By
Adriaan Volker (Former President of IAHS) and Henny Colenbrander (Former Secretary-General of IAHS)
1. HYDROLOGY: Geophysical Science and Basis of Water Management
To understand the history of the International Association of Hydrological Sciences (IAHS) as member of the International Union of Geodesy and Geophysics (IUGG) it is useful to know something about the history of hydrology and about its two facets : geophysical science on the one hand and as basis for water management and hydraulic engineering on the other hand.
Hydrology as the science of the occurrence, movement and properties of water upon and beneath the land areas of the globe in relation to the global water circulation is relatively new. Real development could only start after 1674 when Perrault and Mariotte demonstrated quantitatively that river flow and groundwater are generated by the precipitation falling on the river basin. Whereas the allied science of hydraulics, describing the laws governing the motion of water in well-defined systems developed in the 18th and 19th century together with mathematics and mechanics, little progress was made in the further quantitative analysis of the hydrological processes. The explanation lies in the enormous size of the river basins and aquifers with their great inhomogeneity and the practical impossibility of determining the flow in all channels and passages. An important step forward in the hydraulics of groundwater flow was the publication of the law of Darcy in 1856 with its linear relation between velocity and hydraulic gradient.
Under the impetus of population increase and economic development the need arose for more knowledge of the water resources of the globe. In the second half of the 19th century a modest beginning was made with hydrological inventories of river basins including measurements of river stages and river discharges (hydrometry). There is also a descriptive exercise known as hydrography (The term hydrography is also used in connection with surveys of seas and oceans).
2. 1922 - 1939: First participation of Hydrology in International Scientific Cooperation
It was at the General Assembly of IUGG in Rome in 1922 when an Italian delegate proposed a motion to open within the Union the possibility of dealing with hydrography. A committee was set up to give its opinion on the desirability of such a new activity. The committee gave favourable advice with the amendment that the name of the new organism should be "International Branch of Scientific Hydrology". The adjective "scientific" was added to distinguish the new participants from the charlatans and simpletons who, with the help of all sorts of rods, tried to find water and called themselves hydrologists. Also to make clear that this "branch" would not deal with the commercial exploitation of mineral waters. One of the reasons presented in the proposal was that the new organism would allow the incorporation of the in 1894 founded International Glacier Commission (CIG) of the International Geological Congress, which had almost ceased to exist as a result of the First World War. Thus at the General Assembly of IUGG in Madrid (1924) the Hydrology Branch created a Commission for Glaciers with the mission to assemble and publish data relating to glaciers (glacier reports). The incorporation of the CIG in the Commission for Glaciers was approved at the Prague Assembly in 1927. Since 'snow' issues became more and more of interest, in the early thirties, a Commission on Snow was created too. At the Edinburgh Assembly in 1936 it was decided, however, to amalgamate the two glaciological commissions into a new Commission on Glaciers and Snow. Due to the outbreak of World War II the activities were brought to a halt. During the first Assembly after the war, Oslo 1948, the Commission on Glaciers and Snow reappeared under the current name Commission on Snow and Ice.
During the Madrid Assembly also a Commission on "Statistics" was constituted with the task of trying to bring some uniformity into the publication of hydrological data and into the signs and symbols used (The application of stochastic methods in hydrology came much later; here statistics refers to the numerical data as such). In addition an effort was made to bring together data on the state of hydrology in different countries and also to make an inventory of the water resources of these countries. Thus the first publications of the Branch, which later became an Association, thereafter named the "International Association of Scientific Hydrology" (IASH), was comprised of hardly anything but national reports on this section of hydrology. Two fundamental reports resulted from this, the one by Smetana (Czechoslovakia) on Surface Waters and that of Meinzer (USA) on Subterranean Waters. It was a small and rather special group of scientists who were interested in this type of work. On the European side, most of them were hydraulic engineers, especially teachers of hydraulics who supplemented their teaching with the principles of hydrology. Mention should be made of Smetana (Czechoslovakia), Thijsse (the Netherlands), Bretting (Germany), Allard (United Kingdom), de marchi (Italy) and Tison (Belgium). There were, however, a few specialists like Coutagne, Pardé and Diénert, all from France. On the American side, the scales swung towards pure specialists such as Meinzer and Church.
