dam breach analysis - asfpmwest point jcb • unsteady hec-ras –overtopping failure dam breach...
TRANSCRIPT
![Page 1: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/1.jpg)
Dam Breach AnalysisLarge and Small
June 3, 2015
Matt Scott, Water Resources Engineer
Lisa Brink, Water Resources Engineer
![Page 2: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/2.jpg)
Introduction
• Discussion of Dam BreachTechnical Analysis for a Large and Small Dam
• Dam Safety – Emergency Action Plans
• Considerations for FloodplainAdministrators
![Page 3: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/3.jpg)
Teton Dam Failure - Courtesy geol.ucsb.edu/
Dam Breach Introduction
Dam Break Introduction
Large Versus Small Dams
Lessons Learned
![Page 4: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/4.jpg)
Dam Breach Parameters
• Breach parameter determination fundamental to breach analysis
• Dam breach parameters define the development of a dam breach, and include:
– Breach height, hb
– Breach width, B
– Breach side slopes, m
– Time to full breach formation, tf
m
B
hb
![Page 5: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/5.jpg)
Dam Breach Parameters – Breach Height
hb
hb
Dam in Profile ViewDownstream Face
![Page 6: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/6.jpg)
Dam Breach Parameters – Breach Width
B
Dam in Profile ViewDownstream Face
BB
![Page 7: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/7.jpg)
Dam Breach Parameters – Time to Failure
Dam in Profile ViewDownstream Face
tf
• Directly related to peak flow
• Related to volume of water stored and depth of water stored
![Page 8: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/8.jpg)
Mode of Failure
• Overtopping – uncontrolled flow over the dam
• Piping – seepage through the dam erodes soil, creating a flow path through the embankment
![Page 9: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/9.jpg)
Teton Dam Failure - Courtesy geol.ucsb.edu/
West Point Dam (Large) versus John Creighton Boulevard Dam (Small)
Dam Break Introduction
Large Versus Small Dams
Lessons Learned
![Page 10: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/10.jpg)
Project Introduction
• West Point Dam, Georgia
– Map dam breach inundation
– Inform USACE EmergencyAction Plan
• John Creighton Boulevard (JCB), Omaha, NE
– Map dam breach inundation
– Inform City’s EmergencyAction Plan
Courtesy wikimedia.org
![Page 11: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/11.jpg)
High Hazard
West Point Dam, Georgia JCB, NE
Dam Breach
Large and Small
![Page 12: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/12.jpg)
PurposeWest Point
West Point
– Power Generation
– Recreation
– Flood Control
– Fish and Wildlife
– Area Redevelopment
– NavigationCourtesy fws.gov
![Page 13: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/13.jpg)
PurposeJCB
![Page 14: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/14.jpg)
West Point Dam Size
• At summer normal pool elevation:
– Area of 25,900 acres
– Storage of 604,527 acre-feet
• West Point Dam located on the Chattahoochee River
Courtesy
usace.gov
![Page 15: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/15.jpg)
JCB Dam Size
• Maximum Capacity:
– Area of 14 acres
– Storage of 90 acre-feet (top of dam)
![Page 16: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/16.jpg)
Input Data - Topographic
West Point Omaha
Dam Breach
Large and Small
![Page 17: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/17.jpg)
Input Data – OperationalWest Point Dam
Courtesy lrn.usace.army.milCourtesy lrn.usace.army.mil
![Page 18: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/18.jpg)
Input Data – OperationalJCB
![Page 19: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/19.jpg)
Breach ParametersPrediction of Embankment Dam Breach Parameters
JCB
Dam Breach
Large and Small
Time to breach (hours) 0.71
Final breach width (ft), B 40
Final breach height (ft), hb 8
West Point
Time to breach (hours) 3.8
Final breach width (ft), B 380
Final breach height (ft), hb 96
m
B
hb
![Page 20: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/20.jpg)
Modeling Approach
West Point JCB
• Unsteady HEC-RAS
– Overtopping Failure
Dam Breach
Large and Small
• Unsteady HEC-RAS
– Sunny Day Analysis versus Spillway Design Storm
– Piping Failure
– Downstream limit: 2-foot difference in water surface elevations (Dam breach versus 100-year)
![Page 21: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/21.jpg)
Modeling Approach – FEMA FIS DataWest Point
![Page 22: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/22.jpg)
Modeling Approach - Incremental Hazard Analysis JCB
• Request by Nebraska DNR
• Dam volume small compared to possible hydrologic events
![Page 23: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/23.jpg)
Downstream CharacterizationWest Point
Rural
Small Towns
Downstream
Modeled Extent
![Page 24: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/24.jpg)
Downstream CharacterizationJCB
![Page 25: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/25.jpg)
Teton Dam Failure - Courtesy geol.ucsb.edu/
Lessons Learned
Dam Break Introduction
Large Versus Small Dams
Lessons Learned
![Page 26: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/26.jpg)
Lessons Learned
• Dam Breach analyses help describe total flood risk in a community
– Potential for dams to increase hazard
• EAPs may be helpful in developing local floodplain ordinances
• Dam breach hazards not intuitive or straightforward
![Page 27: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/27.jpg)
Dam Safety Information
http://www.damsafety.org/map/
![Page 28: Dam Breach Analysis - ASFPMWest Point JCB • Unsteady HEC-RAS –Overtopping Failure Dam Breach Large and Small • Unsteady HEC-RAS –Sunny Day Analysis versus Spillway Design Storm](https://reader031.vdocument.in/reader031/viewer/2022022809/5e6bb2de6e4eb5399156f5be/html5/thumbnails/28.jpg)
Questions?
Credit: https://susannesartandlife.wordpress.com/tag/shark/