General description of the River Project and basic planning data

Maciej Jedrysik, Aleksander taski and Jan Zielinski

Abstract. The Vistula is the largest river in and the development of its water resources has a fundamental significance for the overall development of the country. The most recent studies concerning comprehensive development of the Vistula River water resources were under- taken within the framework of the UNDP/UNVistula River Project. They are a continuation of the previous studies which have been in progress for several years. The purpose of the Vistula River Project is to determine the optimal basin-wide solutions by applying mathematical modelling techniques. The present paper describes the Vistula basin and the Vistula River Project. Special emphasis is laid on the methodical preparation of the basic planning data and their scope (input data for the mathematical models).

Résumé. L'aménagement intégré des ressources hydrauliques du bassin de la Vistule, le plus grand fleuve de Pologne, est un problème essentiel pour le développement du Pays. L'étude récemment entreprise dans le cadre du Projet Vistule, patron6 par le PNUD (Nations Unies) fait suite aux études polonaises commencées depuis plusieurs années. Le but de cette étude est de définir la solution optimale de l'aménagement intégré du bassin au moyen d'un modele mathématique d'utilisation des eaux. La présente communication contient une description du bassin de la Vistule et du Projet Vistule, ainsi que la méthode de préparation des données pour le modèle mathématique.

INTRODUCTION AND GENERAL DESCRIPTION OF THE VISTULA BASIN The water economy problems of the Vistula basin and its development have for a long time been of particular interest to Polish hydraulic engineers. The solutions to the problems of developing the Vistula basin and obtaining the optimal utilization of its water resources to meet the demands of the national economy,constitute the basic conditions for a master plan for the development of all Polish water resources. For this reason the people concerned with the general development of the country are also very interested in the results of such studies. The catchment area of the Vistula River covers 174,000km2or 56 per cent of the Polish territory. The catchment area includes the main industrial centres of Upper Silesia, Lódf,Warsaw and Kraków,and huge rural areas, which produce more than 60 per cent of the country's agricultural output. At the same time the Vistula Valley can be thought of as a principal axis of the national economy as it attracts the major new industrial investments. These very general facts help show the exceptional significance which the situation within the Vistula basin and the other factors, that govern the proper development programme, has for the whole national economy.Among these factors are, the water resources, their magnitude, degree of present utilization and prospects of future exploitation.Table 1 shows the water resources of the Vistula basin in selected cross sections of the Vistula River and its main tributaries. The table is concerned with surface water only; the estimation of the water resources, however, cannot be limited to it, as the potential utilizable groundwater resources of the Vistula basin approximate 19,000m3 x IO6 yearly. Such a volume constitutes a considerable share of the total water resources,as the mean annual General description of the Vistula River Project 1057 TABLE 1 Q-discharge (m3/s) Catchment cross area Mean Qmax River section (km2) Min annual Max Qmin Upper Vistula Dwory 5,300 11.6 56 1950 168 Middle Vistula Pufawy 57,100 97.1 422 7390 76 Lower Vistula Tczew 193,900 238.0 976 9170 39 Dunajec (tributary of Upper Vistula) N. Sgcz 4,360 7.7 61 3510 455 San (tributary of Upper Vistula) Radomys'l 16,700 16.1 129 3770 234 (tributary of Lower Vistula) Zegrze 69,050 54.0 281 2940 54 outflow is 31,000 m3 x lo6.Despite the fact that this volume seems remarkable the present level of draw-offoccasionally encounters periodical limitations or involves negative phenomena,closely linked with the hydrological conditions of the basin. A characteristic of the hydrology of the Vistula River and the majority of its tributaries is the great seasonal variation in discharge. The flow pattern is one of long periods of low discharges during the summer,autumn and winter seasons, interspersed with occurrences of violent flood waves. The course of the Vistula River may be divided into three sections,namely: the Upper,Middle and Lower courses, depending upon the morphology,hydrology and degree of development of the adjacent areas.

