Volume 57 (3) — July 2008

Evolving role of WMO in hydrology and water resources management

by Karl Hofius*


  lake & mountain

What was the situation 50 years ago?

In the late 1950s, the time when the Commission for Hydrology was coming into being, our world was very different. There were several thousand million fewer people living on the globe and nature was much more “natural” than today. Vast areas of land were still covered with pristine tropical rainforests and boreal coniferous forests. Agriculture, especially irrigation farming, was by far less intensive than it is today. The concentration of populations in urban areas has increased sharply over the intervening period. The competition between the requirements of industry, agriculture and human settlements in low-lying coastal regions became increasingly evident. Industrial production, as well as road and air traffic, have been multiplying in the past 50 years. All these developments and changes are coupled closely with hydrology and the water balance and its management in quantitative, as well as qualitative, terms.

Meteorology and hydrology have experienced profound changes, both in science and in practical applications: the understanding of global meteorological and climatological circulation processes in the atmosphere, on the land surface and over the oceans, including energetic transport and exchange processes, has become much clearer, highlighting the extent to which meteorology and hydrology are interwoven. Each litre of water that evaporates transports some 2 500 kJ of latent heat into the atmosphere—usually from lower latitudes towards the poles—releasing this latent heat with precipitation as perceptible warmth. The local losses or gains in the energy-balance equation appear in the water-balance equation in the form of evaporation and precipitation.

With their growing knowledge about global circulation processes in the atmosphere, hydrologists began to expand their water-balance modelling concepts in spatial dimensions. Here, they needed more and more the results from meteorology. In turn, meteorologists benefited from outputs of hydrological research. In particular, evapotranspiration can often be better determined by means of the water-balance equation than from the energy-balance equation.

Let’s summarize the initial situation in the 1950s: the steep increase in population, the rapid developments in agriculture and industry, as well as new knowledge about atmospheric circulation and the hydrological cycle, made global, transboundary cooperation indispensable. Another aspect was the lack of knowledge about the size of the water reserves in groundwater and major rivers and their seasonal variability.

Until the early 1950s, hydrology, like other natural sciences, was represented on the global scale nearly exclusively in non-governmental international organizations. Then, the call for participation of governmental organizations and for the implementation of longer-term programmes to promote hydrology became louder.

In 1952, the United Nations Educational, Scientific and Cultural Organization (UNESCO) established a commission for arid regions. These efforts were further enhanced by the International Geophysical Year 1956/1957. In the late 1950s and early 1960s, several conferences were held to prepare a long-term hydrology programme, leading, in 1965, to the establishment of the International Hydrological Decade (IHD). At the beginning, IHD was a purely quantitative programme. Only in the course of the subsequent International Hydrological Programme in 1975 were qualitative and social aspects of the hydrological cycle gradually integrated, until—after publication of the Brundtland Report in 1986—the concept of the sustainable development of water resources came to the fore.

Although UNESCO was formally the lead organization of IHD and IHP, the programme in reality was a broad and coordinated effort of many governmental and non-governmental international organizations, reflecting the diversity of the aspects and interests inherent in water issues.

Integration of hydrology within WMO

The first steps

WMO, too, faced the need to integrate hydrology in a more prominent position into its formal scientific set-up. This was done, on the one hand, by including operational hydrology in the WMO Convention at Sixth World Meteorological Congress in 1971. Following controversial discussions, the task regarding hydrology was defined in Article 2(e) as follows: “To promote activities in operational hydrology and to further close cooperation between Meteorological and Hydrological Services”. On the other hand, this integration had already taken place in the year 1958 by the establishment of the Commission for Hydrometeorology. When, finally, the name “Commission for Hydrology (CHy)” was adopted at the third session of the Commission in 1968, this also meant prolonged and repeated trouble for WMO: this name claims scientific-technical competence in a scope that could hardly be covered by WMO. Hydrology is also the complex terrestrial portion of the water cycle comprising runoff, infiltration into the ground and groundwater recharge, as well as anthropogenic water resources management and waste-water disposal.

At the third session of CHy and at a technical conference held in 1970 by Meteorological and Hydrological Services, a broader field of CHy activities was outlined to cover the whole range of operational hydrology that was defined as:

  • Measurements of hydrological elements with networks of meteorological and hydrological stations; collection, transmission, storage, recovery and publication of basic hydrological data;
  • Hydrological forecasts;
  • Development and improvement of methods, procedures and techniques regarding the planning of measuring campaigns, specifications of instruments, standardization of instruments and observation methods, data transfer and data processing, provision of meteorological and hydrological data for planning purposes and hydrological forecasts.

Development of a WMO Operational Hydrology Programme

Now the ground had been cleared to build, step by step, an independent programme for operational hydrology within WMO. Three aspects deserved special attention here: the programme had to be coordinated with the working fields of the other specialized commissions of WMO, but also with IHD. It was noted in discussions that WMO often lacked a competent hydrological contact partner at national and regional levels, whereas, for meteorology, WMO Members all had their Meteorological Services. Hydrological and water-management issues were handled in most of the countries by several institutions with very different administrative affiliations.

