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1CHAPTER 1 GENERAL INTRODUCTION ollowing a brief introduction to the science of hydrology, this chapter traces itsevolution from the moment the Greeks recognized that water phenomena couldnot be explained by their ancient myths, until the present day, when hydrologyis accepted as a full scientific discipline. Also in this chapter we cover the various facets of hydrology and the range of issues that it attempts to address today. This firstsection, along with a preliminary discussion, also includes a discussion of the main organizations active in the field of the hydrology, whether globally, in Europe, or morelocally in Switzerland, where the federal government plays a strong role in the organi-zation of its institutions. Finally, the chapter closes with an outline of the structure ofthe book. The hydrological sciences occupy a space at the nexus of various disciplines, thegoal beingto understand the mechanisms governing the distribution of wateron theEarths surface as well as its bio-geochemical properties. Thus, the science of hydro-logy studies both the flow of water and the Earths reserves of water, whether on thesurface,underground, or atmospheric.So in itssimplestdefinition, hydrology is thescience of water and its Earth cycle, which is more or less the definition used by theUnited Nations. 1.1 HISTORICAL APPROACHFormuchofhistory,hydrologywasmerelyonecomponentofthescienceofhydraulics, and more specifically, of hydraulic construction projects. Since the mainobjectiveofthisbookistodescribeandexplaintheprocessesofthewatercycle,itseems relevant to review the origin of the first rational explanations of the water cycle. However,becausethemodernhistoryofhydrologyiswelldocumented(Bonnin,1984; Malissard, 2002; Nordon, 1991a; Nordon, 1991b; Purple, 2000), in this chapterwe will limit our discussion to the earliest theories about the hydrological cycle. It isalmost impossible to specify the precise date that marked the beginning of the scienceofhydrology.However,wecanmakeastartbynotingthatsinceAncienttimes,populations haveestablishedthemselvesalongthebanksofwaterwayssuchastheTigris andEuphratesriversofMesopotamia,theNileRiverofEgypt,theIndusinIndia, and the Yellow River of China. Although an understanding of the water cyclemaynothavebeenapriorityforancientcivilizations,thereisnodoubtthattheypossessed acertaindegreeofempiricalknowledge,asisevidencedbyvarioushydraulic constructions such as dams, dikes and irrigation canals, some of which arestill in use today. F 2011 by Taylor and Francis Group, LLCGeneral introduction 21.1.1 Early explanations of the Water Cycle ThefirstrationalexplanationofthewatercyclecoincidedwiththeGreekMiracle (Lord, 1974) in the 6th Century B.C., when Greek philosophy broke from itsancient myth-based explanations for natural phenomena. Before this golden period ofphilosophicalandscientificachievements,therewascertainlyadegreeofhighlyevolvedtechnicalknowledge,butitwasnotuntiltheGreekphilosopherThalesofMilet1that anyone attempted a theory of causal explanations, and more importantly,understood the need to seek such explanations. Thales was also the first to speculatethatallthingsderivedfromasingleelement.ForThales,thisoriginalelementwaswater. As Aristotle later suggested in his Metaphysics, Thales had perhaps noticed thatwater is present everywhere and in everything; it is a necessity for life. WhenhereachedtheriverHalys,Croesustransportedhisarmyacrossit,asImaintain,bythebridgeswhichexistthereatthepresentday;but,accordingtothegeneral belief of the Greeks, by the aid of Thales the Milesian. The tale is that Croesuswas in doubt how he should get his army across... Thales, who happened to be in thecamp, divided the stream and caused it to flow on both sides of the army instead of onthe left only. This he effected thus: Beginning some distance above the camp, he dug adeepchannel,whichhebroughtroundinasemicircle,sothatitmightpasstorearward of the camp; and that thus the river, diverted from its natural course into thenewchannelatthepointwhere thisleftthestream, mightflowbythestationofthearmy, and afterwards fall again into the ancient bed. In this way the river was split intotwo streams, which were both easily fordable.(The History of Herodotus, I, 75, Rawlinson translation)AlthoughThalesdidnotactuallydevelopanexplanationofthewatercycle,hedeservescreditforseekingrationalexplanationsforthings.Itisalsoimportanttoremember that a correct explanation of the water cycle depends, among other things,onanaccurateunderstandingoftheshapeoftheEarth.AlthoughHomeracknowledgedthattheEarthwasspherical(8thCenturyB.C),andin150B.C.themathematicianCratesofMallusactuallybuiltaspheretorepresenttheEarth,suchknowledge was still undiscovered at the time of Thales, and this served as an obstacleto formulating a causal explanation of the water cycle. Two centuries later, Aristotleput forward the first great encyclopaedia of knowledge. Above all, he was the first toattempt to assemble information about the physical properties and interactions of thenatural world. AfterThales,thephilosopherAnaximanderrejectedtheideathatwaterwastheprincipalelement,andAnaximenes,thethirdphilosopherintheMiletSchoolofphilosophy, concluded that everything in the world was composed of air. However, weowe toAristotle the explanations for various specific phenomena such as condensa-tion, the formation of dew, and the salinization ofrivers. It should be noted that theGreeks had a good qualitative approach to the water cycle, but because they lacked1. Thales of Milet, one of the Seven Sages of Greece, was the founder of the Ionian School ofphilosphy. Although it is difficult to establish the precise dates, he was probably born about640-635 B.C. and died about 548-545 B.C. