Dec 17, 2015

Annually resolved late Holocene paleohydrology of the southern Sierra Nevada and Tulare Lake, California

Adams, Kenneth D., Negrini, Robert M., Cook, Edward R., Rajagopal, Seshadri
Water Resources Research
  • Presents a 2000 year long, annually resolved record of streamflow for the Kings, Kaweah, Tule, and Kern Rivers in the southwestern Sierra Nevada of California and consequent lake-level fluctuations at Tulare Lake in the southern San Joaquin Valley
  • Reconstructs annual discharge (using moisture-sensitive tree ring records from the Living Blended Drought Atlas) and routes this discharge to an annual Tulare Lake water balance model
  • The discharge reconstruction and water balance model highlights the differences between these two types of paleoclimate records, even when subject to the same forcing factors
  • Finds the reconstructed streamflow in the southern Sierra responded to yearly changes in precipitation and expressed a strong periodicity in the 2–8 year range over most of the reconstruction
  • Finds the storage capacity of Tulare Lake caused it to fluctuate more slowly, masking the 2–8 year streamflow periodicity and instead expressing a strong periodicity in the 32–64 year range over much of the record
  • Finds that although there have been longer droughts, the 2015 water year represents the driest in the last 2015 years and the 2012–2015 drought represents the driest 4 year period in the record
  • Finds that under natural conditions, simulated Tulare Lake levels would now be at about 60 m, which is not as low as what occurred multiple times over the last 2000 years
  • This long-term perspective of fluctuations in climate and water supply suggests that different drought scenarios that vary in terms of severity and duration can produce similar lake-level responses in closed lake basins