Hydrology: An Introduction

617 Pages·2005·10.38 MB·English

by  Wilfried Brutsaert

Hydrology
Waterinitsdifferentformshasalwaysbeenasourceofwonder,curiosityandpractical
concernforhumanseverywhere.Thistextbookpresentsacoherentintroductiontomany
of the concepts and relationships needed to describe the distribution and transport of
waterinthenaturalenvironment.
Continental water transport processes take place above, on and below the Earth’s
surface,andconsequentlythebookissplitintofourmainparts.PartIdealswithwaterin
theatmosphere.PartIIintroducesthetransportofwateronthesurface.Waterbelowthe
surfaceisthesubjectofPartIII.PartIVisdevotedtoflowphenomenaatthebasinscale
andstatisticalconceptsusefulintheanalysisofhydrologicdata.Finally,thebookcloses
with a brief history of ideas concerning the hydrologic cycle. Hydrologic phenomena
aredealtwithatspatialandtemporalscalesatwhichtheyoccurinnature.Thephysics
andmathematicsnecessarytodescribethesephenomenaareintroducedanddeveloped,
andreaderswillrequireaworkingknowledgeofcalculusandbasicfluidmechanics.
Hydrology–AnIntroductionisatextbookthatcoversthefundamentalprinciplesof
hydrology,basedonthecoursethatWilfriedBrutsaerthastaughtatCornellUniversity
forthepast30years.Thebookwillbeinvaluableasatextbookforentry-levelcourses
in hydrology directed at advanced seniors and graduate students in physical science
andengineering.Inaddition,thebookwillbemorebroadlyofinteresttoprofessional
scientistsandengineersinhydrology,environmentalscience,meteorology,agronomy,
geology,climatology,oceanology,glaciologyandotherEarthsciences.
Wilfried Brutsaert is William L. Lewis Professor of Engineering at Cornell
University.Inalongandprestigiouscareerintheresearchandteachingofhydrology,
Professor Brutsaert has received many awards and honors, including: the Hydrology
AwardandRobertE.HortonMedal,AmericanGeophysicalUnion;President,Hydrology
Section, American Geophysical Union, from 1992 to 1994, Fellow of the American
GeophysicalUnionandAmericanMeteorologicalSociety;theRayK.LinsleyAward,
AmericanInstituteofHydrology;WalterB.LangbeinLecturer,AmericanGeophysical
Union; International Award, Japan Society of Hydrology & Water Resources; Jule G.
Charney Award, American Meteorological Society. He is a member of the National
AcademyofEngineeringandhaspublishedtwopreviousbooks,Evaporationintothe
Atmosphere:Theory,HistoryandApplications(D.ReidelPublishingCompany,1982),
andGasTransferatWaterSurfaces(withG.H.Jirka,D.ReidelPublishingCompany,
1984).Hehasauthoredandco-authoredmorethan170journalarticles.

H Y D R O L O G Y
AN INTRODUCTION
WILFRIED BRUTSAERT
CornellUniversity
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CONTENTS
Foreword page ix
Noteonthetext xii
1 Introduction 1
1.1 Definitionandscope 1
1.2 Thehydrologiccycle 2
1.3 Someestimatesoftheglobalwaterbalance 3
1.4 Methodologiesandprocedures 7
1.5 Conservationlaws:theequationsofmotion 12
References 18
Problems 19
PartI Waterintheatmosphere
2 Wateraloft:fluidmechanicsoftheloweratmosphere 23
2.1 Watervaporinair 23
2.2 Hydrostaticsandatmosphericstability 28
2.3 Turbulenttransportofwatervapor 34
2.4 Theatmosphericboundarylayer 36
2.5 Turbulencesimilarity 41
2.6 Surfaceboundarycondition:theenergybudgetconstraint 55
References 72
Problems 76
3 Precipitation 79
3.1 Formationofprecipitation 79
3.2 Majorprecipitationweathersystems 82
3.3 Precipitationdistributionontheground 92
3.4 Interception 100
3.5 Reliabilityofoperationalprecipitationmeasurements 106
References 111
Problems 116
contents vi
4 Evaporation 117
4.1 Evaporationmechanisms 117
4.2 Masstransferformulations 118
