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Water Resources UpdateUSGS Illinois Water Science Center Newsletter

Fall/Winter 2007

U.S. Department of InteriorU.S. Geological SurveyIllinois Water Science Center1201 W University Ave Ste 100Urbana IL 61801-2347http://il.water.usgs.gov/

Compiled by D.M. Ayers and J.B. Sharpe

Message from the DirectorRobert R. Holmes, Jr., PhD, P.E.

Table of Contents

MessagefromtheDirector.......................................................................................................................................................1NEXRADRadarPrecipitationData:StudiesandUseattheUSGSIllinoisWaterScienceCenter.......................................2EmployeeSpotlight..................................................................................................................................................................4StatewideGeospatialCoordinatingActivities.........................................................................................................................5PreliminaryAssessmentoftheWaterResourcesofKendallCounty......................................................................................6SaltCreekHydrologicInformationtobeAnalyzed,DisseminatedinanIntegratedBrowsableFormat................................8August2007FloodinginNortheasternIllinois..................................................................................................................... 10IllinoisStreamflowConditionsforOctober2006throughSeptember2007......................................................................... 12

Forhydrologicproblems,manyfacetsoftechnologyareoftenbroughttobeartostudyandsolvetheseprob-lems.Twenty-fiveyearsago,manyofusknewlittleaboutcomputerizedgeographicinformationsystems(GIS)orwhatitcoulddoforus.Today,GISandassociateddigitalgeospatialinformationisacrucialpartofthescienceofhydrology.TheeffortsoftheU.S.GeologicalSurvey(USGS)tocoordinatewithStateandlocalagenciesinthegeospatialarenaarebeingspearheadedbyUSGSliaisonslocatedprimarilyintheUSGSWaterScienceCenters.ShelleySilchistheUSGSliaisonforIllinois,sittinghereintheUSGSIllinoisWaterScienceCenter.Youcanreadaboutheractivitiesinthisnewsletterissue.Twoothertechnologicalareasbeingutilizedbythehydrologiccom-munityareNEXRADradarandtheWorldWideWeb.NEXRADprovidesrainfallataspatialdensitynotpracticalwithphysicalraingages.Thisincreasedrainfallinformationhasenhancedourrainfall-runoffmodelingcapabilitiesasisshownintheUSGSIllinoisWaterScienceCenterworkinnorthernIllinoisanddiscussedinthisissue.TheWorldWideWeballowsustoorganizeandsharedatabetweenagenciesandscientists,maximizingcollaborationandtimespentonscience,whileminimizingthetimespentsearchingfordata.ThearticlebyAudreyIshiioutlin-ingtheworkweareconductingwiththeUniversityofIllinoisfortheSaltCreekwatershedisaperfectexampleofthiscollaboration.

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NEXRAD Radar Precipitation Data:Studies and Use at the USGS Illinois Water Science Center

byThomas Over, Hydrologist

Background

In1990,theNationalWeatherService(NWS)begandeployingtheNextGenerationRadar(NEXRAD)WSR-88DweatherradarsaroundtheUnitedStatesandatselectedmilitarybasesaroundtheworld;deploymentwascompletedin1997(figure1).InIllinois,NEXRADradarsarelocatedatRomeovilleandLincoln,andradardatafromseveralradarsinsurroundingstatesarealsorelevantforIllinois.NEXRADradarsprovideinformationonmanyatmosphericparameters,includingthestormmotionandverticalstructure,andhailandtornadoindication;buttheparameterofprimaryinterestforhydrologyandwaterresourcesistheprecipitationrate.

NEXRADradarsarescanningradars,whichmeanstheyscanradially,usingdifferentelevationanglestoprovideinformationonverticalatmosphericstructureandtoavoidman-madeortopographicobstacles(figure2).Thereareseveralscanningpatternsfromwhichtheopera-torscanchoose;themostimportantdistinctionisbetween“clear-air”and“precipitation”modes.Usuallythelowestvalidelevationangleisthebestonetouseforestimatingprecipitationatgroundlevel.Therefore,rawNEXRADdatafollowsaradialcoordinatesystemdefinedbyazi-muth,elevationangle,andrange(distancefromtheradar).

