WSIHIST (12/19/13 0934)

Department of Water Resources California Cooperative Snow Surveys Chronological Reconstructed Sacramento and San Joaquin Valley Water Year Hydrologic Classification Indices Based on measured unimpaired runoff (in million acre-feet), subject to revision. *** See explanatory notes at bottom *** [..........Sacramento Valley..........] [.........San Joaquin Valley..........] [.....Runoff (maf).....] [..WY Index..] [.....Runoff (maf).....] [..WY Index..] WY Oct-Mar Apr-Jul WYsum Index Yr-type Oct-Mar Apr-Jul WYsum Index Yr-type ------------------------------------------------------------------------------------ 1901 3.49 5.58 9.39 4.60 W 1902 1.12 3.81 5.08 3.41 AN 1903 1.45 4.13 5.71 3.45 AN 1904 1.96 5.37 7.64 4.31 W 1905 1.82 3.36 5.30 3.24 AN 1906 12.57 12.92 26.71 11.76 W 2.53 9.24 12.43 6.70 W 1907 18.96 13.45 33.70 14.07 W 3.67 7.61 11.82 6.20 W 1908 8.29 5.60 14.77 7.73 BN 0.98 2.17 3.32 2.40 D 1909 20.61 8.98 30.68 12.10 W 2.85 5.91 8.97 4.59 W 1910 13.12 6.11 20.12 9.38 W 2.87 3.62 6.64 3.65 AN 1911 12.27 13.12 26.38 11.74 W 3.63 7.52 11.48 5.97 W 1912 4.84 5.65 11.41 6.71 BN 0.54 2.57 3.21 2.55 BN 1913 5.72 6.29 12.85 6.24 D 0.44 2.34 3.00 2.00 C 1914 16.72 10.08 27.81 10.92 W 2.72 5.67 8.69 4.35 W 1915 11.41 11.42 23.86 10.99 W 1.29 4.95 6.40 4.10 W 1916 14.25 8.89 24.14 10.83 W 2.67 5.50 8.38 4.65 W 1917 7.25 9.14 17.26 8.83 AN 1.66 4.84 6.66 4.13 W 1918 5.27 4.89 10.99 6.19 D 1.07 3.40 4.59 3.08 BN 1919 8.12 6.77 15.66 7.00 BN 1.06 2.99 4.09 2.62 BN 1920 3.63 4.91 9.20 5.15 C 0.72 3.29 4.09 2.64 BN 1921 15.47 7.52 23.80 9.20 AN 1.97 3.84 5.90 3.23 AN 1922 6.63 10.57 17.98 8.97 AN 1.51 5.99 7.68 4.54 W 1923 6.21 6.27 13.21 7.06 BN 1.39 3.95 5.51 3.55 AN 1924 3.27 1.94 5.74 3.87 C 0.45 1.03 1.50 1.42 C 1925 8.76 6.51 15.99 6.39 D 1.45 3.93 5.51 2.93 BN 1926 6.37 4.79 11.76 5.75 D 0.89 2.56 3.49 2.30 D 1927 14.34 8.75 23.83 9.52 W 1.80 4.56 6.50 3.56 AN 1928 10.24 5.86 16.76 8.27 AN 1.69 2.64 4.37 2.63 BN 1929 4.00 3.84 8.40 5.22 C 0.52 2.29 2.84 2.00 C 1930 8.24 4.65 13.52 5.90 D 0.76 2.44 3.25 2.02 C 1931 3.52 2.09 6.10 3.66 C 0.46 1.18 1.66 1.20 C 1932 6.28 6.24 13.12 5.48 D 1.79 4.69 6.63 3.41 AN 1933 3.73 4.66 8.94 4.63 C 0.49 2.77 3.34 2.44 D 1934 5.68 2.45 8.63 4.07 C 0.98 1.26 2.28 1.44 C 1935 6.27 9.69 16.59 6.98 BN 1.26 5.03 6.41 3.56 AN 1936 10.32 6.41 17.35 7.75 BN 2.00 4.38 6.49 3.74 AN 1937 5.50 7.24 13.33 6.87 BN 1.78 4.66 6.53 3.90 W 1938 17.96 12.93 31.83 12.62 W 3.58 7.33 11.24 5.89 W 1939 4.56 3.04 