Coastal Erosion in Southern California Enhanced by the 1997-1998 El Niño

Coastal Erosion in Southern California Coastal Erosion in Southern California Enhanced by the 1997-1998 El NiñoEnhanced by the 1997-1998 El Niño

By Zachary MoodyBy Zachary Moody

OutlineOutline

Background on ErosionBackground on Erosion Background on 1997-1998 El NiñoBackground on 1997-1998 El Niño Measuring Coastal ErosionMeasuring Coastal Erosion LiDAR TechnologyLiDAR Technology Case Examples from 1997-1998Case Examples from 1997-1998 Human InvolvementHuman Involvement

Typical California CoastlineTypical California Coastline

1997-1998 El Niño1997-1998 El Niño

1997-1998 El Niño Global Effects1997-1998 El Niño Global Effects

Began earlier than normal Began earlier than normal and peaked in Januaryand peaked in January

Temperatures >4Temperatures >4oo than than normal in eastern Pacific normal in eastern Pacific and in some areas >9and in some areas >9oo

Drought and wildfires in Drought and wildfires in IndonesiaIndonesia

Increased number of Increased number of hurricanes off of Mexico’s hurricanes off of Mexico’s coastcoast

2100 deaths and $33 2100 deaths and $33 billion in property damage billion in property damage worldwideworldwide

www.cnn.com/WEATHER/9708/20/el.nino/

1997-1998 El Niño Effects in the 1997-1998 El Niño Effects in the United StatesUnited States

Killer tornadoes in the Southeast U.S.Killer tornadoes in the Southeast U.S. Massive blizzards in the upper Midwest U.S.Massive blizzards in the upper Midwest U.S. Flooding in the Ohio river valleyFlooding in the Ohio river valley California received 2x the normal rainfall which caused California received 2x the normal rainfall which caused

flooding and landslidesflooding and landslides

El Niño related landslides along the California coast.

http://elnino.wr.usgs.gov/ http://elnino.wr.usgs.gov/

El Niño ImpactsEl Niño Impacts

Larger and More Violent Storms Larger and More Violent Storms More Powerful Waves More Powerful Waves Greater Coastal ErosionGreater Coastal Erosion

http://pdphoto.org/PictureDetail.php?pg=5558

Measuring Coastal ErosionMeasuring Coastal Erosion

Methods:Methods: SurveysSurveys Aerial PhotographyAerial Photography Light Detection and Ranging (LiDAR)Light Detection and Ranging (LiDAR)

LiDARLiDAR

Scanning LaserScanning Laser Stream of Light Pulses Stream of Light Pulses

Emitted Side-to-SideEmitted Side-to-Side Acquires Location and Acquires Location and

Elevation DataElevation Data GPS Receivers and GPS Receivers and

Satellites used to Satellites used to indicate location as indicate location as data is collecteddata is collected

LiDARLiDAR

AdvantagesAdvantages Saves Time, Money, and ManpowerSaves Time, Money, and Manpower Greater Coverage AreaGreater Coverage Area Water Depth InformationWater Depth Information Integrated with GPS/GISIntegrated with GPS/GIS Capable of mapping steeped sloped regions, shadowed areas, and Capable of mapping steeped sloped regions, shadowed areas, and

inaccessible areas (such as mud flats and ocean jetties).inaccessible areas (such as mud flats and ocean jetties).

1997-1998 El Niño 1997-1998 El Niño Effects in Southern Effects in Southern

CaliforniaCalifornia

Monty Hampton, USGS

January, 1998

February 1998

Sea cliffs in Pacifica, CASea cliffs in Pacifica, CA

13 meters of cliff erosion in one year13 meters of cliff erosion in one year 1997-98 El Niño accounted for about 50 1997-98 El Niño accounted for about 50

years of cliff erosion at this locationyears of cliff erosion at this location 12 houses were condemned 12 houses were condemned 7 were undercut and fell into the ocean7 were undercut and fell into the ocean

Southern Pacifica

Northern Pacifica

http://coastal.er.usgs.gov/lidar/AGU_fall98/

http://coastal.er.usgs.gov/lidar/AGU_fall98/

Analyzing LiDAR DataAnalyzing LiDAR Data

Landslides

Longshore TransportOverwash

River Breakthrough

San DiegoSan Diego11

22

October, 1997

April, 1998

http://coastal.er.usgs.gov/lidar/AGU_fall98/display.html

http://coastal.er.usgs.gov/lidar/AGU_fall98/display.html

San DiegoSan Diego

33

VenturaVentura11

22

October, 1997

April, 1998

http://coastal.er.usgs.gov/lidar/AGU_fall98/display.html

http://coastal.er.usgs.gov/lidar/AGU_fall98/display.html

Human InteractionHuman Interaction

Erosion is a natural process that is Erosion is a natural process that is inevitable. Humans can intervene but this inevitable. Humans can intervene but this only deters erosion to alternate areas.only deters erosion to alternate areas.

ExamplesExamples-Jetties-Jetties-Seawalls-Seawalls-Groins-Groins-Beach Renourishment-Beach Renourishment

Questions?Questions?

SourcesSources Griggs, G.B. (2002). Coastal Cliff Erosion in San Diego County. Griggs, G.B. (2002). Coastal Cliff Erosion in San Diego County. Sea Grant Sea Grant

California Coastal Ocean Research, California Coastal Ocean Research, R/CZ-157: 3.1.1998-6.30.1999R/CZ-157: 3.1.1998-6.30.1999 Sallenger Jr. A.H. et al. (2002). Sea-cliff erosion as a function of beach Sallenger Jr. A.H. et al. (2002). Sea-cliff erosion as a function of beach

changes and extreme wave runup during the 1997-1998 El Niño. changes and extreme wave runup during the 1997-1998 El Niño. Marine Marine Geology 187Geology 187, no.3-4 p. 279-297 , no.3-4 p. 279-297

Storlezzi C.D. and Griggs G.B. (2000). Influence of El Niño-Southern Storlezzi C.D. and Griggs G.B. (2000). Influence of El Niño-Southern Oscillation (ENSO) events on the evolution of Central California's shoreline. Oscillation (ENSO) events on the evolution of Central California's shoreline. Bulletin of the Geological Society of America 112Bulletin of the Geological Society of America 112, no.2 p. 236-249 , no.2 p. 236-249

http://coastal.er.usgs.gov/lidarhttp://coastal.er.usgs.gov/lidar (2/20/07) (2/20/07) http://www.geotimes.org/nov03/feature_LIDAR.htmlhttp://www.geotimes.org/nov03/feature_LIDAR.html (2/20/07) (2/20/07) http://www.woolpert.com/asp/articles/New_LiDAR_Technology.asphttp://www.woolpert.com/asp/articles/New_LiDAR_Technology.asp (2/20/07) (2/20/07) http://www.cnn.com/WEATHER/9712/06/el.nino.storm/index.htmlhttp://www.cnn.com/WEATHER/9712/06/el.nino.storm/index.html (2/20/07) (2/20/07)