1. Mid-West Electric Consumers Association
Overview Briefing
August 2017
Gary Hinkle, P.E.
Operations Division
Omaha District

2. U.S. Army Corps of Engineer FY17 Customer Funded Hydropower Program
Tracking 46 projects
17 in design, 8 in acquisition, 21 awarded and in construction
Awarded 21 contract actions including:
Installing digital governors at Big Bend
Replacing bulkheads at Fort Peck
Replacing powerhouse potential and current transformers at 5 plants
Refurbishing intake gate hoist gear boxes at Big Bend
Installing programmable logic controllers at Big Bend and Garrison
Replacing 480V transformers at Gavins Point
Replacing intake motor controls at Oahe
Replacing generator exciters at Gavins Paint and Oahe
Making site improvements in the generator yard at Garrison
9 cost shares will be closed out with FY18 contract
$122.5M customer and revolving funds in FY17/18 (74% toward Randall Rehab)
Completed Hydropower Program Management Plan to implement 2016 HMP
Utilizing new project support docs and schedule templates to streamline execution

4. August 2017 Reservoir General COnDitions
Past Runoff Last month’s runoff was 101% of normal. July system inflows were 3.3 MAF. Total system storage on July 31 – 61.4 MAF (Down from 61.8 MAF on June 30) Forecasted Annual Runoff – CY 2017 A discussion on the forecast can be found on the Missouri River Water Management website. Basic – 27.9 MAF (110% of Normal) UB – 29.2 MAF LB – 26.7 MAF Gavins Releases July – 31,700 cfs average release. Releases are currently near 31,000 cfs and will be adjusted as needed based on bird habitat and river conditions downstream.

5. August 2017 Reservoir Monthly Study
Current Water-Year Balancing : balanced for all 3 conditions Basic – Be at the base of flood control. System storage at 56.1 MAF Lower Basic – Below the base of flood control. System storage at 54.1 MAF Upper Basic - At the base of flood control. System storage at 56.1 MAF. Navigation Service Levels The July 1st System storage check was 61.8 MAF. Full-service navigation support Navigation Season Support Length (Jul 1 System Storage Check) Full navigation season; If Upper Basic – 10-day extension. Gavins Winter Release (December thru February) - Sept 1 system storage of 58.0 MAF or more results in a Gavins Point winter release would be at least 17,000 cfs for all 3 conditions. Energy Generation Last month – 1.12BKWhrs actual – long-term average for July, 0.94 BKWhrs. Forecast – Basic Simulation – 9.6 BKWhrs. Long-term average approx 9.3 BKWhrs

6. CY 2017 Missouri River Runoff Above Sioux City, Iowa
Million Acre-Feet
Aug 1, Forecast – 27.9 MAF – 110%
Average: 25.3 MAF

7. Gavins Point Annual Release
Million Acre-Feet
Aug 1, 2017 Forecast Upper Basic: 21.7 MAF Lower Basic: 19.7 MAF

8. Missouri River Mainstem System Forecasted Energy Generation
Energy in GWh
Upper Basic: 10,400 GWh
Basic: 9,600 GWh
Lower Basic: 9,600 GWh

9. Mainstem System Generation
Million Megawatt Hours
Forecast
Aug 1, 2017 Forecast Upper Basic: 10.4 Lower Basic: 9.6

10. System Storage August 1st Forecast
Storage in Million Acre-Feet
Top Exclusive Flood Control – 72.4 maf
Base Exclusive Flood Control – 67.7 maf
upper basic
Actual
basic
Base Flood Control – 56.1 maf
lower basic
Navigation Preclude – 31 maf
2016
2017
2018

11. OAHE Peaking Concerns Flood stage at the Pierre gage is 13 feet
The top of the sheet pile wall at Marion Gardens in Fort Pierre corresponds to a stage of approximately 11 feet.  

13. OAHE Peaking Concerns
Since construction of Oahe Dam, historic elevations for typical operations at the Pierre gauge varied from a low of elevation feet msl to a high of elevation feet msl. It is not uncommon to have daily fluctuations of 5 to 7 feet in the Missouri River and in the development canals.
feet msl corresponds to 13.2 ft at the Pierre gauge.
Dept of Army Permit; Special Permit Conditions
That all structures shall be constructed to a minimum elevation of feet msl or otherwise be flood proofed.
That the permittee will advise all lot owners within the Marians Gardens development area of the Corps of Engineers‘ concern regarding flood levels and water level fluctuations
In years with high runoff including 1995, 1996, 1997, 2010 and 2011, releases required to evacuate water from the reservoir system result in generally high river stages (above ft elev).
Additionally, higher daily average releases in combination with hydropower peaking can result in elevated stages for short periods during the day.
Hydropower peaking has occurred both before and after the construction of the Marion Gardens development. There have been a number of occasions since construction with river stages above the approximate top of the sheetpile wall.

14. Reference Stage (corresponds to elevation 1427.5)
Stage used as target level during winter
Stage used as notification level during winter
Recent Peak Stage (July 2017)
Approximate stage near top of
sheetpile wall
This slide shows the stages at Pierre as well as the approximate top of the sheetpile wall at Marion Gardens. There are a couple of things to note on the graphic: in 2011, the stage went above 19 feet and in the early years (1978 to late 1986) we only got a few readings per day, so that's why it looks like dots.

15. The second slide in the attached file shows hourly stages at Pierre for the past 15 days. We lowered the daily average release this week in order to get a couple feet of water out of Fort Randall reservoir, so stages are peaking around 10 to 10.5 feet instead of 11 to 11.5 ft as they have the past couple weeks. This is only a temporary change since once we get Fort Randall back down, releases will return to previous levels in order to evacuate flood water stored in the reservoir system and prepare for next year.

16. Or Google “Corps Missouri River”
Thank You!
Or Google “Corps Missouri River”