Introduction to hydrology and the water balance

IntroductiontohydrologyandthewaterbalanceThescienceofhydrologyThesciencethatdescribesandpredictstheoccurrence,circulationanddistributionoftheearth’swater.Therearetwoprincipalfoci:•Theglobalhydrologiccycle:Transfersofwaterbetweentheland,oceanandatmosphere•Thelandphaseofthehydrologiccycle:Themovementofwateronandunderthelandsurface,physicalandchemicalinteractionswithearthmaterialsaccompanyingthatmovement,andthebiologicalprocessesthatconductofaffectthatmovement.Q:Whystudyhydrology?A:Humansystemsareintimatelyshapedbytheavailability,flowsandqualityofwater.•Agriculture•Manufacturing•Mining•RecreationThescienceofhydrology(cont.)Dingman2002,Figure1-4Thefigureatleftshowsthepositionofhydrologicscienceinthespectrumofbasicsciencestowaterresourcemanagement.Hydrologyisaninterdisciplinarygeosciencebuiltuponthebasicsciencesofmathematics,statisticsphysics,chemistryandbiology.SpaceandtimescalesofhydrologicprocessesDingman2002,Figure1-3Hydrologicprocessesencompassasuiteofspaceandtimescales;fromthunderstormsthatoccuroverthecourseofminutestohoursandspacescalesofafewkilometersorlesstothedevelopmentofmajorriverbasinstakingplaceovermillionstotensofmillionsofyearsandspacescalesof1000-10,000km.IPCC-AR4ThechallengeofwaterresourcemanagementinColoradoandthewestbringshometheimportanceofhydrologyasafieldofresearchandasavocation.MostoftheprecipitationinColoradoandthewestfallsinthemountainsandmustbedivertedtowhereitisneededforagricultureandotheruses.WaterinthewestThereisstrongconsensusfromdifferentclimatemodelsthatthewestwillbecomewarmer,affectingthewintersnowpackthatdriveswatermanagementstrategies.Itmaybecomedrieraswell.Canwemeetthesechallenges?OfficeoftheStateEngineer,ColoradoBoulderColoradowatersupplyTheCityofBoulderreceivesitsrawwatersupplyfrom:BarkerReservoir--40%ofthecity'sannualwatersupplySilverLakeWatershed--40%ofthecity'sannualwatersupplyBoulderReservoir--20%ofthecity'sannualwatersupplyOnanygivenday,thecitymaybetakingitswatersupplyfromanyoneofthesesourcesorevenallthree.BarkerReservoirTheBarkerSystemwasoriginallyconstructedasahydroelectricpowergenerationsystembytheColoradoPowerCompany.ItwaslaterpurchasedbyPublicServiceCompanyofColorado,nowknownasXcelEnergy.Thesystem,consistingoftheBoulderCanyonHydroelectricProject,BarkerandKosslerreservoirsandtheconnectingpipelineswerepurchasedbytheCityofBoulderinMarch2001.SilverLakeWatershedThecity-ownedSilverLakeWatershedislocatedonNorthBoulderCreekeastoftheContinentalDivide.SevenreservoirsarelocatedintheWatershed.Thesereservoirsstorewaterduringhighstreamflowperiods.WateristhenreleasedduringlowstreamflowperiodstomeetthewaterneedsofBoulder.BoulderReservoirTheBoulderReservoir,locatednortheastofBoulder,receiveswaterfromtheColoradoRiverthroughtheColorado-BigThompson(CBT)systemandtheWindyGapProject.Boulder'sshareoftheseprojectsisdeliveredthroughfacilitiesoperatedbytheNorthernColoradoWaterConservancyDistrict(NCWCD).Reservoirs,locatedontributariesoftheupperColoradoRiveronthewesternslopeoftheRockyMountains,collectthewater.ThewateristhendeliveredtotheeasternslopewhereistreatedformunicipaluseattheBoulderReservoirWaterTreatmentPlant.://://://://=5066DanL.PerlmanThebulkofwateruseinColoradoisforagriculture.Cropsaregrownwithwatertransportedtofieldsviairrigationditches(andthiswateroriginatesinthemountains)andfromgroundwater.Thefamiliar“cropcircles”ofColoradoandtherestofthewestreflecttheuseof“centerpivotirrigators”utilizinggroundwater.Westernwaterlaw:AcomplexissueWaterlawinthewestisacomplexsystem