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1、WATERSUPPLYTABLEOFCONTENTSWhy Treat Water?Uses of WaterWater Supply SystemSources of WaterWater TreatmentWater StorageDistribution SystemDefinitionsCalculating Water Supply PressureWhyTreatWater?Society realized long ago that human health and the welfare of the general population are improved if pub
2、lic water supplies are treated prior to use.Nearly all structures require a water supply.Appropriate flow rate, pressure, and water quality are necessary for effective use.UsesofWaterBathingToiletsCleaningFood preparationCoolingFire protectionIndustrial purposesDrinking water = Potable wateriSWaterS
3、upplySystemSourcesofWaterAquifers(Groundwater)PrimarysourceofdrinkingwaterPorousconsolidatedrockorunconsolidatedsoilGroundwaterfillsspacesWellsandpumpsusedtoremovewaterAquiferCourtesyUSGSathttp:/pubs.usgs.gov/circ/circ1139/htdocs/boxa.htmThisimagewasreproducedfromgroundwater.orgwiththepermissionofTh
4、eGroundwaterFoundation.2010TheGroundwaterFoundation.AllRightsReservedSourcesofWaterSurfaceWaterLakes,reservoirs,riversRiversdammedtocreatereservoirsReservoirsstorewaterduringheavyrain/snowCourtesyNASAhttp:/www.ghcc.msfc.nasa.gov/surface_hydrology/water_management.htmlCourtesyUSDAhttp:/www.ks.nrcs.us
5、da.gov/news/highlights/2006_april.htmlLakeTuscaloosaDamiSWaterTreatmentAmountoftreatmentdependsonqualityofthesourceGroundwaterrequireslesstreatmentthansurfacewaterThecityofSalemwatertreatmentfacilitywithdrawswaterfromtheNorthSantiamRiver.CourtestyUSGShttp:/pubs.usgs.gov/fs/2004/3069/WaterStoragePump
6、edtoStorageTankStorageWaterpressureopsio1psi=2.31feetofwaterNOAAhttp:/www.csc.noaa.gov/alternatives/infrastructure.htmlWaterDistributionSystemConsistsofwaterlines,fittings,valves,servicelines,meters,andfirehydrantsLoopsystemmoredesirablethanbranchsystemIsolationvalvesWaterflowsinmorethanonedirection
7、LOOPSYSTEMBRANCHSYSTEMWaterDistributionSystemTypicalnewsystempipeThermoplasticorductileironReinforcedconcreteinlargermainsOldersystempipeCast-ironorasbestoscementTypicaldistributionpressureof6575psiDesignedforlessthan150psiwikimediaConsumerResidential,commercial,andindustrialfacilitiesResidentialMin
8、.distributionpressure=40psiMax.distributionpressure=80psiPressure-reducingvalveCommercialorindustrialfacilitiesMayrequirehigherpressurePumpscanincreasepressureiSiSDefinitionHeadRelatesenergyinanincompressiblefluid(likewater)totheheightofanequivalentcolumnofthatfluidDefinitionStaticHeadPotentialenerg
9、yofthewateratrestMeasuredinfeetofwaterChangeinelevationbetweensourceanddischargeEx:Whatisthestaticheadataresidentialsupplylineifthewaterlevelintheelevatedtankis943ftandtheelevationatthesupplylineis890ft?943ft890ft=53feetofwaterEPAathttp:/www.epa.gov/region02/superfund/npl/mohonkroad/images.htmlDefin
10、itionStaticPressurePressureofwateratrestMeasuredinpoundspersquareinch(psi)2.31feetofwater=1psiEx:Whatisthestaticpressureatdistributionifthestaticheadis53ftofwater?Isthisthepressureatwhichwaterwouldexitafaucetinthehouse?WaterPressureCalculationsHowfarabovethesupplylinemustthewaterlevelinawatertowerbe
11、inordertoprovideaminimum40psi?Exceptwaterlosespressureasittravelsthroughpipe.NOAAhttp:/www.csc.noaa.gov/alternatives/infrastructure.htmlDefinitionsHeadLossEnergylossduetofrictionaswatermovesthroughthedistributionsystemPipesFittingsElbows,tees,reducers,etc.Equipment(pumps,etc.)Majorlosses=headlossass
12、ociatedwithfrictionperlengthofpipeMinorlosses=headlossassociatedwithbends,fittings,valves,etc.CalculatingHeadLossHazen-WilliamsformulaWhere:hf=headlossduetofriction(ft)L=lengthofpipe(ft)Q =flowrateofwater(gpm) C =Hazen-Williamsconstantd=diameterofthepipe(in.)Hazen-WilliamsConstant,CCalculatingHeadLo
13、ssMinorLossesHazen-WilliamsformulausedforstraightpipeNeedequivalentlengthforeachfittingtoaccountforminorlosses.AcceptedequivalentlengthvaluespublishediSEquivalentLengthinfeetofpipe(Generic)CalculatingTotalEquivalentLengthExampleA10inchflangedcastironwatersupplylineprovidesservicetoahome.Thepipebetwe
14、enthewatertowerandthemeterincludessevenregular90degreeelbows,threelineflowtees,elevenbranchflowtees,andsixgatevalvesbetweenthewatertowerandaserviceconnectiontoaresidence.Whatistheequivalentlengthofthefittingsandvalves?FittingQuantityEquivalent Length (ft)Total Equiv. Length (ft)Reg.90degelbow714.098
15、.0Lineflowtee35.215.6Branchflowtee1130.0330.0Gatevalve63.219.2Total462.8CalculatingHeadLossExampleWhatistheheadlossinthe10inchcastironsupplylinewithaflowrateof110gpmifthepipeis3.2mileslongandincludesthefittingsfromthepreviousslide?CalculatingHeadLossHazen-WilliamsFormulaDefinitionDynamicHeadHeadofam
16、ovingfluidMeasuredinfeetofwaterDynamicHead=StaticHeadHeadLossCourtesyCDefinitionDynamic/ActualPressureMeasuredinpsiDynamicPressure=ActualPressureActualPressure=DynamicHeadWaterPressureCalculationsExampleThewaterlevelinthewatertowersupplyingthehomeinthepreviousexampleis1487ft.Theelevationofthesupplyl
17、ineattheresidenceis1246ft.Findthestatichead,thestaticpressure,thedynamichead,andtheactualpressureofthewaterasitenterstheresidence.ExampleStaticHead=StaticPressure=HeadLoss(majorandminor)=2.94ftDynamicHead=StaticHeadHeadLossDynamicPressure=ReferencesDion,T.(2002).Land development for civil engineers
18、(2nd Ed.). NewYork:JohnWiley&Sons.Lindeburg,M.(2008).Civil engineering reference manual for the PE exam(11thEd.).Belmont,CA:ProfessionalPublications,Inc.ImageSourcesUSDAathttp:/www.ks.nrcs.usda.gov/news/highlights/2006_april.htmlNASAathttp:/www.ghcc.msfc.nasa.gov/surface_hydrology/water_management.htmlNOAAathttp:/www.csc.noaa.gov/alternatives/TheGroundwaterFoundationatwww.groundwater.orgUSGSathttp:/pubs.usgs.gov/fs/2004/3069/EPAathttp:/www.epa.gov/region02/superfund/npl/mohonkroad/images.htmlWikimedia at http:/en.wikipedia.org/wiki/File:L
