Jefferson County - East-West Gateway Coordinating Council

A Regional Overview All-Hazard Mitigation Plan 125
HAZARD ANALYSIS NARRATIVE
Hazard: Dam Failure
Description of Hazard (Type of hazard, pathways/areas likely affected, type of damage,
etc.)
A dam failure is defined as structural failure of materials used in dam construction,
inadequate maintenance, overtopping by flood, foundation defects and piping/cracking
caused by movements from settling of dam.
Damage occurs downstream from a failing dam to lives of residents and their property,
businesses, infrastructure. Depending upon volume of water released, damage could be
catastrophic in a limited area.
Historical Statistics (Frequency, strength, # of lives lost, # of injuries, economic losses, etc.)
Based on the National Dam Inventory maintained by the USCOE, Missouri has 607
dams that are considered a high hazard. Historic dam failures have occurred just
south of the EWGCC region near Lawrenceton in 1968 (Ste. Genevieve County),
Washington County in 1975, in Fredericktown in 1968 (Madison County) and a near
failure in Franklin County in 1978. The EWGCC region has the largest number of
dams in Missouri. No lives have been lost as a result of these dam failures. No data
is available on the number of injuries or economic losses as a result of these failures.
Statement of Future Probable Severity (Catastrophic/Critical/Limited/Negligible). Severity
of future dam failures will be catastrophic in the path of the released waters. For
topographically higher areas surrounding the failed dam, negligible impacts will occur.
Statement of Probable Risk (Likeliness of future occurrence- (Highly
Likely/Likely/Possible/Unlikely). According to Missouri Department of Natural Resources, Dam
and Reservoir Safety Program, it is likely that future occurrences of dam failures will occur
based on the poor conditions of the existing dams.
Statement of Next Disaster’s Likely Adverse Impact on the Community
(Catastrophic/Critical/Limited/Negligible). Severity of future dam failures will be catastrophic
in the path of the released waters. For topographically higher areas surrounding the failed
dam, negligible impacts will occur.
Without mitigation measures: Life Property Emotional Financial
Comments:
Catastrophic Catastrophic Catastrophic Catastrophic
With mitigation measures: Life Property Emotional Financial
Negligible Negligible Negligible Negligible