1. Grindstone Seepage Mitigation Project Village of Ruidoso Ed Toms 2105 NMWDOC Spring Workshop May 12, 2015

2. Overview –History –Site Investigations –Construction Contracting –Design –Closing and Questions 2015 NMWDOC Spring WorkshopPage 2

3. Project History

4. History –139-foot high gravity Roller Compacted Concrete Dam –1,300-foot long section –Built in 1986 –Water supply to the Village of Ruidoso 2015 NMWDOC Spring WorkshopPage 4

5. History - Plan View 2015 NMWDOC Spring WorkshopPage 5

6. History - Sections 2015 NMWDOC Spring WorkshopPage 6

7. History - Facing Elements 2015 NMWDOC Spring WorkshopPage 7

8. History - Issues –High seepage issues since first filling in 1988 –Repairs in 1989, 1996, 2002, and 2009 –Seasonal trends Winter higher seepage rates –Interviews with Original construction personnel - Poorly zones of partially cemented aggregates Transverse thermal cracks Page 82015 NMWDOC Spring Workshop

9. History - Issues –High seepage issues since first filling in 1988 –Repairs in 1989, 1996, 2002, and 2009 –Seasonal trends Winter higher seepage rates –Interviews with Original construction personnel - Poorly zones of partially cemented aggregates Transverse thermal cracks Page 92015 NMWDOC Spring Workshop

10. Site Investigations Phase

11. Site Investigations –Reservoir at El. 6874. El 6860, where lower seal would be installed, was below water. –Cored 3 vertical rustication joints – Joints 44, 46, & 50. –Excavated a test pit at Joint 49 – confirmed foundation contact likely as indicated on record drawings. –Concrete facing was cracked through at all joint locations cored. –Segregated, poorly consolidated RCC encountered at concrete/RCC interface is a potential seepage pathway behind liner. –Sealant in many of the vertical joints was randomly separated from the sides of the joint. 2015 NMWDOC Spring WorkshopPage 11

12. Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 12

13. Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 13

14. Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 14

15. Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 15

16. Construction Contracting

17. Construction Contracting Method –Design/Bid/Build –Construction Manager at Risk (C-MAR) –Construction Manager/General Construction (CM/GC) –Design/Build –Project schedule defined delivery method – CM/GC –CARPI Liner and Contractor Worked closely with AECOM during the design Priced the project based on unit measures Issued a Guaranteed Maximum Price (GMP) o $3.5 million Page 172015 NMWDOC Spring Workshop

18. Design Phase

19. Partial Lining Option –Advantages Lower impact on VOR water operations Less expensive –Disadvantages Lower probability to improve stability and mitigate seepage Sealing facing at 6860 against all pathways may be difficult and costly Remobilization costs if sealing does not mitigate seepage effectively or if stability is in question 2015 NMWDOC Spring WorkshopPage 19

20. Complete Lining Option –Advantages Higher probability to improve stability and mitigate seepage Double seal and grouted cutoff costs not needed and put towards liner No remobilization costs –Disadvantages Higher impact on VOR water operations More expensive, 27,500 SF more compared to lining to dam bottom above 6860 Requires additional excavation and dewatering 27-foot dead pool below intake invert 2015 NMWDOC Spring WorkshopPage 20

21. Design Elements 2015 NMWDOC Spring WorkshopPage 21

22. Design Elements 2015 NMWDOC Spring WorkshopPage 22

23. Design Elements 2015 NMWDOC Spring WorkshopPage 23

24. Design Elements 2015 NMWDOC Spring WorkshopPage 24

25. Design Elements 2015 NMWDOC Spring WorkshopPage 25

26. Construction Phase

27. Foundation Excavation 2015 NMWDOC Spring WorkshopPage 27

28. Dry Pack Mortar 2015 NMWDOC Spring WorkshopPage 28

29. Liner and Internal Profile Material 2015 NMWDOC Spring WorkshopPage 29

30. Anchor System 2015 NMWDOC Spring WorkshopPage 30

31. Curtain Holes Urethane Grout Injection 2015 NMWDOC Spring WorkshopPage 31

32. Construction Coring of Face Element 2015 NMWDOC Spring WorkshopPage 32

33. Chemical Grout 2015 NMWDOC Spring WorkshopPage 33

34. Vertical Joint Low-Modulus Epoxy 2015 NMWDOC Spring WorkshopPage 34

35. Progress – Water Installation 2015 NMWDOC Spring WorkshopPage 35

36. Installed Tension Profile Page 362015 NMWDOC Spring Workshop

37. Final Installation Example Page 372015 NMWDOC Spring Workshop

38. Questions? Ed Toms ed.toms@aecom.com 2015 NMWDOC Spring Workshop