8.18 5.58 D 1.00 1.83 2.90 2.20 D 1940 14.78 6.93 22.43 8.88 AN 2.49 4.04 6.59 3.36 AN 1941 16.32 9.77 27.08 11.47 W 2.22 5.51 7.93 4.43 W 1942 14.33 9.93 25.24 11.27 W 1.93 5.28 7.38 4.44 W 1943 13.37 6.90 21.13 9.77 W 2.86 4.28 7.28 4.03 W 1944 4.81 4.93 10.43 6.35 D 0.87 2.97 3.92 2.76 BN 1945 8.42 5.92 15.06 6.80 BN 2.07 4.37 6.60 3.59 AN 1946 10.89 5.97 17.62 7.70 BN 1.99 3.65 5.73 3.30 AN 1947 5.90 3.83 10.39 5.61 D 1.26 2.12 3.42 2.18 D 1948 5.39 9.55 15.75 7.12 BN 0.56 3.58 4.21 2.70 BN 1949 5.73 5.59 11.97 6.09 D 0.62 3.12 3.79 2.53 BN 1950 7.01 6.72 14.44 6.62 BN 1.02 3.57 4.65 2.85 BN 1951 16.77 5.42 22.95 9.18 AN 4.35 2.83 7.25 3.14 AN 1952 13.86 13.68 28.60 12.38 W 2.18 6.84 9.30 5.17 W 1953 10.84 8.26 20.09 9.55 W 1.07 3.18 4.35 3.03 BN 1954 9.74 6.81 17.43 8.51 AN 1.10 3.16 4.30 2.72 BN 1955 5.19 5.07 10.98 6.14 D 0.78 2.67 3.50 2.30 D 1956 20.32 8.60 29.89 11.38 W 4.14 5.29 9.67 4.46 W 1957 7.72 6.29 14.89 7.83 AN 1.02 3.19 4.29 3.01 BN 1958 16.37 12.24 29.71 12.16 W 1.67 6.40 8.36 4.77 W 1959 7.40 3.84 12.05 6.75 BN 0.98 1.85 2.98 2.21 D 1960 7.72 4.65 13.06 6.20 D 0.85 2.07 2.96 1.85 C 1961 6.87 4.39 11.97 5.68 D 0.54 1.50 2.10 1.38 C 1962 8.17 6.23 15.11 6.65 BN 1.26 4.24 5.61 3.07 BN 1963 12.01 10.09 22.99 9.63 W 1.68 4.37 6.24 3.57 AN 1964 5.90 4.37 10.92 6.41 D 0.93 2.14 3.14 2.19 D 1965 16.59 8.13 25.64 10.15 W 3.20 4.55 8.13 3.81 W 1966 7.42 4.84 12.95 7.16 BN 1.49 2.42 3.98 2.51 BN 1967 12.14 11.01 24.06 10.20 W 2.46 7.09 9.98 5.25 W 1968 8.66 4.12 13.64 7.24 BN 1.02 1.85 2.94 2.21 D 1969 15.33 10.68 26.98 11.05 W 3.84 8.14 12.29 6.09 W 1970 18.87 4.35 24.06 10.40 W 2.55 2.96 5.61 3.18 AN 1971 12.71 8.90 22.57 10.37 W 1.56 3.23 4.91 2.89 BN 1972 7.61 5.02 13.43 7.29 BN 1.25 2.22 3.57 2.16 D 1973 12.80 6.38 20.05 8.58 AN 1.87 4.48 6.47 3.50 AN 1974 21.69 9.78 32.50 12.99 W 2.43 4.53 7.12 3.90 W 1975 9.24 8.95 19.23 9.35 W 1.37 4.65 6.18 3.85 W 1976 4.63 2.75 8.20 5.29 C 0.78 1.07 1.97 1.57 C 1977 2.49 1.93 5.12 3.11 C 0.22 0.80 1.05 0.84 C 1978 14.90 8.12 23.92 8.65 AN 2.57 6.50 9.65 4.58 W 1979 6.06 5.64 12.41 6.67 BN 1.87 3.99 5.98 3.67 AN 1980 15.49 6.00 22.33 9.04 AN 3.74 5.41 9.47 4.73 W 1981 6.81 3.63 11.10 6.21 D 0.85 2.29 3.22 2.44 D 1982 20.56 11.82 33.41 12.76 W 3.78 7.00 11.41 5.45 W 1983 22.75 13.66 37.68 15.29 W 5.42 8.73 15.01 7.22 W 1984 15.98 5.52 22.35 10.00 W 3.51 3.48 7.13 3.69 AN 1985 6.24 4.00 11.04 6.47 D 1.11 2.41 3.60 2.40 D 1986 19.45 5.45 25.83 9.96 W 4.36 4.92 9.50 4.31 W 1987 5.85 2.80 9.27 