Introduction Christopher D. Haker, P.E.
Introduction Christopher D. Haker, P.E. Program Chair and Moderator Principal Engineer Tighe & Bond, Inc.
EBC Dam Management & Climate Change Dam Owner Liability June 5, 2013 Christopher D. Haker, P.E., Principal Engineer - Tighe & Bond Brent McDonald, Associate - Nutter McClennen & Fish, LLP Chad W. Cox, P.E., Principal - GZA GeoEnvironmental, Inc. Daniel R. Buttrick, P.E., Project Engineer - Tighe & Bond Robert D. Muncil, ARM - Cool Insuring Agency, Inc.
Tighe&Bond
Outline
■ Examples of Dam Failures ■ Consequences of Failure and Owner Exposure
■ Understanding Risk ■ Preparing for a Potential Failure (EAPs) ■ Insurance Options and Availability
Tighe&Bond
EBC Dam Management & Climate Change
What Dam Failure Looks Like – Three Case Studies from Hurricane Irene
Christopher D. Haker, P.E., Principal Engineer - Tighe & Bond
Tighe&Bond
What a Year!
■ Jan-Feb: Heavy Snow – Roof Collapses ■ June 1: Tornado
■ August 28: Hurricane Irene ■ October 29: Heavy Wet Snow
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Earthen Embankment Dam with a Curved Concrete Spillway ■ 1,000 feet Long – 85 feet High ■ High Hazard – Large Size ■ Spillway Design Flood (SDF) – ½ Probable Maximum Flood (PMF)
Tighe&Bond
Case Study Granville Reservoir Dam ■ Drainage Area – 5.3 Square Miles (Small but Flashy) ■ Westfield recorded 7.68 inches of rain ■ Approximately 980 cubic feet per second = 440,000 gallons per minute
Tighe&Bond
Case Study 1 Granville Reservoir Dam
Tighe&Bond
Case Study 1 – Granville Reservoir Dam
Tighe&Bond
Case Study 1 – Granville Reservoir Dam
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Curvature of Spillway Channel – Superelevation on outside radius ■ Overtopped channel well before “capacity” was reached
Tighe&Bond
Tighe&Bond
Case Study 1 Granville Reservoir Dam
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Temporary slope stabilization – $75,000
■ Temporary operating procedures to monitor and adjust pond level based on forecast ■ Permanent channel repairs alternatives – – – –
Straighten channel Superelevate outside wall Sectional channel to limit superelevation Closed box through curved section
■ Construction planned for this summer/fall Tighe&Bond
Case Study 2 Green River Dam ■ Earth Embankment Dam with Concrete Spillway ■ 150 feet Long – 25 feet High
■ Significant Hazard – Intermediate Size ■ Spillway design flood is the 100-year storm
■ Watershed area - 52 Square Miles ■ Improvements to dam made in 1992 including tie down anchors on spillway Tighe&Bond
Case Study 2 – Green River Dam
Tighe&Bond
Case Study 2 Green River Dam / The Storm ■ River flows days before the storm about 40 cfs ■ Peak discharge = 17,000 cfs ■ 17,000 cfs = 7,600,000 GPM = 11,000 MGD ■ Highest previously recorded flow over last 40 years was 6,500 cfs
■ Greater than 500 year storm flows experienced during Hurricane Irene ■ Earth Embankment overtopped and failed Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
http://www.youtube.com/watch?v=_CTQIFL3Cns http://www.youtube.com/watch?v=PBO3yj2rHO4
http://www.youtube.com/watch?v=7uba1evgk3I
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 – Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Case Study 2 Green River Dam
Tighe&Bond
Case Study 3 North River Dam ■ Timber Crib Dam/Spillway ■ Significant Hazard – Intermediate Size
■ Spillway design flood is the 100-year storm ■ Watershed area - 85 Square Miles ■ Two other sections of spillway failed in past 15 years
Tighe&Bond
Case Study 3 – North River Dam
Case Study 3 North River Dam / The Storm ■ River flows days before storm less than 300 cfs ■ Peak discharge = 50,000 cfs
■ 50,000 cfs = 22,000,000 GPM = 32,000 MGD ■ Niagara Falls is 100,000 cfs during day and 50,000 cfs at night ■ Section of spillway failed during hurricane
Tighe&Bond
Case Study 3 North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Case Study 3 North River Dam / The Repair? ■ Three Options ■ Remove dam and install groundwater wells to provide 1 MGD needed (tough to get that much water) ■ Replace dam with concrete gravity structure (expensive) ■ Repair failed section in kind (risky)
Tighe&Bond
Take Aways
■ Be Prepared…It can actually help ■ An ounce of prevention is worth a pound of cure ■ Preparing for 1 day in 36,499 or 182,499 days – –
But when will that day happen? August 28, 2011? Are we done for the next 180,000 + days?