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 3measuring capabilities, were unable to proceed to a quantitative understanding2. Forexample, Anaxagoras proposed the idea that rain and groundwater were the source ofthe water in rivers. He also described the formation of hail, and of the seas and theirsalinization,andhetracedtheoriginsoftheNiletothesnowmeltoftheEthiopianmountains(Dumont,1988).Itisimportanttonotethattheseearlyexplanationsforelements of the water cycle were part of a broader endeavour regarding evolution andchange. Change was a main thematic of pre-Socratic philosophy and led some thinkersto try to understand how things worked. Besides Aristotle, who left behind some impressive work, the second great sourceof thought (other than Herodotus) was Strabos Geographica (64 B.C. to 20 A.D.). Thevastsumofknowledgecontainedinits17volumesinspiredNapoleontofinanceatranslation. Strabos Geography compiled almost everything in the history of sciencefrom Homers era to the Age of Caesar Augustus. Strabo was interested in the move-ment of water and in meteorology as well as physical geography. For example, he de-scribed the mechanism whereby rainfall supplies rivers. He also understood that riverflow is dictated by gravity, and that water flows not just on the surface but also under-ground.Likewise,Strabowasinterestedinthecausationoffloodsandstudiedtheflooding of major rivers such as the Nile, Tigris, Euphrates, and some rivers of India.In particular, he wanted to understand what caused the water level of rivers to rise. Even more interesting is Strabos insight about the importance of predicting floods,because although floods can be an asset when they provide for annual irrigation andfertilizethesoil,theycanalsocausedevastation.HenotedthattheEgyptianswerealready aware of these phenomena: for example, they developed the nilometer on theisland of Elephantine in Aswan to measure and track the flood levels of the Nile. Inaddition, Strabo posited explanations for water currents, seas and tidal bores, and evensuggestedatentativeexplanationfortheprocessofevaporation.Thisstudywasdeveloped in parallel to that of Aristotle, who was known to Strabo.Likewise,StrabotooknoteofAristotlesideathatprecipitationzoneswereafunction of latitude, and responded that this was caused by the presence of mountains,which impeded the clouds and promoted water condensation. Strabo did not pay muchattention to precipitation because the phenomenon seemed commonplace, but duringhistimeitwasestablishedthatcloudsareformedasaresultoftheevaporationofwater, which in turn depends on temperature and the extent of surface water. When theresulting clouds are blocked by mountains, the clouds cool and generate precipitation.Given this comprehension of both precipitation and the behaviour of rivers and otherwatercourses, we can reasonably conclude a basic qualitative knowledge of the watercycle already existed by Strabos time. Returning now to the topic of evaporation, Aristotle made a leap forward from hispredecessorswhenherealizedthatairbecomescoolerathigheraltitudes.Healsoproduced explanations for the formation of dew, mist, and snow as a form of frozenwater. Later on, Theophrastus, who is widely considered as the first to give an accurate2. Paradoxically, the Egyptians already knew how to measure water discharge. 2011 by Taylor and Francis Group, LLCGeneral introduction 4descriptionofthecompletewatercycle,addedtoAristotlesobservationsbyhigh-lighting the role of wind not only in the process of evaporation but also of precipitation. From a technical point of view, we should add that the Greeks not only studied thenature of water, they embarked upon water diversion projects, as Maneglier remindedus (1991). In the 6th Century B.C., Peisistratus undertook a project to divert water from MountHymettusintotwocanalstosupplytheOdeonofHerodusAtticus.Meanwhile,Eupalinoscarriedoutwhatwasundoubtedlythegreatestengineeringfeatofthecentury,constructingtheaqueductonSamosIslandtosupplythecitysfountains.Whatwasremarkableaboutthisachievementwasthe1100meterlongTunnelofEupalinos,whichwasconstructedbyexcavatingfrombothends.Eupalinosusedgeometric calculations to ensure that the two ends of the tunnel joined in the middle.Even though his design suffered from some imperfections, there is no denying that thisconstruction which included some twenty ventilation and maintenance shafts was anamazingachievementforitstime.Atthesametime,theGreeksalsoexploitedthesiphon technique, and used it to supply water at the rate of 2700 liters per minute to theAcropolis of Pergamon in the city of Lycia. Although the first recorded siphons weredesignedtoconveywatertoJerusalem,itwastheGreekswhofullyexploitedthetechnology, employing them regularly to pass over obstacles in steep areas. Later on,theRomanswouldconstructaqueductsalongcontourlinesratherthanemploythesiphon method. The Greek were soon to face the problem of conveying water for everyday use, inpart because they constructed their earlier cities on higher ground They had to resortto impluvia to store rainwater and also because it was not possible to rely on riversto supply them with water year round, especially during the dry seasons when waterlevels were low. This helps to explain why the Greeks developed such mastery of theirwater resources. 1.1.2 Water in Ancient Egypt The discovery in 1896 of the King Scorpion Macehead provided the first evidenceoftheexistenceofartificialirrigationtechniquesinancientEgypt.Thepictorialdepicts the Scorpion King using a hoe to breach a dyke or dam (Figure 1.1). Althoughsome experts question the depiction and the date when irrigation first appeared, it isgenerally accepted that the technique was first employed towards the end of the FirstPharaonic Dynasty, around 2200 B.C. (Vercoutter, 1992). The advent of irrigation wasclosely linked with the Nile River, and more specifically, the flooding of the Nile, asthefloodingratherthantheriveritselfwasthesourceofEgyptsprosperity.Butalthough we tend to acknowledge the benefits of the Niles floods in providing waterand silt, we must not forget that irrigation was also developed in part to protect againsttheuntolddamagefloodscouldcause.TheEgyptiansunderstoodthisparadoxicalnature of water and responded with some significant technical advances, even thoughthis did not lead them to any rational understanding of the phenomena connected to thewater cycle. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 5Everything in Egypt was determined by the Nile, soil, agriculture, the species ofanimals and birds that made their homes there. The Egyptians were more conscious ofthis than anyone and showed it: they embraced their river as a God and called it Hapi,and never failed to celebrate its bounty.G. Maspero, Histoire ancienne des peuples de lOrientIn Egypt, then, the story of the water resource is indisputably the story of the Nile.From a historical viewpoint, this is shown in part by the Macehead discovery we havejust discussed, and also by a particular period in Egyptian history, known as the reignofAmenemhatIII(1853-1809B.C.).ThiswasaperiodofpoliticalcalminEgypt,which allowed the new Pharaoh to concentrate on priorities other than military, suchas developing the Sinai mines and controlling the water level of the Nile at the citiesof Semma and Koumma, south of Aswan. During the reign of Amenemhat III, 18 damswere built on the Nile, which led Vandersleyen (1995) to conclude that the choice andthewilltocontrolthelevelsoftheNilewouldhavebeenscientific.However,weshould note a strange phenomenon during this period. During the reign of AmenemhatIII,thelevelsoftheNileatKoummawere8to13metersabovethosenormallyobserved when the Nile floods. Although at first reading we might conclude that thesemeasurementswereatransientphenomenon,wehavetodiscardthatideawhenwerealizethatthesehighwaterlevelspersistedforsome75years.Wealsohavetosupposethatbecausetheselevelsweresocarefullyrecorded,itwasduetotheirextremenature.Inanycase,suchhighwaterlevelsshouldhavehadcatastrophicconsequences.Despite some tentative explanations, no one really understands the records from thisperiod, which obliges us to conclude that the Nile underwent some sort of an excep-tional phase. The Nile was a source of constant political concern in ancient Egypt asFig. 1.1 : The Scorpion Macehead, depicting King Scorpion breaching a dyke (Ashmolean Museum, Oxford). 2011 by Taylor and Francis Group, LLCGeneral introduction 6it is still is, actually but one must remember that the knowledge they were workingwith was relatively limited. Even though the ancient Egyptians were able to measurethe flood levels of the Nile, they were unable to explain them. The Nilometer The nilometer, which was probably first constructed of wood, was one of the firsthydrological measuring instruments because it could be used to determine the waterlevel of a river (Figure 1.2)3. Later nilometers were constructed of masonry, and theseconstructions made it possible to record average and extreme flood levels. Today, it isstill possible to see such nilometers on the island of Elephantine in Aswan and at thetemples of Kom Ombo and Edfou. InformationaboutthelevelsoftheNileiscontainedatothertemples,aswell,including the Temple of Karnak. In 1895, M. LeGrain discovered a series of 40 record-ingsofNilefloods.Theserecordsgobacktoabout800B.C.,andallowus,forexample, to evaluate the rate of silt deposits which resulted in a 2.68 meter rise in theNiles average level at this location over a span of 2800 years. Although the Egyptiansshowed a degree of willingness to control these rises in water level, they clearly lackedthe means to build adequate dams to control them. Nevertheless, they did attempt toforecast floods and implement some significant management practices to control thewater levels. It is entirely possible that Lake Karoun was constructed artificially in adepressionwiththegoalofregulatingtheNilesfloods.Thislake,locatedinthedepression of Fayoum to the south-west of the current capital of Egypt, was perhapsconnected to the Nile by two canals towards the end of the 12th Dynasty (circa 2000B.C.), resulting in the creation and development of the oasis. Qanat water systemsEven in ancient times, water was required for many purposes, and one of the mostimportant was for agriculture. Of the various hydraulic systems employed, one of the3. An earlier and more rudimentary measuring technique was to inscribe the height of the wateron the riverbank. Fig. 1.2 : Construction of a nilometer from wood (Gille, 1978). 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 7most ingenious was a system that combined wells and qanat. The term qanat meansreed in Akkadien (the language of ancient Mesopotamia); the technology is still inuse in parts of the Middle East and Northern Africa, where it is known as a foggara(Nordon, 1991a). A qanat is a gently sloping underground tunnel designed for drainingan aquifer, and the installation can take several forms (Bousquet, 1996). Usually, thetunnel is dug from downstream to upstream in the direction of the water table that is toserveasthereservoir.Theexcavatedearthisremovedthroughaseriesofverticalshafts along the length of the qanat, which later serve as wells. AccordingtoGoblot(1979),qanatswereoriginallydevelopedtodrainminingtunnels. They were first used about 700 B.C. under the reign of Sargon II, an Assyrianking. Eventually, qanat were used mostly to supply water for daily consumption ratherthanforagriculturalusessuchasirrigation.In20thcenturyIran,thisuniquewatersystem continued to supply 75% of the water consumed.The Hydraulic Noria The hydraulic noria, or more simply noria, is a wheel designed for raising water toa given height. In general, a noria consists of a fairly thin wheel on which buckets arefixed. A noria installation can accommodate a number of these wheels (Figure 1.3). The technology made its first appearance in Egypt under the Roman Empire, andwassubsequentlyintroducedthroughouttheMiddleEast(Viollet,2000).Usually,norias areinstalledalongriverswithafluvialregimewheregravityirrigationisdifficult to establish. The Shadoof Lastly,weshouldmentiontheshadoof,which,alongwiththedeviceknownasFig. 1.3 : Hydraulic noria in the Egyptian Fayoum (Picture C.Higy). 2011 by Taylor and Francis Group, LLCGeneral introduction 8Archimides screw (although no doubt it predated Archimides himself) is the simplestofallthedevicesusedtoliftwater(Figure1.4)Composedofaleatherbagandacounterweight, this asymmetrical system requires a man to raise the counterweight inorder to plunge the bag into the water before allowing the bag to lift back up alone.Usually,thissystemwasoperatedbytwomen,andtheycouldliftwaterintotheirrigationditches atarateofaboutsixcubicmetersperhour.InMesopotamia,anetwork of shadoofs placed along the terraced fields made it possible to irrigate fieldssome eight meters above the water level of the river. 