Initialprocessingoftherawradardataisperformedautomaticallyattheradarinstallationandincludesthefol-lowingsteps:(1)combinationofdifferentelevationanglesintothe“best”singlescan;(2)removalofnon-precipita-tionreturns;(3)convertingreflectivity(Z)torainrate(R)byuseofaZ-Rrelation,Z = aRb;(4)correctingforhailreturns;(5)correctingforrangebias;and(6)conversionfromradialcoordinatestotheHydrologicRainfallAnaly-sisProject(HRAP)grid,whosepixelsareapproximately4by4kminsize.Executionofthesesteps,amongothers,createstheDigitalPrecipitationArray(DPA).Thisarrayispassedontotheriverforecastingcenters(RFC’s)oftheNWS,whereDPAfieldsfromdifferentradarsarecom-binedtogetherandtheprecipitationratesareadjustedbyNWShydrometeorologistsbycomparisonwithraingagesthatreportinreal-time.TheresultiscalledtheMulti-sensorPrecipitationEstimate(MPE).VariousNEXRADradarprecipitationestimatesareavailablefromarchivesmaintainedbytheNWSandtheNationalClimaticDataCenterandareaccessibleviatheWorldWideWeb.

Use of NEXRAD Data at the USGS Illinois Water Science Center

MPEfieldscreatedattheNorthCentralRFC(NCRFC)inChanhassen,Minnesota,aresenttotheUSGSIllinoisWaterScienceCenter(IWSC),processed,andmadeavailabletotheSaltCreeknear-real-timestreamflowsimulationproject.Theprojectisruncoop-erativelywiththeDuPageCountyStormwaterManage-mentDivisioninordertosupplementtheavailableraingagedata,whichmaybesubjecttovariouskindsoferrorsormaybemissing(figure3).Seethearticle,SaltCreek

Figure �. NEXRAD radar sites in the continental United States (figure from http://www.ncdc.noaa.gov/nexradinv/)

Figure �. NEXRAD Volume Coverage Pattern (VCP) 11, used for severe and non-severe precipitation (from Federal Meteorological Handbook, No. 11, Part C, 2006).

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HydrologicInformationtobeAnalyzed,DisseminatedinanIntegratedBrowsableFormat,onpage8ofthisnews-letter.TheMPEdataisavailable2to12hoursaftertheprecipitationactuallyfell.BeforetheMPEdataisavail-able,theautomaticallyprocessedDPAdataisavailabletobeusedasaninitialestimateoftheradarprecipitationvalue.

TheIWSCalsoprovidesMPEdataoverthewholeNCRFCdomain,alongwithIWSCraingagetotals,tothepublicinaprecipitationmap-pinginterfaceathttp://munster.er.usgs.gov/rainfall/ andhasbeenusedbyIWSChydrolo-giststospatiallydistributetheprecipitationformodelingtheJuly1996floodinBlackberryCreek(seereportathttp://pubs.usgs.gov/sir/2005/5270).

Comparison of MPE and Rain Gage Data in DuPage County

InordertoassesstheaccuracyofNEXRADdata,inparticulartheMPEproduct,forSaltCreekstreamflowsimula-tion,astudywascarriedoutattheIWSC,incooperationwiththeDuPageCountyStormwaterManagementDivision,tocom-paretheprecipitationmeasuredbytheDuPageCountytip-ping-bucketraingagenetworkandtheNEXRADMPEdataprovidedbytheNCRFC.Thecomparisonwasdoneatthedailytimescaleduringabove-freezingconditionsbetweentheamountofrainrecordedateachraingageandtheMPEtotalinthecellinwhicheachgagelies.Themainlessonlearnedfromthisstudyisthatthecorrespon-dencebetweenthegageandNEXRADrainfallvalueshasfluctuatedovertime,buthasbeenquiteclose,whenaver-agedoverallthegages,duringtheperiodfrom2001through

2005(figure4).AsimilarstudyisongoingtocomparetheDPAandMPEvalues.

