The North Carolina State Dam
Safety Program
http://portal.ncdenr.org/web/lr/dams
By: Tami Idol, EI Tami.Idol@ncdenr.gov
Let’s start with the basics
What is the Mission of the Dam
Safety Program?
To prevent property damage, personal
injury and loss of life from the failure of
dams
2
Dams Provide Benefits:
•Water Storage for Municipal and Industrial Use
•Cooling Water for Thermal Power Plants
•Flood Reduction
•Hydroelectric Power
•Minimum Flows to dilute sewage treatment plant
discharge
•Storm Water Treatment
•Irrigation Water Storage
•Animal Waste Storage and Treatment
•Recreation
Negative Effects of
Dams:
•Environmental Alteration in the Impoundment
•Environmental Alteration Downstream
•Displacement of People
•Loss of Cultural and Historical Resources
•Expensive to Construct
•Expensive to Maintain
•Hazard Potential for People and Property
Downstream
Jurisdictional Dams
• If Dam is 25 Feet in Height or Greater as
Measured from the Highest Point on the
Crest of the Dam to the Lowest Point on
the Downstream Toe, AND
• If the Dam has an Impoundment Capacity
of 50 Acre-Feet or Greater as Measured at
the Highest Point on the Crest of the Dam
Jurisdictional Dams –
High Hazard Potential
• If Failure of the Dam Could Result in Loss of
Human Life or Significant Damage to Property
Below the Dam regardless of height or
impoundment capacity. GS 143-215.25A (a)(6)
How is the Dam Safety Program
Organized?
7 DENR Regional Offices (RO), 1 Raleigh Central Office (RCO)
Staffing: 9 FTE’s in the RO’s and 9 FTE’s in the RCO
49 LQS regional staff are cross trained for Dam Safety, Sediment
and Erosion Control, and Mining
7
The Dam Safety Program carries out its mission
through Four Basic Functions designed to ensure
Safe Dams (IREE):
We Perform Dam Inspections
We Review and Issue Construction Approvals
We Carry Out Enforcement Actions
We Assist with Emergency Response
8
State-wide Jurisdictional Inventory
12-31-2011
•
•
•
•
1,118 - High Hazard Dams
245 - Intermediate Hazard Dams
622 - Low Hazard Dams
Grand Total - 1,985 Dams
• Includes Low and Intermediate hazard dams 25 feet
in height or larger and 50 acre-feet of maximum
impoundment capacity or larger
• Includes high hazard dams of any size
9
What would you do?
Do Dams Fail in NC?
Well… yes, sometimes
Historic Dam Failures
in North Carolina
Lake Toxaway Dam – 1916
Transylvania County
• After days of heavy rain from tropical
systems, the original Toxaway Dam failed on
August 13, 1916. Over 16,000 acre-feet (5.2
Billion Gallons) of water scoured the gorge
downstream to bedrock.
• There was no known loss of human life.
Property damage, however, was extensive.
Bearwallow Dam Failure
Bearwallow Dam Failure
Buncombe County
•
•
•
•
•
•
Failed February 22, 1976
Approximately 30 feet high with a 3.5 acre lake
Resulted in Four Deaths
There was apparently no engineering
supervision during construction of the dam
Dam was unknown to regulators prior to failure
Resulted in the expansion of the Dam Safety
Program
Roxboro Reservoir Dam
Person County
Municipal water supply dam
Failed March 7, 1984, as a result of internal
erosion (piping) under the concrete chute
spillway
Resulted in loss of a 280 acre reservoir and a
highway bridge
No loss of life
Roxboro Dam Failure
19
1989 Evans and Lockwood Dam
Failures (Fayetteville)
• Several dams in series failed.
• They were unknown to DLR at that time as they
were below jurisdictional size
• Loss of life (2 children) and property damage
resulted
• As a result of this event, legislation was passed
that rendered all high hazard dams jurisdictional
regardless of size (remember the 1989
amendment?)
Damage to Dams, Fall 1999
(Floyd)
• More than 100 jurisdictional dams had
some damage.
• 35 dams failed.
• 16 high hazard dams failed.
• There was no loss of life attributed to the
dam failures.
Damage to Dams from
Frances and Ivan 2004
• One failure of a high hazard dam, no loss of life or
property damage but a road was overtopped.
• Three high hazard dams damaged so severely
they had to be drained and breached.
• Two dams undergoing repairs were damaged.
• One failure of a jurisdictional low hazard dam
• Several small non-jurisdictional dams failed.
• Damage to remaining 300 plus high hazard dams
inspected was relatively light, none requiring that
the impoundments be drained.
Hope Mills Dam
Cumberland County
Municipal recreation dam
Construction completed April, 2009
Failed June 17, 2010, as the result of a foundation
cutoff failure
Resulted in loss of reservoir and extensive spillway
damage
No loss of life
Ironically, this structure was installed as repair for
failure of the original dam in 2003
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Hope Mills Dam
Background of Emergency Action
Planning for Dams
• Since 9/11, requirements by FEMA have
increased priority toward EAPs
• EAPs are not required by law in NC
• In order to meet FEMA requirements, NC dam
safety staff are requesting owners of high
hazard dams to have an EPA. Often times this
means working 1 on 1 with each owner.
