Transcript Slide 1

Observed Climate and Streamflow Variability in
the Sacramento, San Joaquin, and Colorado
River Basins and Projections for the 21st
Century
JISAO Center for Science in the Earth System
Climate Impacts Group
and Department of Civil and Environmental Engineering
University of Washington
November, 2003
Alan F. Hamlet
Andrew W. Wood
Dennis P. Lettenmaier
Observed Trends in Basin Average
Temperature and Precipitation in the
Sacramento and San Joaquin River Basins
(Water Year 1916-1997)
Note: Data is adjusted for topographic variations, and corrections for
spurious trends associated with heat island effects, station moves,
instrumentation changes, different groupings of stations, etc. have
been applied.
1996
1992
1988
1984
1980
1976
1972
1968
1964
1960
1956
1952
14
1948
1996
1992
1988
1984
1980
1976
1972
1968
1964
1960
1956
1952
1948
1944
1940
1936
1932
1928
1924
1920
1916
Temperature (C)
3
1944
1940
1936
1932
1928
1924
1920
1916
Temperature (C)
Observed Temperature Trends over the Sacramento San Joaquin Basin 1916-1997
Winter (O-M)
9
8
7
6
5
4
y = 0.0094x + 5.4767
2
Summer (A-S)
18
17
16
15
y = 0.0097x + 15.658
13
1991
1996
1996
1966
1961
1956
1951
1946
1941
1936
1991
0
1986
y = 0.1874x + 106.61
1986
50
1981
100
1981
150
1976
200
1976
250
1971
Summer (A-S)
1971
1966
1961
1956
1951
1946
1941
1936
1931
1926
1921
1916
Total Precipitation
(mm)
200
1931
1926
1921
1916
Total Precipitation
(mm)
Observed Precipitation Trends over the Sacramento San Joaquin Basin 1916-1997
Winter (O-M)
1200
1000
800
600
400
y = 1.2532x + 506.56
0
Streamflow Reconstructions from the
Paleoclimatic Record
Thanks to:
Hugo Hidalgo, Scripps Institution of Oceanography
Dave Meko, Laboratory of Tree-Ring Research, University of Arizona
Connie Woodhouse, Paleoclimatology Branch, NOAA National Climatic Data Center
Sacramento River Flow Reconstructed from Tree Rings
(6-year running mean)
Source: Meko et. al, 2001, J. Amer. Water Res. Association, 37(4) 1029-39 (Fig 5)
Sacramento and Upper Colorado Annual Flow
Reconstructions
Concurrent periods of low flow are indicated by pink bands
Meko, D.M. and C.A. Woodhouse, in review. Tree-ring footprint of joint
hydrologic drought in Sacramento and Upper Colorado river basins, western
USA. Journal of Hydrology
Overview of Streamflow Reconstructions for Water Managers:
http://www.ncdc.noaa.gov/paleo/streamflow/study.html
Sacramento River Reconstructions:
Meko, D.M., Therrell, M.D., Baisan, C.H., and Hughes, M.K., 2001, Sacramento
River flow reconstructed to A.D. 869 from tree rings: J. of the American Water
Resources Association, v. 37, no. 4, p. 1029-1040.
Meko, D.M. and C.A. Woodhouse, in review. Tree-ring footprint of joint hydrologic
drought in Sacramento and Upper Colorado river basins, western USA. Journal
of Hydrology
Colorado River Reconstructions:
Water Resources Bulletin, 31(5) (Special Issue on climate variability and drought
in the Colorado River Basin)
Stockton, C.W. and Jacoby Jr., G.C. 1976. Long-term surface-water supply
and streamflow trends in the Upper Colorado River Basin based on tree-ring
analysis. Lake Powell Research Project Bulletin 18, Institute of Geophysics
and Planetary Physics, University of California, Los Angeles.
Some Selected Results from the Accelerated
Climate Prediction Initiative (ACPI)
Accelerated Climate
Prediction Initiative
(ACPI) –
NCAR/DOE Parallel
Climate Model
(PCM) grid over
western U.S.
A hydrologic simulation model and a
reservoir operations model were run in
each portion of the domain.
Both sensitivity and adaptive response
capability were evaluated.
Bias Correction
bias-corrected climate scenario
month m
raw climate scenario
from NCDC observations
month m
from PCM historical run
Note: future scenario temperature trend (relative to control run)
removed before, and replaced after, bias-correction step.
Downscaling
monthly PCM
anomaly (T42)
interpolated to
VIC scale
VIC-scale
monthly simulation
observed
mean fields
(1/8-1/4 degree)
The Main Impact
Pathway in the West:
Loss of Snowpack.
