Epic Flooding in Georgia, 2009 - USGSEpic Flooding in Georgia, 2009 Metropolitan Atlanta—September...
Transcript of Epic Flooding in Georgia, 2009 - USGSEpic Flooding in Georgia, 2009 Metropolitan Atlanta—September...
EXPLANATION
USGS office
Streamflow at one or more USGS streamgages exceeded the given annual exceedance probability
1 percent (100 year)0.5 percent (200 year)0.2 percent (500 year)
GEORGIA
U.S. Department of the InteriorU.S. Geological Survey
Epic Flooding in Georgia, 2009Metropolitan Atlanta—September 2009 Floods• TheepicfloodsexperiencedintheAtlantaareainSeptember2009wereextremelyrare.EighteenstreamgagesintheMetropolitanAtlantaareahadfloodmagnitudesmuchgreaterthantheestimated0.2-percent(500-year)annualexceedanceprobability.
• TheFederalEmergencyManagementAgency(FEMA)reportedthat23countiesinGeorgiaweredeclareddisasterareasduetothisfloodandthat16,981homesand3,482businesseswereaffectedbyfloodwaters.Tenliveswerelostintheflood.Thetotalestimateddamagesexceed$193million(H.E.Longenecker,FederalEmergencyManagementAgency,writtencommun.,November2009).
• OnSweetwaterCreeknearAustell,Ga.,justnorthofInterstate20,thepeakstagewasmorethan6feethigherthantheestimatedpeakstageofthe0.2-percent(500-year)flood.FloodmagnitudesinCobbCountyonSweetwater,Butler,andPowderSpringsCreeksgreatlyexceededtheestimated0.2-percent(500-year)floodsforthesestreams.
• InDouglasCounty,theDogRiveratGa.Highway5nearFairplayhadapeakstagenearly20feethigherthantheestimatedpeakstageofthe0.2-percent(500-year)flood.
• OntheChattahoocheeRiver,theU.S.GeologicalSurvey(USGS)gageatViningsreachedthehighestlevelrecordedinthepast81years.Gwinnett,DeKalb,Fulton,andRockdaleCountiesalsohadrecordflooding.
South Georgia March and April 2009 Floods• TheMarchandApril2009floodsinSouthGeorgiaweresmallerinmagnitudethantheSeptemberfloodsbutstillcausedsignificantdamage.
• Noliveswerelostinthisflood.Approximately$60millioninpublicinfrastructuredamageoccurredtoroads,culverts,bridgesandawatertreatmentfacility(JosephT.McKinney,FederalEmergencyManagementAgency,writtencommun.,July2009).
• FlowattheSatillaRivernearWaycross,exceededthe0.5-percent(200-year)flood.FlowsatsevenotherstationsinSouthGeorgiaexceededthe1-percent(100-year)flood.
Fact Sheet 2010–3107 October 2010
Measuring Sweetwater Creek floodflow over Interstate 20 near Atlanta, Georgia. Photo by Alan M. Cressler, USGS.
Altamaha Regional Park, Glynn County, Georgia, April 14, 2009. The water is 3 feet deep. Photo by Alan M. Cressler, USGS.
USGS Role During the Floods• OneoftheprimarymissionsoftheUSGSisthemeasurementanddocumentationofthemagnitudeandextentofhydrologichazards,suchasfloods,droughts,andhurricanestormsurge.
• InGeorgia,theUSGSmaintainsanetworkofmorethan300stream-gagesthatprovidedatainrealtimeviatheInternet.Datafromthesestreamgagesareusedbylocal,State,andFederalofficialsfornumerouspurposes,includingpublicsafety,NationalWeatherService(NWS)floodforecasting,andtoaidemergencymanagementofficialsinmakinginformeddecisionsbefore,during,andafterfloodevents.
• Duringthesetwofloodevents,USGSpersonnelmademorethan100discretefloodmeasurements,performedextensiveongoinganalysisofratingsandfloodfrequency,collectedwater-qualitysamplesinfloodedareas,andprovidedroutingbriefingstoUSGSHeadquarters,NWS,localgovernmentofficials,andthepress.