The Future of NEXRAD at IL WSC

WeexpectcontinueduseofNEXRADradarprecipi-tationdataintheSaltCreekforecastingprojectandinrainfall-runoffstudies,suchasanongoingstudyofKish-waukeeRiverheadwatersinKaneCounty.AtestofthepossiblevalueofNEXRAD-based“nowcasting”forthe

Figure �. Salt Creek watershed in DuPage and Cook Counties, with rain gages and NEXRAD grid.

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SaltCreekproject.Thisproject,whichisplannedforthecomingyear,usestheobservedmotionofprecipitationsystemsoverthepastfewhourstopredicttheirmotionoverthenextfewhours.NEXRADradarprecipitationdatawillalsofigureprominentlyinanewpartnershipwiththeUniversityofIllinoisatUrbana-Champaign,Depart-mentofCivilandEnvironmentalEngineering,andtheNationalCenterforSupercomputingApplications.SaltCreekwillbeusedasatest-bedforthedevelopmentofa“digitalwatershed”.

Figure �. Double-mass curve analysis of NEXRAD versus gage precipitation in DuPage County.

NEXRAD Radar Precipitation Data: Studies and Use at the USGS Illinois Water Science Center—Continued. EMPLOYEE SPOTLIGHT

Jon Hortness(Hydrologist)

JonHortnessisaHydrologist/EngineerintheUSGSIllinoisWaterScienceCenter’sDeKalbOffice.AspartoftheHydrologicDataCol-lectionandAnalysisSection,Jon’scurrentdutiesincludeoversightofstreamflow,sediment,ground-water,andrainfalldatacollectioneffortsatover80locationsinnorthernIlli-nois,aswellasassistingwithdatacollectionandanaly-siseffortsforspecifichydrologicinvestigationsinthearea.

JonholdsBSandMSdegreesinCivilEngineeringfromtheSouthDakotaSchoolofMinesandTechnol-ogyinRapidCity.HealsoisaregisteredProfessionalEngineerinIllinois,Idaho,andWisconsin.JonbeganhiscareerwiththeUSGSin1996intheSouthDakotaWaterScienceCenterwhilepursuinghisMSdegree.Followingthat,hespent8yearswiththeIdahoWaterScienceCenterintheScientificInvestigationsSectionasprojectchiefforvarioussurfacewaterprojects.Thisworkincludedfloodmodeling,surface-water/ground-waterinteractions,analysesoflow-flowanddroughts,regionalizationofstreamflowestimates,andanalysisofin-streamaquatichabitats.JonalsoservedastheWest-ernRegionspecialistforHydroacousticsandCable-ways,andprovidedandassistedwithtrainingintheseareas.

Jon,hiswifeNicole(alsoaCivilEngineerwhopreviouslyworkedforDuPageCounty)andchildren,Brooke(11),Bradley(6),andKyle(1),movedtoIlli-noisinthesummerof2006tobeclosertofamily.Jonworkedashorttimeforanengineeringconsultingfirmonvariouswaterresourcestypeprojects.AmajorityoftheworkwasbeingperformedfortheIllinoisDepart-mentofTransportationandMetropolitanWaterRecla-mationDistrictofGreaterChicago.InMarch2007,JonacceptedthepositionintheDeKalbOffice.

AlthoughJon’spreviousexperiencedealtmainlywithspecificprojectwork,heunderstandstheimpor-tanceofqualitywaterresourcesdata.Hesaid,“When-everIwasworkingonaproject,Iwouldcollectthenecessarydatamyselformakesurethatthepeoplewhowerecollectingthedataknewexactlywhatitwasgoingtobeusedfor.Thefinalresultofanyanalysisisonlyasgoodasthedatathatwentintoit.”JonfeelsthatqualitydatathatiscollectedconsistentlyacrosstheNationandisreadilyaccessibletothepubliciskeytotheUSGSmission.“Inmyshortcareer,I’veseenahugeincreaseinthepublic’sawarenessanduseofourdata.Ithinkit’simportantthatwecontinuetotrytoimproveourdatacollectiontechniqueswithnewmethodsandtechnologysowecanbeasaccurateandefficientaspossible.”