Smetana was one of the first presidents. He was succeeded by Lütschg (Switzerland), who used to assemble the Association Council every year in Switzerland and who had carried out considerable amount of hydrological investigations, in the first place in the field of mountain hydrology. But he was also attached to what is now called an experimental basin, the Montieux Bay Basin. In such a small basin detailed hydrological studies could be carried out. It was a new methodology which only twenty years later became generally accepted by the international community of hydrologists.
In the thirties the Association began to cover an increasing number of aspects of hydrology and many new commissions: potamology, limnology, instruments and measurements, and subterranean waters were established. These topics were mostly considered from the geophysical point of view. In the beginning there was a certain confusion but things improved when the meetings were no longer based on a vague general programme but on clearly defined "questions" (subjects). The establishment of the International Association of Hydraulic Research (IAHR) led to a better distinction between hydrology and hydraulics.
The last General Assembly before the outbreak of World War II was held in Washington in 1939. Over the period 1939-1947 no reports about IASH activities are available.
3. 1948 - 1970 : Recognition and Expansion of IASH
Before the World War II hydrology, as it is understood today, was unknown to the general public. Hydrology was not taught at the universities as a separate subject. Fundamental aspects of it were included in such disciplines as physical geography, hydraulic engineering and hydraulics. In the period 1948-1970 hydrology became a generally recognized science which was considered to be of great significance for economic development. This had, of course, a great impact on the activities of IASH and its position in international scientific circles.
The post-war growth of the economy entailed a greater utilization of the natural resources of the earth, water being one the first. Control and management of this resource became necessary in order to ensure adequate water supply for all sectors of the economy and protection against floods even under unfavourable conditions. This could have been only achieved by hydraulic works and structures like storage dams and reservoirs, diversion canals, embankments, ground-water recovery etc. The hydraulic design of these works required hydrological data extending over a sufficient number of years and knowledge about the hydrological processes. This is especially true for the prediction of extreme events like major floods and serious droughts and their frequency of occurrence. Soon it was found that in many cases this sort of information was missing, and this was not only the case in the so-called developing countries. The design and implementation of urgent hydraulic works had to be postponed to avoid technical or economic failures. It was realized that scarcity of hydrological information could form an obstacle to economic development and also that the water resources were limited even in the humid zones. Thus hydrology, often mistakenly confused with water control, became an important discipline in the view of the general public and the decision makers. This development explains the expansion of IASH in the period 1948-1970. The meetings during the General Assemblies of IUGG of Oslo (1948), Brussels (1951) and Rome (1954) were attended by an increasing number of participants of various backgrounds, like hydraulic engineering, physical geography, hydrometeorology, water management, etc. The need was felt to organize more frequent meetings than would be possible in the framework of the Union. The first meeting of this type was the Darcy Symposium at Dijon (1956) on the occasion of the Centenary of the law of Darcy. Not only groundwater but also evaporation and floods were discussed. It was followed by a symposium on Snow and Ice (1958) and another on the Hydrology of Woodlands and Lysimeters (Hannoversch Münden, 1959). The frequency of these meetings, organized independently from the Union, increased and in the sixties hardly a year passed by without one or even two symposia being convened under the primary responsibility of the Association. All the proceedings were published as a series of monographs, known as "the red books". In 1948 Professor Léon Jean Tison from Belgium had assumed his duties as Secretary-General and for more than twenty years he was to serve the Association with great devotion and zeal. Tison succeeded in getting the papers printed near his home at low cost, and with small delays so that the publications could be available at the meetings. Tison did all the secretarial work and the management of the affairs of the Association himself, assisted by his son and daughter. The story goes that his wife carried the books on her bicycle to the post office for mailing.
The IASH/IAHS Proceedings and Report Series, is starting with the proceedings of the Assembly in Rome in 1922. The series, known as the Redbook series, became quite famous and sold well. A series on Snow and Ice, co-edited with UNESCO was started in 1967. This series contains mainly information on the fluctuation of glaciers.