5.86 D 0.55 1.48 2.08 1.86 C 1988 5.78 2.90 9.23 4.65 C 0.86 1.55 2.48 1.48 C 1989 9.03 5.07 14.82 6.13 D 1.07 2.42 3.56 1.96 C 1990 4.94 3.72 9.26 4.81 C 0.83 1.59 2.46 1.51 C 1991 3.90 4.01 8.44 4.21 C 0.56 2.57 3.20 1.96 C 1992 5.41 2.93 8.87 4.06 C 0.86 1.66 2.58 1.56 C 1993 12.44 8.98 22.21 8.54 AN 2.49 5.65 8.38 4.20 W 1994 4.55 2.73 7.81 5.02 C 0.66 1.80 2.54 2.05 C 1995 19.83 13.60 34.55 12.89 W 3.67 8.01 12.32 5.95 W 1996 13.05 8.37 22.29 10.26 W 2.57 4.51 7.22 4.12 W 1997 20.22 4.39 25.42 10.82 W 5.75 3.59 9.51 4.13 W 1998 17.65 12.54 31.40 13.31 W 2.82 7.11 10.43 5.65 W 1999 12.97 7.26 21.19 9.80 W 1.90 3.85 5.91 3.59 AN 2000 12.06 5.96 18.90 8.94 AN 1.98 3.78 5.90 3.38 AN 2001 5.64 3.46 9.81 5.76 D 0.92 2.23 3.18 2.20 D 2002 9.32 4.57 14.60 6.35 D 1.27 2.75 4.06 2.34 D 2003 10.71 7.74 19.31 8.21 AN 1.25 3.49 4.87 2.81 BN 2004 10.95 4.40 16.04 7.51 BN 1.51 2.25 3.81 2.21 D 2005 8.40 9.28 18.55 8.49 AN 2.73 6.28 9.21 4.75 W 2006 18.06 13.09 32.09 13.20 W 2.86 7.37 10.44 5.90 W 2007 6.59 3.04 10.28 6.19 D 0.99 1.46 2.51 1.97 C 2008 5.90 3.82 10.28 5.16 C 0.99 2.45 3.49 2.06 C 2009 7.05 5.30 13.02 5.78 D 1.51 3.35 4.94 2.72 BN 2010 7.45 7.78 16.01 7.08 BN 1.43 4.53 6.08 3.55 AN 2011 12.68 11.53 25.21 10.54 W 3.68 6.90 10.99 5.58 W 2012 5.69 5.46 11.83 6.89 BN 0.83 1.86 2.76 2.18 D 2013 8.20 3.02 11.86 5.73 D 1.33 1.67 3.05 1.71 C min 2.49 1.93 5.12 3.11 0.22 0.80 1.05 0.84 mean 10.98 6.47 18.26 8.19 1.95 3.81 5.95 3.29 max 22.75 13.68 37.68 15.29 5.75 9.24 15.01 7.22 1961-2010 mean Eight River Runoff [maf] WY Dec Jan Feb Mar Apr May ------------------------------------------------------ 1901 1902 1903 1904 1905 1906 0.55 3.69 2.93 7.00 5.34 6.43 1907 2.14 2.83 6.01 10.40 7.32 5.86 1908 1.43 2.27 2.12 2.19 2.53 2.59 1909 0.66 11.14 6.85 3.71 4.22 4.78 1910 3.09 2.90 2.55 4.84 4.21 3.30 1911 1.15 4.11 3.61 5.88 6.36 5.71 1912 0.55 1.20 0.94 1.61 1.58 3.33 1913 0.77 1.60 1.01 1.32 2.81 3.31 1914 1.72 8.50 3.99 4.18 5.05 5.28 1915 0.76 1.86 5.43 3.54 4.43 6.38 1916 1.52 3.75 4.89 5.71 5.03 4.44 1917 1.28 1.01 3.13 2.15 4.29 4.37 1918 0.70 0.57 1.22 2.99 3.09 2.53 1919 0.68 1.20 3.13 2.74 3.89 4.06 1920 0.68 0.57 0.58 1.71 2.58 3.20 1921 2.90 4.34 3.15 4.22 3.30 4.01 1922 1.16 1.07 2.63 2.41 3.66 6.68 1923 2.03 1.75 1.20 1.51 3.38 3.66 1924 0.49 0.56 1.16 0.64 1.07 1.10 1925 0.92 0.94 4.99 2.18 3.82 3.70 1926 0.67 0.76 3.18 1.73 3.79 2.18 1927 2.01 2.22 6.05 3.53 4.82 4.28 1928 1.10 1.37 1.94 5.69 3.73 3.02 1929 0.64 0.61 1.12 1.29 1.63 2.49 