Virginia Department of Conservation

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Virginia Department of Conservation Recreation

• Virginia Dam Safety Floodplain Programs
• William G. Browning, Director
• Dam Safety Floodplain Management

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Dam Safety Floodplain Organization

• Department reorganization effective November 1,
  2003
• Merged Dam Safety and Floodplain Management
  Programs
• Purpose is to reduce risks and hazards to the
  Commonwealth from dam failure and floods.

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Dam Safety Floodplain Organization
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Dam Safety Program
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Virginia Dam Safety Act of 1982 Amended July 1,
2002

• Provides for the proper and safe design,
  construction, operation and maintenance of
  impounding structures to protect public safety.
• No impounding structure can ever be completely
  fail-safe, because of
• incomplete understanding of/or uncertainties
  associated with natural and man-made destructive
  forces
• material behavior and responses to those forces
• quality control during construction

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Code of Virginia Requirements

• The law regulates impounding structures
  including dams used to retain or store waters or
  other materials. With a few exceptions, the
  following structures are regulated
• gt Impounding structures 25 feet or higher
• with a maximum impoundment capacity of
• 15 acre-feet or more
• gt Impounding structures 6 feet or higher
  with
• a maximum impoundment capacity of 50
• acre-feet or more

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Definitions

• Dam height is the vertical distance from the
  streambed at the downstream toe to the top of the
  dam.
• Maximum Impounding Capacity of a dam is the
  volume capable of being impounded at the top of
  the dam.
• Acre-foot is a volume of one foot of depth over
  one acre of area

50 acre-feet
6-25 high
15 acre-feet
25 or higher
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Classifying Regulated Dams

• Impounding structures are classified by hazard
  potential and size
• Hazard potential relates to downstream losses
  that may occur if the dam fails

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Classes of Hazard Potential If Structure Fails

• Class
• I Probable loss of life
  Excessive economic loss
• II Possible loss of life
• Appreciable economic loss
• III No loss of life expected
• Minimal economic loss
• IV No loss of life expected
• No economic loss to others

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Performance Standards Required for Impoundments

• The required spillway design flood is based on
  the combination of
• hazard classification
• size classification

4 VAC 50-20-50
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Spillway Functions

• Prevents dam overtopping
• Prevents erosion at base of dam

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Classifications of Dams
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What are the Responsibilities of Dam Owners?
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Documents Required For Certification

• Operation and Maintenance Application I, II
  III
• Emergency Action Plan - I, II III
• Re-inspection Report I II
• Inventory Report III IV
• Note Class IV inventory report can be completed
  by owner

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Frequency of Submittal
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In addition

• Owners of Class I, II, III and IV structures
  shall perform an annual owners inspection and
  submit the report in years when a professional
  re-inspection is not required.

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Upon Submission of Forms

• Dam Safety Regional
• Engineers
• Review submitted materials
• May inspect structure
• Make recommendations to the Soil and Water
  Conservation Board

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The Soil and Water Conservation Board Issues

• Regular Operation And Maintenance Certificates
• Conditional Operation And Maintenance
  Certificates
• Construction Permits for new dams
• Alteration Permits to repair and/or upgrade dams
• Transfer of Ownership

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Regional Engineers Also

• Review new construction and alteration
  applications
• Advocate dam safety to local governments
• Respond to emergencies
• Provide training

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Number Of Impoundments In Database
May need permitting based on regulation
criteria change July 1, 2002
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Types of Non-Regulated Dams
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Why Does Dam Safety Floodplain Management
Matter?

• At least 18 declared flood or hurricane disasters
  since Hurricane Camille in 1969
• Timberlake dam failure killed 2 people
• Flooding is the most costly and frequent Virginia
  natural hazard

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Hurricane Floyd September 1999

• 13 dam failures in eastern Virginia
• Devastated Southampton County and Franklin
• Floodwaters did not receed for 11 days

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How Do We Prevent Damage From Floods and
Hurricanes?

• Through Proper Dam Maintenance
• Build At or Above The Base Flood Elevation
• Elevate, Relocate or Demolish Flood-prone
  Structures
• Conserve Floodplains for Habitat, Open Space,
  Flood Capacity and Storage

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Dam Safety Floodplain Management Programs Need
Your Help
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Please Contact Us Regarding

• Use of Downstream Inundation Zones
• Training In Floodplain Management Dam Safety
• Floodplain Ordinance Review
• Technical Assistance For Dams Floodplain
  Construction
• Floodplain Management Community Assistance Visit
• Dams 6 Feet or Higher That Are Not Properly
  Maintained

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Contact Information

• Department of Conservation Recreation
• Dam Safety and Floodplain Management Programs
• 203 Governor Street, Suite 206
• Richmond, VA 23219
• 804-371-6095
• www.dcr.state.va.us

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