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TheNationalSpatialDataInfrastructure(NSDI)1CooperativeAgreementsProgram(CAP)isanannualprogramtoassistthegeospatialdatacommunitythroughfundingandotherresourcesinimplementingthecom-ponentsoftheNSDI.ThisprogramisopentoFederal,State,localandtribalgovernments,academia,commer-cial,andnon-profitorganizations.Thisprogramprovidessmallseedgrantstoinitiatesustainableon-goingNSDIimplementations.Theprogramemphasizespartnerships,collaborationandtheleveragingofgeospatialresourcesinachievingitsgoals.TheStateofIllinoisisarecipientofa2007CAPgrantfor$50,000intheFiftyStatesInitiative2category.

TheFiftyStatesInitiativeisapartnershipbetweentheNationalStatesGeographicInformationCouncil(NSGIC)3andtheFederalGeographicDataCommittee(FGDC)4.ThisinitiativeisdesignedtobringallpublicandprivatestakeholderstogetherasStatewideGIScoordina-tionbodiesthathelptoformeffectivepartnershipsandlastingrelationships.IllinoishasbeenanactivememberofNSGICforanumberofyears.Inadditiontotheini-tiative,NSGIChaspublishedninecriteriathatmembersbelieveareessentialforeffectiveStatewidecoordinationofgeospatialinformationtechnologies.Theseninecrite-riainclude:(1)Afull-time,paidcoordinatorpositionisdesignatedandhastheauthoritytoimplementtheState’sbusinessandstrategicplans;(2)aclearlydefinedauthorityexistsforStatewidecoordinationofgeospatialinformationtechnologiesanddataproduction;(3)theStatewidecoor-dinationofficehasaformalrelationshipwiththeState’sChiefInformationOfficer(orsimilaroffice);(4)acham-pion(politicianorexecutivedecisionmaker)isawareandinvolvedintheprocessofcoordination;(5)responsibili-tiesfordevelopingtheNSDIandaStateClearinghouseareassigned;(6)theabilityexiststoworkandcoordinatewithlocalgovernments,academia,andtheprivatesector;(7)sustainablefundingsourcesexisttomeetprojectedneeds;(8)coordinatorshavetheauthoritytoenterintocontractsandbecomecapableofreceivingandexpendingfunds;and(9)theFederalGovernmentworksthroughtheStatewidecoordinatingauthority.

Asarecipientofthe2007CAPgrant,IllinoisisinterestedinrevitalizingtheactivitiesoftheIllinoisGeo-graphicInformationCouncil(ILGIC),revisetheexistingStatestrategicplan,anddevelopabusinessplantosupportgeospatialactivitiesinIllinois.Thestrategicplanningpro-cesswillbuildontheexistingadministrativefoundationofILGIC.TwooftheprimarygoalsofthisprocesswillbetoprovidestrategicdirectiontoILGICandtostrengthenitseffectivenessastheprincipalgeospatialoversightgroupinIllinois.TheStrategicandBusinessPlansforIllinoiswillidentifytheneedsforenhancedgeospatialcoordina-tionandintegrationamongalllevelsofgovernment,theprivatesector,andstakeholders.ByusingtheNSGICFiftyStatesInitiativeasamodel,thecoreprojectteamwillfocusonthedevelopmentofpracticalstrategiestohastenasuccessfuloutcome.Therevised5-yearstrategicandbusinessplanswillserveasroadmapsthatwillguidefutureeffortsconcerningthefiscal,administrative,andtechnicalrequirementsofanintegratedgeospatialtechnol-ogyinfrastructureforIllinois.

ThefirstStatewidestakeholdermeetingwasheldinChampaign,IllinoisonJuly25,2007.Therewereover140attendeesatthisfirstgathering.Twoprimarygoalsofthismeetingwere:(1)explainthecurrentstatusofcoor-dinationandcollaborationthroughouttheState,and(2)garnerinputfromstakeholdersforthepurposeofcraftingthestrategicandbusinessplans.Anadditionalgoalofthismeetingwastorecruitnominationsforasmallergrouptobeginworkonthestrategicandbusinessplans.Nomi-nationswereacceptedandacoregroupofstakeholderswasselectedtoworkonthesecondstepoftheprocess.Thissecondstepencompassestheworkneededtoout-lineanddraftthestrategicandbusinessplans.ThiscorestakeholdergrouphadtheirfirstmeetinginSpringfieldonAugust28,2007.FuturemeetingsareplannedforOctoberandNovember2007.Thefinalphaseofthisprojectwillbetopublicizetheplansandtoincorporatecommentsandsuggestions.Foraditionalinformationandtokeepup-to-datewiththeactivitiesofthisproject,pleasevisit:http://www.ilgisa.org/GIS_Initiative_2007/index.html.