1930 2.37 1.41 1.84 2.78 2.64 2.29 1931 0.39 0.80 0.78 1.20 1.23 1.18 1932 1.68 1.33 1.84 2.50 2.73 4.16 1933 0.42 0.70 0.58 1.89 1.97 2.36 1934 1.04 1.47 1.59 1.90 1.61 1.09 1935 0.79 1.87 1.56 2.13 6.18 4.74 1936 0.51 3.22 5.04 2.77 3.83 3.71 1937 0.45 0.54 2.36 3.28 3.77 4.92 1938 4.81 1.86 5.27 7.50 5.98 7.34 1939 0.80 0.79 0.81 1.91 2.26 1.47 1940 0.68 3.88 5.68 6.22 4.61 3.77 1941 3.41 4.28 5.07 4.72 4.62 5.75 1942 3.58 4.18 5.10 2.23 4.64 4.76 1943 1.83 4.67 2.84 5.33 4.23 3.59 1944 0.55 0.78 1.44 1.94 1.88 3.34 1945 1.50 1.07 4.13 2.17 2.82 3.82 1946 4.60 2.64 1.31 2.29 3.45 3.68 1947 1.06 0.64 1.57 2.51 2.20 2.05 1948 0.50 1.91 0.70 1.56 4.34 4.51 1949 0.66 0.53 0.92 3.32 3.27 3.39 1950 0.43 1.82 2.54 2.46 3.74 3.73 1951 5.95 3.40 3.52 2.66 2.81 3.15 1952 3.36 3.48 4.03 3.68 6.35 7.51 1953 1.92 5.40 1.52 2.06 3.25 3.38 1954 0.80 2.20 2.84 3.66 4.56 3.27 1955 1.35 1.16 0.96 1.27 1.97 3.22 1956 9.14 7.52 3.71 3.07 3.51 5.24 1957 0.61 0.79 2.65 3.41 2.36 3.85 1958 1.62 2.39 7.61 4.71 6.04 6.74 1959 0.58 2.25 2.50 1.98 2.27 1.82 1960 0.47 0.90 3.15 3.22 2.50 2.39 1961 1.36 0.86 2.14 1.93 2.02 2.16 1962 1.19 0.78 4.08 2.39 3.89 3.14 1963 1.90 1.70 4.66 2.10 5.60 4.99 1964 0.85 1.55 1.01 1.15 1.92 2.44 1965 8.66 5.61 2.26 1.97 4.74 3.81 1966 1.04 1.85 1.56 2.52 3.33 2.52 1967 2.98 3.34 2.52 4.09 3.82 6.26 1968 0.85 1.49 3.71 2.55 2.17 2.15 1969 1.77 7.91 4.73 3.36 5.44 7.34 1970 3.30 10.68 3.02 3.12 1.82 2.77 1971 3.26 3.05 1.83 3.73 3.40 4.18 1972 1.19 1.40 1.73 3.30 2.52 2.61 1973 1.83 4.08 3.66 3.27 3.08 4.76 1974 3.68 6.93 2.10 6.18 5.07 4.69 1975 0.86 1.01 2.92 4.65 2.89 5.40 1976 0.76 0.65 0.88 1.34 1.35 1.44 1977 0.38 0.47 0.48 0.54 0.69 0.91 1978 1.90 5.91 3.48 5.36 4.40 4.70 1979 0.53 1.44 2.10 2.90 2.67 4.50 1980 1.24 6.89 5.93 3.62 3.11 3.67 1981 0.92 1.57 1.76 2.48 2.32 2.11 1982 5.58 3.50 5.57 4.74 8.05 5.68 1983 3.69 4.25 6.46 10.57 4.87 6.96 1984 6.72 2.85 2.29 3.08 2.50 3.60 1985 1.20 0.84 1.21 1.59 2.79 2.14 1986 1.25 2.62 11.55 7.09 3.19 3.56 1987 0.53 0.78 1.48 2.60 1.73 1.48 1988 1.70 1.84 1.01 1.26 1.48 1.59 1989 0.72 0.85 0.99 6.17 3.59 2.22 1990 0.45 1.27 0.88 1.84 1.80 1.77 1991 0.34 0.37 0.45 2.64 1.95 2.40 1992 0.47 0.58 2.41 1.99 2.17 1.33 1993 1.25 4.06 3.13 5.70 4.33 5.23 1994 0.78 0.78 1.23 1.49 1.57 1.79 1995 1.06 8.11 3.12 10.19 5.61 7.18 1996 1.72 2.47 6.25 4.25 3.97 5.50 1997 6.84 12.15 2.74 2.45 2.70 2.96 1998 1.18 5.19 7.44 5.11 4.53 5.53 1999 1.88 2.60 4.59 3.67 3.26 4.27 2000 0.65 2.55 5.49 4.08 3.55 3.62 