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8/17/2019 Dam Safety DamBreakModeling
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2015 National Dam Safety Program Technical Seminar No. 22:
Dam Breach Modeling
and Consequence Assessment
Overview of Failure Modes
Jay N. Stateler
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Embankment
Dams
Foundation Soil
Foundation Soil
Earthfi ll Zones
Filters
Riprap
Slope
Protection
Grout Curtain
Toe
Drain
Foundation Rock
Riprap
Slope
ProtectionEarthfill
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Potential
Failure Mode
Foundation Soil
Foundation Soil
Earthfi ll Zones
Filters
Riprap
Slope
Protection
Grout Curtain
Toe
Drain
Foundation Rock
Riprap
Slope
ProtectionEarthfill
• Seepage through
dam
• Erodes earthfil l
• Carries earthfilldownstream
• Eventually
breaches dam
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Hadlock Pond
New York
Constructed: 1896
Modified: 2004-2005
Failed: July 2, 2005
Seepage Failure0 Fatalities
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Baldwin Hills Dam
Los Angeles, California
Constructed: 1947-1951
Failed: December 11, 1963
Seepage Failure
5 Fatalities
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San Francisco Dam
New Mexico
Constructed: 1960’sFailed: May 24, 2003
Flood – Seepage Failure
No Fatalit ies
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Delhi Dam, Iowa
Constructed: 1929
Failed: July 24, 2010
Flood – Some overtopping,
but failed due to seepage
0 Fatalities
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Potential
Failure Mode
Foundation Soil
Foundation Soil
Earthfi ll Zones
Filters
Riprap
Slope
Protection
Grout Curtain
Toe
Drain
Foundation Rock
Riprap
Slope
ProtectionEarthfill
• Seepage through
dam
• Erodes earthfil l
• Carries earthfilldownstream
• Eventually
breaches dam
• Filter lets waterthrough, but not
earthfil l carried by
seepage
• Stops failure mode
development
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Potential
Failure Mode
Foundation Soil
Foundation Soil
Earthfi ll Zones
Filters
Riprap
Slope
Protection
Grout Curtain
Toe
Drain
Foundation Rock
Riprap
Slope
ProtectionEarthfill
• Seepage through
foundation soil
• Erodes soil
• Carries soil to a
downstream exit
point
• Eventually creates
a dam breach
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20 feet high
Arthur V. Watkins DamConstructed: 1958-1964
Nearly Failed: November, 2006
Seepage
Foundation soi l
deposits in SouthDrain
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Potential
Failure Mode
Foundation Soil
Foundation Soil
Earthfi ll Zones
Filters
Riprap
Slope
Protection
Grout Curtain
Toe
Drain
Foundation Rock
Riprap
Slope
ProtectionEarthfill
• Seepage through
foundation soil
• Cutoff trench, grout
curtain, cutoff wall,
etc. limit seepage
through foundation
• Downstream fil ters
and toe drain collect(and fi lter seepage)
• Potential for failure
mode development
is reduced
Cutoff Trench
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Potential
Failure Mode
• Seepage carries
earthfi ll into
foundation
• Erodes earthfil l• Carries earthfill
downstream
• Eventually breaches
dam
Into Coarse Layers in Foundation Soil
Into Joints, Openings, Etc. in Foundation Rock
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Teton Dam, Idaho
Constructed: 1975
Failed: June 5, 1976
Seepage Failure –
During first filling11 Fatalit ies
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Quail Creek Dike
Constructed: 1984
First Filling: 1985
Failed: January 1, 1989
Seepage Failure –During first fill ing
No Fatalit ies
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Potential
Failure Mode
• Seepage carries
earthfi ll into
foundation
• Filter protects against
earthfil l being carried
by seepage into
foundation soil
• Foundation treatment
seals openings in rock
– no seepage into rock
Into Coarse Layers in Foundation Soil
Into Joints, Openings, Etc. in Foundation Rock
Filter
Protection
Foundation Treatment
(slush grouting, dental
concrete, etc.)
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Potential
Failure Mode
• Seepage along
conduits through dam
embankment
• Erodes earthfil l• Carries earthfill
downstream
• Breaches dam
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Filter material
needs to becompletely wrapped
around the conduit –
stops development
of the failure mode
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Lawn Lake Dam
Colorado
Constructed: 1903
Failed: July 15, 1982Seepage
3 Fatalities
Isabel Myron Dam
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Isabel Myron Dam
Colorado
Constructed: Unknown
Failed: 1978
Wind Tree Toppling
Overtopping (?)or Seepage (?)