Statewide Geospatial Coordinating Activitiesby

Shelley L. Silch, Physical Scientist

1 TheNSDIisameanstoassemblegeographicdataNationwidetoserveavarietyofusers.2 Initiativethatidentifiesthecriteria,characteristics,andactivitiesthatwillidentifyeffectivecoordinationcouncils.3 NSGICisanorganizationcommittedtoefficientandeffectivegovernmentthroughtheprudentadoptionofgeospatialinformation

technologies.4 FGDCisaninteragencycommitteethatpromotesthecoordinateddevelopment,use,sharing,anddisseminationofgeospaticaldataon

aNationalbasis.

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Preliminary Assessment of the Water Resources of Kendall Countyby

Robert T. Kay, Hydrologist

KendallCountyislocatedonthefringeoftheChi-cagoMetropolitanareainnortheasternIllinois(figure1).ThepopulationofKendallCountyhasincreasedsteadilysinceabout1950,reachinganestimated66,565peoplein2003.Thispopulationgrowthisexpectedtocontinueandby2030,thepopulationofKendallCountyisprojectedtobeabout170,000—nearly10timesthepopulationin1950.

Asaresultofpopulationgrowth,wateruseinKendallCountyalsohasincreasedfromabout1.2milliongallons

perdayin1957tomorethan5milliongallonsperdayin2000.WateruseinKendallCountywillincreasesubstan-tiallyinthefutureasthepopulationcontinuestoincrease.Tohelpmeetfuturedemandsforcleandrinkingwater,theUSGSandtheCountymadeapreliminaryassessmentofthewaterresourcesinKendallCounty.ThisassessmentispresentedinUSGSScientificInvestigationsReport2005-5122,availableathttp://il.water.usgs.gov/pubs/sir2005-5122.pdf.

TheFoxRiveristheprimarysurface-waterbodyinKendallCountyandisusedforbothwastewaterdisposalandasadrinking-watersupplyupstreamofthecounty.WaterfromtheFoxRiverrequirestreatmentforuseasdrinkingwater,buttheriverisapotentiallyviableaddi-tionalsourceofwaterforthecounty.

WatersupplyneedsinKendallCountyaremetexclu-sivelyfromgroundwaterderivedfromglacialdriftaqui-fersandbedrockaquifersopentoSilurian,Ordovician,andCambrianageformations(figure2).

Thefullextentofglacialdriftaquiferscapableofyieldingsufficientwaterformunicipalsupplyisnotknow,buttheyarelikelypresentinnorthernKendallCountyalongtheFoxRiver,andintheNewarkValleyanditstributaries(figure3).Knownglacialdriftaquiferscapableofyieldingsufficientwaterforresidentialsupplyarepresentinmostofthecounty,withtheexceptionofthesoutheasternportion.Volatileorganiccompoundsandtracemetalsandpesticideshavebeendetectedatconcen-trationsbelowlevelsofconcerninglacialdriftaquifersnearwaste-disposalsites.Agricultural-relatedchemicalconstituentshavebeendetectedinfrequentlyinglacialdriftaquifersnearagriculturalareas.However,widespreadproblemswithwaterqualityarenotapparentintheseaquifers.Theseaquifersareaviablesourceforadditionalwatersupply,butrequirefurtherstudytodeterminetheirfullextentandpotentialpriortofulldevelopment.