THE UPPER VISTULA The Upper Vistula, which runs along the southern mountainous (Carpathians) part of the country,drains about 25 per cent of the whole basin and receives the highest precipitation, namely mean annual totals ranging from 600 to 1000mm.Several mountain tributaries characterized by very unstable flow and of considerable flood potential join the Vistula along this section. The floods are mainly from summer storms. The water resources of this part of the basin greatly exceed the average resources of the basin and consequently at the lowest point of the Upper Vistula (below the confluence with San River) the mean annual outflow reaches 40 per cent of the total outflow of the Vistula River. This part of the basin has a decisive influence on the regime of the Middle Vistula and is clearly observable in the flow pattern of the Lower Vistula. The Upper Vistula runs across the intensively industrialized centre of Upper Silesia and then through the Kraków Industrial Centre. A considerable amount of effluent is carried into the Vistula from the Upper Silesia industrial centre by a tributary,the Przemza River and so the water pollution level is high. The water is practically unacceptable for domestic use and only partially'suitable for industrial consumers. To cover the water requirements of these centres, a programme of con- struction of storage reservoirs was initiated and has been going on for several years. The programme also includes a system of water transfer installations. The reservoirs are generally located on the tributaries of the Vistula River, where a reserve of clean water is still available. Despite these measures a serious water deficit is experienced within this area which necessitates further studies and urgent decisions. Because of the rich natural deposits (coal) and the high degree of industrialization in the vicinity of the river, development of navigation has been discussed for a long 1058 Maciej Jqdrysik, Aleksander taski and Jan Zielitkki time. This stretch of the river was controlled before the First World War. The develop- ment of a navigable waterway was started in the fifties (three barrages provided with navigation locks were built) but the idea was later abandoned and still awaits a final decision. As already mentioned the Upper Vistula basin suffers from frequent floods that cause serious economic losses. The flood storage capacity of the existing reservoirs is insufficient and therefore the compilation of the flood-controlprogramme for this portion of the basin, taking into account both the Vistula River and its tributaries, is an urgent and very important task.

THE MIDDLE VISTULA The Middle Vistula is the most neglected stretch of the river. Here the channel has a character of a typical lowland river. Often the unstable channel consists of several branches, enclosing islands, and the main river current changes its position after almost every flood. Navigation is practically non-existent here because the width and shallowness make its development almost impossible. The shallow channel and difficult flow conditions are factors that make the threat of ice jams and resulting floods very real. The river carries an adequate supply of water and runs through the centre of the country. Labour is readily available from the adjacent agricultural areas. All these circumstances make the region suitable for the development of large industrial establishments;this factor has been reflected in the investment policy of the Govern- ment in recent years. Thus there is an urgent need to develop the river, the undisputable priorities being bed stabilization and the establishment of navigation. In recent years controlling work has been started along several stretches of this part of the river. Water shortages occur in the basin on both sides of the river as a result of industrial and agricultural activities. Solutions to the problem involve either erection of local water storage reservoirs on the tributaries or the transfer of water from the Vistula River. The selection of the best solution to this problem requires complex studies and investigations. THE LOWER VISTULA The water resources of the Lower Vistula are enriched considerably by tributaries, the Narew and the . For centuries it has constituted an important axis of economic development of the country. The relatively deep valley, convenient for the building of dams,and the considerable hydropower development potential of the Lower Vistula, has attracted the interest of Polish hydraulic engineers for a long time. The studies being carried out indicate that the building of a series of barrages from Warsaw to the mouth of the river is an economic undertaking. Apart from the power generated, the scheme would create an excellent waterway, provide several bridges over the river, create several artificial lakes, as well as introducing convenient conditions for water intakes and cooling systems of the thermal power stations. There is only one barrage built at present. It is located at Wfodawek. Among the tributaries of the Lower Vistula the Narew and the Bug deserve the greatest attention. The main problems linked with these rivers are the large quantity of water needed for the intense agricultural development in the region and the flood control of this area. It should be mentioned that in contrast to the mountainous tributaries of the Upper Vistula, all tributaries of the Middle and Lower Vistula have a flood season in the early spring caused by snow melt.