Most of the papers of the Redbook series dealt in this period with the fields that would soon be called "Applied Hydrology" or "Engineering Hydrology". From 1948 onward they were grouped according to a new division of the Association into commissions: Surface Water, Groundwater, Land Erosion and Snow and Ice. The books also contributed to the drafting of textbooks and handbooks. Before 1939 these did no exist. In 1942 a monograph was published by Meinze (ed.) as one of the volumes of a series on "Physics of the Earth". The first book in English on hydrology as a tool in hydraulic engineering was "Applied Hydrology" by Linsley, Kohler and Paulhus (1949). It was followed by "Engineering Hydrology" by the same authors. Many other books in various languages followed of similar purport. The Quarterly Bulletin of the Association was started in 1956, renamed in 1971 to Hydrological Sciences Journal. It is the oldest of the various journals dealing with hydrology and is published six times a year since 1988.
Around 1960 international governmental cooperation (United Nations and the specialized agencies) commenced in the field of water. An early fore-runner was the Economic Commission for Asia and the Far East (ECAFE) which in 1948 established a Bureau of Flood Control. This was followed by ECE (Europe) with the Committee on Water Problems and ECA (Africa). Of more direct relevance to hydrology was the establishment of a Commission for Hydrometeorology in 1961, within the World Meteorological Organization (WMO) soon renamed as Commission of Hydrology. A major programme was launched by UNESCO as its International Hydrological Decade (IHD) in 1965. With the acceptance of the IHD a large number of member states committed themselves to carry out jointly a well-defined programme of hydrological studies and research extending over not less than ten years. This was a novelty in UNESCO and considered as an experiment. One of the conditions for the success of the venture was a good understanding and cooperation with IASH, a non-governmental organization of individual scientists. There was some doubt within the Association whether an entity like UNESCO dealing with sophisticated exact and human sciences would be the most appropriate place to discuss in a down-to-earth-way the very practical problems of hydrology and water resources development. Tison, the Secretary-General of the Association, realized that IHD would enable projects to be launched which were beyond the potential of IASH, Cooperation would be facilitated by the fact that many representatives of member states in the Coordinating Council were active participants in IASH. The cooperation did become effective. The IASH did help formulate programmes, and did contribute to the activities of working groups. Symposia were organized jointly and also the publishing of the proceedings of these symposia. The Association also produced monographs of various sorts with UNESCO, but particularly on the subjects of snow and ice. Similar relationships were created with WMO and its programme in operational hydrology, although less close.
In 1964 the International Council of Scientific Unions (ICSU), a grouping of unions including with IUGG, created a Committee on Water Research (COWAR) to promote the necessary contacts and interrelationships between the Scientific Unions dealing with water issues. This refers in the first place to the IUGG and the Unions on Geological Sciences; on biological Sciences and the International Geographical Union, all belonging to the ICSU family.
The same economic factors that promoted the expansion of IASH during the sixties led also to a spectacular increase in the activities of many non-governmental technical organizations in the field water viz.: hydraulic research; irrigation and drainage; large dams; water supply; water pollution, etc. All of these associations were established after 1950. These organizations included in their programmes many topics which were closely related to the activities of IASH. This did not entail, however, much competition or duplication at that time because in the activities of all these organizations, to a large extent, a different type of people were involved. A body for mutual consultation and coordination of the scientific and technical organizations was established later and will be described in the next sections. Towards the end of the sixties the Union saw itself confronted with difficulties of managerial nature. In 1967 it was decided that henceforth the General Assembly meetings of IUGG would be convened every four years instead of three and that they would be reduced to administrative meetings embellished by joint symposia of two or more Associations. This decision had little consequences for IASH because most of its activities were already taking place outside the Union Assemblies. More serious was the increase in workload of the IASH Secretary-General (13 symposia and 25 publications in the period 1965-1969). He suffered a stroke in November 1970 when he was about to leave his home to travel to New Zealand to participate in a symposium on Representative and Experimental Basins. His withdrawal threatened the existence of the Association.
4. 1971 - 1981: Transformation of IASH into IAHS and further Growth
The critical situation of the Association after the withdrawal of Tison was saved by Rodier (France) and Kovacs (Hungary) with the support of their national agencies and the help of the son of Tison. A new type of management of the Association was introduced with a treasurer, and an editor with an assistant located at the Institute of Hydrology in Wallingford (UK). Furthermore the Bureau met more frequently than before. The number of symposia and publications increased after 1970 and much was achieved in cooperation with UNESCO, WMO and others.