TheshallowbedrockaquiferiscomposedofthesandstoneunitsoftheAncellGroup,thePrairieduChienGroup,andGalena-Plattevilledolomite,theMaquoketaGroup,andtheSiluriandolomitewheretheseunitsarethebedrocksurfaceundertheglacialdrift.Theavailabilityofwaterfromtheshallowbedrockaquiferdependsprimar-ilyonthegeologicformationused.TheSiluriandolomite,

Figure �. Location of Kendall County and the Chicago Metropolitan area (pink shading) in northeastern Illinois.

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Figure �. Well yields of glacial drift in Kendall County (modified from Schicht and others, 1976).

Galena-Plattevilledolomite,andAncellGroupcanyieldsufficientwaterforresidentialandmunicipalsupplyinatleastsomepartsofthecounty.

TheCambrian-Ordovicianaquifersystemcomprisesthemostwidespread,productiveaqui-ferinnorthenIllinoisanditsuseformunicipal-watersupplyhasincreasedwithinthecountyinthepastseveralyears.WaterlevelsintheCambrian-Ordovicianaquifersystemhavedeclinedbyasmuchas600feetinKendallCountysincethelate1800sandtheaquiferfrequentlycontainsconcentrationsofradiumaboveestablishedhealthguidelines,necessitatingtreatmentofthiswater.

References

Schicht,R.J.,Adams,J.R.,andStall,J.B.,1976,Waterresourcesavailabil-ity,quality,andcostinnortheasternIllinois:IllinoisStateWaterSurveyReportofInvestigation83,90p.

Figure �. Generalized hydrogeologic column showing stratigraphy and hydrogeologic units in Kendall County.

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regardingreservoirmanagementandotherflood-controlmeasures.

TheUSGS,togetherwithDPCSMD,operates36rain-fallgagesthroughoutandnearDuPageCounty.Streamelevationsaremonitoredatmorethan15locations,andstreamflowsat11sitesaremonitored,computed,andpublishedbytheUSGS.NWSNEXRADestimatesofprecipitationdatafor4-kilometerby4-kilometerareasareformattedforstreamflowsimulationmodelsandmadeavailablethroughtheInternet(seetherelatedarticleinthisissue).MeteorologicaldatacollectedbyArgonneNationalLaboratoryarereviewedannually,missingperi-odsestimated,andmadeavailableinanhourlyformatforuseinlong-termsimulations.

FortheSaltCreekwatershed,anearreal-timestream-flowsimulationsystemhasbeendevelopedthatincor-poratesreal-timesensordata,includingstage,computedstreamflow,precipitation(includingtheQuantitativePrecipitationForecast[QPF]producedbytheNationalWeatherService)dataandNEXRADprecipitationesti-mates,temperature,wind,dewpoint,andsolarradiationintoacontinuoushydrologicmodel(HSPF).TheresultingrunoffisthenroutedthroughthedynamicwavemodelFull-Equations(FEQ),todeterminewaterelevationsatkeylocationsalongthelowerSaltCreek.Selectedhydro-logicandmeteorologicdatacollectionstationsintheSaltCreekareaareshowninthefigurebelow.

TheDigitalWatershedprojectwillgraphicallypres-enttheNEXRADdataandprovidecomparisonwiththeprecipitation-gageandstreamgagedatainrealtime.TheforecastelevationsdeterminedthroughthecomputermodelsoperatedbytheDPCSMDwillbeimprovedbytheaccesstotheanalyzedanddisplayeddata.Thecomputermodelresultswillbealsoincorporatedintotheinterfaceforoperationaldecisionsupport.

AlsofundedthroughtheAESISinitiative,severalotherresearchprojectsfocusonaspectsofwater-usedecisions,optimizationofdata-collectionnetworks,waterdetentionbasineffectsonWestNilevirusoutbreaks,humanimpactsonwatershedmanagement,andstormwa-termanagementoptimization.