Reductions in
Pacific Northwest
Snowpack for
PCM Scenarios
(low sensitivity)
Results for the Sacramento and San Joaquin
Basins
Van Rheenen, N.T., A.W. Wood, R.N. Palmer and D.P. Lettenmaier, 2004, Potential
Implications of PCM Climate Change Scenarios for Sacramento - San Joaquin River
Basin Hydrology and Water Resources, Climatic Change (accepted)
BAU 3-run average
historical (1950-99)
control (2000-2048)
PCM
Business-as-Usual
scenarios
California
(Basin Average)
PCM
Business-as-Usual Scenarios
Snowpack Changes
California
April 1 SWE
PCM
Business-AsUsual
Mean Monthly
Hydrographs
Shasta
Reservoir
Inflows
1
month
12
1
month
12
Sacramento River Basin
Lake Shasta
Storage: 4552 taf
Trinity
Shasta
Whiskeytown
Trinity River
Clear Creek
Dam
Power Plant
River
Sacramento River
Oroville (SWP)
Feather River
American River
Transfer
Delta
Folsom
Delta & San Joaquin R Basin
Mokelumne River
Delta Outflow
Delta
Sacramento-San
Joaquin Delta
Millerton
Lake
New
Melones
Res 2
Area:
1200
Don
Pedro/McClure
Pardee/Camanche
Storage: 761 mi
taf
Pardee
& Camanche
Storage:
2420
Storage:
3055taf
taf
Reservoir
Storage: 615 taf
Calaveras River
New Hogan
San Joaquin River
San Luis
Stanislaus River
New Melones
Tuolumne &
Merced Rivers
Dam
Power Plant
River/Canal
Transfer
Eastman,
Hensley,
& Millerton
New Don Pedro
& McClure
Central Valley Water Year Type Occurrence
0.6
hist (1906-2000)
Percent Given WY Type
0.5
2020s
2050s
2090s
0.4
0.3
0.2
0.1
0.0
Critically Dry
Dry
Below Normal
Water Year Type
Above Normal
Wet
Current Climate vs. Projected
Climate
Storage Decreases
• Sacramento
Range: 5 - 10 %
Mean: 8 %
• San Joaquin
Range: 7 - 14 %
Mean: 11 %
Current Climate vs. Projected
Climate
Hydropower Losses
Central Valley Hydropower Production
1400000
• Central Valley
Range: 3 - 18 %
Mean: 9 %
• Sacramento System
Range: 3 – 19 %
Mean: 9%
• San Joaquin System
Range: 16 – 63 %
Mean: 28%
Ctrl mean
2000-2019
2020-2039
2040-2059
2060-2079
2080-2098
1200000
Megawatt-Hours
1000000
800000
600000
400000
200000
ct
O
ov
N
D
ec
Ja
n
b
Fe
M
ar
pr
A
M
ay
n
Ju
l
Ju
ug
A
p
Se
Results for Colorado River Basin
Christensen, N.S., Wood, A.W., Voisin, N., Lettenmaier, D.P. and R.N. Palmer, 2004,
Effects of Climate Change on the Hydrology and Water Resources of the Colorado
River Basin, Climatic Change, (accepted)
PCM Projected Colorado R. Basin
Termperature
ctrl.
avg.
hist. avg.
Period 1 2010-2039
Period 2 2040-2069
Period 3 2070-2098
PCM Projected Colorado R. Basin
Precipitation
hist. avg.
ctrl.
avg.
Period 1 2010-2039
Period 2 2040-2069
Period 3 2070-2098
Changes to Seasonal Hydrograph
Simulated Historic (1950-1999)
Control (static 1995 climate)
Period 1 (2010-2039)
Period 2 (2040-2069)
Period 3 (2070-2098)
Deliveries to Central Arizona Project
&
Los
Angeles Metro. Water District
Figure
11
1.4
1 BCM = 810,832 acre-ft
1.2
BCM / YR. / Probability
1
0.8
0.6
0.4
probability of CAP shrtg
if CAP shrtg, avg. amount
probability of MWD shrtg
If MWD shrtg, avg. amount
0.2
(probability)
(BCM /YR.)
(probability)
(BCM /YR.)
0
Historical
Control
Period 1
Period 2
Period 3
Conclusions and Comparative Analysis
• 1) California system operation is dominated by water supply
(mostly ag), the reliability of which would be reduced
significantly by a combination of seasonality shifts and
reduced (annual) volumes. Partial mitigation by altered
operations is possible, but complicated by flood issues.
• 2) Colorado system is sensitive primarily to annual
streamflow volumes. Low runoff ratio makes the system
highly sensitive to modest changes in precipitation (in winter,
esp, in headwaters). Sensitivity to altered operations is
modest, and mitigation possibilities by increased storage are
nil (even if otherwise feasible).
• 3) These potential impacts highlight the need for contingency
planning to cope with reductions in water supply and flexible
demand management strategies for the future.