JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
<br />Vol�#S, No: '' AMERICAN WATER RESOURCES ASSOCIATION August 2009
<br />DROUGHT RESILIENCE OF THE CALIFORNIA CENTRAL VALLEY
<br />SURFACE- GROUND - WATER - CONVEYANCE SYSTEM'
<br />Norman L. Miller, Larry L. Dale, Charles F. Brush, Sebastian D. Vicuna,
<br />Tariq N. Kadir, Emin C. Dogrul, and Francis L Chung
<br />ABSTRACT: A series of drought simulations were performed for the California Central Valley using computer
<br />applications developed by the California Department of Water Resources and historical datasets representing a
<br />range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping
<br />patterns, and water demand were held fixed at the 2003 level and water supply was decreased by amounts rang-
<br />ing between 25 and 50 %, representing light to severe drought types. Impacts were examined for four hydrologic
<br />subbasins, the Sacramento Basin, the San Joaquin Basin, the Tulare Basin, and the Eastside Drainage. Results
<br />suggest the greatest impacts are in the San Joaquin and Tulare Basins, regions that are heavily irrigated and
<br />are presently overdrafted in most years. Regional surface water diversions decrease by as much as 70 %.
<br />Stream -to- aquifer flows and aquifer storage declines were proportional to drought severity. Most significant was
<br />the decline in ground water head for the severe drought cases, where results suggest that under these scenarios
<br />the water table is unlikely to recover within the 30 -year model - simulated future. However, the overall response
<br />to such droughts is not as severe as anticipated and the Sacramento Basin may act as ground -water insurance
<br />to sustain California during extended dry periods.
<br />(KEY TERMS: drought simulation; surface - ground -water response; pumping.)
<br />Miller, Norman L., Larry L. Dale, Charles F. Brush, Sebastian D. Vicuna, Tariq N. Kadir, Emin C. Dogrul, and
<br />Francis I. Chung, 2009. Drought Resilience of the California Central Valley Surface - Ground - Water- Conveyance
<br />System. Journal of the American Water Resources Association (JAWRA) 45(4):857 -866. DOI: 10.1111/j.1752-
<br />The western United States (U.S.) has experienced
<br />periods of long drought conditions since the last
<br />glacial epoch 11,000 years ago. The period between
<br />900 and 1400 A.D. was a time when severe long -
<br />duration droughts occurred in the western U.S. (Cook
<br />et al., 2004). This medieval mega- drought period was
<br />followed by a less severe drought period that was
<br />'Paper No. JAWRA -08- 0063 -P of the Journal of the American Water Resources Association (JAWRA). Received April 9, 2008; accepted
<br />January 15, 2009. © 2009 American Water Resources Association. Discussions are open until six months from print publication.
<br />2 Respectively, Staff Scientist and Adjunct Professor (Miller), Climate Science Department, Berkeley National Laboratory and Geography
<br />Department, University of California, Berkeley, California 90 -1116, One Cyclotron Road, Berkeley, California 94720; Staff Scientist (Dale),
<br />Energy Analysis Department, Berkeley National Laboratory, Berkeley, California 90 -4000, One Cyclotron Road, Berkeley, California; Water
<br />Resources Engineer, Senior Engineer, Water Resources Engineer, Principal Engineer, (Brush, Kadir, Dogrul, Chung), Modeling Support
<br />Branch, Bay -Delta Office, Department of Water Resources, 1416 9th Street, P.O. Box 942836, Sacramento, California 94236; and Graduate
<br />Student (Vicuna), Civil and Environmental Engineering Department, University of California, Berkeley, Davis Hall, Berkeley, California
<br />94720 (E- Mail/Miller: nlmiller @lbl.gov).
<br />JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 857 JAWRA