LocatedintheGreaterChicagoMetropolitanRegion(GCMR),theSaltCreekWatersheddrainsfromLakeCounty,throughCookandDuPageCountiestotheDesPlainesRiver.InAugust1987,theGCMRexperiencedheavyfloodingresultingin4deathsanddamagesinexcessof$62.4million(Curtis,1990),themostsevereofwhichwasinthecommunitiesalongtheDesPlainesRiverandSaltCreek(Baldingetal.,1992).Subsequently,withexpandedauthorityfromtheState,DuPageCounty(DPC)strengtheneditsdevelopmentofastormwatermanage-mentprogramincludingtheconstructionandmanagementoftwooperationalfloodcontrolfacilitieswithhydrologicdatacollectionbytheU.S.GeologicalSurvey-IllinoisWaterScienceCenter(USGS-IWSC)asoneofitscorner-stones.

Overthenexttwoyears(August2007-May2009)theDuPageCountyStormwaterManagementDivision(DPCSMD)andtheUSGS-IWSCwillbeworkingwithresearchersfundedbytheUniversityofIllinoisatUrbana-Champaign(UIUC)throughtheAdaptiveEnvironmentalSensingandInformationSystems(AESIS)initiative.OneofthefiveprojectstheAESISinitiativewillbefundingis—AnUrbanDigitalWatershed—Real-timeHydrologi-calDataDisseminationandAnalysisusinganIntegratedStormwaterManagementInformationSysteminandneartheSaltCreekwatershed.

ThiscooperativeworkistoenhancetheSaltCreekReal-TimeStreamflowSimulationSystem,developedbytheDPCSMDandtheUSGS.Thisprojectwillincorpo-ratereal-timestreamflow,NEXRADprecipitationesti-mates,andprecipitationgageinformationcollectedbyDPCSMD,theMetropolitanWaterReclamationDistrictofGreaterChicago(MWRDGC),theNationalWeatherService(NWS),theUSGS,andotheragencies.

Thereal-timedatapresentationwillbeaccessibleasamapinterfaceoverlayingaerialphotographimageswithhydrologicdatathatwillimprovepublicaccessandunder-standingofstreamflow-relatedconditionssuchasfloodingandpotentialfloodingintheSaltCreekwatershed.Thereal-timedataanalysis,especiallythedatasummariesandtheimproveddetectionofanomalousdata,anddatagapswillassistDPCSMDengineersandotheremergencyandfloodcontrolagenciesinoperationaldecision-making

Salt Creek Hydrologic Information to be Analyzed, Dissemination in an Integrated Browsable Format

byAudrey L. Ishii, Chief, Surface-Water Investigations Section

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AccordingtoBarbaraMinsker,UniversityofIllinoisprofessorofCivilandEnvironmentalEngineeringanddirectorofAESIS,“…theSaltCreekwatershedprovidesanexcellenttestbedforprototypingtheDigitalWatershedinsupportingbothresearchanddecisionmaking,giventhelargeinvestmentsmadeindatacollectionnetworksandmodelinginfrastructurebytheSMDandotheragen-cies.”

AESISisfundedbytheUniversityofIllinoisUrbanaChampaignViceChancellorforResearch,NationalCenterforSupercomputingApplications,andDept.ofCivilandEnvironmentalEngineering.AccordingtoJamesF.Zay,ChairmanoftheDuPageCountyStormwaterManagement

PlanningCommittee,“ThisresearchstudyrecognizesthepeopleofDuPageCountywhohavemadeatremendousinvestmentinproactivestormwatermanagementandflooddamageprevention.”

References

Balding,G.O.,Ishii,A.L.,1992,FloodsofSeptember26–October4,1986,andAugust14–17,1987,inIllinois:U.S.GeologicalSurveyWater-ResourcesInvestigationsReport92-4149,p.25.

Curtis,G.W.,1990,StormandfloodsofAugust13to15,1987,inCookandDuPageCounties,Illinois,inNationalWaterSummary1987—hydrologiceventsandwatersupplyanduse:U.S.GeologicalSurveyWater-SupplyPaper2350,p.50.

Figure �. Locations of precipitation gages and streamflow-gaging stations in vicinity of the Salt Creek Watershed, DuPage and Cook Counties.

