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Missouri Headwaters Basin Study Issues and Potential Adaptation Strategies Irrigation in the Missouri Headwaters

Lower Ruby Valley Landsat composite image with irrigated lands delineated Source: State Water Plan Irrigation Changes

Flood Irrigation

Sprinkler Irrigation Irrigation Water Use Schematic About 22% ditch loss Potential New Irrigation Development

• Basin Closures – Missouri Basin above Great Falls – Teton River Basin • Water Contracting – Canyon Ferry Reservoir – Tiber Reservoir • Water Reservations – Up to about 18,000 acres mostly below Great Falls 20,000 – 40,000 acres Measures for Evaluating Impacts and Adaptation Strategies • Irrigation deliveries – Average annual – Wet years – Dry years • Irrigation shortages • Irrigation consumptive use • Irrigation allotments Hydropower

Black Eagle Dam and Falls Source: Montana State Water Plan Turnbull Project GID: 13 MW Tiber Dam: 7.5 MW

About 418 MW total

Source: Montana State Water Plan below Normal Range of Flow 20,000

18,000 Highest Year in 10 16,000 Middle Year 14,000 Lowest Year in 10 12,000

10,000 Turbine Capacity at Holter Dam 8,000

6,000

4,000 FlowCubic in Feet Per Second 2,000

0 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Measures for Evaluating Impacts and Adaptation Strategies

• Total Hydropower Production – Average annual – Wet years – Dry years • Headwaters Benefits Changes Ecological Fish and Wildlife Habitat Endangered and Threatened Species Missouri River at Fort Benton Pre-Post Canyon Ferry Comparison 25,000

20,000 Before Canyon Ferry Reservoir

After Canyon Ferry Reservoir 15,000

10,000

5,000 FlowCubic in Feet Per Second

0 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Big Hole River

Mike Roberts Arctic grayling

Recreation

Riparian and Aquifer Recharge Snow Carrot Basin SNOTEL Site Normal Snow Water Equivalents (1981-2010 data) 35

30

25

20

15 Inches 10

5

0 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep

Madison Range, Gallatin River Watershed: 9,000 feet Average Annual Precipitation: 43 inches Missouri River at Toston Date of Peak Flow (1955-2012) 30

25

20

15

10 Number of Years

5

0 April May 1-15 May 16-31 June 1-15 June 16-30 Measures for Evaluating Impacts and Adaptation Strategies

• Flow Distributions – Monthly – Daily – Percentile • Date of flow peak or flow volume centroid • Percent of time minimum instream flows are equaled or exceeded (Murphy Rights, Water Reservations) • Percent exceedance of high and low flow conditions at various locations – 7- day minimum flow – 7- day maximum flow

Reservoirs Canyon Ferry Reservoir

Photos from U.S. Bureau of Reclamation Canyon Ferry Reservoir Storage Through Time 2,500,000

Replacement and Flood Control Zone

2,000,000 Feet

- 1,500,000

Joint Use Zone 27 feet

1,000,000

Storage in Acre Active Conservation Zone

500,000

0 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 08 10 12 ------Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan

Gibson Reservoir Near the End of the Irrigation Season Sun River

Ruby Reservoir Measures for Evaluating Impacts and Adaptation Strategies

• Percent exceedance of identified reservoir elevations – Recreation targets – Flood control pool – Others • End of September storage

Municipal, Domestic and Industrial Water Use

Rocky Boy’s North Central Montana Regional Water Project Potential Service Areas Federal Reserved Water Rights Groundwater Recharge Associated with Irrigation

Summer water table

Irrigation Ditch

Flint Creek

Winter water table Saturated zone

Bdrx Potential Effect to Streamflow Associated with Groundwater Pumping