PREVIOUS STUDIES AND OBJECTIVES OF THE VISTULA RIVER PROJECT The above short review of some problems of the watertconomy of the Vistula and its basin clearly indicates that in contrast to the majority of other rivers there is no single General description of the Vistula River Project 1059 purpose which would justify its development. It may only be achieved by very comprehensive analysis of requirements and benefits for all branches of the national economy involved. Proposed solutions have to take into account the present and future development of the basin as well as the process of urbanization. These reasons mean that the studies aiming at the formulation of the prospective programme of development of the Vistula’s water resources have been continuous for several years. The studies undertaken in the years preceding the Second World War were continued with particular intensity after the War. Then several proposals evolved - proposals outlining the solution of complex problems of particular regions in the basin, of the river valley and finally of the whole basin - all in connection with the national plan of development of the water economy. The studies covered among others such regions as the Dunajec River basin, then the Vistula River Cascade, the National Plan of the Development of the Water Economy for the years 1961-1980 (revised later for the years 1966-1985) and finally in 1968 the General Basic Principles for training and developing the Vistula River. During recent years the gradual development of technical solutions for the develop- ment of water resources in the basin may be observed. At the same time some new ideas on the role and importance of particular elements of development of the Vistula River System have evolved. The high investment costs of the series of barrages, existence of valuable agricultural areas in the valley, ever increasing water demands in the basin, increases in pollution, all indicated that there is a necessity to seek a general solution embracing the whole spectrum of the water problems of the basin. Now the Vistula River is not only treated as a potential waterway,a source of cheap electric power and the cause of dangerous floods but the ever increasing intensity of the national development underlies the significance of the Vistula River system as a powerful source of utilizable water for all branches of the national economy and at the same time as a huge collector of the pollution loads discharged from an area equal almost to two-thirdsof the total area of Poland. This attitude to the problem has turned our attention to the change of rlows in the basin river system. Under the term change,apart from the natural seasonal variations caused by meteorological phenomena,the influence of human activities is included. Here the main problem is to find out the trend of these changes and their reasons. In the future the relationship between any changes and the development of every branch of the national economy must be established, including the rapidity and the likely size of these changes. All relevant forecasts,moreover, are to be projected into the future and the possibilities of controlling undesirable phenomena analysed. All this information should be included in the basic planning data for any present-day study of water economy of the river basin. The decision to undertake the new phase of broad studies reflects this attitude. The studies are meant to lead to the formulation of the optimum investment programme for the comprehensive development of the Vistula River system. The studies were started in 1969 with the assistance of the United Nations Develop- ment Programme (Special Fund) on the basis of an agreement signed between the Government of the Polish People’s Republic and the United Nations. To implement this project the Bureau of the Plan of Operation ‘Vistula’was established by the National Water Authority. The Consulting Engineers Bureau of Studies and Designs for Hydraulic Engineering ‘Hydroprojekt’was appointed the general executor and coordinator of the project. This study now generally called the Vistula River Project extends well beyond the strictly conceived optimization analysis of the investment programme. This analysis will constitute only one of few final elements of the whole work. Indeed,the tasks set before the executors of the Vistula River Project have a far 1060' Maciej Jqdrysik, Aleksander taski and Jan Zielihski wider scope. Not only will the final optimization analysis need to be based on the most up-to-datebasic data but one of the most important aspects of the Vistula River Project will be the development of the methodology for the preparation of compre- hensive plans for water system development, for use when the national economy expands intensively and the water resources as well as the possibilities for hydraulic engineering investments are limited. The basic investigations carried out within the framework of the Vistula River Project include the following problems: (1) Analysis of the present utilization of the water resources,the present water pollution levels, and the existing flow control structures on the Vistula River, including waste-watertreatment plants. (2) Determination of the future water requirements in the basin and the expected pollution loads,based on the overall plan of economic development. (3) Determination of possible hydraulic engineering solutions in the Vistula basin (storage reservoirs, barrages, water transfer facilities). (4) Establishment of the possible solutions alternative to the utilization of surface water resources through the use of hydraulic engineering structures (utilization of groundwater resources,changes of technology in every branch of industry to reduce water needs and pollution loads, construction of waste-watertreatment plants). (5) Development of the methodology for analysis of several engineering alternatives for the development of the Vistula River and for optimization of the operating policies of the basin water system to satisfy indicated requirements. (6) Analyses of the water economy with regard to engineering alternatives and the related comparative analyses of the investment programmes to choose the group of optimal alternatives. (7) Final analysis for the chosen group of investment programme alternatives for the Vistula River system,which will take into account the factors not included in the optimization analysis, and formulation of the proposed investment programme.

