INTERNATIONAL CO-OPERATION ON HYDROLOGY OF THE CENTRAL AND EASTERN EUROPEAN COUNTRIES

Transcription

1 381 INTERNATIONAL CO-OPERATION ON HYDROLOGY OF THE CENTRAL AND EASTERN EUROPEAN COUNTRIES Urszula Soczynska Warsaw University, Faculty of Geography and Regional Sciences Within the framework of the International Hydrological Programme of UNESCO, regional projects with an objective to develop and consolidate collaboration in research on hydrological phenomena and processes in the different natural environs of few neighbouring countries, are considered of special importance. In accordance with the recommendations, given by the Interngovernmental Council for the IPH, The National Committees of the IHP in the Central and Eastern European countries had put forward the idea in 1968 to devise a number of mutual scientific research topics in the framework of regional co-operation. The regional projects have been performed by seven countries: Bulgaria, Czechoslovakia, GDR, Hungary, Poland, Rumania and USSR. The undertaken international topics had not a special source of financing; so, all works consitute the scientific input of particular countries, co-ordinated during meetings of the working groups. For reason of different organization of the co-operation the results do not very closely correspond to FRIENDS project, but som of them may be interesting during the second phase of it. There has been presented below the short review of the more important results achieved within the regional co-operation on hydrology of the Central and Eastern European countries. Projects accomplished 1. Underground Flow for the Territory of Central and Eastern Europe/ Moscow I982, Leningrad 1983/ This publication is an effect of more than 10 years international cooperation within the IHD and IHP project under co-ordination of the

2 382 USSR National Committee. The book consists of 3 parts. In the part I there have been discussed the main directions of the research, methods of regional estimation of the underground flow as well as the regionalization of the research territory on the basis of forming the underground flow. The part II deals with characteristics of the underground flow in the particular provinces and within them - in particular regions. In the part III there have been described the basical regularities of forming and the spatial distribution of the underground flow as well as its meaning in the general water balance. The carthographic result of the co-operation is the map of the underground flow for the territory of Central and Eastern Europe on the scale 1: 1, , consisting of 16 sheets. The map has been done on the hydrographie base what facilitates its application in hydrology and water management. The map was the first time presented at the XXVII International Geological Congress i Moscow in It would be on all accounts purposefull extention of the work to the total European territory. 2. Water Balance Maps for the Territory of Central and Eastern Europe /Budapest 1984/ This work was launched in 1972 with participation of seven European countries. The major co-ordinator of the topic was the National Committee of Hungary for the IHP. In accordance with the working group program the summary maps present average annual values of precipitation, runoff, evaporation and ground-water flow into rivers for the years 1931~1960. The values of water balance elements are expressed by isolines. The maps had been made on the scale of 1: by summarising and generalizing the national maps concerned with the corresponding water balance elements, prepared for their own territories on the scale of 1: The summary map of groundwater flow into the rivers has

3 383 been made by generalization of the Map of Groundwater Run-off for Central and Eastern Europe on a scale of 1: Correction and mutual co-ordination of the national maps around borderline territories has been reached by interconnecting the adjacent 'isolines drawn with regard to the conditions of forming the water balance elements in every country. Special methodological technics used are described in the publication. Relationships of water balance elements For flat areas of the territory under the study a common regularity is the change of water balance elements with latitude. Interrelationships between the elements of water balance differ in the Northern and Southern regions of the territory. In basins, located in the Northern regions of the GDR, Poland and the ET of the USSR, in the zone of surplus and adequate humidification, dependence of evaporation on precipitation is significant, because evaporation is close to its possible maximum and doesn't fluctuate sizeably with time /year after year/. Surplus of precipitation is for the forming of surface and underground flow. Thus, for such conditions a close relation of precipitation with total river run-off and almost completely uncorrelated precipitation and evaporation are characteristic. With exception of the Northern parts in the South of the territory in the zone of inadequate humidification, relation between run-off and precipitation is slight, but the relationship between run-off and evaporation is closer. In river basins of these regions precipitation is not raised mainly for increasing run-off, but for increasing evaporation because of a constant deficit in air saturation by water vapour. Such a character between water balance elements is typical for the rivers of the steppe zone of the ET of the USSR, the arid regions of Rumania and Bulgaria. Watersheds located in the central part of the territory under study, have intermediate character in view of the relationships between water balance elements. Relationship between precipitation, run-off and evaporation is much more complicated in the mountainous regions. A common tendency of closer relationship between precipitation and run-off is found with