1.1.3 And Elsewhere? We chose the example of Egypt to illustrate water management systems of ancienttimes, but it should be noted that other civilizations also developed competencies formanaging the water supply quite early. However, these competencies were primarilytechnical,andsofallmoreintothesphereofhydraulicsandirrigationthanof hydrology. WeknowthatinMesopotamia,significantadvancementhadbeenmadeinthediggingofirrigationditchesandspecificirrigationtechniquesasearlyasthethirdmillennium B.C. In Mesopotamia, unlike Egypt, lack of water was a permanent condi-tion.By1200B.C.,undergroundwaterpipeswerebeingduginPalestine.Usually,citieswerebuiltonhilltops,nexttorivers.Duringperiodsofwar,suchcitieswerevulnerable because it was easy for enemies to access and cut off their water supplies,so it was routine to try to keep the location of both ends of the water conduits a secret. Palestinealsodevelopedtechniquesformeasuringprecipitation.InChina,theyactually set up entire networks of rainfall gauges constructed of reeds.These gaugeswere positioned along mountain slopes, and some of them were definitely used to carryout measurements of snowfall.Fig. 1.4 : Example of a shadoof (Gille, 1978). 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 91.1.4 Water in the Middle Ages There was such an abundance of water in the Middle Ages that there was no needtoaddressproblemswithwaterqualityorwatermanagement.Waterwassimplyanatural element. This led on the one hand to the domestication of water, but on the other hand, to itsmystification,whichresultedinacertainambivalencebetweenunderstandingthephenomenon of water and mastering hydraulics. Nonetheless, water worked duringtheMiddleAgesbecausegreatstridesweremadeinthedevelopmentofriverandmaritime navigation. Fromtechnicalandeconomicperspectives,waterplayedanessentialrole;thewater-millplayedacentralpartinthemedievaleconomyfromthe12thCenturyonwards. Water also played an essential part in the development of poetic thought byproviding its rhythm.It was no accident that Saint James was the saint credited withthe most power. Saint James was the one who ruled the seas and tamed rivers and whoendowed springs with their healing powers. Water in the Middle Ages was somethingelse, too it contained the power to baptize and to redeem. Medievalencyclopaediasaddressedthisthemeofwater,anddiscusseditinconnection to at least seven specific fields of study: cosmology, chemistry, geography,technology, medicine, zoology, meteorology and geology. In the encyclopaedia of aFranciscanmonk,BartholomeusAnglicus,wateristhesubjectofanentirechapter.The author tries to describe the various properties of water as well as its relationshipwithotherelements.Furthermore,theauthordescribesvariouscategoriesofwaterincludingrain,snow,andspringwater.Inthissameencyclopaedia,Bartholomewdiscusses the utility of water to humans, and even mentions the floods of the Nile; andhe was not the only one to address these topics. As for the idea of the river, beyond thefascination with the actual water it contained, its importance was recognized for thetransportation of goods, for waste disposal, and as a source of energy to power mills.Thinkers in the Middle Ages, taking inspiration from the work of Plato and Aristotle,were also aware of the presence of groundwater. But despite all this, the circulation ofwater was considered to be a terrestrial phenomenon, and we have to wait until the 17 th Century for the scientific understanding of atmospheric water circulation. Meanwhile,thefirsttechnicaldevelopmentsandquantitativeunderstandingofprocesses related to water arrivedwith Leonardo de Vinci, and later, Pierre Perrault(1510-1589), who noted in particular that the discharge of a river represents only oneportion of the incident precipitation (Chow et al, 1988). During this same period, theDutchmadesubstantialeffortstoprotectthemselvesfromfloods.Thefirstpolderswerebuiltabout1435,followingthecatastrophicfloodsfromthe13thtothe15thCenturies (Labeyrie, 1993). Overnight, between the 18th and the 19th of October, 1421,65villageswereinundatedandsome100,000peopleweredrownedwhenthelandbetween the Meuse and Scheldt rivers flooded (Gille, 1964). By the 15th Century, suchproblems were effectively eliminated through a combination of dike systems and thedraining of the Poitevin Marsh under the leadership of Dutch engineers. 2011 by Taylor and Francis Group, LLCGeneral introduction 101.1.5 Ancient Legislations Related to Water Historically, civilizations have been establishing codes and laws to regulate the useofwatersincetheinventionofwriting,asmentionedearlier.ThefamousCodeofHammurabiincludessevenarticlesrelatedtotheuseofwater,mainlyrulesforresolving disputes concerning irrigation. Discovered by a French archaeological teamin Suse (Iran) in 1901, this Code is probably the most complete set of laws created bytheBabyloniansandtheSumerians.Theirrulesconcerningirrigationseemtohavebeen created not only to ensure the allocation of water, but also to limit damage due tofloods. AsfortheEgyptians,theydevelopedadecentralizedsystem,grantinglocalauthorities the autonomous power to manage irrigation processes and the distributionof water. In addition, there existed a hierarchy of regulation depending on the degreeof importance of the waterway. One admirable aspect of Egyptian water regulation wasthat water was measured as a function of time rather than volume. This indicates thatthe parameters for calculating a quantity of water were the size of the waterway, theheight of the water, and time. 1.2 THE MODERN CONCEPT OF WATER Despite the technical and conceptual progress made between ancient times and theMiddle Ages, it was not until 1850 that hydrology moved beyond the contemplativephase to an explanatory phase, by incorporating the essential dimension of scientificmodelling. About that year, the Irish engineer Mulvanay, who was in charge of agricul-tural drainage, proposed a rational formula making it possible to determine the floodflowatagivenpointbasedontheintensityofprecipitation,thesizeofthedrainage area, and a coefficient that roughly divides the percentage of rainwater thatinfiltratesthesoilfromthepercentagethatflowsonthesurface.Despiteitsmanysimplifying assumptions,thisformularemainsthemostwidelyknownandutilizedprecisely because of its simplicity. The American Geophysical Union (AGU) did not establish a separate hydrologybranch until 1930. In 1931, Horton presented a report dedicated to the objectives andthestatusofhydrology,butdidnotevenmentiontheimportanceofstudyingtheimpactsofhumanactivityonwater.Thusittooknearly4,000yearstoseetheemergence of an actual scientific discipline, and we had to wait until the 20th centuryand the development of an understanding of hydrological processes for hydrology toreach the status of paradigm.To illustrate this progression, Table 1.1 lists some of theimportantlandmarksinthehistoryofhydrologyand,inabroadersense,themanagement of water. It is worth noting that the importance of better managing ourwater resources was only generally recognized in the past 30 or so years. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 111.2.1 Current problems Although great effort has been applied in the area of integrated water management,the growing pressures on the environment causedby humans are producing impactsTable 1.1 : Historical milestones. DateEventOutcome 1972UN Conference on the Human Environment, Stockholm The UN Declaration on the Human Environment 1977UN Conference on Water, Mar Del Plata Mar del Plata Action Plan 1981-1990 International Drinking Water and Sanitation Decade Importance of comprehensive and balanced country-specific approaches to the water and sanitation problem. 1992International Conference on Water and the Environment, Dublin Dublin Statement on Water and Sustainable Development, taking into account the vulnerability of the water resources, the role of women in sustainable development, and the economic value of water. 1992UN Conference on Environment and Development (UNCED Earth Summit), Rio de Janeiro Rio Declaration on the Environment and Development, and Agenda 21 1994UN International Conference on Population and Development, Cairo Action Plan: Population, environmental and poverty eradication factors are integrated in the sustainable development policies, plans and programmes. 1995World Summit for Social Development, Copenhagen Copenhagen Declaration on Social Development. 1995UN Fourth World Conference on Women, Beijing Beijing Declaration and Platform Action Plan, highlighting the necessity to ensure the right of access to water to all. 1996UN Conference on Human Settlements (Habitat II), Istanbul The Habitat Agenda promotedhealth, water and sanitation19971st World Water Forum, Marrakech Marrakech Declaration 20002nd World Water Forum, The Hague World Water Vision: Making Water Everybodys Business. The Millennium Declarations of the UN regarding water. An official conference on the security of water in the 21st century. 2001International Conference on Freshwater, Bonn Recommendation to abolish poverty and to ensure sustainable development in all countries 2002World Summit on Sustainable development, Rio+10, Johannesburg Implementation Plan 20033rd World Water Forum, Japan1st edition of United Nations World Water Development Report. It includes the final declarations regarding the main objectives of the Millennium. (By the year 2015 decrease by 50 % the proportion of population without access to clean water or sanitation 2011 by Taylor and Francis Group, LLCGeneral introduction 12that are often difficult to predict.Urbanization, agricultural practices, and the exploi-tation of underground aquifers show that man has the power to despoil and change thewater cycle. If our intention is to ignore the various aspects of negative human impacts,we havetobear in mind that every modification to the water cycle can have drasticrepercussions far beyond the impacts we envision at the time. For example, defores-tation can produce increased water flow which may have an immediate positive effect,but at the same time can increase the risk of catastrophic floods or lead to increasedsoilerosion.Deforestationcanalsoleadtoreducedprecipitationasaresultofthedecrease in evapotranspiration. Conversely, reforestation or intensive agriculture candramaticallyincreaseevapotranspirationandthereforecontinentalprecipitation,becausemuchofthisprecipitation(approximatelytwo-thirds)comesfromlandmasses. This situation leads to or at least can lead to an increase in surface runoff.Thisparadoxicalbehaviourservestounderscoretheinterdependenceofthemecha-nismsinvolvedinthehydrologicalcycleandalsothefactthatthewatercycleisacomplex adaptive system. The issue of deforestation or reforestation is obviously notthe only human impact, but is one of many changes resulting from land use practices.Thus, we need to modify our cultural practices that lead to problems such as the over-exploitation of groundwater for irrigation purposes, or the increased pollution of thegroundwater resources through the use of phytosanitary products. 1.2.2 Floods and inundations Thedamagecausedbyfloodsandinundationsduetoinsufficientorbadmanagementisverysignificant,andinvolveshighsocialandfinancialcosts.Thefinancial cost of floods has increased exponentially over recent years as a function ofincreasedsocialandeconomicdevelopmentoftheregionsinwhichtheyoccur.Ifcatastrophic floods have become more common in certain countries such as India orBangladesh, we must not overlook the fact that they are also occurring more frequentlyin Europe, and especially in Switzerland. The floods of September 1987 cost more than1.3 billion Swiss Francs and the single flood that took place in Brigue that Septemberkilled three people and cost 650 million Swiss Francs. In Switzerland, the cost of damages due to bad weather averaged 228 million SwissFrancs between 1972 and 1996. Beyond the strict financial cost of such catastrophicevents, they can also produce unacceptable losses in human life, which obviously canneverbemonetarilyquantified;53peoplehavediedinSwitzerlandduetoextremeevents since 1971 (OcCC, 1998). We can conclude from the foregoing that problems related to water managementarediverseinnatureandcanoccuratvariousscalesrangingfromaparcelofland(whenproblemsarerelatedtoculturalpractices)toacontinentortheentireplanet(whentheproblemishowtoestimatethewaterresourcesthatwillbeavailableforhumanity in the coming century). To this range of topics and scales we also need toaddthevariabilitiesintimescales,aswellastheimportanceofunderstandingallaspects of the subject from a systematic and integrated perspective that considers notjustthetechnicalaspectsbutthesocial,economicandculturalaspectsaswell.Obviously, we cannot address all of these problems at once, but it is essential to stressthe interdependencies. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 131.3 ORGANIZATIONS INVOLVED WITH WATER To conclude this introductory chapter, we want to mention the main organizationsinvolvedinhydrologicalactivitiesonaworldscaleaswellasinEurope,andin particular, Switzerland. Although there are a number of international organizationsengaged in water management activities, we will first discuss the various organizationsconnectedtotheUnitedNations(UN).Thenwewilldiscusssomeofthemajorresearch organizations,andclosewithadiscussionoftheroleofnon-governmentalorganizations (NGOs). 