BASIC ASSUMITIONS AND DATA IN THE VISTULA RIVER PROJECT The wide scope of the project requires collection and processing of basic data. At the same time certain basic conditions have to be observed to ensure the uniformity of the whole work. These conditions are listed below, but it was necessary to omit some of them: (1) The whole work will be carried out for the target date of 1985 (as a transitional stage) and for the target date of 2000 (final stage). (2) The analysis will include only the main tasks of the water economy, namely: (a) water supply for industry,municipalities and agriculture, (b) protection against water pollution, (c) guarantee of the minimum acceptable flow, (d) flood control, (e) preservation,within the economically justified limits of the present basic functions of our water resources (navigation, hydropower generation,tourism, recreation). (3) The analysis will be based on the sequence of hydrological observations expressed in the form of the mean monthly flows during the period of 15 years (1 95 1 -1965) for the whole area of the Vistula basin. For the optimization of the storage reservoirs' operation longer periods of observations are used. General description of the Vistula River Project 1061 (4) Hydraulic structures (storage reservoirs, water transfers,barrages, levees, river training works and sewage treatment plants) which play an important role in the solution of the basic problems of water economy in the Vistula River basin are considered as elements in the basin development. (5) The water supply for human consumption has the highest priority; the decision concerning distribution of water among other users is based on estimation of the economic loss while the water supply is cut off, or alternatively on the cost of the substitute investments. The preparation of the initial data for the comprehensive plan of the Vistula River system development was a problem of particular significance. The problem called for specific attention in the first phase of works. Due to the scope of the task, the data were prepared, not by the ‘Hydroprojekt’but by several specialized consulting engineers of relevant ministries and scientific institutes. The compilation of the collected raw data and their presentation in a form suitable for utilization by a mathematical model have remained,however, the full responsibility of ‘Hydroprojekt’. Due to the amount of basic data and the shortage of time,in spite of simplifications, it was not possible to wait for the finalization of the methodology with the compilation of several groups of input data. The negative effects of this practice may now be observed, as in several cases the need for amendments or even recompilation arises. In some cases the initial data determine the exactness and even the feasibility of the calculations. The initial data may be divided into several basic groups: (1) Hydrological data. (2) Water requirements and return flow of every consumer. (3) Economic loss attributable to the lack of sufficientwater supply or the cost of alternative solutions,and the relative importance of every consumer. (4) Technical and economic parameters of the hydraulic structures considered by t’le VistfiL PrGjeCt. (5) Supplementary data such as minimum acceptable flow in selected river profiles, additional loss of water following the erection of water control structures and resulting from increase of evaporation and infiltration. (6) Information about the amount and composition of pollution loads directed to the surface waters, as well as scope,size and costs of treatment plants necessary to bring the water to the required level of purity on various stretches of the rivers. (7) Evaluation of losses and their distribution in areas that suffer from floods depending upon the magnitude and frequency of floods for both present and fu,ture conditions. (8) Enumeration of systems of mutual links between particular technical structures of the basin and determination of the intake and return flow points in relation to the network of water channels and to the siting of hydraulic structures. Each of the above-mentionedgroups of initial data could be discussed in far more detail but as space is limited only problems selected as being the most characteristic and essential are discussed here.

HYDROLOGICAL DATA

Hydrological data consist of the mean monthly flows for 15 years (1 95 1 -1965) for 100 selected water gauges in the Vistula River basin. The mean monthly flows for these years were computed by the National Hydro-MeteorologicalInstitute by using existing gauges chosen not only for a credible record for the period concerned but also considering the future distribution of demands and location of hydraulic structures in 1062 Maciej Jedrysik, Aleksander taski and Jan Zielihski the basin. The studies were aimed at the formulation of the hydrological characteristic of all important rivers of the Vistula basin. These hydrological data were corrected at the confluences and along the main course to eliminate, by means of a specially prepared programme, the negative values of flow increases which appeared between successive sections. The longer sequences (21 -4 1 years) were used to determine criteria for the operational policy of reservoirs. The data for 30 gauges,which include the basic 1 5-yearperiod, have been used for this purpose. The hydrological study is supplemented by the analysis of the six highest floods recorded on the Vistula River and its tributaries. Before the hydrological report was compiled it was decided to limit the model investigation to the Vistula River itself and its 11 main tributaries. This leaves smaller tributaries beyond the scope of the model. During selection the decisive factor was not the discharge of the relevant river, but the relation of this discharge to the flow in the Vistula River just below the confluence. For the comparison the mean values from the observation period were used.