Another major development in the period 1971-1981 was the reorganization of the scientific framework of the Association. This had to be supplemented because of the considerable progress that had been made in the analysis of the intricate hydrological processes. Before that many basic questions could only be answered by applying semi-empirical approaches. A better understanding and a more sophisticated and a higher conceptual level was reached by the application of system analyses, stochastic methods and analysis of time series. These techniques of applied mathematics had been elaborated two decades earlier but it took a long time before they became a part of hydrological practices. The term "parametric hydrology" came in vogue. The methods can be applied to various systems and subsystems of both surface and groundwater and cut through partitions. A "Committee on Mathematical Models" (Committees are units of the Association ad hoc or standing) was set up and later received the status of "Commission on Water Resources Relations and Systems". The title indicates that the field of work had been broadened to topics beyond pure hydrology. Likewise the scope of the geochemical commission was changed during the Moscow Assembly in 1971 into Commission on Water Quality.
To express the broadening of the scope of the Association at the Moscow Assembly a major decision was taken in 1971, namely to change the name of the Association to the "International Association of Hydrological Sciences" (IAHS).
The success of the IHD programme in the period 1965-1974 was the motivation for UNESCO to extend the programme in hydrology beyond 1974 as the International Hydrological Programme (IHP I, 1975-1980). The cooperation between UNESCO and IAHS remained very much the same as for the IHD.
Another fact worth mentioning is the transformation in 1976 of the previously mentioned ICSU Committee on Water research (COWAR) into a Joint Committee of ICSU and UITA, the Union of International Technical Associations and Organizations. In this way a platform was created for scientific and technical organizations enabling a better relationship and contacts between the various scientific and technical communities.
5. 1981 - 1995: IAHS in a Changing Environment
In 1981 a new set-up of Assemblies was adopted. In the first place it was decided to hold Scientific Assemblies every four years in the mid term between the IUGG General Assemblies. At these Assemblies, various symposia are organized by the Association as well as workshops and working group meetings. Visits and scientific excursions are also be included in the programmes. The first IAHS Scientific Assembly was held in Exeter, UK in 1982. The second one was in Budapest, Hungary in 1986, the third one in Baltimore, USA in 1989 and the fourth one took place in Yokohama, Japan in 1993. At the same time it was decided to organize during the General Assemblies of IUGG substantial scientific programmes of the Associations. Of course the administrative matters such as the election of officers, adoption of changes of the Statutes and Bye-laws of the Association and Regulations of the Commissions, remained basic to the administrative part of the General Assembly.
The Association continued the organization of specialized symposia, mainly through its own Commission, Committees and through National Committees. It also sponsors symposia in partnership with other bodies as mentioned earlier and supports symposia of other bodies which are concerned with hydrology and water resources. The symposia the Association organizes itself are usually arranged by one of the Association's Commissions. The policy is to make the Commissions more self-reliant than they were before and their names have been changed into "International Commission .....".
To improve the contacts between the Association and the individual scientists in the different countries a Corresponding Membership was introduced. This membership network came in addition to the network of National IAHS Commissions and Representatives. The Corresponding Members are, from time to time, informed about the various IAHS activities and are entitled to buy IAHS publications and subscribe to the Journal at substantial reduced rates. To improve the distribution of information about the Association since 1980 regularly an 'IAHS Newsletter' is distributed (for the time being three issues per year), an 'IAHS Handbook' is published after each General Assembly and a 'Catalogue of Publications' is issued once in the 2 to 3 years. Edited by one of the Chinese IAHS members the IAHS Newsletter is published in Chinese four times a year. A new series of 'Special Publications' was recently started for scientific reports not fitting into the other series.
