资源描述:
《groundwater flow models》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、GROUNDWATERFLOWMODELSC.P.KumarScientist‘E1’NationalInstituteofHydrologyRoorkee–247667(Uttaranchal)1.0INTRODUCTIONTheuseofgroundwatermodelsisprevalentinthefieldofenvironmentalscience.Modelshavebeenappliedtoinvestigateawidevarietyofhydrogeologicconditions.Morerecently,groundw
2、atermodelsarebeingappliedtopredictthetransportofcontaminantsforriskevaluation.Ingeneral,modelsareconceptualdescriptionsorapproximationsthatdescribephysicalsystemsusingmathematicalequations;theyarenotexactdescriptionsofphysicalsystemsorprocesses.Bymathematicallyrepresentinga
3、simplifiedversionofahydrogeologicalsystem,reasonablealternativescenarioscanbepredicted,tested,andcompared.Theapplicabilityorusefulnessofamodeldependsonhowcloselythemathematicalequationsapproximatethephysicalsystembeingmodeled.Inordertoevaluatetheapplicabilityorusefulnessofa
4、model,itisnecessarytohaveathoroughunderstandingofthephysicalsystemandtheassumptionsembeddedinthederivationofthemathematicalequations.Groundwatermodelsdescribethegroundwaterflowandtransportprocessesusingmathematicalequationsbasedoncertainsimplifyingassumptions.Theseassumptio
5、nstypicallyinvolvethedirectionofflow,geometryoftheaquifer,theheterogeneityoranisotropyofsedimentsorbedrockwithintheaquifer,thecontaminanttransportmechanismsandchemicalreactions.Becauseofthesimplifyingassumptionsembeddedinthemathematicalequationsandthemanyuncertaintiesinthev
6、aluesofdatarequiredbythemodel,amodelmustbeviewedasanapproximationandnotanexactduplicationoffieldconditions.Groundwatermodels,however,evenasapproximations,areausefulinvestigationtoolthatgroundwaterhydrologistsmayuseforanumberofapplications.Applicationofexistinggroundwatermod
7、elsincludewaterbalance(intermsofwaterquantity),gainingknowledgeaboutthequantitativeaspectsoftheunsaturatedzone,simulatingofwaterflowandchemicalmigrationinthesaturatedzoneincludingriver-groundwaterrelations,assessingtheimpactofchangesofthegroundwaterregimeontheenvironment,se
8、ttingup/optimisingmonitoringnetworks,andsettingupgroundwaterprotectionzones.Themod