An occasion to tackle this problem came at the fourth session of CHy in Buenos Aires, Argentina, in 1972, when the planning for the independent Operational Hydrology Programme (OHP) took place. Moreover, the proposal was made to appoint hydrological advisers to assist the permanent representatives of WMO Members, if required. Later, hydrological advisers were also provided for the presidents of the six WMO regional associations. Seventh Congress in 1975 then saw the official establishment of OHP and appointment of the hydrological advisers. With these decisions, CHy and Congress gave the starting signal for the rapid development of operational hydrology within WMO that is now being continued through the Hydrology and Water Resources Programme (HWRP). The HWRP used to consist of three mutually supporting components—OHP Basic System, OHP Applications and Environment, and the Programme on Water-related Issues. It was only in the mid-1990s that CHy added programme components dealing with the sustainable development of water resources.

How did this development advance in detail?

This development led, on the one hand, to special WMO publications in the field of operational hydrology and, on the other hand, to the Hydrological Operational Multipurpose System (HOMS), the World Hydrological Cycle Observing System (WHYCOS) and the Global Runoff Data Centre (GRDC), as well as a series of cooperative links with global research programmes.

As early as 1958, WMO issued publications on the planning of hydrological observation networks and methods to determine existing water resources. Only in 1973, however, was a separate publication series for operational hydrology established: Operational Hydrology Reports. Thus, an opportunity was provided to disseminate the results of the efficient working groups and the achievements of ambitious projects. The aforementioned tendency to focus on the global water cycle presupposed the reliable, coordinated and, as far as possible, standardized acquisition, processing, storage and distribution of data. Moreover, hydrological networks were established in developing countries to provide data for local, regional and global process studies and model concepts. Instructions for the handling of data and the establishment of networks can be found in WMO Technical Regulations (WMO-No. 49), Volume III—Hydrology. These Technical Regulations are supplemented by a number of specific Guides. At its first session in 1961 (Washington DC, USA), CHy had recommended the formulation of the Guide to Hydrological Practices and the first edition was published in 1965. The fifth edition, issued in 1994, consisted of six parts with 59 chapters.


kids carry water In Africa, thorough joint planning and management of scarce and overused water resources is often the only way to achieve sustainable development. (Photo courtesy of UN Water for Life Decade, 2005-2015 (http://www.un.org/waterforlifedecade/))

Chapters 1-5 (Part A) provide information of a general nature concerning the water-related activities of WMO and other international organizations, as well as the WMO standards and regulations in hydrology and on the functions and responsibilities of National Hydrological Services. Chapters 6-25 (Parts B and C) deal with instruments and methods of observation, the design of hydrological networks and the collection, processing and publication of data. Chapters 26 to 59 (Parts D, E and F) deal with methods of analysis, hydrological forecasting and other applications to water-management projects and problems. The significance attributed by Member countries to this Guide is highlighted by the fact that it is available not only in the official WMO languages (English, French, Russian and Spanish) but was also translated into several more languages. At present, the Guide is under review; a final draft will be submitted to the 13th session of CHy in November 2008.

The significant role played by WMO in the field of operational hydrology is also highlighted by the information that is available in the digital metadatabase INFOHYDRO. It contains valuable details about available hydrological data and activities in water-resources of States and a variety of regional and international organizations.

Preparation and updating of the Technical Regulations, Guide to Hydrological Practices and INFOHYDRO are core activities of WMO and are mainly handled by WMO staff. Parallel components and publications exist within WMO for meteorology.

International cooperation

The necessity to acquire reliable, globally comparable hydrological and water-related data gave the impetus for a whole series of further WMO activities, in which Member countries are intensively involved. WHYCOS and HOMS are examples of a strong integration of countries that form one geographically contiguous or economically linked region. These programmes contribute not only to closer cooperation of developed and developing counties but also to a beneficial cooperation between developing countries of one region. The jointly acquired and administered data and water-related information in the individual Hydrological Cycle Observing System (HYCOS) components has been of considerable benefit for tasks such as estimating water resources, forecasting floods, monitoring droughts and building dykes, dams and storage reservoirs.

Moreover, it has contributed to a more peaceful coexistence of peoples. I am sure that WMO and its specialized programmes can also help to reduce water-related conflicts in the future. This certainly applies to many regions in Africa, where thorough joint planning and management of scarce and overused water resources is often the only way to achieve sustainable development. Regional components such as SADC-HYCOS (southern Africa) and MED-HYCOS (Mediterranean) are far advanced. Although WHYCOS is a programme component with strong regional orientation, the collected data and research results are also mosaic pieces for use in supra-regional and global models. This is the meaning of the letter “W” in WHYCOS. I am convinced that the results of the cooperation in WHYCOS will also be useful for terrestrial monitoring programmes (Global Terrestrial Observing System).

map The World Hydrological Cycle Observing System (WHYCOS) is a WMO programme aiming at improving basic observation activities, strengthening international cooperation and promoting the free exchange of data in the field of hydrology: http://www.whycos.org/

HOMS, conversely, has had a global orientation since its inception. At the fifth session of CHy in 1976 (Ottawa, Canada), the proposal was made to establish HOMS. It was intended to be an information system, whereby Hydrological Services could find information about available hydrological instruments, measuring methods, data-processing techniques, models, etc. In 1979, Congress approved the establishment of HOMS.