4.3 Energybudgetandrelatedformulations 123
4.4 Waterbudgetmethods 142
4.5 Evaporationclimatology 148
References 151
Problems 156
PartII Wateronthesurface
5 Wateronthelandsurface:fluidmechanicsoffreesurfaceflow 161
5.1 Freesurfaceflow 161
5.2 Hydraulictheory:shallowwaterequations 163
5.3 Frictionslope 167
5.4 Generalconsiderationsandsomefeaturesoffreesurfaceflow 174
References 194
Problems 196
6 Overlandflow 198
6.1 Thestandardformulation 198
6.2 Kinematicwaveapproach 201
6.3 Lumpedkinematicapproach 210
References 213
Problems 213
7 Streamflowrouting 216
7.1 Twoextremecasesoflargefloodwavepropagation 217
7.2 Alumpedkinematicapproach:theMuskingummethod 224
7.3 EstimationoftheMuskingumparameters 232
References 241
Problems 242
PartIII Waterbelowthesurface
8 Waterbeneaththeground:fluidmechanicsinporousmaterials 249
8.1 Porousmaterials 249
8.2 Hydrostaticsofpore-fillingwaterinthepresenceofair 251
8.3 Watertransportinaporousmaterial 268
8.4 Fieldequationsofmassandmomentumconservation 287
References 298
Problems 303
contents vii
9 Infiltrationandrelatedunsaturatedflows 307
9.1 Generalfeaturesoftheinfiltrationphenomenon 307
9.2 Infiltrationintheabsenceofgravity:sorption 310
9.3 Infiltrationcapacity 326
9.4 Raininfiltration 332
9.5 Catchment-scaleinfiltrationandother“losses” 343
9.6 Capillaryriseandevaporationatthesoilsurface 346
References 357
Problems 361
10 Groundwateroutflowandbaseflow 366
10.1 Flowinanunconfinedriparianaquifer 366
10.2 Freesurfaceflow:afirstapproximation 377
10.3 Hydraulicgroundwatertheory:asecondapproximation 382
10.4 Linearizedhydraulicgroundwatertheory:athirdapproximation 398
10.5 Kinematicwaveinslopingaquifers:afourthapproximation 415
10.6 Catchment-scalebaseflowparameterizations 416
References 431
Problems 433
PartIV Flowsatthecatchmentscaleinresponsetoprecipitation
11 Streamflowgeneration:mechanismsandparameterization 441
11.1 Riparianareasandheadwaterbasins 441
11.2 Stormrunoffmechanismsinriparianareas 443
11.3 Summaryofmechansimsandparameterizationoptions 457
References 461
12 Streamflowresponseatthecatchmentscale 465
12.1 Stationarylinearresponse:theunithydrograph 465
12.2 Identificationoflinearresponsefunctions 472
12.3 Stationarynonlinearlumpedresponse 493
12.4 Non-stationarylinearresponse 498
References 501
503
Problems
13 Elementsoffrequencyanalysisinhydrology 509
13.1 Randomvariablesandprobability 509
13.2 Summarydescriptorsofaprobabilitydistributionfunction 511
13.3 Someprobabilitydistributionsfordiscretevariables 519
13.4 Someprobabilitydistributionsforcontinuousvariables 523
13.5 Extensionofavailablerecords 543
References 550
Problems 553
contents viii
14 Afterword–ashorthistoricalsketchoftheoriesaboutthewater
circulationonEarth 557
14.1 Earliestconcepts:theatmosphericwatercycle 557
14.2 Greekantiquity 559
14.3 TheLatinera 566
14.4 Fromphilosophytosciencebyexperimentation 572
14.5 Closingcomments 585
References 586
Appendix Someusefulmathematicalconcepts 590
A1 Differentiationofanintegral 590
A2 Thegeneralresponseofalinearstationarysystem 590
A3 Thegeneralresponseofanonlinearsystem 597
References 598
Index 599
FOREWORD
Waterinitsdifferentformshasalwaysbeenasourceofwonder,curiosityandpractical
concern for humans everywhere. The goal of this book is to present a coherent intro-
duction to some of the concepts and relationships needed to describe the distribution
and transport of water in the natural environment. Thus it is an attempt to provide a
more thorough understanding, and to connect the major paradigms that bear upon the
hydrologiccycle,thatisthenever-endingcirculationofwateroverthecontinentsofthe
Earth.