ARE WE DOING IT RIGHT?
WE NEED YOUR INPUT!!!!!
EMERGENCY
RESPONSE
34
Emergency Response
• NC Dam Safety staff Role:
– Counsel local Incident Commanders as to level of emergency in
a dam incident situation
– Assist with interpretation of the EAP (if one exists)
– Advise the Local Incident Commander concerning the need to
evacuate
– Assist owner of dam and local responders in preparing an EAP
• All Dam Safety RCO staff are SERT (State Emergency
Response Team) members:
– Serve in the infrastructure discipline
– Man the state Emergency Operations Center (EOC) when it is
activated during any situation which may threaten dams
• All LQS staff are on duty 24-7 in the event of a dam
emergency
– 18 two-person inspection teams from the RO’s available
– Plus RCO staff rotates on 8 to 12 hours shifts at the EOC during
activation
35
FEMA requires all states to adhere to:
National Incident Management System
(NIMS)
Incident Command System
(ICS)
36
Implement
Document
Procure
Pay & Audit
37
Emergency Operation Center
800-858-0368
38
Emergency Action Plans (EAPs)
• An Emergency Action Plan (EAP) outlines
procedures to minimize risks to life and
property when the integrity of a dam may
be in jeopardy.
• Two parts to the EAP equation:
– The EAP shall consider all potential
emergency situations, both natural and
manmade. Owners & engineers responsibility
– shall identify appropriate responses. Local
responders responsibility
Planning, Training, and Exercises
All Hazard focused plans
Collaboration
Practice and experience
Collaboration
• Collaboration between NC Dam Safety and
NC Emergency Management , Flood Plain
Mapping Program:
• Producing a web based fill in the blank EAP for
•
•
owners based upon the current template.
Flood mapping may be completed by the owners
engineer or
based upon a risk assessment, one of 3 levels of
analysis, Bronze, Silver or Gold level mapping will be
completed through collaboration and provided to
responders.
Example Vicinity Map
BRONZE
SILVER
• Medium risk high hazard dams
• Possibly using a method recently beta
tested by NC Dam Safety and NCFPMP
• This method produces a GIS shapefile,
just like the GOLD level would, with
slightly less effort in data collection and
input. This output will show more
structures in the flooded area than a more
detailed analysis.
GOLD
• High risk high hazard dams
• Using a full scale HEC RAS analysis.
• This method produces a GIS shapefile as
well. With more detail and effort going
into data collection, the results will be
closer to what reality would be.
GIS Capability
Open Troublesome Creek EAP maps
What does the Dam Safety program need?
47
We need more EAP’s
• EAP’s for high hazard dams !!!!!
– Only 32% of high hazard dams in NC have EAP’s on file today
• The problem - No statutory authority to require them
• How do we procure them now?
– Through requests to dam owners
– By stipulation in approvals
– Local responders could be invaluable in getting the ball rolling
• Nothing is more valuable during a dam incident
– Emergency Management uses the EAP to develop evacuation
plans
48
St. Francis Dam - 1928
• Estimated 450
•
•
fatalities
1200 buildings
destroyed or
damaged
24,000 acres
of agricultural
land
destroyed
Teton Dam
11:20 AM June 5, 1976
Teton Dam,
11:20 AM June 5, 1976
Teton Dam,
11:30 AM June 5, 1976
Teton Dam,
~11:40 AM June 5, 1976
Teton Dam,
~11:50 AM June 5, 1976
Teton Dam,
~11:55 AM June 5, 1976
Teton Dam,
Early afternoon June 5, 1976
Teton Dam
• 11 human
•
•
fatalities &
13,000 head of
cattle
Original cost of
construction $100
Million
US Gov’t paid
over $300 Million
in claims related
to the failure
Kelley Barnes Dam, Georgia
Just after midnight nearly
thirty years ago on
November 6, 1977, the
Kelly Barnes Dam
failed, releasing 176
million gallons of
water just above
Toccoa Falls College
campus in northern
Georgia. Thirty-nine
people lost their lives.
Sadly, twenty of those
deaths were children.
Video
Failure of this dam
prompted President Carter
to begin the National Dam
Safety Program.
Aerial view of Kelly Barnes Lake area -looking downstream. Washed out dam is near
shadow area near upper edge of picture.
Additional outflow occurred at white area near
right edge of picture.
Aftermath
$30 million
damages
Photographs and descriptions courtesy of Vernon B. Sauer,
USGS retiree and a member of the Federal Investigative Board
that examined the Kelly Barnes Dam failure.
Tami Idol, EI
NC Assistant State Dam Safety Engineer
Tami.idol@ncdenr.gov
919-707-9220