WATER NEEDS AND RETURN FLOWS Water needs and return flows data, which illustrate the overall water requirements within the basin, constitute one of the most time-consumingand difficult jobs. Water requirements have been estimated for industry (with a breakdown by type of industry), thermal power stations,municipalities and agriculture,for the target dates of 1985 and 2000. The target date of 2000 has been adopted to ensure the proper prospective for a water economy plan to avoid a misdirection of effort. However,this condition caused difficulties due to lack, in several cases, of definite knowledge of trends of the development of each region or of each branch of industry for such a distant date. It indicated the necessity to revise, from time to time, the results of the mathematical model, as more accurate data become available. The experience gained while executing previous plans indicates that scrutiny of water requirements of all users and consumers with the same degree of exactness is unnecessary and not recommended,as some requirements do not influence investment in basic hydraulic structures in the basin. Therefore consumers have been divided into three groups, the division taking into account the consistency of their demand and the role they play in the water balance. Group A consists of consumers with the highest water demands. The basic planning of the hydraulic structures should meet the requirements of Group A consumers.At the same time the amount of water required, in comparison to the local resources, suggests the need to investigate other ways of satisfying demand (alternative resources or change of a consumer localization,or perhaps adoption of different technology). Group B consists of consumers whose water demand is essential for planning the development of the basin, but do not require the additional analyses, specified for group A. Finally all other consumers whose water demand has only local significance and are sited in areas not foreseen for development, belong to group C. Their demands will be reflected in water balances by a change of outflow from the catchment areas concerned. In some cases the method that combines the demands of several consumers has been employed. The need to introduce water allocation in seasons and areas of water deficiency stimulated the investigations of the losses involved resulting from the shortage of water, or the cost of an alternative solution. The relative scale of requirement impor- tance has been adopted due to the considerable difficulties of loss evaluation that concerns each particular class of consumers. Top priority has been reserved for human consumption;the priority given to industrial consumers being evaluated by a relative index that is expressed by the value of the final product per consumed unit of water. General description of the Vistula River Project 1063 In the case of agriculture the method is different, depending on the nature of the requirement and the location of the areas being irrigated. The reduction of water resources due to agricultural intensification and water intakes for irrigation of pastures not influenced by basic water control structures is expressed by changes of outflow which is considered an absolute condition. For the water intake for irrigation of pastures and arable lands located in areas influenced by the basic planned hydraulic structures an evaluation of priorities was introduced, similar to that employed for supplying industrial consumers.

HYDRAULIC STRUCTURES AS ELEMENTS OF THE VISTULA BASIN DEVELOPMENT The determination of technical and economic parameters of basic hydraulic structures called for investigation of the ability to store and transfer water as well as to develop the channels of the main rivers within the whole basin. The main task was to determine possible technical solutions of the basin development as an assembly of initial data to enable the choice of alternative solutions,being the subject of the optimization analyses of the investment programme. Several factors are decisive when considering the successful finalization of the analysis and resulting conclusions. These are: the proper choice of structures (and their design) which should accommodate the foreseeable trends and future demands, and the observation of the principle of full comparability.between particular structures and their alternatives from two standpoints: the cost and reality of implementation. Special attention has been paid to ensure a solution which is sufficiently flexible to offer a choice among several alternative schemes, both to meet the present and the maximum demand of the year 2000. It was decided when starting to design hydraulic developments of the Vistula River to use as far as possible the results of all previous studies. To ensure the comparability of the soiutions,the iiivestmeii: costs f~r a!! sttructi?rer cinridereb have been based on a specially prepared list of cost indices. Every structure was costed in that way in addition to a much more exact schedule of prices which accompanied some of the selected designs. The latter figures only served as a check of the results of the figures obtained through the cost indices method. The elements of hydraulic development of the Vistula basin discussed may be divided into several basic groups: (1) Storage reservoirs on the Vistula tributaries. (2) Storage reservoirs on the Middle River. (3) Water transfers between regions of the same basin. (4) Canalization of the Vistula by means of a series of barrages and locks. (5) Levees and river training. Figure 1 shows all the works considered in the Vistula Project and shows the hydro- graphic network of Poland. In this figure each reservoir is labelled with a number and further information about the reservoirs is given in Table 2. Obviously several groups of these reservoirs are alternatives to other groups and not all will finally be constructed but the widening of the scope of studies is advantageous, as it gives a better chance to choose the most economic and effective solutions. Existing reservoirs and those currently being built are analysed together with anticipated new structures in a group,to judge the likely effect of these future structures,on the operation policy of the existing reservoirs. Among the listed reservoirs some deserve special mention. The storage reservoir Porqbka II extends over the areas covered by both existing reservoirs Porqbka and Tresna. By building a new dam just below the existing Porqbka Dam and still keeping 1064 Maciej Jedrysik, Aleksander taski and Jan Zielihski nh