2001 0.67 0.87 1.50 2.39 2.03 2.49 2002 2.50 2.70 1.74 2.31 2.82 2.60 2003 3.24 3.40 1.66 2.52 3.27 4.82 2004 2.14 1.90 3.98 3.47 2.64 2.29 2005 1.56 2.49 2.01 3.75 3.18 7.23 2006 5.83 5.16 3.42 5.38 8.56 6.84 2007 1.32 0.87 2.14 2.07 1.74 1.67 2008 0.70 1.70 1.81 1.79 1.89 2.68 2009 0.57 0.96 2.32 3.64 2.40 4.21 2010 0.71 2.48 2.31 2.31 3.25 3.70 2011 4.31 2.10 1.96 6.20 5.23 4.94 2012 0.49 0.96 0.74 3.03 3.70 2.27 2013 3.78 1.34 1.08 1.71 2.02 1.43 min 0.34 0.37 0.45 0.54 0.69 0.91 mean 1.95 2.99 2.95 3.45 3.23 3.68 max 9.14 12.15 11.55 10.57 8.56 7.51 1961-2010 mean Official Year Classifications based on May 1 Runoff Forecasts Sacramento Valley Index San Joaquin Valley Index WY Index Yr-type Index Yr-type 1995 12.4 W 5.5 W 1996 9.7 W 3.9 W 1997 11.0 W 4.2 W 1998 12.4 W 4.9 W 1999 10.0 W 3.4 AN 2000 9.2 W 3.3 AN 2001 5.9 D 2.3 D 2002 6.5 D 2.3 D 2003 8.0 AN 2.7 BN 2004 7.7 BN 2.2 D 2005 7.4 BN 4.2 W 2006 13.0 W 5.5 W 2007 6.2 D 1.9 C 2008 5.4 C 2.1 C 2009 5.5 D 2.4 D 2010 6.9 BN 3.5 AN 2011 10.0 W 5.1 W 2012 6.9 BN 2.2 D 2013 5.8 D 1.6 C Abbreviations: WY Water year (Oct 1 - Sep 30) W Wet year type AN Above normal year type BN Below normal year type D Dry year type C Critical year type % exc. Probability in % that a given value will be exceeded [maf] Million acre-feet Notes: Unimpaired runoff represents the natural water production of a river basin, unaltered by upstream diversions, storage, export of water to or import of water from other basins. Sacramento River Runoff is the sum (in maf) of Sacramento River at Bend Bridge, Feather River inflow to Lake Oroville, Yuba River at Smartville, and American River inflow to Folsom Lake. The WY sum is also known as the Sacramento River Index, and was previously referred to as the "4 River Index" or "4 Basin Index". It was previously used to determine year type classifications under State Water Resources Control Board (SWRCB) Decision 1485. Sacramento Valley Water Year Index = 0.4 * Current Apr-Jul Runoff Forecast (in maf) + 0.3 * Current Oct-Mar Runoff in (maf) + 0.3 * Previous Water Year's Index (if the Previous Water Year's Index exceeds 10.0, then 10.0 is used). This index, originally specified in the 1995 SWRCB Water Quality Control Plan, is used to determine the Sacramento Valley water year type as implemented in SWRCB D-1641. Year types are set by first of month forecasts beginning in February. Final determination is based on the May 1 50% exceedence forecast. Sacramento Valley Water Year Hydrologic