Hydrology and Land Surface Studies
Climate and floods still govern California levee breaks
Article first published online: 21 NOV 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 22, November 2007
How to Cite
2007), Climate and floods still govern California levee breaks, Geophys. Res. Lett., 34, L22403, doi:10.1029/2007GL031702., and (
- Issue published online: 21 NOV 2007
- Article first published online: 21 NOV 2007
- Manuscript Accepted: 15 OCT 2007
- Manuscript Revised: 26 SEP 2007
- Manuscript Received: 16 AUG 2007
- levee break
 Even in heavily engineered river systems, climate still governs flood variability and thus still drives many levee breaks and geomorphic changes. We assemble a 155-year record of levee breaks for a major California river system to find that breaks occurred in 25% of years during the 20th Century. A relation between levee breaks and river discharge is present that sets a discharge threshold above which most levee breaks occurred. That threshold corresponds to small floods with recurrence intervals of ∼2–3 years. Statistical analysis illustrates that levee breaks and peak discharges cycle (broadly) on a 12–15 year time scale, in time with warm-wet storm patterns in California, but more slowly or more quickly than ENSO and PDO climate phenomena, respectively. Notably, these variations and thresholds persist through the 20th Century, suggesting that historical flood-control effects have not reduced the occurrence or frequency of levee breaks.