■ Is climate change real? – It’s hard to not be a believer
■ When people say “That won’t happen in our lifetime”, show them these photos Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 3 North River Dam
Tighe&Bond
Flood Warning and Preparation ■ Hurricanes don’t come inland often, but when they do, they bring lots of water (1938, 1955, 2011, 2012) ■ Predictions that Hurricane Irene would move inland were pretty accurate – provided good warning
■ Dam owners generally prepared well – – – – –
Reviewed Emergency Action Plans Lowered pond elevations in advance Removed flash boards/opened gates Warned downstream property owners Executed evacuations
Tighe&Bond
Case Study 2 Green River Dam / The Repair ■ No observed damage to spillway ■ Cofferdams to re-establish river flow away from work and to re-create the impoundment ■ Reconnect water supply line from dam to pump station
■ Encapsulate existing deteriorated wingwalls in new concrete
Tighe&Bond
Case Study 2 Green River Dam / The Repair ■ Rebuild embankment with new reinforced concrete core wall ■ Provide overtopping protection in the form of articulated concrete blocks (ACBs) just in case ■ Approximately $1.3 Million to reconstruct
■ Construction completed in May 2012
Tighe&Bond
EBC Dam Management & Climate Change Dam Owner Liability June 5, 2013 Christopher D. Haker, P.E., Principal Engineer - Tighe & Bond Brent McDonald, Associate - Nutter McClennen & Fish, LLP Chad W. Cox, P.E., Principal - GZA GeoEnvironmental, Inc. Daniel R. Buttrick, P.E., Project Engineer - Tighe & Bond Robert D. Muncil, ARM - Cool Insuring Agency, Inc.
Tighe&Bond
Outline
■ Examples of Dam Failures ■ Consequences of Failure and Owner Exposure
■ Understanding Risk ■ Preparing for a Potential Failure (EAPs) ■ Insurance Options and Availability
Tighe&Bond
EBC Dam Management & Climate Change
What Dam Failure Looks Like – Three Case Studies from Hurricane Irene
Christopher D. Haker, P.E., Principal Engineer - Tighe & Bond
Tighe&Bond
What a Year!
