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Historical Bathymetric Change in Suisun Bay 1867 - 1990
United States Geological Survey
Cappiella, K., Malzone, C., Smith, R. E., and Jaffe, B. E.
  • Between 1867 and 1887, approximately 115 million cubic meters of sediment was deposited in the Suisun Bay area. This is equivalent to about 2.5 cm/yr accumulation over all of Suisun Bay. Almost two-thirds of Suisun Bay was depositional during this period. Most of this is debris from hydraulic gold mining in the Sierra Nevada, and is likely contaminated with mercury which was used to extract gold from tailings.
  • Hydraulic mining ceased in 1884, while water distribution and flood control projects increased during the 20th century. These factors decreased the input of sediment to the Bay, and from 1887 to 1990 Suisun Bay was erosional.
  • On average, Suisun Bay deepened during the study period. From 1867 to 1990, Suisun Bay lost more than 100 million cubic meters of sediment. This is equivalent to a loss of 74 cm over the entire Suisun Bay area. 
  • Changes in sedimentation in Suisun Bay affected its ecosystem in many ways. For example, the area of tidal flat, rich habitat, and sources of sediment to the wetlands increased by approximately 10 square km from 1867 to 1887 due to the input of hydraulic mining debris. From 1887 to 1990, however, tidal flat area decreased from 52 square km to 12 square km.

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