Water Measurement Presentation Some Units for Describing Water - PowerPoint PPT Presentation

Water Measurement Presentation Some Units for Describing Water Acre-foot [af]: volume of water which inundates one acre Compact Implementation Technical Team to a depth of one foot. Commonly used for reservoirs and seasonal volumes in canals or streams March 15, 2016 Cubic feet per second [cfs]: near- instantaneous discharge Overview of Presentation of water across a cross section of stream or canal a) Historical Perspective 1 cubic foot per second = 448.8 gallon per minute b) Review of some hydrologic trends 1 cubic foot per second over a day = 1.983 acre-foot 1 cubic foot per second over a year = 724 acre-feet c) Role of Water Measurement, and reference within Compact Graphical representation of water - hydrograph d) Current Water Measurement Proposal discharge or Units of volume Time

Historical Perspective 1860 1865 – High water year, flooding documented in western Montana papers. Portland, Ore. floods 1860’s-1870’s – Indian irrigation ditches constructed in Jocko Valley, Vanderburg Ditch on Finley Creek - 1864 1875 Around 1885, headworks and canal started at present location of Jocko K Canal 1890 1894 – Flood of record, lower Flathead River = 110,000 cfs; next largest flood 1928 = 82,800 cfs 1906 – 1918 – early U.S. Geological Survey streamflow records Jocko, Mission, Little Bitterroot Valley, records available on USGS website 1905 Much of the measurement predates FIIP irrigation diversion 1908 – Flood of record for much of Western Montana, Jocko River 7,500 cfs; Post Creek 2,800 cfs 1916 – Regional high water year, including Reservation 1920 1928 – Regional high water year, including Reservation 1929 - 1944 – Most severe continuous drought in measured record for Montana 1935

1935 1939 through 1946 – Compilations of water supply and water use for FIIP prepared by US Indian Irrigation Service and USDOI Office of Indian Affairs Irrigation Division 1941 and 1944 – Droughts of record for western Montana 1948 – Regional flood year, second largest recorded flood on Jocko River 1950 Starting in 1940’s, FIIP initiated stream and canal measurement program Approximately 70 ratings were developed spanning into 1960’s. Records indicate measurement program very limited after 1960’s 1964 – Regional flood year, FIIP Project Engineer reports 3.92” rain in 42 hours, many FIIP canals and headworks destroyed 1965 1974 – Regional flood year 1980 1982 – CSKT Water Measurement Program starts. USGS cooperative program starts, USGS stream gaging information available 1982 - present 1987 – Measurement and compliance for Interim Instream Flow and Minimum Reservoir pool levels begins 1987 and 1988 - Severe drought in western Montana 1992 – Severe single year drought 1995 1997 – High water year, Jocko River peaks at 2,710 cfs 2001 – Drought, one of five lowest water years on record 2005 – Very elevated peak flows – driven by rain event, not snowmelt 2011- volumetrically very high water year, similar to 1997 – sustained high flows 2010 2015 – Low water year, very below average snowpack, below average precipitation, above average temperatures, strong el nino signature through later 2015 carrying into 2016

Northwest Montana watersheds are considered either snow-dominated or rain and snow dominated Typically > 75 % of surface runoff comes as snowmelt in the April – July period This pattern is widely recognized to be changing, with earlier runoff and a greater percent of precipitation occurring as rainfall

Snow observations are consistent with longer-term 65 temperature data 60 Missoula first order weather 55 annual temperatures, in degrees f station (USC00245740) 50 45 Air temperature data 1895 – 40 2015 35 30 For each trend line air 25 temperature has increased 20 by approximately 1.5 1895 1898 1901 1904 1907 1910 1913 1916 1919 1922 1925 1928 1931 1934 1937 1940 1943 1946 1949 1952 1955 1958 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 degrees Fahrenheit over the average annual maximum annual average average annual minimum time period

