34:
494: m) of water) as a large landslide fell into the reservoir along with 30 feet (9.1 m) of the crest and upstream face reducing the freeboard to about 5 feet (1.5 m). This failure was predominantly due to liquefaction of the hydraulic fill. To reduce the risk of catastrophic failure, the water level was lowered as rapidly as possible, 13.5 feet (4.1 m) in
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483:
Originally, the Lower Van Norman reservoir was operated near full capacity of 1,134.6 feet (345.8 m). However, the maximum operating height was reduced to 1,125 feet (343 m) in 1966 following seismic hazard review. Fortuitously, at the time of the 1971 San
Fernando earthquake the water
531:
The near failure of the Lower Van Norman Dam brought about major changes in the way public agencies and engineers viewed seismic safety, particularly regarding embankments of fine sands and silts and numeric dynamic analysis of dams. Also, it resulted in many mandated dam safety reassessments.
444:
The Lower Van Norman Dam was constructed with hydraulic and rolled fill. Hydraulic fill height was about 102.4 feet (31.2 m), while rolled fill was added at least five times in the dam's history, each time increasing the dam's height, totaling 39.6 feet (12.1 m) rolled fill. The last
472:
The Upper Van Norman reservoir was operating at about one-third capacity at the time of the earthquake. The quake lowered dam height 3 feet (0.91 m) and displaced the dam laterally 5 feet (1.5 m).
903:
846:
1607:
1557:
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519:
As a replacement, the Los
Angeles Dam was constructed between the original Lower and Upper Van Norman Dam structures in a more stable location. During the
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753:
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541:
211:
1261:
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646:
523:, the Lower Van Norman reservoir area was again severely damaged, but as then it was in use only as a holding basin, the consequences were minor.
508:
days, at the rate of 700 cubic feet per second (20 m/s). This rate was limited by earthquake damage to the outlet lines and drainage towers.
68:
895:
637:. Building Research Division, Institute for Applied Technology, National Bureau of Standards. U.S. Government Printing Office. p. 367.
425:
and were subsequently decommissioned due to the inherent instability of the site and their location directly above heavily populated areas.
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703:
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Reconstruction was proposed, but abandoned after geologic evaluation showed the inherent instability of the dams' foundations.
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immediately below. 80,000 were evacuated for three days. Later, it was estimated that a dam failure could have killed 123,400.
242:
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The 1971 San
Fernando earthquake significantly damaged the dams, resulting in evacuation of thousands of people from the
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581:
Bardet, J. P.; Davis, C. A. (July 1996). "Performance of San
Fernando Dams during 1994 Northridge Earthquake".
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38:
An oblique aerial view of the Lower Van Norman Dam, taken after the
February 9, 1971 San Fernando Earthquake
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983:
California Sec. Earthquake Task Force
Committee, Association of Metropolitan Water Agencies (1973).
33:
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55:
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804:
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1184:"The Disaster that Helped the Nation Prepare for Future Earthquakes: Remembering San Fernando"
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875:
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height was 1,109 feet (338 m) (about half capacity: 3.6 billion US gallons (14
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322:
228:
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1204:"February 1971: The Magnitude-6.5 San Fernando Earthquake Shakes Southern California"
402:
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1077:"Expectable Earthquakes and their ground motions in the Van Norman Reservoirs Area"
1076:
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421:, supplying about 80 percent of Los Angeles' water, until they were damaged in the
103:
1341:
1279:
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778:
746:"Lower San Fernando Dam (California, 1971) | Case Study | ASDSO Lessons Learned"
546:
433:
The Upper Van Norman Dam initially was constructed with 42 feet (13 m) of
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1473:
1336:
1008:
839:"California's aging dams face new perils, 50 years after Sylmar quake crisis"
83:
70:
1289:
872:
Proceedings : Fifth
Benchmark Workshop on Numerical Analysis of Dams
1016:
1123:
1092:
1046:
608:"75,000 to Witness Official Aqueduct Opening Tomorrow". Section 2.
642:
628:
Lews, H. S.; Leyendecker, E. V.; Dikkers, R. D. (December 1971).
1030:
Yerkes, R. F.; Bonilla, M. G.; Youd, T. L.; Sims, J. D. (1974).