4 384 increasing altitude. This can be explained by the fact that evaporation - in contrast to precipitation - doesn't change significantly in the different altitude zones, and the forming of run-off depends mainly on the regime of precipitation. This rule is not true for watersheds in high-mountainous zones, where glaciers are the main regulators of run-off. A very close relationship between run-off and precipitation is observed on the windward slopes of mountainous massives of the Carpathians, Sudetas, Beskidas, Harz, Ore Mountains and Caucasus. Ratio of groundwater flow to total river run-off generally reduces with increasing altitude. In the low-mountainous zones about 50$ of the ground-water takes part in the forming of river run-off. In the middle-high mountainous zones /altitude 1000 m above sea level/ this ration decreases to 20-25^. For these altitude crystalline rock are of common extension being unable to store groundwater. These regularities between water balance elements in mountains are common but they are unable to count for all water balance relations, which depend on altitude, exposition of slopes, orientation to saturated winds, content of soil, slop gradient, etc. 3- International manual for the methods of the main hydrological characteristics design /Leningrad 1984/ The manual has been worked out on the basis of information sent by all participating countries under co-ordination of the USSR National Committee. The manual consists of 9 chapters containing recommended computational methods as well as examples of practical computations of different flow characteristics. In chapter 1 /General assumptions/ there have been presented practical possiblilities of application of the described methods as well as processing the hydrometeorological and physiographic data under natural and anthropogenic conditions. Chapter 2 /Methods of hydrological computations on long series of data/ is devoted to the computational methods of hydrological characteristics of specified exceedance probability. There have been discussed methods of sample homogeneity/gniedenko-koroliuk method/, independence of sample elements /Wald-Wolfowitz method/ and the trend on

5 385 the basis of linear dependence of the sample mean on time. For estimation of the agreement between the theoretical and empirical distributions is recommended the Fishcer-Sidiarto and Kolmogorov criterion. There have been discussed different types of the theoretical probability distribution functions and methods of parameter estimation. finally there have been described methods of non-homogeneity probability distribution function determination. Chapter 3 /Methods of basical hydrological characteristics computations on short series of data/. In case of short series of data one recommend their extrapolation on regresion relationships with one or more sites on selected streams-analogues. Presented methods allow determine the basical parameters as the mean and variation coefficient on long-term series in basins-analogues. Chapter 4 /Methods of annual flow computation/. For estimation of the many years fluctuations of the annual flow is recommended analysis of the flow integration curves, autocorrelation and spectral functions. The achieved results may be used for estimation of the annual flow series representativeness. In case of long record of data is recommended application of the theoretical probability distribution functions /Pearson III or Kricki-Menkel/. In case of short series there is recommended their extrapolation on information from the basins-analogues. Chapter 5 /Methods of computation of inter-annual flow distribution/. Here are described methods for analysis of the flow distribution within the hydrological year /months, seasons, half years/ as well as methods for estimation of their many years fluctuations in sites of sufficient and unsufficient record length. Chapter 6 /Methods of maximum flow computations/. The methods depend mainly on the record length. The minimum number of the sample elements is dependent on the required probability and on the stream characteristics described with the variability coefficient. In case of sufficient number of data there is recommended computation of maximum flows separately for snow-melt and rainfall floods. If such distinct division is not possible then should be considered only one peak flood within the year. In case of unsufficient record length it should be

6 386 extrapolated basing on hydrological analogy. In case of lack of the respretive basins-analogues or hydrometric data there are recommended the empirical formulae. They relate the maximum probability flow to different physiographic characteristics of the basin. There are also given methods for flood volumes and hydrographs computations. Chapter 7 /Methods of low flow computations/. In the chapter in descriptive way only are discussed problems of low flows estimation. According to practical requirements the approach for low flow estimation may be different. Low flows should be considered as one or multi-dimensional variable. There is given consideration to the areal distribution of low flows. In ungauged sites there are recommended the regional maps of low flows. The last two chapters are devoted, to the methodology of the sediment transport calculation /chapter 8/ and to the reservoir sedimentation /chapter 9/- 4. Estimation of the reservoirs impact on flow regime and water quality /Sofia 1987/ The co-ordinator of the working group has been established the Bulgarian National Committee for IHP. Moreover in the work participated Poland, USSR and Czechoslovakia with taking into account the information from GDR. As an effect of the co-operation during the period there was worked out and published "Recommendations for estimation of the reservoirs impact on water resources and flow regime". The publication consists of 8 chapters. In the first two chapters have been characterised the bigger water reservoirs localised on the territory of the Central and Eastern Europe and their classification. The third chapter deals with the qualitative reservoir impact estimation on flow regime elements depending on type of the reservoir. Chapter four is devoted to the analysis of the water balance elements variations, mainly to the outflow volume and evaporation due to inundating of large areas of the catchment. The last chapters /5 _ 8/ are devoted to the computational methods for estimation of changes of different flow characteristics /annual, monthly, maximum and minimum flows/ downstream the reservoir.

