This section is intended to provide information about floods in California's past. Historical information regarding previous floods is essential in developing our understanding of current floods. Have earlier floods been larger or smaller? How big can floods get? We ask these questions in order to try to predict the size of floods and to give warnings about the potential flood risk. The goal is to protect life and property from flooding.
The first flood reported in California occurred on the Los Angeles River in 1770.
— H. B. Lynch
Rainfall and Stream Run-off in Southern California Since 1769
Metropolitan Water District of Southern California, August 1931, p. 2
Synopsis of California's Flood Measurements
Written accounts of floods began with the arrival of Spanish missionaries to Southern California in 1769. California's first rainfall measurements were recorded in 1847. James W. Marshall discovered gold in 1848 on the South Fork of the American River in northern California. The influx of people brought individuals and the U.S. Army, which in 1850 started measuring rainfall in San Diego. (Lynch, 1931, p. 5) Since 1850, rainfall measurements have been taken in Sacramento, San Francisco, and San Diego.
Contents of This Section
Resources available to researchers are included in this section and organized into different areas as follows:
- Rainfall and Stream Run-off (1769-1931) — data from California's Spanish Mission period apply to Southern California. [H. B. Lynch (1931)]
- Peak Discharge Data for Estimating 1862 American River Flood (possible input to a HEC-RAS Model) — the idea is to use modern modeling tools on available historic data to evaluate peak discharge estimates for the American River. The model produced could then be compared to estimates developed over the past 150+ years by the U.S. Army Corps of Engineers and the U.S. Geological Survey. [Gary Estes (2017)]
- Historic descriptions and pictures of the four floods of the Sacramento Valley from December 1861 through January 1862 — examining whether such an extreme precipitation event could happen again, run-off potential and peak flow estimates are examined. [Leon Hunsaker and Claude Curran (2005, 2006)]