Emergency Action Planning



About EAPs

About EAPs

Samples of Typical Dam Failures in North Carolina

Typical failure modes of earthen dams in North Carolina include:

  • conduit failure and particularly aging CMPs
  • uncontrolled seepage or "piping"
  • overtopping of embankment
  • embankment slides
  • washout of earth channel emergency spillways usually the result of excavation for burried utilities
Conduit failure, particularly aging CMPs Conduit failure, particularly aging CMPs Uncontrolled seepage or 'piping' Uncontrolled seepage or 'piping' Overtopping of the embankment Overtopping of the embankment Embankment slides Washout of earth channel emergency spillways Washout of earth channel emergency spillways

Toxaway NC Dam Failure in 1916

  • after days of heavy rain, the first Toxaway Dam failed on 1916. Over 16,000 acre-feet of water roared down the gorge into South Carolina
  • There was no known loss of human life. Property damage, however, was extensive

Bearwallow Dam Failure
Bearwallow Dam Failure

View down Toxaway Gorge
View down Toxaway Gorge

Dam problems that can lead to failure

These photos illustrate many of the types of dam "incidents" that can rapidly become dam emergencies and trigger an Emergency Action Plan if not addressed by the dam owner soon enough. Dam owners, neighbors, or passers-by who see these types of problems at a dam should contact the state dam safety officials immediately.

Inadequate Spillway Spillway pipe failure creates sinkhole Fences in Spillways Blockage across Spillways Erosion Erosion from Spillway Pipe Failure Undermining Cracking Spalling and disintegration of concrete Erosion around inlet Debris in inlet Vegetation around inlet Outlet pipe deterioration Damaged members Inoperable outlet gate Rusted valve