1.3.1 Around the World World Meteorological OrganizationTheWorldMeteorologicalOrganization(WMO4),aspecializedagencyoftheUnitedNations,wasestablishedin1950followingthe1947WorldMeteorologicalConvention. Based in Geneva, the WMO operates as the UN systems scientific voiceon matters concerning our planets atmosphere and climate. Currently, the WMO has189 members (183 States and 6 territories), all with hydrological services. In additiontoitsgoverningCongress,theWMOincludesvariousregionalassociationsandtechnicalcommissions,anExecutiveCouncil,aSecretariat,andvariousworkinggroups. The Member States of the WMO are grouped into six regional associations5.Eachassociationcoordinatesactivitiesrelatedtometeorologyandhydrologyinitsregion. The technical commissions of the WMO, eight in number, deal with the followingfields:aeronauticalmeteorology,agriculturalmeteorology,atmosphericsciences,basic systems, climatology, hydrology, instruments and methods of observation, andoceanography and marine meteorology. In accordance with its constitution, the objectives of the WMO are: To facilitate world co-operation in establishing networks for hydrological andmeteorological measurement and observation. To develop the exchange of data. To promote standardization of meteorological observations and in connection,the publication of data and statistics. To encourage activities in the fields of meteorology and hydrology, and theteaching and development of hydrological services. The WMO manages a number of scientific and technical programs, the main ones4. The website of the WMO is http://www.wmo.int5. The regions represented are Africa, Asia, Central America, Europe, Pacific South-west, NorthAmerica and South America. 2011 by Taylor and Francis Group, LLCGeneral introduction 14being World Weather Watch, the world climate program, the atmospheric research andenvironment program, applications of meteorology program, the hydrology and waterresourcesprogram(HWRP),aneducationandtrainingprogramandatechnicalcooperation program. TheHWRPistheWMOprogramthatdealsspecificallywithhydrology.Moreprecisely, the programs goal is to assist the hydrological services of WMO membersin the field of operational hydrology to decrease the risks resulting from droughts andfloods.Thisprogramtreatsinaninterdependentmannerallaspectsofoperationalhydrology techniques (measurements, data collection, archiving of water-related infor-mation, etc.) and of its practice (modelling, hydrological forecasting). In addition, theprogram makes significant contributions to a great number of other UN programmesand institutions as well as to governmental and non-governmental organizations. UNESCOTheprincipalobjectiveofthisUnitedNationsorganizationistocontributetomaintainingpeacethroughthedevelopmentofeducation,science,culture,andcollaborationbetweennations6.Unescowasestablishedin1946,followingaUNconvention in 1945, and as of October 2009, had 193 member states and 7 associatemembers. MuchliketheWMO,UNESCOhasacomplexorganizationalstructurethatincludes a General Conference, an executive board and a secretariat. Its head office isin Paris but it has 73 regional offices distributed around the world. Its main fields ofactivitiesareeducation,communicationandinformation,culture,socialandhumansciences,andthenaturalandphysicalsciences.Inthis lastarea, UNESCOisactiveboth| through specific programs in the natural sciences, and through intergovernmentalprograms such as the International Hydrological Program (IHP) and the World WaterAssessment Program (WWAP7).The IHP was created during the International Hydrological Decade (1964-1975).Attheendofthisperiod,itwastransformedtobecomealong-termprogram,andalthoughtheIHPmaintaineditsoriginalobjectives,itsoperationwasallocatedintospecific phases, each phase dedicated to a specific theme.In Phase I, or IHP-I (1975-1980),theIHPcontinueditsactivitiesfromtheInternationalHydrologicalDecade,with its focus on research. In IHP-II and III (1981-1983 and 1984-1989) the organi-zationconcentratedmorespecificallyonthepracticalissuesofhydrology.IHP-IV(1990-1995)introducedtheconceptofsustainabledevelopmenttothehydrologicalsciences.Finally,the two last phases,IHP-V (1996-2000)andIHP-VI(2002-2007),focusedonstrengtheningthelinksbetweenresearch,practicalapplicationandteaching, and as well, in the current phase, on a better comprehension and integrationof the social, economic and ecological aspects of water resource management. It is fairto say, then, that theIHP has metamorphosed into atruly interdisciplinary program.6.http://www.unesco.org7.For further detail, visit the internet portal at http://www.unesco.org/water 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 15Integrating not only the scientific components of hydrology but also more pragmaticpoliticalandsocialcomponents,theIHPhasbecomeoneofthemostambitiousprograms within the United Nations system. TheWorldWaterAssessmentProgram(WWAP),meanwhile,istheUnitedNations` main division for the evaluation of water resources. The WWAP publishes ayearly report on the development of water resources around the world. This documentprovides a reliable inventory of the planets water resources. The three organizations we have just touched upon are by no means the only onesactive in the field of hydrology on an international scale. It is important to understand,however,thattheconceptofwaterresourcemanagementextendsfarbeyondthestudyofhydrologywhichisthefocusofthisbook;itisarecurringthemeinthechallenge of reducing poverty and increasing international co-operation. In this regard,other components of the United Nations system also address the topic of water. TheFoodandAgricultureOrganization(FAO)isconcernedwiththeissueofwaterforagriculture, theWorldHealthOrganization(WHO)isconcernedwithitshealthaspects, and the International Atomic Energy Agency (IAEA) employs it for the use ofisotopic tracers, the objective being the peaceful use of the atom. Although the UN hadset up in 1950 an administration for technical assistanceto bring together the directorsofthevariousUNagenciesactiveindevelopmentwork,theUNGeneralAssemblydecided to create a special fund with the goal of raising additional financial resourcesinordertobeabletocarryoutlarge-scaleprojects.Soin1965,theUnitedNationsDevelopment Program (UNDP) was established. This program has a very broad