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.