2007 PACLIM
PRESENTATION
By
Michael Anderson and Maurice Roos
May 2007
McCloud River Nov 05
Sacramento River Unimpaired Runoff Since 1906
Sacramento River Unimpaired Runoff Since 1971
San Joaquin River Unimpaired Runoff Since 1906
San Joaquin River Unimpaired Runoff Since 1971
Northern Sierra Precipitation
Northern Sierra Precipitation
in Inches
WY 2005
WY 2006
WY 2007
Average
26.0
24.0
22.0
20.0
18.0
INCHES
16.0
14.0
12.0
10.0
8.4
8.0
2.0
8.0
6.3
6.0
4.0
9.0
6.9
3.9
3.0
2.1
1.0
0.0
October
November December
January
February
MONTH
March
April
May
June
Northern Sierra Precipitation 8-Station Index
Snow Surveys Seasonal Precipitation
October 1, 2005 through April 30, 2007
Snow Water
Content
Snow Water Content
240
220
200
Percent of Average
180
160
140
120
100
80
60
40
20
0
1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007
Year
Storage in 151 Major In-State Reservoirs on April 1
40
Storage in MAF
35
Capacity
37.6
30
25
Average
27.9
20
15
10
5
0
1977
1983
2002
2003
Year
2004
2005
2006
2007
April – July Runoff Percent
Sacramento River Runoff
April - July Runoff in percent of Water Year Runoff
70%
70%
Percent of Water Year Runoff
65%
Linear Regression (least squares) line showing historical trend
65%
3-year running average
60%
60%
55%
55%
50%
50%
45%
45%
40%
40%
35%
35%
30%
30%
25%
25%
20%
20%
15%
15%
10%
1906
10%
1916
1926
1936
1946
1956
1966
1976
Water Year (October 1 - September 30)
1986
1996
2006
Notable Events WY2007
For Northern Sierra precipitation totals in
January and March 2007 were each the 6th
driest month in 88 years
Mid-January freeze extended across California
causing widespread agricultural losses
Mid-March heat set daily maximum
temperature records across state
20% loss of snowpack in March
Downtown Los Angeles recording its
driest year
Drought Monitor Maps
DWR Drought Definition
Water year runoff (or multiple year runoff)
in lowest 10 percent
Reservoir storage at 70 percent
of average or less
Current conditions in San Joaquin Basin
satisfy first condition at near 10 percent
(Sacramento at 15 percent)
⌧Current reservoir storage is at least 80% for
Central Valley reservoirs with many at or
above 100%
What about next year…
Given a wet or normal December followed by a dry
January has occurred in 1932, 1948, 1949, and 1991
as well as this year.
In those past years, the following year was also dry.
Questions?
Email: manderso@water.ca.gov