Missouri River Mainstem System MidWest Electric Consumers Association

Missouri River Mainstem System Mid-West Electric Consumers Association Meeting US Army Corps of Engineers BUILDING STRONG®

Missouri River Basin Mountain Snowpack Water Content 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Total above Fort Peck 85% of June 4 average 23. 0” peaked on April 19 4. 6” on June 4 O N D J F M A M J J A S 2017 -2018 Month 1981 -2010 Ave 2011 Inches of Water Equivalent June 4, 2018 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Total Fort Peck to Garrison 91% of June 4 average 20. 1” peaked on April 15 5. 0” on June 4 O N D J F M A M J J A S 2017 -2018 Month 1981 -2010 Ave Fort Peck peaked on April 19 at 141% of the normal Fort Peck to Garrison peaked on 15 April 15 at 137% of the normal 2011

Current Reservoir Levels – June 8, 2018 Elevation in feet msl Fort Peck Exclusive Flood Control Annual Flood Control & Multiple Use 2250 2245. 7 2246 2234 Carryover Multiple Use 1854 Exclusive Flood Control Annual Flood Control & Multiple Use 1848. 9 1850 1837. 5 Carryover Multiple Use Permanent Pool 11. 7 feet above base of Flood Control zone 2160 2030 Elevation in feet msl Oahe Exclusive Flood Control Annual Flood Control & Multiple Use Garrison Elevation in feet msl 1620 1611. 6 1617 1607. 5 Carryover Multiple Use Permanent Pool 11. 4 feet above base of Flood Control zone Fort Randall Exclusive Flood Control Annual Flood Control & Multiple Use 1357. 3 1775 1673 Elevation in feet msl 1375 1365 1350 Carryover Multiple Use Permanent Pool 4. 1 feet above base of Flood Control zone 1540 1415 Permanent Pool 7. 3 feet above base of Flood Control zone 1320 1240

Missouri River Mainstem System Annual Runoff above Sioux City, IA 70 Million Acre-Feet Historic Drought Periods 60 2018 50 40 30 20 34. 5 MAF 10% 30. 6 25% U. D. U. Q. 24. 6 50% Med. 19. 3 16. 1 75% 90% L. Q. L. D. 10 0 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year

Monthly Runoff above Sioux City, IA 2018 Forecast 8 Million Acre-Feet (MAF) 2018 Calendar Year Forecast = 34. 6 MAF 7 6 5 4 3 2 1 0 Jan Feb Mar Apr May Jun Observed Jul Aug 2018 Forecast 16 Sep Oct Average Nov Dec

System Storage 75 Storage in Million Acre-Feet June 1 st Forecast Top Exclusive Flood Control – 72. 4 maf 70 Base Exclusive Flood Control – 67. 7 maf upper basic 65 Actual 60 lower basic Base Flood Control – 56. 1 maf 55 50 45 40 35 Navigation Preclude – 31 maf 30 J F M A M J J A S O N D J 2017 F M A M J J A S O N D J FM 2018 2019

Mainstem System Generation 16 Million MWhs 14. 6 13. 5 14 12 13. 0 11. 2 10. 4 10 14. 3 9. 3 10. 0 11. 1 9. 6 8. 7 7. 5 7. 6 8 6. 1 6 5. 2 10. 6 10. 4 8. 5 7. 6 6. 5 6. 3 9. 5 7. 6 6. 6 5. 6 4. 9 4 2 0 1967 -2017 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 UB Med LB Average June 1, 2018 Forecast

Missouri River Mainstem System Forecasted Energy Generation 1600 Energy in GWh 1400 1200 1000 800 600 400 200 0 Jan Feb Mar Apr May Actual Jun Jul Aug 2018 Forecast Sep Oct Nov Dec J 19 F 19 1967 -2017 Basic: 13, 000 GWh BUILDING STRONG®

2018 Reservoir Operations • • All 2017 water was evacuated in mid-January Currently 8. 4 MAF of 16. 3 MAF of flood storage is available Service level increased 15, 000 cfs in mid-April Navigation flow support above full service flows ► ► Above full service flow support likely following July 1 storage check 10 -day season length extension on basic forecast • Hydropower: annual generation forecast is 13. 0 Bk. Wh • Recreation, Water Supply and Irrigation ► ► Good support; no problems anticipated at this time Gavins Point winter releases of 20, 000 cfs under basic forecast • Fish and Wildlife / Endangered Species ► ► ► Fort Peck, Garrison and Oahe were all held steady to rising during the forage fish spawn (Apr - early June) No March and May spring pulses from Gavins Point Currently not peaking at Garrison and Fort Randall due to high releases.

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