fieldofactivities,andothermorespecificprogramshavesincebeenestablishedthatfunction underitsumbrella.Forexample,in 1962,theWorldFoodProgram(WFP)was created in collaboration with FAO, and in 1973 the FAO set up a revolving fundfor the exploitation of natural resources. The International Bank for Reconstruction and Development (IBRD) was createdin 1945 in accordance with the Bretton Woods Agreement in an effort to help EuroperecoverfromtheeffectsoftheSecondWorldWar.Howeversincethemid1950s,IBRDhasconcentrateditseffortsonthefinancingofprogramsandprojectsindeveloping countries.SubsequenttothecreationoftheInternationalFinanceCorporation (IFC) in 1956 and the International Development Agency (IDA) in 1960,IBRD has evolved into what we know today as the World Bank. Since 1985, the WorldBankhasbeentheprincipalcreditorofThirdWorldcountries,dedicatingsome20billion dollars eachyeartofinancing development projects (Brunel, 1997). Some ofthese funds are dedicated to the issues of improved water access and sanitation. TheInternational Monetary Fund (IMF), which is often linked with the World Bank andwascreatedatthesametimeasIBRD,isanotherspecializedagencyoftheUnitedNations. The IMF can be viewed as the guardian of the international monetary order;it supervises exchange policies between member states (Black-Defarges, 2000). 1.3.2 In Europe The European Community (EC) and its Parliament acts on environmental issues,through, on the one hand a combination of research programs and, on the other hand, 2011 by Taylor and Francis Group, LLCGeneral introduction 16the European Environment Agency (EEA). This agency is responsible for collecting,recordingandanalyzingenvironmentaldataandfurnishingthemembersoftheECwith objective information. The priorities of the EEA are air quality, water quality, soilconditions,faunaandflora,utilizationoflandandnaturalresources,wastemanagement, noise and chemicalemissions, andfinally, the protection of coastlinesand the marine environment. A second well-known organization that must not be overlooked is the Organizationfor Economic Cooperation and Development (OECD). Created in 1947 as the Organi-zation for European Economic Cooperation, it became the OECD in 1961. Despite itsEuropean origins, the OECD is now an international organization with member statesfrom North America as wellas Mexico,Japan, NewZealand andKorea. Among itsmultiple activities, the OECD has since 2001 employed a strategy for the environmentwhich was approved by the environment ministers of its member states. This strategysetsoutfivepriorityobjectivesdesignedtoachievesustainabledevelopmentinallmember states. The first of these objectives gives prime importance to water resources,specificallystating:Tomaintaintheintegrityofecosystemsthroughrationalmanagement ofnaturalresources,andinparticularbyrespectingtheclimate,waterresources and biodiversity. Every two years, the OECD publishes an important studyregarding the costs of supplying and purifying water. 1.3.3 Switzerland In Switzerland, two main organizations deal with water issues at the national level.The first is the National Hydrological Survey, and the second is the Federal Office ofMeteorologyandClimatologyknownasMeteoSwiss.TheNationalHydrologicalSurvey (NHS) is one of the Divisions of the federal office of the environment, whichis attached to the federal department of the environment, transport, energy and commu-nication. The role of the NHS is to collect and analyze hydrological data on a national scale.It operates approximately 400 measuring stations that collect information relating tothe quantity and the quality of surface and groundwater. In addition, the NHS conductshydrological forecasts and operates the station for calibrating the hydrometric currentmeters (Chapter 9), it provides advice for communities and the private sector, and itrepresents Switzerland at various international organizations. The NHS also publishesahydrologicalatlasofSwitzerland,whichmakesmapsofhydrologicalinformationavailable to a broad audience. Finally, the NHS was specifically mandated by the StateSecretaryoftheeconomyandtheSwissagencyfordevelopmentandcooperation(DDC) to re-establish hydrological services in the Aral Sea basin for the period from1994 to 2011. Currently, the NHS is divided into five sections which are: Hydrometry.Thissectionisresponsibleforprojecting,construction,operation, and maintenance of all measuring stations on rivers, lakes, and ingroundwater;forcollectionoffielddata,operatingwarningstationsandsupportingwarningorganizations.ItalsoadvisesthirdpartiesonstationdesignandcarryingoutdischargemeasurementsandrepresentsSwissstandard organizations in groups of international experts. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 17 Instrumentsandlaboratory.Thesectionassuresthemaintenanceofmeasuringdevices,developsnewinstruments,managestheofficialcalibration station, and plans the measuring systems. DataProcessingandinformation.Inadditiontoprocessingandanalyzingdata, this unit is responsible for verifying, correction and archiving. It is alsoresponsible for publishing the Hydrological Yearbook of Switzerland. Analysis and forecasting. The analysis and forecasting unit carries out studieson changes in river trends, handles data relating to water quality and developsnewdata-processingtools(geographicalinformationsystem).Italsomanages thenationalnetworksformeasurementandobservationofthephysicochemical properties of water as well as the Swiss hydrological studyareas. Hydrogeology.Thisnewsectionisresponsibleforcarryingoutnationalgroundwater monitoring and for providing information on the qualitative andquantitative condition of Swiss groundwater sources. It also provides hydro-geologicalinformation,makesavailablehydrogeologicaldataandassessments and produces hydrogeological summaries and overview maps ofSwitzerland.TheFederalOfficeofMeteorologyandClimatology,MtoSwiss,carriesoutmeteorological observations as well as forecasts. MtoSwiss is attached to the FederalDepartment of Home Affairs. Thisservicemaintainsandpublishesdataproducedbythetwoprincipalmeasurement networks. The ANETZ network is composed of seventy-two automaticsampling and measuring stations, which sample hydro-meteorological data every tenminutes.Inaddition,theKLIMAnetworkwhichisaconventionalnetworkofapproximately25stationstakesreadingsthreetimesperday.Inadditiontothesenetworks,MtoSwissmanagesapproximately400raingaugestationsandreportsdailyresults,andalsopublishesinmapformthevarioushydro-meteorologicalparameters as well as radar images of precipitation in Switzerland (Chapter 8). 