WSP08775

• File Number: 8056
• Description: Drought Preparedness
• State: CO
• Basin: Statewide
• Date: 1/1/1979
• Author: USGS
• Title: Hydrologic and Human aspects of the 1976-77 Drought
• Water Supply Pro - Doc Type: Report/Study

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HYDROLOGIC AND HUMAN ASPECTS OF THE 1976-77 DROUGHT

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EXPLANATION

Water year
.......--..----1924
-------1931
---- 1976
1977

June

July

Aug.

Sept.

Figure 25, Monthly mean discharges for four selected drought years, North Fork American
River at North Fork Dam, Calif.

winter, and the snowmelt runoff in the spring
was not only much lower than normal but did
not last as long; and 1977 had the most skewed
distribution of flow. Except for October,
November, May, June and JUly, the monthly
mean discharges in the 1977 water year were
new record minimums for the month, and those
for October and May exceeded the minimum of
record by less than 4 percent. The October
and November minimums occurred in 1949 and
1959, respectively. The year 1924 with 20
percent of normal runoff occurr-ed between

two years of near normal runoff, but 1931 with
26 percent of normal runoff followed two
years that had 42 and 68 percent of normal
runoff and was followed by a year of near
normal runoff. In comparison, the runoff in
1975 was 107 percent of normal and that in
1976 and 1977 was 29 and 12 percent, respec-
tively,

The trends in streamflow for six selected
streams with natural flow in California are
shown in figure 26, The plots are of the ac-