In the 1980s, before the age of the World Wide Web, HOMS experienced its heyday. The HOMS Office at the WMO Secretariat helped the HOMS National Reference Centres in numerous countries inventorying and exchanging HOMS components. HOMS is divided into sections and subsections that are related to the core tasks of a Hydrological Service. This makes beneficial transfers of knowledge and experience possible between developed countries and developing ones alike. This exchange of knowledge took place not only in written form: some Hydrological Services were willing to present the components at their disposal in workshops for small groups of experts and to provide special training.

As I mentioned at the beginning of this article, hydrology and water-resources management have close links with many natural-scientific, economic and social aspects. Consequently, it is small wonder that WMO with its Operational Hydrology Programme made substantive contributions to a series of important conferences and research activities. Conversely, these conferences and research efforts have also raised the importance of the Hydrology and Water Resources Programme within WMO.

Already at the first UN Conference on Water in Mar del Plata, Argentina, in 1977, WMO and UNESCO were commissioned with a Water Resources Assessment. This special competence of WMO was again invited in 1992 at the International Conference on Water and the Environment in Dublin, Ireland, and, later the same year, at the UN Conference on Environment and the Development in Rio de Janeiro. However, I have a critical view of WMO’s involvement in the World Water Fora. They are simply oversized, with too many participants and a myriad of separate, often simultaneous events. This gigantism makes it impossible to keep an overview of the outcome; the results become uncontrollable and are thus of little value for practical applications.

At the beginning of the 1980s, WMO was requested, in the context of the Global Atmospheric Research Programme, to collect river discharge datasets to be used as inputs to, or validation of, global atmospheric circulation studies. This contribution was first delivered by an institute of Munich University. However, the growth of datasets to be stored and the increasing number of institutions requesting data made it necessary to have a permanent and professionally operated database. The German Federal Institute of Hydrology in Koblenz volunteered to run this database and on 1 May 1987, a permanent Global Runoff Data Centre (GRDC) was established in Koblenz under the auspices of WMO (http://grdc.bafg.de). The GRDC provides a mechanism for the international exchange of data pertaining to river flows and surface water runoff on a continuous, long-term basis. All data archived at the GRDC are available to users. Currently, the GRDC holds river discharge data for 7 332 stations in 156 countries in its main database, with more than 276 000 station-years of runoff data.

Free and unrestricted exchange of data

It is often not easy for data centres and research groups to obtain the required data. A number of reasons may make the collectors of data hesitate to disseminate their material. This may be because of the costs of measurements and primary data treatment, but also the quality of the data—and, sometimes, secrecy aspects play a role. The international exchange of data was promoted and encouraged by the adoption of two resolutions of Congress, first for the free and unrestricted exchange of meteorological data (Twelfth Congress, 1995) and for the free and unrestricted exchange of hydrological data (Thirteenth Congress, 1999).

Why was hydrology excluded from the 1995 resolution? The reason is again that, in contrast to meteorology, there are no uniform Hydrological Services. We find Hydrometeorological and Hydrological Services. Very often, the National Service consists of several institutions—in some States as many as 30—of which each has its particular competence for different sectors of the “water world”. The national hydrological institution is frequently part of a ministry with special sectoral responsibility such as irrigation or electricity generation. Despite all difficulties, the resolutions were helpful for researchers to implement their programmes.

Importance of hydrology in the climate change discussion

Weather, climate, water

At the end of the 1970s, the concern was first voiced that climate would change as a consequence of intensified emissions of carbon dioxide. Accordingly, WMO held the first worldwide climate conference in 1979. In a joint effort with the United Nations Environment Programme and the International Council for Science, the World Climate Programme (WCP) was built from a number of components.

Since water problems were also gaining in significance in the context of expected global warming (bearing in mind that water vapour is the most important gas in the atmosphere), a separate programme consisting of several sub-programmes, WCP-Water was founded in the early 1980s. A second climate conference took place in 1990. At this conference, it was clearly pronounced that climate changes will have the severest impacts on the water cycle, so water resources management and the socio-economic system were also addressed. At the same time, the awareness of the global scope of these changes emerged, leading to the establishment of the World Climate Research Programme. WMO rendered essential contributions to all these activities with its Hydrology and Water Resources Programme. The combination of meteorology, climate and hydrology in one hand proved to be advantageous for WMO.

A significant step in projecting this image of WMO was the adoption of the slogan “Weather, climate, water”, which reflects the fields of responsibility of WMO. It was decided to use the slogan on all official documentation, correspondence and publications. Is there better evidence of the enormous growth in the significance of hydrology and water resources management within and outside WMO than this subtitle?


* Former president of the WMO Commission for Hydrology (1993-2000)

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