985:"Contending With Earthquake Disaster: Committee Approved Report"
417:, also known as the San Fernando Dams, were the terminus of the
1225:
1075:
Wesson, R. L.; Page, R. A.; Boore, D. M.; Yerkes, R.F. (1974).
874:. Denver, CO: U.S. Committee on Large Dams. 2000. p. 11.
438:
317:
223:
896:"Lest we forget: learning from international dam incidents"
1032:"Geologic environment of the Van Norman Reservoirs area"
612:. Vol. XL, no. 2. November 4, 1913. p. 1.
437:. In 1922, the dam was raised 18 feet (5.5 m) with
1086:. Circular (691–B). United States Geological Survey.
1041:. Circular (691–A). United States Geological Survey.
1122:
Page, Robert A.; Boore, David M.; Yerkes, Robert F.
1497:
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1386:
1297:
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1124:"USGS Fact Sheet 096-95: The Los Angeles Dam Story"
631:
Engineering aspects of 1971 San
Fernando earthquake
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930:International Water Power & Dam Construction
900:International Water Power & Dam Construction
16:Former dam in Los Angeles County, California, US
750:Lessons Learned from Dam Incidents and Failures
1237:
773:
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752:. Association of State Dam Safety Officials.
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811:. Los Angeles Firemen's Relief Association.
212:Los Angeles Bureau of Water Works and Supply
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989:Journal (American Water Works Association)
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1608:Geology of Los Angeles County, California
1558:History of Los Angeles County, California
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805:"LAFD History – Los Angeles Dam Failures"
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542:List of dams and reservoirs in California
1182:Goldbaum, Elizabeth (February 4, 2021).
1158:California Department of Water Resources
832:
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453:For broader coverage of this topic, see
866:
864:
779:"San Fernando Hydro Power Plant CA USA"
595:10.1061/(ASCE)0733-9410(1996)122:7(554)
568:
1573:Earthquake and seismic risk mitigation
1548:Dams in Los Angeles County, California
815:from the original on November 26, 2020
674:
663:
652:from the original on December 8, 2020
21:Dam in Los Angeles County, California
7:
1202:Lloyd, Jonathon (February 9, 2021).
837:Sahagún, Louis (February 10, 2021).
583:Journal of Geotechnical Engineering
1603:History of the San Fernando Valley
1154:"History of California Dam Safety"
1134:from the original on June 14, 2021
1056:from the original on April 3, 2021
1001:10.1002/j.1551-8833.1973.tb01785.x
906:from the original on March 6, 2021
849:from the original on July 18, 2021
756:from the original on June 10, 2021
14:
1543:Dam failures in the United States
936:from the original on June 9, 2021
926:"San Fernando: a case in history"
1388:LA Department of Water and Power
1288:
1262:CA Department of Water Resources
1103:from the original on May 6, 2021
803:Borden, Frank (March 31, 2017).
1254:Los Angeles County, California
445:addition was made in 1929–30.
1:
1455:Van Norman (aka San Fernando)
1299:LA Department of Public Works
956:"The Lower San Fernando Dam"
704:"The Upper San Fernando Dam"
455:1971 San Fernando earthquake
449:1971 San Fernando earthquake
423:1971 San Fernando earthquake
345:Elevation at crest
307:1,213.2 feet (369.8 m)
265:Elevation at crest
157:; 103 years ago
137:; 105 years ago
123:; 105 years ago
379:1,134.6 feet (345.8 m)
348:1,144.6 feet (348.9 m)
1624:
1466:US Army Corps of Engineers
1084:Geological Survey Circular
1039:Geological Survey Circular
610:Los Angeles Evening Herald
521:1994 Northridge earthquake
452:
1286:
783:Global Energy Observatory
31:
1568:Reservoirs in California
329:Height (foundation)
249:Height (foundation)
809:The Firemen's Grapevine
552:Baldwin Hills Reservoir
361:20,000 acre⋅ft (25
340:2,080 feet (630 m)
312:Lower dam and spillways
289:1,800 acre⋅ft (2.2
268:1,218 feet (371 m)
260:1,200 feet (370 m)
218:Upper dam and spillways
118:Construction began
1578:Dams completed in 1921
1553:History of Los Angeles
1188:U.S. Geological Survey
1128:U.S. Geological Survey
376:Normal elevation
318:Type of dam
304:Normal elevation
224:Type of dam
191:February 9, 1971
169:November 5, 1913
1563:Los Angeles Aqueduct
932:. January 17, 2013.
