University of California Water Resources Center
Long Term Variability of Fresh Water Flow into the San Francisco Estuary using Paleoclimatic Methods
- Author(s): Wells, Lisa E
- Goman, Michelle
- Byrne, Roger
- et al.
Sediment cores were raised from fringing marshes along the northern reach of the San Francisco Bay. A variety of stratigraphic analyses were utilized to reconstruct sea level and river flow (salinity) over the past 7000 yr. Over thirty A.M.S. dates provide chronostratigraphic control. An overall trend in RSL rise of 0.12-0.14 cm/yr is established for the northern reach of the estuary. River discharge was broadly comparable to modem flows. However, an extended period of higher flow commenced approximately 3800 yr and continued for almost 2 millennia. Superimposed upon these general trends are numerous short-term events. Acute droughts and salinity intrusion occurred during the period of high river flow. No extreme flood events are noted during this period, although evidence for abnormally high discharge occurs at other times.