1. Estler Lake Dam Rehabilitation
Allied Engineering Services, Inc.
Montana Association of Dam and Canal Systems
Estler Lake Dam Rehabilitation
October 19, 2016
Presented by:
Koy Holland
Paul Sanford, MSCE, PE, CFM

2. Presentation Outline Pre-Project Condition Goals & Objectives
Rehabilitation Components
Design Process
Project Implementation
Post-Construction Monitoring
Owner’s Perspective
Questions and Answers
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3. Project Collaborators
Owner: Rattlesnake Reservoir & Water Company
Review Agencies
DNRC: Michele Lemieux, PE; John Connors, PE
USFS: Scot Shuler; Mark Libby; Kyle Schmitt
Consultant: Allied Engineering
Contractor: RE Miller and Sons, Inc.
Landowner: USFS
Funding Agency: DNRC
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4. Vicinity Map 19.5 miles NW of Dillon Beaverhead NF
Southern end of East Pioneer Mountain Range
Elevation over 7,800 feet
Staging area 1.1 miles downstream of Kelley Reservoir
3.8 miles from Kelley to Estler via ATV trail
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5. Site Map
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6. Allied Engineering Services, Inc.

7. Rehabilitation Summary
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8. Project Description: Pre-Project Condition
Dam constructed in 1903
Between 1903 and 1963 – minor repairs
1963 – dam reconstructed
Replacement of existing outlet controls
Upstream extension of low level outlet
Reconstruction of the upstream face of dam
On-stream (Estler Creek) storage reservoir
Earthen embankment roughly 330 feet long
Height of 35 feet
Allied Engineering Services, Inc.

9. Project Description: Pre-Project Condition
Normal storage volume of 470 acre-feet
Low-level outlet
40-ft section of 24-inch CMP (upstream end)
79-ft section of 24-inch wide x 36-inch tall concrete arch pipe
Inclined slide gate controlled by hand-wheel on crest of dam
Principal spillway
Rock channel on left abutment
2.9 feet freeboard from crest to low point on the top of embankment
15-feet wide
No emergency spillway
Allied Engineering Services, Inc.

10. Project Description: Pre-Project Condition
Downstream Embankment
Lower course (~14.6 vertical feet) – near vertical stacked rock
Second course (~7.6 vertical feet) – grouted rock ~1H:1V
Third course (~6.0 vertical feet) – stacked rock, ~0.8H:1V
Upper portion – earth, 2H:1V
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11. Project Description: Pre-Project Condition
Concrete arch low-level outlet pipe and downstream embankment (stacked rock wall).
Allied Engineering Services, Inc.

12. Project Description: Pre-Project Condition
Principal spillway – lined with rock and some steel slip scrapers
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13. Project Description: Pre-Project Condition
Downstream embankment
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14. Project Description: Problems
Photo courtesy of MT DNRC
Project Description: Problems
1. Low-level outlet reaching end of design life.
2. Inclined gate difficult to operate and did not seal properly.
2. Limited freeboard and no emergency spillway.
3. Downstream embankment susceptible to deformations during seismic activity.
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15. Project Description: Goals & Objectives
Provide reliable water storage and delivery for another 100 years
Agricultural preservation
Provide increased ease of operation
Minimize maintenance
Objectives
Rehabilitate the low-level outlet
Stabilize the embankment
Construct an emergency spillway
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16. Project Description: Rehabilitation Components
3 Primary Components: Low-level outlet; embankment; emergency spillway
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17. Components: Low-level outlet
Components (downstream to upstream)
Concrete encased 18-inch HDPE: 28 feet
Slipline concrete arch with 18-inch HDPE: 81 feet
Reinforced concrete pressure pipe (18-inch): 54 feet
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18. Components: Low-level outlet
Components (downstream to upstream)
Concrete encased 18-inch HDPE: 28 feet
Slipline concrete arch with 18-inch HDPE: 81 feet
Reinforced concrete pressure pipe (18-inch): 54 feet
Allied Engineering Services, Inc.

19. Components: Low-level outlet
Components (downstream to upstream)
Concrete encased 18-inch HDPE: 28 feet
Slipline concrete arch with 18-inch HDPE: 81 feet
Reinforced concrete pressure pipe (18-inch): 54 feet
Allied Engineering Services, Inc.

20. Components: Embankment
Toe Drain
Diaphragm filter
Rock fill on downstream face
Raise embankment 1.2 feet
Flatten upstream face at low-level outlet
Allied Engineering Services, Inc.

21. Components: Embankment
Toe Drain
Diaphragm filter
Rock fill on downstream face, 1.5H:1V
Raise embankment 1.2 feet
Flatten upstream face at low-level outlet
Allied Engineering Services, Inc.

22. Components: Embankment
Toe Drain
Diaphragm filter
Rock fill on downstream face, 1.5H:1V
Raise embankment 1.2 feet
Flatten upstream face at low-level outlet
Allied Engineering Services, Inc.

23. Components: Embankment
Toe Drain
Diaphragm filter
Rock fill on downstream face, 1.5H:1V
Raise embankment 1.2 feet
Flatten upstream face at low-level outlet
Allied Engineering Services, Inc.

24. Components: Emergency spillway
14-feet wide
Crest elevation 2-ft above principal spillway
Activated at 50-year and greater flows
2-feet freeboard
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25. Design Process Inspection and Topographic Survey: July 2013
Reservoir full during inspection & survey
Feasibility Study: February 2015
Design & Permitting: May – September 2015
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26. Project Implementation
Construction completed November 2015
Construction Phases
Demolition
Sliplining
Toe Drain & diaphragm filter
RCP Pressure Pipe
Upstream notch backfill and outlet tower
Downstream rock fill
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27. Project Implementation: Demolition
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28. Project Implementation: Sliplining
Cellular concrete (cement, water, foaming agent) – lighter than cement grout, flowable.
Dewatering
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29. Project Implementation: Toe Drain & Diaphragm Filter
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30. Project Implementation: RCP Pressure Pipe
18-inch pressure pipe
Concrete cradle
Select backfill
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31. Project Implementation: Upstream Notch Backfill & Outlet Tower
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32. Project Implementation: Downstream Rock Fill
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33. Project Implementation: Challenges
Elevation, access, schedule.
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34. Post-Construction Monitoring & Performance
Fill Inspections: January, March, May, and July of 2016
Photo courtesy of DNRC
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35. Owner’s Perspective The Big Picture! Image courtesy of Zoetis
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36. Owner’s Perspective Funding & Cost Summary
DNRC Private Water Grant: $5k
DNRC Water Development Loan: $400k
Project Cost: ~$450k
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37. Owner’s Perspective Recap of Steps Taken Not a bad setting to work in!
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38. Questions and Answers Not a bad setting to work in!
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