Classification: Year Type: Water Year Index: Wet Equal to or greater than 9.2 Above Normal Greater than 7.8, and less than 9.2 Below Normal Greater than 6.5, and equal to or less than 7.8 Dry Greater than 5.4, and equal to or less than 6.5 Critical Equal to or less than 5.4 San Joaquin River Runoff is the sum of Stanislaus River inflow to New Melones Lake, Tuolumne River inflow to New Don Pedro Reservoir, Merced River inflow to Lake McClure, and San Joaquin River inflow to Millerton Lake (in maf). San Joaquin Valley Water Year Index = 0.6 * Current Apr-Jul Runoff Forecast (in maf) + 0.2 * Current Oct-Mar Runoff in (maf) + 0.2 * Previous Water Year's Index (if the Previous Water Year's Index exceeds 4.5, then 4.5 is used). This index, originally specified in the 1995 SWRCB Water Quality Control Plan, is used to determine the San Joaquin Valley water year type as implemented in SWRCB D-1641. Year types are set by first of month forecasts beginning in February. Final determination for San Joaquin River flow objectives is based on the May 1 75% exceedence forecast. San Joaquin Valley Water Year Hydrologic Classification: Year Type: Water Year Index: Wet Equal to or greater than 3.8 Above Normal Greater than 3.1, and less than 3.8 Below Normal Greater than 2.5, and equal to or less than 3.1 Dry Greater than 2.1, and equal to or less than 2.5 Critical Equal to or less than 2.1 Eight River Index = Sacramento River Runoff + San Joaquin River Runoff This Index is used from December through May to set flow objectives as implemented in SWRCB Decision 1641. The 'reconstructed' table is based on observed runoff, and does NOT show the official year-types, which are based on May 1 forecasts of future runoff. The current water year indices based on forecast runoff are posted at http://cdec.water.ca.gov/water_supply.html and published in DWR Bulletin 120 (also available at http://cdec.water.ca.gov/snow/bulletin120) These indices have been used operationally since 1995, and are defined in SWRCB Decision 1641 (see http://www.waterrights.ca.gov/baydelta/d1641.htm) This report is updated each fall once the data is available. For more information, contact CDWR Flood Management, Hydrology Branch Dave Rizzardo (916) 574-2983 david.rizzardo@water.ca.gov John King (916) 574-2637 john.j.king@water.ca.gov Steve Nemeth (916) 574-2634 stephen.nemeth@water.ca.gov Andy Reising (916) 574-2181 andrew.reising@water.ca.gov Sean de Guzman (916) 574-2208 sean.deguzman@water.ca.gov