1.3.4 The Role of Nongovernmental Organizations The number of nongovernmental organizations (NGOs) that play an increasinglyimportantroleinwaterresourcemanagement,andespeciallytheprotectionoftheresource, is too numerous to list here. In a sense, nongovernmental organizations cansucceed in cases that governmental organizations cannot when, for example, politicalissues get in the way. These organizations play an essential role because they are oftenvery involved in specific situations and thus have access to local information relatedtowatermanagement.UNESCOkeepsanup-to-datelistofinstitutionsandorganizations active in the field of water resource management. This list includes 550organizations divided into various categories, as shown in Table 1.2. Of these organi-zations, about one in three is nongovernmental. 2011 by Taylor and Francis Group, LLCGeneral introduction 181.4 LEGAL ASPECTS: THE CASE OF SWITZERLAND Beforeconcludingthisintroductorychapter,wehavetodiscussthelegalissuesrelated to water, which become more significant daily due to the increasing complexityofsocietyanditsoperatingpatterns,nottomentiontheincreasingenvironmentalimpacts of human activities. 1.4.1 Protecting the environment in general InSwitzerland,theprotectionoftheenvironmentiswrittenintothefederalconstitutionandinvolvesaverybroadfieldofapplicationwhichisoutlinedinthefederal law on environmental protection adopted on October 7, 1983. In particular, thelaw aims to protect the health and well-being of humans, to preserve or restore naturalcycles, to preserve the land and non-renewable resources such as water and air, and toprotect cultural and economic assets. This ambitious program can succeed only withthe judicious use of legal instruments and if certain fundamental principles are writteninto law. In Switzerland, such principles entered the law in three phases. Theprecautionaryprinciple8,thepolluterpaysprinciple9,theprinciplesofthegeneralevaluationofharm10,andofco-operation11 haveallbeenenteredintolaw.Following the Rio Conference in 1992, Switzerland enacted legislation incorporatingTable 1.2 : Type of organizations active in the field of water resources management.Type Number Percentage of total Research and Education67 12.2Governmental Organizations153 27.8Inter-Governmental Organizations34 6.2Non-Governmental Organizations173 31.5Other65 11.8UN Agencies58 10.5Total 550 1008. The principleofprevention isfundamentalto thestudyof environmentalimpacts.The pre-cautionary principle, in combination with the principle of prevention, imposes the obligationto intervene even when there is not yet formal scientific proof that an action or policy willharm the environment. 9. Thisprincipleimposestheburdenofcostonthepersonorentityresponsibleforenvironmental damage. 10. This principle, endorsed by article 8 of the LPE, is a systemic principle in that it asserts thatenvironmentalimpactsmustbeassessedonagloballevelsothatanymeasurestakentoreduce harm do not produce more harm than the original impact. 11. This principle stresses the importance of co-operation between various players in the federalsystem, not only between economic and political entities but also between the confederationand the cantons. 2011 by Taylor and Francis Group, LLCHydrology: A Science of Nature 19the principle of sustainable development12. Finally, in 1999, the principles of preven-tion, causality, and sustainable development were written into the Swiss Constitution. 1.4.2 Water Protection in Switzerland In the contents of Swiss national law, the protection of water resources appears firstinthedomainofhealth,andmorespecificallyinthedomainofprotectingthe ecological balance, in the same way that air and soil are protected. The generic actprotecting the ecological balance is a federal law adopted October 7, 1983 the LPE.Protection of water falls under the federal law of January 24, 1991 (LEaux) and of itsorder of application (OEaux). If LEaux establishes a specific number of principles inconnection with clean water supplies and the disposal of wastewater, this is of greatinterest to the hydrologist because it determines the acceptable limits of discharge tobeusedbyhumans. Inadditiontothesetwolaws,Swisslegislationincludesotherspecific lawsdealingwithwastewaterspillage,theuseofwaterpower,andthedevelopment of waterways. 1.5 OBJECTIVES AND ORGANIZATION OF THIS BOOK1.5.1 ObjectivesThemainobjectiveofthisbookistoprovidethestudent,thepractitioner,theresearcher and anyone curious about the discipline of hydrology with a complete intro-duction to the study of the water cycle, by addressing its various components one at atime;itcontainsonlybasicinformationaboutthemethodsusedbypracticinghydrologists (which is the topic of the second volume of this work). This book, then,isateachingtoolthatattemptstodescribeandexplainthe basic mechanismsofthewater cycle as well as the current methods of measurement. 1.5.2 Organization Thebookisorganizedintoelevenchapters.Followingageneralintroductiontoplacethedisciplineofhydrologywithinitshistoricalcontext,thesecondchapterdiscusses the hydrological cycle and its assessment on several scales, global to local;the second chapter concludes with a description of other related cycles. The followingchaptersdescribe inmoredetail thecomponents of thewatercycleandtheir spatialreference.Thecomponentsofthewatercycleincludetheconceptofthewatershed (Chapter3),precipitation(Chapter4),evaporationandinterception(Chapter5),andflowsandinfiltration(Chapter 6),andwaterstorageandreserves(Chapter 7). After that, we look at the issues related to data acquisition (Chapter 8),dataanalysisandhandling(Chapter9),andtheconceptofhydrologicalregimes12. Sustainabledevelopmentsatisfiestheneedofthepresentgenerationwithoutcompromisingthe possibility that futures generations will be able to satisfy their own needs (DDC, 1993, LaSuisse et la Confrence de Rio sur lenvironnement et de dveloppement. Cahiers de la DDC,3. DDC, Bern.) 2011 by Taylor and Francis Group, LLCGeneral introduction 20(Chapter10).Toconclude,inChapter11wereturntotheconceptofhydrologicalprocesses and try to answer, in a detailed manner, two basic questions of hydrology the source of the water in rivers and the fate of these waters. 2011 by Taylor and Francis Group, LLC