St Francis Dam Disaster Melissa Schlothan 15 February

St. Francis Dam Disaster Melissa Schlothan 15 February, 2007 Environmental Geology Dr. Sarah Gray http: //web. umr. edu/~rogersda/st_francis_dam/046. jpg

Outline • • Geography and Geology Background Impacts Disaster Management and Response Why did the St. Francis Dam fail? What happened to the community? Recommendations Lessons

Geography • Located 40 miles NE of Los Angeles – In city of Santa Clarita – Developing city • Agriculture, electricity (Edison), mostly immigrants • Inside San Francisquito Canyon

St. Francis Dam Castaic Lake

Geology • San Francisquito Fault line • Paleolithic landslide area • Schist (severely laminated, cross-faulting, interspersed with talc) • Sandstone • Conglomerate http: //en. wikipedia. org/wiki/Image: Schist. jpg

http: //wps. prenhall. com/esm_keller_envgeology_8/0, 7260, 264377 -, 00. html

Background • Designed by William Mulholland, Dept. of Power and Water • 1924 – construction began – Originally • Capacity: 30, 000 acre-feet • 180 ft high, 600 ft long – 1 st change • 10 ft height increase • Capacity: 32, 000 acre-feet – 2 nd change (July 1925) • 10 ft height increase • Capacity: 38, 000 acre-feet • Wing dyke added (600 ft long) • 1926 – construction complete http: //web. umr. edu/~rogersda/st_francis_dam/reassessment_of_st_francis_dam_failure. pdf William Mulholland

St. Francis Dam Construction http: //web. umr. edu/~rogersda/st_francis_dam/reassessment_of_st_francis_dam_failure. pdf

St. Francis Dam construction Completed and filled reservoir http: //www. scvhistory. com/scvhistory. htm

• 1926 -1928 – Cracks developing in dam and abutments • Mulholland investigates and dismisses – 7 March 1928 • Reservoir fills to capacity • More leaks develop • Mulholland investigates and dismisses – 12 March 1928 • East side of reservoir roadbed sagging 1 – 5 feet • More leaks and cracks • Mulholland assistant inspect and dismiss http: //www. scvhistory. com/scvhistory. htm Evidence of leaks

• 12 March 1928 – Dam fails 11: 57 pm – 12 bill gallons of water – 18 mi/hr initially, 5 mi/hr into Pacific – Traveled 55 miles to the Pacific Ocean • Took 5 ½ hrs Dam after failure http: //www. scvhistory. com/scvhistory. htm

http: //web. umr. edu/~rogersda/st_francis_dam/Mapping%20 the%20 St%20 Francis%20 Dam%20 Outburst%20 Flood%20 with%20 GIS. pdf View of water entering Pacific Ocean

http: //web. umr. edu/~rogersda/st_francis_dam/Mapping%20 the%20 St%20 Francis%20 Dam%20 Outburst%20 Flood%20 with%20 GIS. pdf Reservoir Area

http: //web. umr. edu/~rogersda/st_francis_dam/Mapping%20 the%20 St%20 Francis%20 Dam%20 Outburst%20 Flood%20 with%20 GIS. pdf Flood path

Impacts • Deaths: 450 estimated – Many found downstream – Tent residents of unknown count • • • +900 homes destroyed 1, 200 buildings damaged 10 bridges knocked out Power lost in multiple cities Crops, businesses and livestock affected

Debris and overturned cars Overturned railroad tracks http: //www. scvhistory. com/scvhistory. htm

Damaged highway Flood path http: //www. scvhistory. com/scvhistory. htm

Damaged pecan fields http: //www. scvhistory. com/scvhistory. htm Broken electric poles

Waterline http: //www. scvhistory. com/scvhistory. htm

Disaster Management • Awareness and preparedness – No disaster plan • No one ever thought it would break – Mulholland was aware of cracks/leaks and maximum capacity • Dismissed them because said, “This is typical for a concrete dam of this size. ”

Disaster Response • Immediate response by Red Cross – Set up national fund drive – 100’s of volunteers – Provided: • Search and rescue • Care for injured/needy • Clearing debris and dying or dead people and animals – Total spent: $237, 190 http: //news. softpedia. com/images/news 2/1 -Week-After-Katrina-The-American-Red-Cross-Is-Setting-A-Record-Relief-Pace-2. jpg

• Los Angeles County – Took full responsibility for event – $1 million set aside for programs and funds – “Council of Fourteen” – Continued work on clean-up • 1, 000’s volunteers and 100’s tractors utilized – Completed in 90 days

Reconstruction Phases I and II • Mulholland Dam – Reinforced with rocks and earth on face • Built like St. Francis • Fears of similar dam break • Bouquet Reservoir – 1934 – 15 miles west of Palmdale – Part of L. A. Aqueduct system • Castaic Dam – 1973 – Near Castaic – Hydroelectric power plant

Why did the dam fail? • Major reasons: – Rock Formations • Conglomerate: expands with water • Schist: badly laminated, interspersed with talc – Fault line – Erosion • from running water at cracks along sides – Paleolithic landslide http: //wps. prenhall. com/esm_keller_envgeology_8/0, 7260, 264377 -, 00. html

Why did the dam fail? • Cracks – Created when conglomerate on side swelled when wet causing the dam to rise and crack • Construction – Underground base missing steps • Tilting – from extra capacity unaccounted for with increased height • Sabotage theory – Previous unrest about taking water into aqueduct from Owens River Valley

How was the community affected? • Many people lost jobs – Edison electric power plants ruined – Agriculture crops devastated • Agriculture devastated – 7, 900 acres • Citrus, walnuts, apricots, grapes, alfalfa, pecans • Tent residents – Lost jobs and displaced • Rebuild homes and businesses – Took very long for people to get back on their feet

Recommendations • Warning system needed – You can never be too careful, the risk of failure will always be there no matter the confidence • More response by police force – Efficiency needed with system of communication • Reservoir shouldn’t have been built there – The geography is extremely dangerous

Lessons • More geological knowledge of area • Complete reinforcement for changes is always needed

Sources • http: //www. scvhistory. com/scvhistory. htm • http: //en. wikipedia. org/wiki/San_Francisquito_Canyon • http: //web. umr. edu/~rogersda/st_francis_dam/lessons_le arned_from_the_st_francis_dam_failure(geostrata_marapr_2006). pdf • http: //web. umr. edu/~rogersda/st_francis_dam/reassessm ent_of_st_francis_dam_failure. pdf • http: //web. umr. edu/~rogersda/st_francis_dam/Mapping% 20 the%20 St%20 Francis%20 Dam%20 Outburst%20 Flood %20 with%20 GIS. pdf • Outland, Charles F. Man – Made Disaster: the story of St. Francis Dam. Glendale, California: The Arthur H. Clark Company, 1963.