■ Jan-Feb: Heavy Snow – Roof Collapses ■ June 1: Tornado
■ August 28: Hurricane Irene ■ October 29: Heavy Wet Snow
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Earthen Embankment Dam with a Curved Concrete Spillway ■ 1,000 feet Long – 85 feet High ■ High Hazard – Large Size ■ Spillway Design Flood (SDF) – ½ Probable Maximum Flood (PMF)
Tighe&Bond
Case Study Granville Reservoir Dam ■ Drainage Area – 5.3 Square Miles (Small but Flashy) ■ Westfield recorded 7.68 inches of rain ■ Approximately 980 cubic feet per second = 440,000 gallons per minute
Tighe&Bond
Case Study 1 Granville Reservoir Dam
Tighe&Bond
Case Study 1 – Granville Reservoir Dam
Tighe&Bond
Case Study 1 – Granville Reservoir Dam
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Curvature of Spillway Channel – Superelevation on outside radius ■ Overtopped channel well before “capacity” was reached
Tighe&Bond
Tighe&Bond
Case Study 1 Granville Reservoir Dam
Tighe&Bond
Case Study 1 Granville Reservoir Dam ■ Temporary slope stabilization – $75,000
■ Temporary operating procedures to monitor and adjust pond level based on forecast ■ Permanent channel repairs alternatives – – – –
Straighten channel Superelevate outside wall Sectional channel to limit superelevation Closed box through curved section
■ Construction planned for this summer/fall Tighe&Bond
Case Study 2 Green River Dam ■ Earth Embankment Dam with Concrete Spillway ■ 150 feet Long – 25 feet High
■ Significant Hazard – Intermediate Size ■ Spillway design flood is the 100-year storm
■ Watershed area - 52 Square Miles ■ Improvements to dam made in 1992 including tie down anchors on spillway Tighe&Bond
Case Study 2 – Green River Dam
Tighe&Bond
Case Study 2 Green River Dam / The Storm ■ River flows days before the storm about 40 cfs ■ Peak discharge = 17,000 cfs ■ 17,000 cfs = 7,600,000 GPM = 11,000 MGD ■ Highest previously recorded flow over last 40 years was 6,500 cfs
■ Greater than 500 year storm flows experienced during Hurricane Irene ■ Earth Embankment overtopped and failed Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
http://www.youtube.com/watch?v=_CTQIFL3Cns http://www.youtube.com/watch?v=PBO3yj2rHO4
http://www.youtube.com/watch?v=7uba1evgk3I
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 2 – Green River Dam
Tighe&Bond
Case Study 2 Green River Dam
Case Study 2 Green River Dam
Tighe&Bond
Case Study 3 North River Dam ■ Timber Crib Dam/Spillway ■ Significant Hazard – Intermediate Size
■ Spillway design flood is the 100-year storm ■ Watershed area - 85 Square Miles ■ Two other sections of spillway failed in past 15 years
Tighe&Bond
Case Study 3 – North River Dam
Case Study 3 North River Dam / The Storm ■ River flows days before storm less than 300 cfs ■ Peak discharge = 50,000 cfs
■ 50,000 cfs = 22,000,000 GPM = 32,000 MGD ■ Niagara Falls is 100,000 cfs during day and 50,000 cfs at night ■ Section of spillway failed during hurricane
Tighe&Bond
Case Study 3 North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Tighe&Bond
Case Study 3 – North River Dam
Case Study 3 North River Dam / The Repair? ■ Three Options ■ Remove dam and install groundwater wells to provide 1 MGD needed (tough to get that much water) ■ Replace dam with concrete gravity structure (expensive) ■ Repair failed section in kind (risky)
Tighe&Bond
Take Aways
■ Be Prepared…It can actually help ■ An ounce of prevention is worth a pound of cure ■ Preparing for 1 day in 36,499 or 182,499 days – –
But when will that day happen? August 28, 2011? Are we done for the next 180,000 + days?
■ Is climate change real? – It’s hard to not be a believer
■ When people say “That won’t happen in our lifetime”, show them these photos Tighe&Bond
Case Study 2 Green River Dam
Tighe&Bond
Case Study 3 North River Dam
Tighe&Bond
Flood Warning and Preparation ■ Hurricanes don’t come inland often, but when they do, they bring lots of water (1938, 1955, 2011, 2012) ■ Predictions that Hurricane Irene would move inland were pretty accurate – provided good warning
■ Dam owners generally prepared well – – – – –
Reviewed Emergency Action Plans Lowered pond elevations in advance Removed flash boards/opened gates Warned downstream property owners Executed evacuations
Tighe&Bond
Case Study 2 Green River Dam / The Repair ■ No observed damage to spillway ■ Cofferdams to re-establish river flow away from work and to re-create the impoundment ■ Reconnect water supply line from dam to pump station
■ Encapsulate existing deteriorated wingwalls in new concrete
Tighe&Bond
Case Study 2 Green River Dam / The Repair ■ Rebuild embankment with new reinforced concrete core wall ■ Provide overtopping protection in the form of articulated concrete blocks (ACBs) just in case ■ Approximately $1.3 Million to reconstruct
■ Construction completed in May 2012
Tighe&Bond
