|
|
Dam Failures and Incidents
|
Dam Failures and Incidents
Hundreds of dam failures have occurred throughout U.S. history. These failures have caused immense property and environmental damages and have taken thousands of lives. As the nation’s dams age and population increases, the potential for deadly dam failures grows.
No one knows precisely how many dam failures have occurred in the U.S., but they have been documented in every state. From Jan. 1, 2005 through Jan. 1, 2009, state dam safety programs reported 132 dam failures and 434 "incidents" - episodes that, without intervention, would likely have resulted in dam failure.
|
Historic Dam Failures
Legislative Actions
Causes of Failures
Web Resources
|
|
The map below is based on a (non-comprehensive) list of dam and levee failures compiled by ASDSO. The map demonstrates that dam failures are not particularly common but they do continue to occur. Locations are approximate.
The large red dot on the Gulf Coast represents the New Orleans levee failures resulting from Hurricane Katrina. A few other levee failures are included such as all of those indicated in Northern California. If levee failures from the 1993 floods were included, more failures would be indicated in the center of the map.
|
|
Map courtesy of James S. Halgren, Office of Hydrologic Development, National Weather Service, National Oceanic and Atmospheric Administration |
Historic U.S. Dam Failures
At 7:20 a.m. on May 16, 1874, the 43-foot-high Mill River Dam above Williamsburg, Massachusetts failed, killing 138 people, including 43 children under the age of ten. This failure was the worst in U.S. history, up to that time.
Fifteen years later, on May 31, 1889, this tragedy was replayed on a larger scale in Pennsylvania. Over 2,200 people - more than one in five residents of Johnstown - perished in the flood caused by the failure of South Fork Dam, nine miles upstream.
Many more failures - in Arizona, Tennessee, Oregon, North Carolina, Texas, Virginia, West Virginia, and elsewhere across the U.S. - occurred around the turn of the century, and some early state dam safety legislation was passed.
The failure of St. Francis Dam, in March 1928, was a landmark event in the history of state dam safety legislation, spurring legislation not only in California, but in neighboring states as well. However, most states had no substantive dam safety laws prior to a series of dam failures and incidents that occurred in the 1970s:
February 26, 1972 - Buffalo Creek Valley, West Virginia
The failure of a coal-waste impoundment at the valley’s head took 125 lives, and caused more than $400 million in damages, including destruction of over 500 homes.
June 9, 1972 – Rapid City, South Dakota
The Canyon Lake Dam failure took an undetermined number of lives (estimates range from 33 to 237). Damages, including destruction of 1,335 homes, totaled more than $60 million.
June 5, 1976 – Teton, Idaho
Eleven people perished when Teton Dam failed. The failure caused an unprecedented amount of property damage totaling more than $1 billion.
July 19-20, 1977 – Laurel Run, Pennsylvania
Laurel Run Dam failed, killing over 40 people and causing $5.3 million in damages.
November 5, 1977 – Toccoa Falls, Georgia
Kelly Barnes Dam failed, killing 39 students and college staff and causing about $2.5 million in damages.
|
Dam Safety Legislation & the National Dam Safety Program
Following the Toccoa Falls tragedy, President Jimmy Carter directed the US Army Corps of Engineers to inspect the nation’s non-federal high-hazard dams. This “Phase I Inspection Program” lasted from 1978-1981.
The findings of the inspection program were responsible for the establishment of dam safety programs in most states, and, ultimately, the creation of the National Dam Safety Program, which supports dam safety programs in 49 states – all but Alabama, which has yet to pass dam safety legislation.
Overtopping
Overtopping of a dam, as shown above, is often a precursor of dam failure. National statistics show that overtopping due to inadequate spillway design, debris blockage of spillways, or settlement of the dam crest account for approximately 34% of all U.S. dam failures.
Foundation Defects and Slope Instability
Foundation defects, including settlement and slope instability, cause about 30% of all dam failures.
Piping
Another 20% of U.S. dam failures have been caused by piping (internal erosion caused by seepage). Seepage often occurs around hydraulic structures, such as pipes and spillways; through animal burrows; around roots of woody vegetation; and through cracks in dams, dam appurtenances, and dam foundations.
Other Causes
Other causes of dam failures include structural failure of the materials used in dam construction and inadequate maintenance. |
--ASDSO Computer Animations of failure modes: Overtopping - Piping
--ASDSO maintains a list of dam failures and incidents dating from from 1869 to present. This listing is a work in progress; please contact info@damsafety.org to supply additional information.
--Photographs and descriptions of dam failures are posted in the ASDSO Picture Gallery, located in the Publications and Resources section of the website. (Choose "Dam Failures & Incidents" in the Category drop-down box.)
--FEMA: Dam Failure - Before, During, & After. Dam failure information from the National Dam Safety Program.
--National Performance of Dams Program. The NPDP, based at Stanford University maintains a database of dam failures and their causes.
--Cracking Dams. This educational site features computer simulations and case studies.
--Tailings Dam Failures. A list of failures of dams that impound mine wastes, maintained by the World Information Service on Energy (WISE).
Selected Dam Failures, by Location
California
Baldwin Hills, Dec. 14, 1963
St. Francis, Mar. 12-13, 1928
Table of California Dam Incidents
Colorado
Lawn Lake, July 15, 1982
Florida
Martin Plant Cooling Reservoir, October 30,1979
Georgia
Kelly Barnes, Nov. 6, 1977
Hawaii
Kaloko, March 14, 2006
Idaho
Teton, June 5, 1976
Photos of Teton flood (Western Waters Digital Library)
Missouri
Taum Sauk - Dec. 14, 2005
Pennsylvania
South Fork, May 31, 1889
Washington
Table of dam failures in Washington
West Virginia
Buffalo Creek - Feb. 26, 1972
|
.
|