FIGURE.1. Location of storage reservoirs. 1 -boundary of the Vistula basin; 2 - boundary of tributary basins, 3 - reservoirs existing and under construction; 4 -potential reservoir sites subject to analysis. the waters of the River Sola at the Tresna Reservoir level a reservoir with a capacity of more than 150 per cent of the combined capacity of the existing reservoirs would be created. It would make possible a remarkable increase in the guaranteed outflow,SO much needed in the deficient region of Silesia. The estimated cost of the undertaking is very encouraging. A similar solution is considered €or another reservoir - CzchÓw II on the River Dunajec. The construction of the CzchÓw Dam directly below the existing CzchÓw II Dam,would keep the water level at the present height of the RoinÓw Dam (or perhaps slightly higher) and would create huge usable and flood- control capacity. The dam could control more than 75 per cent of the catchment area of the River Dunajec and would be a valuable tool in the management of water distribution of the whole Vistula basin. These ideas have resulted from the Iavourable topography of the existing dam sites (the reservoirs contained by them being too small for present needs). The attractive factor in both cases is the relatively small loss of arable land in comparison with alternative sitings. Another attractive solution concerns the planning of the big reservoirs in the lower course of the tributaries - the Melsztyn, Olszyny, Kamienica and Krasiczyn Dams. The latter is worth particular consideration. It is a new site giving the possibility of a considerably increased capacity, in suitable topographical conditions. Its submerged area is located mostly downstream of the River San,and is suitable far the creation of a big storage reservoir. Together with the large Solina Dam which unfortunately controls only a small fraction of the river catchment area, the Krasiczyn Dam would General description of the Vistula River Project 1065 TABLE 2 Reservoir no. Name River Remarks 1.1 Goczaikowice Vistula Existing 1.2 Solec Vistula Planned 1.3 Kazimierz Vistula Planned 2.1 Przeczyce Przemsza Existing 3.1 Tresna Soia Existing 3.2 Porabka Sofa Existing 3.3 Porgbka II Soia Planned 4.1 Swinna Porqba Skawa Newly designed 5.1 Stróza Raba Newly designed 5.2 Dobczyce Raba Newly designed 6.1 Czorsztyn Dunajec Under construction 6.2 Jazowsko I Dunajec Newly designed 6.3 Jazowsko II Dunajec Newly designed 6.4 RoinÓw Dunajec Existing 6.5 Witowice tososina Newly designed 6.6 CzchÓw II Dunajec Planned 6.7 Melsztyn Dunajec Planned 6.8 Olszyny Dunajec Planned 7.1 Brzegi Nida Newly designed 8.1 KlimkÓwka Ropa Newly designed 8.2 Krlty Wisloka Newly designed 8.3 Dukla Jasiofka Newly designed 8.4 Kamienica Wisfoka Newly designed 9.1 Solina San Existing 9.2 Niewistka San Newly designed 9.3 Krasiczyn San Planned 9.4 Krosno Wislok Planned 10.1 Nielisz Planned 10.2 LubartÓw Wieprz Planned 11.1 Suiejów Pilica Under construction 11.2 Spaìa Piiica Plariried 11.3 N. Miasto-tggonice Pilica Newly designed 11.4 N. Miasto-Wy'smierzyce Pilica Planned 12.1 Mielnik Bug Newly designed 12.2 Granne Bug Newly designed

