WhatIsHydraulicEngineering?JamesA.Liggett1Abstract:Thispaper,writtentomarkASCE’s150thanniversary,tracestheroleofhydraulicengineeringfromearlyormid-twentieth-centurytothebeginningofthetwenty-firstcentury.Ahalf-centuryagohydraulicengineeringwascentralinbuildingtheeconomiesoftheUnitedStatesandmanyothercountriesbydesigningsmallandlargewaterworks.Thatprocessentailedaconcentratedeffortinresearchthatrangedfromtheminutedetailsoffluidflowtoageneralstudyofeconomicsandecology.Graduallyoverthelasthalf-century,hydraulicengineeringhasevolvedfromafocusonlargeconstructionprojectstonowincludetheroleofconservationandpreservation.Althoughthehydraulicengineerhastraditionallyhadtointerfacewithotherdisciplines,thataspectoftheprofessionhastakenonanewurgencyand,fortunately,issupportedbyexcitingnewtechnologicaldevelopments.He/shemustacquirenewskills,inadditiontoretainingandimprovingthetraditionalskills,andformclosepartnershipswithsuchfieldsasecology,economics,socialscience,andhumanities.DOI:10.1061/͑ASCE͒0733-9429͑2002͒128:1͑10͒CEDatabasekeywords:Hydraulicengineering;History.Introductioninteractionswithotherprocesseseasilyunderstandable.TheyalsoincludetheuseofmodernelectronicsfordatagatheringintheTheanswertothetitlequestionwillbeframedbytheexperiencelaboratoryandthefieldandamyriadofothertoolssuchassat-oftheindividualreader.Hydraulicengineeringisabroadfieldellitephotography,datatransmission,global-positioningsatel-thatrangesfromthebuildertotheacademicresearcher.Withoutlites,geographicaldatasystems,lasersforlaboratoryandfieldsucharangeitwouldnotbethedynamicfieldthatitisand,moremeasurement,radar,lidar,andsonar.Mostimportantly,theyin-importantly,itcouldnothavecontributedtosocietyintheposi-cludethehydraulicengineer’sinteractionwiththenaturalenvi-tivewaythatithasoverthepastcentury,anditwouldnotcon-ronmentandecology,aninteractionthatholdsgreatpromiseandtinuetobeaviable,challenging,andimportantprofession.Tochallenge.Indeed,thechallengesofthelastcentury,brilliantlyillustratethehisto