0 Fatalit ies (believed)
Sl I t bili t
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Slope Instabili ty
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Potential
Failure Mode
Embankment
Dams
Dam overtopping in a flood• The capacity of the spillway(s) is
exceeded by flood flows
• Water flows over the dam crest• The overtopping flow erodes the
dam embankment
• Dam breaches
Auxi liary
spillway
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Erosion Begins
Dam is Breached
Rainbow Dam
Michigan
Failed: 1986
Flood - Overtopping
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Ka Loko Dam
Hawaii
Constructed: 1890Failed: March 14, 2006
Flood – Overtopping
7 Fatalities
B il
http://upload.wikimedia.org/wikipedia/commons/d/d2/Kaloko_breach.jpg
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Brazil
Failed: 1980’s
Flood – Overtopping
Spillway gates not opened
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Noppikoski Dam, Sweden
Constructed: Not known
Failed: September 6, 1985
Flood – Overtopping – Could not
remove stoplogs in t ime
0 Fatalities
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Spillway
failure in
a flood
event
El Guapo Dam
Venezuela
Failed: December 16, 1999
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Embankment Dams – Earthquake-Related Failure
Earthquake causes strength loss in
foundation soil leads to instability
and failure by dam overtopping
Potential
Failure Mode
Foundation so il that is saturated
and loose (not very dense)
Earthquake shaking causes
it to lose strength (liquefy)
The liquefied soil i s
more like a fluid –
has litt le shear
strength
The dam slides in the
downstream direction on
the weak layer
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Earthquake causes strength loss in
foundation soil leads to instability
and failure by dam overtopping
Potential
Failure Mode
Dam failure occurs
almost immediately after
the earthquake
Embankment Dams – Earthquake-Related Failure
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Sheffield Dam
California
Constructed: 1917
Failed: June 29, 1925
Earthquake – Liquefaction
No Fatali ties
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Lower San Fernando
(Van Norman) Dam
Los Angeles, California
Constructed: 1912, Raised 1921Nearly Failed: February 9, 1971
Earthquake
No Fatalities
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Potential
Failure Mode
Earthquake-caused cracks and/or
damage that leads to seepage-
related dam failure
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Major Types of Dams
• Embankment• Rockfill
– Central Core
– Impervious Upstream Face
• Concrete
– Gravity
– Arch
– Buttress• Masonry
• Composite
• Mostly rock, rather
than soil
• Thin impervious core
• Potential failure
modes and monitoring
are similar to
embankment dams
• Filter protection for
the core is key
Rock Rock
Impervious
Earthfill
Core
Filtering
Transition
Zones
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Rockfill Dam
Impervious
Upstream
Face
Rock
Should be free draining
Could be:
Geomembrane
Concrete
Asphalt
Steel
Clay
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Settlement of rockfill and/or earthquake shaking
could cause damage to the upstream face and
leakage
– If the rockfil l is free-draining (as it should be), this
would not be an issue (except for the lost water)
– If the rockfil l is not free-draining, then water
pressure buildup could cause slope instabili ty and
dam failure
Rock
Could be:
Geomembrane
Concrete
Asphalt
Steel
Clay Should be free draining
Rockfill Dam
Impervious
Upstream
Face
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Rock
Could be:
Geomembrane
Concrete
Asphalt
Steel
Clay Should be free draining
Rockfill Dam
Impervious
Upstream
Face
• Overtopping flow in a flood could result in
erosion at the downstream slope and toe area
• Competent rockfi ll and foundation materialshould not suffer much damage, but significant
erosion could occur in poorer materials
• Erosion Oversteepened slope Slope
Failure
Taum Sauk Dam Missouri
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Taum Sauk Dam, Missouri
Constructed: 1962
Failed: December 14, 2005
Overtopping – operational
issues
0 Fatalities
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Key Issue for all Concrete Dam Types:
Foundation Support of Structure
• Loads on the dam ultimately are transferred and carried
by the foundation (and abutments for arch dams)
• Problems with foundation support have been the cause
of the majority of concrete dam failures
Bayless (Austin) Dam
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Bayless (Austin) Dam
Pennsylvania
Constructed: 1909
Failed: September 30, 1911
Failed by Sliding in Flood
78 Fatali ties
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St. Francis Dam
CaliforniaConstructed: 1926
Failed: March 12, 1928
Sliding of Abutment
in First Filling
~450 Fatali ties
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St. Francis Dam
CaliforniaConstructed: 1926
Failed: March 12, 1928
Sliding of Abutment
in First Filling
~450 Fatali ties
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
8/17/2019 Dam Safety DamBreakModeling
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By: J. David Rogers, Professor of
Geological Engineering, MissouriUniversity of Science and Technology
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Malpasset Dam
France
Constructed: 1959
Failed: December 2, 1959
Abutment Movementin First Filling
421 Fatali ties
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Camara Dam
Brazil
Constructed: 2002Failed: June 2004
Foundation Movement
in Essentially First Filling
5-25 Fatali ties
Gibson Dam Montana 1964 dam overtopping
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Gibson Dam Montana 1964 dam overtopping
Overtopping flow could erode foundation material
Gibson Dam Montana 1964 dam overtopping
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Overtopping protection
provided after the event
To protect againsta future possibly
larger f lood event
Gibson Dam Montana 1964 dam overtopping
Overtopping flow could erode foundation material
Cascade Dam
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Cascade Dam
Colorado
Failed: July 15, 1982
Overtopping due to failure of
upstream Lawn Lake Dam
2 Fatalities
Lawn Lake Dam
Colorado
Constructed: 1903
Failed: July 15, 1982
Seepage
3 Fatalities
Most potential
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Masonry
Dams
failure modes
similar to
concrete gravity
dams
Good foundation
support is
crucial
Castlewood Dam, ColoradoConstructed: 1890
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Constructed: 1890
Failed: August 3, 1933
Failed in Flood – Erosion at toe of dam
7 Fatalities
Leakage
May, 1990
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Delhi Dam, Iowa
Constructed: 1929
Failed: July 24, 2010
Flood – Overtopping, but failed due to seepage
0 Fatalities
Virginia Kendall Dam, Ohio
Constructed: 1930’s
Overtopped: July 21, 2003
Did not fail
Frozen Lake Dam
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Washington
Constructed: 1930
Failed: Hopefully Never
A. Embankment Dam
Seepage Failure
B. Embankment Dam
Seepage Failure
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C. Embankment Dam
Overtopping in Flood
F. Embankment Dam
E th k
E. Embankment DamEarthquake
Delayed
Failure
D. Concrete Dam
All Failure Types
Seepage Failure
Unconstrained
Development
Seepage Failure
Constrained
Development
Sudden Failure?(Limited Warning Time)
Sudden Failure
Sudden
Failure
Sudden
Failure
Not Sudden
F il
Not Sudden Failure
Large Dam
Failure Flood?
Very Large Flow
Large Flow
Large FlowLarge Flow
Maybe
No Water
Released
Maybe NoWater Released