River basin
Active streamgage
EXPLANATION
Altamaha
Chattahoochee
Coosa–Tallapoosa
Flint
Ochlockonee
Ogeechee
Satilla–St. Marys
Savannah
Suwannee
Tennessee
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Augusta
Columbus
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Clinch
Worth
SumterCrisp
Miller
Macon
Marion
Randolph
Warren
Calhoun
Evans
Dougherty
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Web
ster
Schley
Ware
Burke
Clinch
Wayne
Laurens
Hall
Early
Floyd
WorthCoffee
Bulloch
Charlton
Emanuel
Long
Camden
Dodge
Screven
Decatur
GradyThomas
Troup
Tift
Liberty
Wilkes
Harris
Irwin
Cobb
Jones
Appling
Polk
Sumter
Dooly
Gilmer
Bibb
Colquitt
Telfair
Bartow
Rabun
Walker
Fannin
Carroll
Mitchell
Talbot
Coweta
Echols
Union
Taylor
Wilcox
Elbert
Pike
Greene
Stewart
Hart
Henry
Pierce
Upson
Crisp
Heard
Clay
Putnam
Bacon
Walton
Gordon
Miller
Jackson
Butts
Lee
Fulton
Bryan
Glynn
Brooks
Macon
Bake
r
Berrien
Lowndes
Washington
JasperHancock
Marion
Twiggs
Jefferson
Monroe
ToombsChatham
Brant
ley
Jenkins
Effingham
GwinnettM
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Wilkinson
Mcintosh
Cook
Morgan
Randolph
Cherokee
Houston
White
Terrell
Mer
iwet
her
Turner
Banks
Atkinson
Warren
DeKalb
Lumpkin
Oglethorpe
Newton
Paulding
Dade
Johnson
Madison
Wheeler
JeffDavis
Richmond
Lincoln
Pulaski
Columbia
Baldwin
Calhoun
Ben Hill
Evans
Crawford
Lanier
Lamar
Franklin
Whi
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Pickens
Dougherty
Candler
Forsyth
McDuffie
Haralson
Chattooga
Sem
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Dawson
Towns
Fayette
Haber
sham
Peach
Oconee
Web
ster
Bleckley
Schley
Douglas
Spalding
TreutlenMuscogee
Barrow
Quitman
Stephens
Catoosa
Mon
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TaliaferroC
layt
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Clarke
Chattahoochee
Glascock
Rockd
ale
Tattnall
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84°
34°
32°
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September 2009 flood is greater than the 0.2 percent (500 years) annual exceedance probability flood.
19 20 21 22 23 24 25September
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ft3 /s
02392975 Noonday Creek at Shallowford Road, near Woodstock, Georgia
1 percent AEP
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10,000
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30,000
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September 2009 flood exceeded the 0.2 percent (500 years) annual exceedance probability flood. Streamgage was inundated which resulted in loss of continuous data. USGS personnel were at the site and measured the peak streamflow.
0
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ft3 /s
02337000 Sweetwater Creek near Austell, Georgia
September 2009 flood about equal to the 0.2 percent (500 years) annual exceedance probability flood. Streamgage was inundated which resulted in loss of continuous data. The peak streamflow was determined from high water marks.
02207120 Yellow River at Ga. 124, near Lithonia, Georgia
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Dashed whereestimated
September 2009 flood magnitude is about equal to the 0.5-percent (200-year) AEP flood.
September 2009 flood is between the 1 and0.5 percent (100 and 200 years) annual exceedance probability flood.
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ft3 /s
02336000 Chattahoochee River at Atlanta, Georgia
19 20 21 22 23 24 25September
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100,000
02327500 Ochlockonee River near Thomasville, Georgia
AprilMarch25 30 4 9 14 19 24 29
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ft3 /s
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100
10,000
100,000
02226500 Satilla River near Waycross, Georgia
AprilMarch25 30 4 9 14 19 24 29
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ft3 /s
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100
10,000
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September 2009 flood magnitude greatly exceeded the 0.2-percent (500-year) AEP flood.
September 2009 flood magnitude is between the 1- and 0.5-percent (100- and 200-year) AEP flood.
September 2009 flood magnitude exceeded the 0.2-percent (500-year) annual exceedance probability (AEP) flood.
By Anthony J. Gotvald and Brian E. McCallum
Design and layout by Caryl J. Wipperfurth
http://ga.water.usgs.govhttp://www.usgs.gov
For more information contact:USGS Georgia Water Science Center3039 Amwiler Road, Suite 130Atlanta, Georgia 30360telephone: 770–903–9100
April 2009 flood magnitude is about equal to the 0.5-percent (200-year) AEP flood.
April 2009 flood magnitude is between the 1- and 0.5-percent (100- and 200-year) AEP flood.