902:. October 28, 2010.
479:Lower Van Norman dam
468:Upper Van Norman dam
419:Los Angeles Aqueduct
384:Commission date
332:142 feet (43 m)
276:20 feet (6.1 m)
239:Los Angeles Aqueduct
188:Demolition date
84:34.2862°N 118.4796°W
1588:1971 in Los Angeles
1583:San Fernando Valley
462:San Fernando Valley
358:Total capacity
286:Total capacity
252:60 feet (18 m)
80: /
1593:1971 in California
1505:Brown Mountain Dam
1275:Elderberry Forebay
673:Unknown parameter
273:Width (crest)
89:34.2862; -118.4796
56:Los Angeles County
1530:
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1415:(unsafe: emptied)
1409:(unsafe: emptied)
843:Los Angeles Times
744:Sykora, Davis W.
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152:Opening date
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1450:Stone Canyon
1373:Sierra Madre
1347:Puddingstone
1322:Devil's Gate
1211:. Retrieved
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1191:. Retrieved
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1136:. Retrieved
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995:(1): 22–38.
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387:October 1922
368:
296:
195:53 years ago
104:Water supply
58:, California
18:
1516:Little Rock
1444:St. Francis
1439:Silver Lake
1429:Los Angeles
1362:Santa Anita
1357:San Gabriel
1312:Big Tujunga
547:Dam failure
439:rolled fill
183:(lower dam)
167:(upper dam)
147:(lower dam)
133:(upper dam)
87: /
75:118°28′47″W
63:Coordinates
1537:Categories
1434:Mulholland
1413:Dry Canyon
1407:Chatsworth
1327:Eaton Wash
1307:Big Dalton
563:References
407:2× 2.8 MW
243:Bull Creek
200:1971-02-09
178:1913-11-05
72:34°17′10″N
1523:(disused)
1507:(disused)
1484:Sepulveda
1369:(disused)
1352:San Dimas
1009:0003-150X
677:ignored (
666:cite book
643:70-186531
512:Aftermath
1479:Santa Fe
1457:(failed)
1446:(failed)
1424:Fairmont
1398:(failed)
1332:Live Oak
1317:Cogswell
1252:Dams in
1213:July 19,
1193:July 19,
1163:July 22,
1138:July 18,
1132:Archived
1107:July 18,
1098:Archived
1060:July 18,
1051:Archived
1017:41267174
968:July 22,
963:GeoSlope
940:July 19,
934:Archived
910:July 19,
904:Archived
853:July 19,
847:Archived
819:July 18,
813:Archived
788:July 23,
760:July 18,
754:Archived
716:July 22,
711:GeoSlope
656:July 18,
647:Archived
536:See also
403:Turbines
371: m)
299: m)
235:Impounds
208:Built by
52:Location
1402:Bouquet
1342:Pacoima
1280:Pyramid
1270:Castaic
503:⁄
198: (
176: (
160: (
140: (
126: (
100:Purpose
44:Country
1521:Rindge
1474:Hansen
1419:Encino
1367:Sawpit
1337:Morris
1015:
1007:
878:
641:
337:Length
257:Length
110:Status
1498:Other
1101:(PDF)
1080:(PDF)
1054:(PDF)
1035:(PDF)
1013:JSTOR
959:(PDF)
707:(PDF)
650:(PDF)
635:(PDF)
193:;
171:;
1215:2021
1195:2021
1165:2021
1140:2021
1109:2021
1062:2021
1005:ISSN
970:2021
942:2021
912:2021
876:ISBN
855:2021
821:2021
790:2021
762:2021
718:2021
679:help
658:2021
639:LCCN
413:The
393:Type
162:1921
155:1921
142:1919
135:1919
128:1919
121:1919
1088:doi
1043:doi
997:doi
591:doi
587:122
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