Designation:D5981−96(Reapproved2008)StandardGuideforCalibratingaGroundwaterFlowModelApplication1ThisstandardisissuedunderthefixeddesignationD5981;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoverstechniquesthatcanbeusedtocalibrateagroundwaterflowmodel.Thecalibrationofamodelistheprocessofmatchinghistoricaldata,andisusuallyaprerequisiteformakingpredictionswiththemodel.1.2Calibrationisoneofthestagesofapplyingaground-watermodelingcodetoasite-specificproblem(seeGuideD5447).Calibrationistheprocessofrefiningthemodelrepresentationofthehydrogeologicframework,hydraulicproperties,andboundaryconditionstoachieveadesireddegreeofcorrespondencebetweenthemodelsimulationsandobservationsofthegroundwaterflowsystem.1.3Flowmodelsareusuallycalibratedusingeitherthemanual(trial-and-error)methodoranautomated(inverse)method.Thisguidepresentssometechniquesforcalibratingaflowmodelusingeithermethod.1.4Thisguideiswrittenforcalibratingsaturatedporousmedium(continuum)groundwaterflowmodels.However,thesetechniques,suitablymodified,couldbeappliedtoothertypesofrelatedgroundwatermodels,suchasmulti-phasemodels,non-continuum(karstorfractureflow)models,ormasstransportmodels.1.5GuideD5447presentsthestepstobetakeninapplyingagroundwatermodelingcodetoasite-specificproblem.Calibrationisoneofthosesteps.Otherstandardshavebeenpreparedonenvironmentalmodeling,suchasGuidesD5490,D5609,D5610,D5611,D5718,andPracticeE978.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.1.7Thisguideoffersanorganizedcollectionofinformationoraseriesofoptionsanddoesnotrecommendaspecificcourseofaction.Thisdocumentcannotre...