Continental water transport processes take place above, on and below the Earth’s
landsurfaces.Accordingly,inPartI,waterisconsideredasitpassesthroughthelower
atmosphere; this part consists of a general description of atmospheric transport in
Chapter 2, followed by the application of these concepts to precipitation and evapo-
rationinChapters3and4,respectively.InPartII,watertransportontheEarth’ssurface
is dealt with; this part consists of a general description of the hydraulics of free sur-
faceflowinChapter5,whichisthenappliedtooverlandrunoffandstreamflowrouting
in rivers in Chapters 6 and 7, respectively. Water below the surface is the subject of
Part III; again, a general introduction to flow in porous materials in Chapter 8 is
followed by applications to phenomena involving infiltration and capillary rise in
Chapter 9, and groundwater drainage and baseflow in Chapter 10. Part IV is devoted
toflowphenomena,mostlyfluvialrunoff,inresponsetoprecipitationatthecatchment
andriverbasinscales,whichresultfromthecombinationofflowsbothaboveandbelow
theEarth’ssurface,alreadytreatedatsmallerscalesseparatelyinPartsIIandIII.Various
interactionsoftheseflowphenomenaandthemajorparadigmsregardingthesubscale
mechanismsaredescribedinChapter11.Thisisfollowedbyatreatmentoftheavailable
parameterizations in Chapter 12. In Chapter 13 the fourth part of the book concludes
withabriefdescriptionofsomeofthemorecommonstatisticalconceptsthatareuseful
intheanalysisofhydrologicdata.Finally,asanafterword,Chapter14closesthebook
withabriefhistoryoftheideasonthewatercycle,whichoverthecenturiesevolvedto
our present understanding; Santayana’s dictum may be a bit worn by now, but several
recent reinventions of the hydrologic wheel could have been avoided, if the past had
beenbetterremembered.
Thesetransportphenomenainthehydrologiccycleonlandaretreatedatspatialand
temporalscales,atwhichtheyarecommonlyencounteredineverydaylifeandatwhich
theyaretractablewithpresentlyavailabledata.Hydrologyisaphysicalscience,andthe
languageofphysicsismathematics.Accordingly,plausibleassumptionsareintroduced
andthemathematicalformulationsandparameterizationsarederived,whichdescribethe
foreword x
morerelevantmechanismsinvolvedinthedifferentphasesofthecontinentalhydrologic
cycle. The resulting equations are then examined and, if possible, solved for certain
prototypesituationsandboundaryconditions.Themotivationforthisis,first,togaina
betterunderstandingoftheirstructureandunderlyingassumptions,andofthephysics
theyareintendedtorepresent;andsecond,toprovidethebasisandbackgroundformore
complexmodelingexercises,simulationsandpredictionsinpracticalapplications.
Thesubjectmaterialcoveredinthisbookgrewoutofthelecturenotesformycourses
inhydrologyandrelatedtopicsintheSchoolofCivilandEnvironmentalEngineering,
at Cornell University. I have not tried to cover all possible angles and points of view
of the subject matter. Rather, I have followed a line of thought, which over the years
I have come to find effective in conveying a broad understanding of the more impor-
tantphenomena,andinstimulatingfurtherinquiryinthesubject.Similarly,noattempt
has been made to compile a complete bibliography. But the references that are listed
refer to other works, so that it should be possible to trace back the more important
developments.
Asitssubtitleindicates,thisbookisintendedasanintroduction;assuch,itshould
be suitable as a textbook for an entry-level course in hydrology directed at advanced
seniorsandbeginninggraduatestudentsinengineeringandphysicalscience,whohave
a working knowledge of calculus and basic fluid mechanics. The book contains much
morematerialthancanreasonablybecoveredinafirstcourse.Thusitwilldependonthe
objectivesofthecourse,andontheorientationandlevelofthestudents,whichspecific
topicsshouldbeselectedforcoverage.Naturally,theinstructorshouldbetheultimate
judgeinthis.However,tofacilitatethisselection,thetextisprintedintwodifferenttype
formats.Themainsubjectmatter,whichintheexperienceoftheauthorcanbesuggested
forinclusioninafirstcourse,ispresentedinregulartype.Anefforthasbeenmadetolay
outthispartofthetextinsuchawaythatthestudentshouldbeabletograspthematerial
withlittleornorelianceonthemoreadvancedsections.Forcertaintopics,clarification
byanexperiencedinstructorinthelectureswillundoubtedlybehelpful.Subjectmatter
ofamoreadvancedorspecializednature,isprintedasindentedtextinaslightlysmaller
typeandwithagreyruleontheleft-handsideofthepage.Thismaterialisintendedeither
asoptionalorexplanatoryreadingforthefirstcourse,orassubjectmattertobecovered
in a second and more advanced course. Sections of this second type of material have
alsobeenusedasmajorportionsinmorespecializedcourses,namelyinGroundwater
Hydrology(Chapters8,9and10)andinBoundaryLayerMeteorology(Chapters2,3
and4)atCornell.
The book is intended mainly for students of hydrology; it should, however, also
be more broadly of interest to professional scientists and engineers, who are active
in environmental matters, meteorology, agronomy, geology, climatology, oceanology,
glaciology and other Earth sciences, and who wish to study some of the underlying
conceptsofhydrology,relevanttotheirdiscipline.Inaddition,itishopedthatthebook