In 1981, it was decided to award annually, in cooperation with UNESCO and WMO, an International Hydrology Prize. The Prize, a silver medal, is awarded to a hydrologist who has made an outstanding contribution to the science. This prize was first awarded in 1981 to the former IAHS Secretary-General Tison for his services to the Association and for his research and teaching. At the Hamburg Assembly in 1983 it was agreed to establish an Award to mark the contributions of young scientists to the Association. This Award, known as the Tison Award, is made annually, on the basis of a paper published in the Hydrological Science Journal or in another IAHS publication. The Award was given for the first time to Dr Z.W. Kundzewicz (Poland) in 1987. The Association has a policy of distributing free copies of its publications to nearly 50 addresses (mainly libraries) in developing and other countries in need. In addition the IAHS Bureau has introduced in 1995 the so-called 'Training Assistance Programme' (TAP). This programme aims at making funds available for the training of young hydrologists from developing and other countries in need.
During the past decades the analysis and understanding of hydrological processes has been improved further e.g. through more application of advanced mathematics and the introduction of high-speed computers. This made it possible to develop more sophisticated hydrological models that are producing results closer to physical reality than the models of the sixties. Progress was also achieved by studies of movement of water in the unsaturated zone and in dynamic meteorology (evaporation). The changes of the physical environment as for instance in the land use by deforestation, urbanization, certain types of land reclamation and land drainage, soil and water conservation, nature restoration etc. affect the rainfall-runoff relationships in different ways. In spite of progress achieved in hydrologic modelling in particular with the so-called distributed models, this prediction in quantitative terms remains a difficult matter. Remote sensing techniques became highly useful tools in the acquisition of the required data. In view of this a Committee on Remote Sensing and Data Transmission was set up in IAHS in 1981. This committee, and some other IAHS commissions, are also dealing with the very important issue of GIS, the Geographical Information Systems. An important tool in hydrological data determination is the application of artificial and natural tracers like radio active isotopes. In view of the rapidly increasing significance of this specialized technique, it was decided to establish a Committee on Tracers in 1991.
The dominating research issue of the last decade or so, is a possible climatic change due to the so-called 'greenhouse effect'. One of the weak parts of current 'Global Circulation Models (GCM's), is the simulation of the continental phase of the cycle and especially the interaction between the atmosphere and the land areas of the globe. Climatic change will have a great impact on the hydrological regime through changes in rainfall, evaporation, river flow, soil moisture and groundwater. Considering the importance of this field or research the IAHS Bureau decided at its meeting in Vancouver in 1987 to initiate the formation of an ad-hoc Committee on Atmosphere-Soil-Vegetation Relations. After a successful symposium on this topic at the Yokohama Assembly in 1991, the ad-hoc Committee was transformed into an official International IAHS Committee with the same name. This committee is cooperating with programmes as the BAHC project (Biospheric Aspects of the Hydrological Cycle) of the IGBP (International Geosphere-Biosphere Programme) of ICSU. In this relation the IAHS/WMO Working Group on GEWEX, the Global Energy and Waterbalance Experiment, has also made important contributions. This Working Group was established during the Baltimore Assembly in 1989. Climatic change and the changes in the physical environment reduce the value of historic time series and entail uncertainties in the hydraulic design of projects and structures.
UNESCO continued its International Hydrological Programmes with IHP III (1981-1983), IHP III (1984-1989) and IHP IV (1990-1995) which included for instance a project on "Water transport through the atmosphere-vegetation-soil system". During the IHP Council meeting in January/February 1995, IHP V (1996-2001) was adopted. The involvement of IAHS in these programmes remained in principle the same over the years, although the number of joint IHP/IAHS publications has decreased during the past decade. Worth mentioning is the joint bi-annual IHP/IAHS George Kovacs Colloquium organized since 1992, which directly precedes the IHP Council meetings.
COWAR, the committee discussed in the previous Section, was dissolved by ICSU on 1 January 1994. It was replaced by SCOWAR, the Scientific Committee on Water Research. This committee, however, does not have a liaison function and thus the liaison facility between the Associations was lost. To compensate for this loss at a meeting of the Associations in Cairo in November 1994, a new committee, IWALC (International Water-related Associations Liaison Committee) was established. IWALC has to play an important role since the activities of the Associations have substantially.
At present the nature of most activities of the Association is determined by recent environmental change, both in the global physical environment and in the international organizational framework in which the Association is operating. It is very likely that these circumstances will remain an important factor in the planning of activities of the Association for many years to come.
Dated 1995