurement program to collect the necessary information.
Winds have less effect on slope currents, which tend to flow northwestward.
Significant variations of currents with geographic location and depth indicate that the fate of dredged materials will depend on the location of the disposal site. Materials that reach the seafloor will disperse less in quiet areas on the slope than in the more energetic regions on the shelf. Partly on the basis of this data, the EPA chose a disposal site on the slope in 2,800 m. In February 1991, the USGS began a year-long field program to gather data on circulation patterns over the seafloor west of San Francisco. This program was undertaken to help the EPA choose among several candidate sites for the ocean-floor disposal of material dredged from San Francisco Bay.