Saint Ignatius weather station 2.50 16% 15% a) 14% percent of average annual precipitation Average monthly precipitation, in 14% Precipitation patterns average monthly precipitation, as 2.00 12% 9% 9% 10% 1.50 8% inches 8% 7% 7% a) Monthly precipitation patterns 7% 6% 6% 6% 1.00 5% 6% using 1909 – 2015 average 4% monthly values 0.50 2% 0.00 0% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 30 b) b) Average annual precipitation for 1909 – 2015 period (average = 25 12.83 annual precipitation, in inches 15.84 inches). Orange is trend 8.77 20 line. a) 1935 lowest annual 15 precipitation in 107 year 10 period; b) 2015 24 th lowest annual 5 precipitation in last 107 0 1909 1912 1915 1918 1921 1924 1927 1930 1933 1936 1939 1942 1945 1948 1951 1954 1957 1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014 years

d) St Ignatius station March and c) St Ignatius station December – trend line (average = 16%). Orange is each years annual precipitation April precipitation as percent of Orange is trend line precipitation (average = 18%). percent of each years annual February precipitation as 2015 c) d) March-April precipitation as percent of December-February precipitation as annual precipitation percent of annual precipitation 10% 15% 20% 25% 30% 35% 10% 15% 20% 25% 30% 35% 40% 45% 50% 0% 5% 0% 5% 1909 1909 1912 1912 1915 1915 1918 1918 1921 1921 1924 1924 1927 1927 1930 1930 1933 1933 1936 1936 1939 1939 1942 1942 1945 1945 1948 1948 1951 1951 1954 1954 1957 1957 1960 1960 1963 1963 1966 1966 1969 1969 1972 1972 1975 1975 1978 1978 1981 1981 1984 1984 1987 1987 1990 1990 1993 1993 1996 1996 1999 1999 2002 2002 2005 2005 2008 2008 2011 2011 2014 2014

f) St Ignatius station July and e) St Ignatius station May and June Orange is trend line precipitation (average = 14%). of each years annual August precipitation as percent line (average = 30%). Orange is trend years annual precipitation precipitation as percent of each 2015 e) f) July -August precipitation as percent of May-June precipitation as percent of annual precipitation annual precipitation 10% 20% 30% 40% 50% 60% 70% 10% 15% 20% 25% 30% 35% 40% 0% 0% 5% 1909 1909 1912 1912 1915 1915 1918 1918 1921 1921 1924 1924 1927 1927 1930 1930 1933 1933 1936 1936 1939 1939 1942 1942 1945 1945 1948 1948 1951 1951 1954 1954 1957 1957 1960 1960 1963 1963 1966 1966 1969 1969 1972 1972 1975 1975 1978 1978 1981 1981 1984 1984 1987 1987 1990 1990 1993 1993 1996 1996 1999 1999 2002 2002 2005 2005 2008 2008 2011 2011 2014 2014

g) September – November Orange is trend line precipitation (average = 23%). each years annual precipitation as percent of 2015 g) Sept-Nov precipitation as percent of annual precipitation 10% 15% 20% 25% 30% 35% 40% 45% 0% 5% 1909 1912 1915 1918 1921 1924 1927 1930 1933 1936 1939 1942 1945 1948 1951 1954 1957 1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014

a) 600,000 Swan River at Bigfork 500,000 departure relative to 1923 - 2014 average 400,000 USGS station 12337000 300,000 200,000 (837,575 acre-feet) Long-term representative 100,000 natural flow gage for region 0 -100,000 -200,000 Surplus – deficit plots -300,000 -400,000 a) Shows (+ or –) departure of yearly average flow volume from long-term b) 300,000 3 year moving average of departure from average flow volume. 200,000 Orange is trend line 1923 - 2015 average, in af 100,000 b) 3-year moving average 0 smooths annual values -100,000 helping to illustrate multi- -200,000 year patterns, such as droughts of 1940’s and -300,000 early 2000’s

Swan River at Bigfork 90% USGS station 12337000 80% April – September runoff volume as percent of annual runoff 70% April - September runoff as percent of annual runoff volume (average = 76%) 58% 60% 55% Red bars 1934; 58 % 50% 2015; 55 % 40% 2015 – earliest peak on record March 19 th 30% Orange is trend line 20% April - September runoff is decreasing as percent of annual 10% runoff volume at this station 0%

90,000 a) 80,000 Natural Flows on Reservation 70,000 (average = 43,850 acre-feet) annual runoff, in acre-feet 60,000 a) Annual runoff South Fork 50,000 Jocko River (USGS gage 40,000 30,000 12381400) 20,000 10,000 0 18,000 b) 16,000 annual runoff, in acre-feet 14,000 (average = 6,600 acre-feet) b) Annual runoff Mill Creek 12,000 (USGS gage 12372450) 10,000 8,000 6,000 4,000 2,000 0 Post- Chippy Creek fire