allow the utilization of the water resources of the River San,which is the most seaward main Carpathian tributary of the River Vistula. The reservoirs of the Middle River, namely Kazimierz and Solec, are not new proposals. However,the results of their likely construction and their influence on water economy of the river system made it necessary to re-examinethe possible variations of technical solutions and to analyse in detail several problems not only technical but also demographic and economic. The comparisons indicated that the creation of a reservoir with a large capacity in the Middle Vistula by the Solec Dam may well be abandoned. It does not offer a capacity similar to that of the Kazimierz Reservoir, moreover, the Solec Reservoir of the same capacity would be more expensive than the Kazimierz Reservoir. From other studies and partial economic analyses, it has been proved that it is possible and desirable to decrease the inundated areas and particularly the extent of the evacuation of inhabitants.This goal may be achieved by means of levees for the protection of areas located on the fringe of reservoirs. The analysis of several variants of this reservoir including varying head and capacity, , considered by the Vistula Project, suggests that it might be possible to carry out the project gradually,and demonstrates the definite limits for further studies. 1066 Maciej Jqdrysik, Aleksander taski and Jan Zielitkki The separate group of reservoirs planned is in connection with water transfers between portions of the basin. Figure 1 shows two of them,namely the Krosno Reservoir on the River Wistok and the Nielisz Reservoir on the River Wieprz. The first was proposed as a result of the investigation into the possible increase of storage capacity on the River Wisbka. The results were negative due to the ,topography and considerable development in the river valley. In this case the problem may be solved by transferring the excess waters of the River WisIok from the Krosno Reservoir to the catchment area of the River Wistoka. The water then may be stored in the Kamienica Reservoir. The Krosno Dam therefore plays the role of a starting point for transfer and simultaneously provides a certain storage capacity for the River Wis€okitself. A different task is attributed to the Nielisz Reservoir. It is to store the Wieprz River waters to augment the transfer canal Wieprz-Krzna, which feeds the areas that are beginning to experience water deficiency for agricultural purposes. Simultaneously it may be utilized as a final destination of water transferred from the Vistula River. This water transfer, together with others, is shown in Fig. 2. The water transfers considered in the Vistula Project are listed in Table 3.The numbers correspond to those shown in Fig. 2. Three .om the listed transfers deserve special attention. The water transfer ,hnajec-Slqsk and Central Canal are proposed as future mutually exclusive alternatives. Their basic task is to supply water to the deficient area of Silesia but they have quite different characters.

FIGURE 2. Location of water transfers. 1 - boundary of the Vistula basin; 2 - boundary of tributary basins; 3 - water transfers, existing and under construction; 4 - water transfers subject to analysis. General description of the Vistula River Project 1067 TABLE 3 No. Name Remarks

Sofa-Sl¿@ Existing and under extension Skawa-Slgsk Planned Raba-Krakbw Under construction Dunajec-KrakÓw-hgsk P 1 anne d Wisiok -Wisioka Planned Wisia-Wieprz Planned Wieprz -Krzna Existing Pilica- tÓdi Existing and under extension Central Canal Vistula-Silesia Planned

