Summer 2011, Volume 57, Number 3 - San Diego History Center

The Journal of San Diego History
moved their settlement several miles upstream—to Mission San Diego de Alcala—
where they could obtain both year-round potable well water and water via an
aqueduct from Padre dam.
For almost two centuries, little happened in the valley except agriculture
and scattered Native American encampments. After World War II commercial
development began, continuing at accelerated paces ever since. 2 The development
tended to hide the river, and it was easy to find newer residents who, fooled by
our generally arid climate, had no idea there was even a river there.
Dry years and droughts were not the only periodic problems associated with
the San Diego River. Occasional wet years and high levels of upstream run-off
could produce significant floods. 3 The huge flood of 1916, which cut off San Diego
from Los Angeles and destroyed the Lower Otay Dam, is well chronicled, and is
the largest flood having an officially calculated size estimate (Figure 2). 4 An even
larger deluge, however, is believed to have occurred in 1862, and several other
very large floods are recorded in the last third of the nineteenth century. A good
overview of some of the major flooding events in San Diego County can be found
in the Spring 1971 issue of The Journal of San Diego History. 5 Interestingly, there is
a rather poor correlation between the rainiest years in San Diego, and the years
of the largest San Diego River floods (Table 1, Figure 3).
In the twentieth century, the ten largest floods occurred in 1916, 1918, 1921,
Fig. 3. Aftermath of the 1941 flood on the San Diego River. Photo by Dr. Lauren Post.
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