7 387 Projects under realization 1. The assessment of the effect of urbanization on the hydrological system and water quality The methodological manual on the assessment of the effect of urbanization on the hydrological system and water quality, elaborated by the working group of Central and East European countries under the IHP, is the first work of that kind in hydrological literature. It is a collective ' work co-ordinated by Poland and USSR. Publication of it is forseen by the end of The first two chapters of the manual deal with two main notions, namely urban area and urban hydrology. The term of urban hydrology is closely connected with a growing degree of urbanization in the world. An urban area is the area in which the dominant factors of anthropogenic transformation are the industralization and urbanization. The urban and industrial area is marked by a dense land development, occupying new territories lying within its range for settlement, and establishing suburban settlements. The effect of such settlement is the increasing impermeable area, such as roofs, streets, markets etc. As a result, the hydrological cycle undergoes major transformation being an effect of changes of the particular components of water balance. Chapter three comprises methods of the assessment of territorial changes of hydrographie objects using cartography photo-interpretation and satellite data. The analysis is made of the methods of research on the disappearance of water-cources and small water basins, particularly in areas of subterranean mining and quarries. It was found out that there were possibilities of the appearance of new basins following the rise in the number of the post-mining pits /lignite mining, stone and gravel exploitation etc./. Chapter four is devoted to the hydrological cycle in urban areas, and particularly its changes and their evaluation. Emphasis was put on the acquisition of basic data, storing and processing of data from measurements and observations, as well as evaluating their reliability and precision. The main stress was laid on methods of the assessment of changes of the elements of the hydrological cycle.

8 388 Changes in transportation of the solid matter are discussed in chapter five. An intensive management of rivers within urban areas causes considerable changes in transportability of the suspended and bedload sediments. The volume of this transport increases due to the flow of debris from the city. On the other hand the bed load is often dredged for building, which disturbs the balance of the sediments transport and causes the scour of the river bed, deposition of the load below the city etc. Chapter six of the manual is devoted to changes in the quality of surface and underground waters, and especially to methods of water quality assessment. First of all, forms of changes in water quality /hydromorphological, hydrological, chemical and biological/ were discussed. The final chapter comprises recommendations concerning the prevention of a negative effect of urbanisation on the particular elements of the environment. The chapter includes the analysis of this effect and preventive measures that are illustrated with tables of indispensable parameters of the environment. The manual contains some more important items of literature related to the subject from countries that participated in the publication of the manual. 2. Improvement of the methods for land evaporation estimation The problem is realized by 6 countries /without Rumania/, co-ordinated by the Hungarian National Committee for IHP. The main task of the working group is working out the guide for the land evaporation estimation consisted of 3 parts: 1/ physical foundations of the land evaporation process, 2/ measurement methods of the evaporation from water and land surfaces, 3/ computational methods of the evaporation from water and land surfaces, Completion of the work is forseen by the end of 1990.

9 Methodological research in experimental basins The main co-ordinator of the working group is Polish National Committee for IHP. The activity of it goes in two directions: '1/ working out the monograph of the hydrological processes in the basin, 2/ verification of the models describing hydrological prosesses in selected experimental basins. Within the first task there has been prepared a publication on physically based models of the basical processes of the water circulation in a basin /precipitation, interception, évapotranspiration, infiltration, surface and subsurface flow/, worked out and used in different countries. Description of the model will consist of the alghorythm, methods of parameters identification as well as description of the instruments and measurement installations required for parameters, input and output data determination. Within the second task there is forseen verification and intercomparison of the models describing the component processes worked out in different countries in the selected experimental basins. The work should be completed in Parallelly to the activity of this working group the Rumanian National Committee for IHP is co-ordinating the theme "Research in experimental and representative basins". Within it, it is organized every 3 years international seminars where different countries present the more important results achieved in the research basins. k. Influence of the acid rainfall on water quality The working group was set up in 1986 under co-ordination of the Czekoslovakian National Committee for IHP. The aim of the group is co-operation of the specialists on the spatial and temporal distribution of the acid rainfalls, unification of the methods of taking up and analysis of the rainfall water samples as well as working out the forecast

10 390 of the influence of the rainfall acidification on the hydrological system. The program of the working group consists of the following problems: 1/ depositting the atmospheric pollution in the particular countries, 2/ state and changes of the acidification of the surface water, 3/ mathematical modelling the hydrological processes with account to the water quality. Acknowledgment I would like to express my gratitude to professor Zdzislaw Mikulski - Chairman of the Polish National Committee for the 1HP - for making available the information and materials-constituting the basis of this elaboration.