1. WEE WAH LAKE DAM AND POND No. 3 DAM REHABILITATION PROJECT
Village of Tuxedo Park
Meeting: March 15, 2017
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.

2. Critical Dam Safety Criteria
Wee Wah Lake Dam
Is Spillway Capacity sufficient to pass SDF (50% of PMF)
Stability of the concrete gravity and earthen embankment
Can outlet works effectively drawdown the pool level in event of dam emergency

3. Wee Wah Lake Dam Left Abutment Stilling Basin
Wee Wah Road (Crest of Dam)
Earthen Embankment
Auxiliary Spillway
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Wee Wah Lake
Service Spillway
Stop Log Gate
Right Abutment

4. Contract Drawings & Permitted Improvements
Clear Brush and Large Trees and Flatten D/S Slope, Provide Drainage and Monitoring

5. Contract Drawings & Permitted Improvements
Construct Low Level Outlet w/in Service Spillway

6. Contract Drawings & Permitted Improvements

7. Service Spillway Service Spillway & LLO
Service Spillway (Crest El 496.9’)
Service Spillway Weir Currently at El ’, New El. 492’
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Service Spillway
Service Spillway & LLO

8. Contract Drawings & Permitted Improvements
Repair and Improve Stability of Auxiliary Spillway, Mitigate Seepage Discharge through Floor of Spillway Structure

9. Auxiliary Spillway (Left Side)
Auxiliary Spillway Weir El ’ currently, new crest to El ’
Auxiliary Spillway Training Wall
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Auxiliary Spillway (Left Side)

10. Auxiliary Spillway (Left Side)
Auxiliary Spillway Weir El ’
Auxiliary Spillway Training Wall
Leakage Through Auxiliary Spillway
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Auxiliary Spillway (Left Side)

11. Auxiliary Spillway (Lower Floor)
Seepage Discharge through Auxiliary Floor
Reinforced Concrete Slabs over Pore water Relief Wells
Auxiliary Spillway Stone/Masonry Floor
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Auxiliary Spillway (Lower Floor)

12. Contract Drawings & Permitted Improvements

13. Contract Drawings & Permitted Improvements
Construct Parapet Wall along Crest of Dam

14. Parapet Wall Parapet Wall Along Right Side of Road Wall Alignment
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Left Abutment
Parapet Wall

15. Contract Drawings & Permitted Improvements
Wee Wah Road (Dam Crest) at approx. El. 498
Parapet Wall

16. Pond No. 3 Dam Left Abutment Earthen Embankment
Discharge Channel to Wee Wah Lake
(Crest of Dam)
1. So the task at hand was to understand…how to improve stability of a dam
2. Recognize the “previous modes”... post-tensioned anchors through the dam
3. Expand on them and take a more inclusive approach which was to consider passive rock mass reinforcement.
Low Level Outlet Channel Beneath Splash Pad
Third Pond
Primary Spillway
Right Abutment

17. Critical Dam Safety Criteria
Pond No. 3 Dam
Is Spillway Capacity sufficient to pass SDF (the 100-yr Storm)
Structural Stability of the stone masonry and earthen embankment segments of the dam.
Can outlet works effectively drawdown the pool level in event of dam emergency

18. Contract Drawings & Permitted Improvements
Intake
Discharge
Flow Priming and Control Vault
LLO Siphon System

19. Contract Drawings & Permitted Improvements
Flow Priming and Control Vault
Intake
Discharge
LLO Siphon System

20. Contract Drawings & Permitted Improvements
Sound Mortar
Repointing Stone Masonry
Open Masonry Joints

21. Questions?