San Francisco Bay is a tidally-energetic estuary where clay muds are the dominant sediment building wetlands, depositing in channels and harbors, and responding to sea level rise since San Francisco Bay was most recently inundated about 8,000 years ago. These sediments mainly come from the Central Valley and become cohesive when they encounter enough salinity in the western Delta. This causes the cohesive sediments to flocculate into larger particles which then settle, deposit, erode, circulate, and redeposit where the tides and flow take them.