The proposals of the Central Canal Project, submitted with the Vistula River Project, vary considerably from the preceding projects under the same title. According to the present proposals Central Canal is to transfer waters of the Vistula River to Silesia only thus leaving the development of navigation out of the question. Consequently the project will be more adaptable as regards the selection of the route and will be much less expensive. The route of this canal enables it to be used for delivery of water to the industrial regions of LódB and Czestochowa and supply water to the Odra-Vistula watershed areas along the route. The latter function may be illustrated by the proposal to supply the Upper Note6 region. The terminal reservoirs of the transfer canal,located in the catchment area of Przemsza River, may constitute not only the reserves for water supply of Silesia region but also the starting point for augmentation of low flows of the Upper Vistula River. The quantity of transfer considered in the Vistula River Project allows, in the extreme case, the guaranteed flow at Kraców to be increased very nearly to the present-day mean annual discharge. Such a project could revolutionize the whole water iììaaagcment pdiq of the Virtu!u Piver system. The water transfer canal Vistula- Wieprz would also be interesting because it would allow augmentation of the KraSnik and Lublin vicinities, in addition to that provided by the above-mentioned existing canal, Wieprz-Krzna. It is a typical example of multi-purposewater transfer, whose functions are linked with the needs of various branches of the national economy. At the same time it may constitute the alternative solution for several projects, each to meet a single function, e.g. groundwater intakes for settlements and transfers or agricultural reservoirs. The final group of hydraulic structures, among basic elements of the Vistula River development,are barrages on the Vistula River itself. Several earlier proposals, suggesting the series of barrages on the Vistula River, were summarized in 1962 in a single report which, since then, is regarded as representing the case for this solution to the problem. In the Vistula River Project the costs in this solution were brought up-to-dateand alternative solutions for certain stretches were presented. Besides, two new proposals were considered: either to decrease the number of barrages on the Lower Vistula River by increase of head and change of location or a change in the function of the dams on the Upper Vistula and also perhaps on the Middle Vistula. The dams, provided with power generating plant, currently proposed would be transformed into barrages built purely for navigational purposes. Both solutions resulted from the tendency to reduce the investment costs while preserving the basic functions of the relevant stretch of the Vistula River cascade. The estimated savings in comparison to the proposal of 1962 indicate that'the possibilities of various interesting solutions have not yet been exhausted and that the consideration of several variants of the Vistula valley development is fully justifiable. 1068 Maciej Jedrysik, Aleksander taski and Jan Zielihski

WATER QUALITY The problem of water quality within the Vistula River basin was reviewed by the estimation of pollution loads in the years 1985 and 2000. These loads refer to the planned economic development of the basin. The capacities of water treatment projects were adopted in the Vistula River Project since they were required as input data for the mathematical model. The capacities were determined by the requirement that every section of the Vistula River and its main tributaries should maintain high standards of water purity as well as by the investment costs in relation to the normal discharges in such sections (which depend upon which plan is adopted). To determine this relation it was necessary (while preparing the initial data) to estimate the possible scope of the flow changes from the existing conditions of the selected sections up to the possible flows resulting from basin development up to the year 2000. This was necessary to allow the proper calculations of water balances in the mathematical model of the water economy to be done.

FLOOD CONTROL The flood losses which were recorded in the Vistula basin during the period of hydro- logical observations as well as the estimated future losses are data necessary to estimate the size of the required flood-controlmeasures and to satisfactorily protect the potential flood areas. The limits of these areas and magnitude of losses were estimated for selected main tributaries of the Vistula River. The relation between the value of loss and the discharge was established for particular sections. Due to the lack of sufficient data the influences of the wave duration as well as the season of flooding were ignored. The reliability of this data is questionable due to the limited statistical material available, and even this for only some of the rivers considered. It results also from the fact that the majority of the Vistula River valley and considerable portions of the tributaries is already protected against flooding by means of levees. Therefore there are not sufficient data to estimate the loss that would be inflicted if the peak stage was higher than the levee crest level.

THE FINAL FORM OF DATA PREPARATION AND FURTHER INVESTIGATION The initial data were combined in the form of diagrams suitable for mathematical models. The diagrams were prepared for each part of the basin according to the initially accepted division. Thus the division on parts called subsystems was introduced to’ facilitate calculations and simultaneously to facilitate the systematic gathering and setting up of the data. The diagrams prepared for the subsystems superimposed on the background of the hydrometric network illustrate the position of the water intake and return points, water gauge and control sections,the minimum acceptable flows on particular stretches of the river, changes of flows, and also the scheme of the hydraulic structures and their mutual relations. The diagrams, together with the tabulated digital values of each group of the initial data, constitute the final material, utilized by the model. The next stage of work, discussed at length in the following two papers, is concerned with the utilization of the mathematical modelling results for the initial choice of the investment programme. The final proposal of such a programme will be formulated after the post-optimization analyses are completed. These analyses will allow for those factors which, for various reasons,could not be accounted for at the mathematical model stage. General description of the Vistula River Project 1069 Shortcomings in preparation of the initial data, as well as the methodological difficulties encountered during the present stage of work will have to be removed in the framework of further studies. It should lead towards a more perfect picture of the basin water economy and an optimum programme ofdhe Vistula basin development. This attitude is reflected in the decision to undertake further studies of the problem, entitled ‘Developmentand preservation of the Vistula River and its basin’ during the years 1971-1975.