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OnAugust7,2007,intenselocalprecipitationof5–7inchescausedsevereurbanfloodingindowntownRockford.TherainfallseemedtobecenteredonthehighgroundseparatingtheRockRiverandKishwaukeeRiver,threateningtheAlpineDamandfloodingstreetsandvia-ductsalongravinesleadingthroughboththeeastandwestsidesofthecity.AlthoughRockfordwasnotaffectedassignificantlybysubsequentflooding,forthecityAugustwasthewettestmonthinrecordedhistory.Althoughthelocalizedrainfallhadlittleeffectonover-allstreamflowatthetime,saturatedsoilconditionscreatedbythisearliereventcontributedtothehighdischargelevelslaterexperi-encedontheRockandKishwaukeeRivers.

OnAugust19,theremnantsofTropicalStormErinbegantofeedmoistureintoastationaryfrontoversouth-easternMinnesotaandsouthernWisconsin.TheresultwascatastrophicfloodinginWinona,Minnesota.ThestationaryfrontpersistedoversouthernWisconsinforthefollowingweek,producingextendedperiodsofheavyrainfall.

ThefirsteffectsinnorthernIllinoiswerelocalizedfloodingsimilartotheRockfordevent,withtheKishwau-keeRiverrisingagainfromlocalrainfall.SmallerstreamsintheChicagoareawereaffectedbythescatterednatureoftheprecipitation,withinitialpeaksoccurringinseparatesmallbasinssuchastheFoxRivertributariesinthewesternsuburbs,theSkokieRiverinthenorth,andtheLittleCalumetRivertributariesinthesouth.

Thelong-termeffectsoftheAugust19precipitationbeganwithinflowfromtheheadwatersoflargerstreamsorigi-natinginsouthernWisconsin.InitialfloodingbeganontheDesPlainesRiver,followedbytheFoxRiver,andtheRockRiver.

ThefinalstormeventoccurredonAug.23,whenheavyrainfallandhighwindstorethroughtheChicagoArea.Therainfallwasagainhighlylocalized.TheSouthBranchKishwaukeeRivernearDeKalb,TylerCreeknearElgin,andDeerCreeknearChicagoHeights,allbasinshit

bytheearlierprecipitationonAugust19,suffered100-yearfloods.LargerbasinssuchastheDuPageRiverwerepusheduptothe50-yearfloodlevel,whiletheSaltCreekbasinsufferedfloodingcomparabletothe1987levels.Localrainfallcombinedwithmain-steminflowtopushtheFoxRiveratAlgonquintoa40-yearlevel.

Becausetherainfalloccurredoveranextendedperiodoftime,withseveralhighlylocalizedeventsoveralargearea,thegreatesteffectwastoincreasetheflowofthelargerbasins,oftenatpointsfarremovedfromthesiteofthestormevents.Themostpervasivefloodingwasthere-foreseenalongthedownstreamreachesoftheRock,Fox,andDesPlainesRivers.Althoughfloodrecurrencelevelsfortheselargerstreamswereonlyinthe5–10yearrecur-rencerange,theyremainedabovefloodstageforseveralweeks.

Inall,over50streamgagingsitesfromtheQuad-Cit-iestoChicagoweresignificantlyaffectedbythepersistentflooding,andcrewsmadeover70dischargemeasure-ments,inmanycasesonrisesandrecessionsovermultipleevents.Moreinformationaboutmeasurementsmadeandthefloodactivitieslogcanbefoundat

http://il.water.usgs.gov/flooddata/view.cgi?date=20070820

August 2007 Flooding in Northeastern Illinoisby

Marvin Harris

Flooded neighborhood east of the Kishwaukee River in De Kalb, Illinois.

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Downstream side of the U.S. Route � bridge on Aux Sable Creek, Grundy County.

Graphs developed at http://nwis.waterdata.usgs.gov/il/nwis/

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DailymeandischargefromOctober1,2006throughSeptember30,2007comparedwithpercentiledistribu-tionofmeandailydischargedforthe30-yearperiod,1961-90,for3representativestreamgagingstations.Adailymeandischargeisinthedeficient-flowifitsvalueislessthanorequaltothe25thpercentile,inthenormal-flowrangeifitsvalueisbetween25thand75thpercentiles,andintheexcessive-flowrangeifitsvalueisequaltoorgreaterthanthe75thpercentile.

Illinois Streamflow Conditions for October 2006 through September 2007