Bulletin 1.pdf - California Department of Water Resources - State of ...

346 WATER RESOURCES OF CALIFORNIA
RUNOFF
Estimated mean seasonal natural runoff of the Central Valley Area
for the 53 years from 1894-95 to 1946-47 is 33,636,000 acre-feet, or 47.5
percent of total surface runoff from mountain and foothill lands in the
State. The minimum seasonal flow of 9,280,000 acre-feet occurred in
1923-24, and the maximum, totalling 63,300,000 acre-feet, in 1906-07. The
10-year period from 1923-24 to 1932-33 was the driest of record in this
Area. Runoff during each of those 10 years, except 1926-27, was less than
the 53-year mean, and the average was only 66.3 percent of this long-time
mean.
Runoff from drainage basins of the Central Valley Area is derived
largely from snow. Consequently, the major portion of seasonal runoff
comes during late spring and early summer months from March to June,
inclusive. For Sacramento River the runoff during these months is 42.8
percent of the seasonal total, for American River, 65.4 percent, and for
Kings River, 71.8 percent. Minimum runoff comes from August to
October, inclusive, flow for this period being 9.7 percent of total seasonal
runoff for Sacramento River, 2.1 percent for the American, and 5.5 percent
for the Kings. Sacramento River drains a region of porous lava
formation, with large underground storage capacity. Summer flow of
the Sacramento is therefore better sustained than is that of other streams
in the Area.
An indication of variation in monthly flow of Central Valley Area
streams, and of the percentage of seasonal runoff that comes during .
each month, is given by data for Sacramento River at Red Bluff, American
River at Fair Oaks and Kings River at Piedra listed in Table 59.
The first records of stream flow in the Central Valley Area were
obtained by Wm. Ham. Hall, State Engineer from 1878 to 1884. The
only stream gaging station then maintained in the Sacramento River
Basin was at Collinsville, at the mouth of the Sacramento. In the San
Joaquin River Basin 20 gaging stations were maintained, most of them
at the base of the foothills. All stations established by State Engineer
Hall were discontinued after 1884, when the office of State Engineer
was abolished. As of September 30, 1947, records from 96 stations were
published by the United States Geological Survey in the Sacramento
River Basin and 105 in the San Joaquin River Basin.
The first gaging station established in the Sacramento River Basin
by the Geological Survey wa,