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TITLE : Regional and International Aspects ofStrategic Water
Development i nRiparian Countries of the Danub eWatersheds
AUTHOR: Dr . Michael A . Rozengurt
THE NATIONAL COUNCILFOR SOVIET AND EAST EUROPEAN
RESEARC H
1755 Massachusetts Avenue, N .W .Washington, D .C. 20036
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PROJECT INFORMATION :*
CONTRACTOR :
United States Global Strategy Counci l
PRINCIPAL INVESTIGATOR :
Michael A . Rozengurt
COUNCIL CONTRACT NUMBER :
804-2 2
DATE :
March 24, 199 3
COPYRIGHT INFORMATION
individual researchers retain the copyright on work products
derived from research funded b yCouncil Contract. The Council and
the U .S. Government have the right to duplicate written reportsand
other materials submitted under Council Contract and to distribute
such copies within th eCouncil and U.S. Government for their own
use, and to draw upon such reports and materials fo rtheir own
studies; but the Council and U.S. Government do not have the right
to distribute, o rmake such reports and materials available outside
the Council or U.S. Government without th ewritten consent of the
authors, except as may be required under the provisions of the
Freedom o fInformation Act 5 U.S.C. 552, or other applicable law
.
The work leading to this report was supported by contract funds
provided by the National Council forSoviet and East European
Research . The analysis and interpretations contained in the report
are those of th eauthor.
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ABSTRACT
The catastrophic degradation of watersheds of major rivers of
the south of the forme r
U .S .S .R . along with soil pollution has raised international
awareness about vulnerability of river-
estuary-sea ecosystems . Yet, international procedures and
institutions for coping with their environ-
mental economic and political problems are only just beginning
to evolve . Current approaches to the
management of surface water have lacked an international
cooperation in preservation of limited wate r
resources, for they have concerned mainly the economic
utilization of water resources ; the problems
of water depletion and ecological degradation have generally not
enjoyed the same status .
During the past few years, there has been a growing
international concern about environmen-
tal and socio-economic impacts and conflicts associated with the
extensive use of Danube wate r
resources by the eight riparian countries : Federal Republic of
Germany, Austria, Czechoslovakia ,
Hungary, Yugoslavia, Romania, Bulgaria, and the Soviet Union .
In addition, relatively smal l
territories of Italy, Switzerland, and Albania belong to the
Danube catchment area .
Four post-war decades of trial-and-error water development
policies have led to the unprece-
dented environmental degradation of the lower Danube-Black Sea
ecosystem . Consequently, the
current degraded environment constitutes a limiting factor in
regional economic and societa l
development and threatens to damage international stability
among riparian countries . There are
severe shortcomings concerning compatibilities of projects as
opposed to societal demands fo r
upgrading the general quality of life .
A new approach of the International Danube Commission stresses
public acceptance an d
environmental safety of resource development alternatives,
although this approach has not yet becom e
the managerial banner for the Danube riparian countries .
Faced with the need to make decisions regarding the growing
water, soil, and energy defici t
in the region, a set of aggressive programs has developed, which
might upgrade the societal an d
economic conditions of the Danube basin with primary investment
costing about $100 billion over th e
next 10 to 12 years .
This project analyzes the role and quantifies the weight of
various factors (ecological ,
demographic, economic, and political) affecting economic
development in the Danube basin .
Particular attention is given to internal and international
aspects of water development policy in thi s
crucial and sensitive area where soil and water both are major
monetary and political tools i n
pursuing local and international aims.
The project also identifies and provides environmental and
political risk assessment analysis
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a
regarding infrastructural resource planning and development .
The study illustrates the links betwee n
economic growth and the sustainable capabilities of regional
natural resources . This study shed s
considerable light on the cause-and-effect problems of the eight
riparian countries' environmental
economy .
The study addresses some of the crucial issues regarding the
hydrologic regime and majo r
water resources problems of the Danube watersheds . The project
aims to provide a comprehensive ,
preliminary analysis of the significance of the Danube for the
economic development of its riparia n
countries, as well as of the role of existing and proposed dams
for flood control, municipal an d
industrial water supply, hydraulic power, navigation, and
irrigation on the lower Danube and th e
adjacent part of the Black Sea .
Accordingly, substantial attention is paid to an analysis of
conflicting utilization of limited
river water resources which inevitably have triggered the
deterioration of physical and other wate r
quality properties of the Danube environmental systems .
The study underscores that in the course of the current
unbalanced socio-economic develop-
ment of the Danube riparian countries, the necessity for
international co-operation has become
imperative in order to maintain the political and economic
stability of Western and Central Europe .
The study's conclusions are on pages 73 to 77 .
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TABLE OF CONTENTS
I .
INTRODUCTION 1
II . WATER RESOURCES OF THE DANUBE BASIN 6
A. Geographical and Geophysical Settings 6
B. Flow Characteristics 1 6
C. Sediment Transport and Deposition 26
III . HYDROCHEMICAL REGIME AND WATER QUALITY 2 8
A. Water Quality 2 8
B. The Role of the River Impoundment on the Hydrochemical Regim
eof the Danube 32Austria, Czechoslovakia and Hungary 32Yugoslavia
and Romania 37Former U .S .S .R 40Hydrochemical Regime of the Lower
Danube 40
IV. INTERNATIONAL IMPORTANCE OF THE DANUBE BASIN 4 1
A .
The Major Natural Resources of the Danube Basin 4 1Federal
Republic of Germany 4 1Austria 4 1Czechoslovakia 42Hungary
42Yugoslavia 42Romania 42Bulgaria 42Former U .S .S .R 42Cities and
Towns 42
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B. Utilization of Danube Water Resources 43Flood Control
44Federal Republic of Germany 44Austria 47Czechoslovakia 47Hungary
47Yugoslavia 48Bulgaria 48Romania 48Irrigation 49Hydropower 5
1Navigation 58Fishery 63
V . POLITICAL AND ENVIRONMENTAL INTRICACIES 64
A. The Lower Danube Canal 67
B . The Degradation of the Western Black Sea 68
VI. CONCLUSIONS 73
VII . REFERENCES 78
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ANNEXESTABLE OF CONTENTS
ANNEX I .
Declaration on the Cooperation of the Danube Countries on Water
Management an dEspecially Water Pollution Control Issues of the
River Danube 87
ANNEX II .
Environmental Impact Assessment of the Gabsikovo -Nagymaros Dam
System 9 1
* Development of water management in the Danube Valley 9 1
* The purpose of the Gabsikovo-Nagymaros Dam system 92
* The task of planning and design 93
* History of preparatory planning 95
* Environmental concerns related to the project 96
* Some general conclusions of the impact assessment 98
ANNEX III.
Historical Water Development : Waterways, Dam sand Irrigation
100
* Historical Development of Waterworks 100
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Germany 103Austria 104Czechoslovakia 105Hungary 106Yugoslavia
108Bulgaria 109
* Dams and Irrigation 110
Austria 110Czechoslovakia 11 1Hungary112Yugoslavia 11 3Bulgaria
11 5Romania 11 5
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LIST OF FIGURES
FIGURE 1 The Danube River Watershed and Riparian Countries 2
FIGURE 2 Bottom Slope Conditions of the Danube 7
FIGURE 3 Precipitation Over the Danube Watershed 1 2
FIGURE 4 Hydrographic Network of the Lower Danube and its Delta
1 5
FIGURE 5 Left/Right Run-Off Inputs by Major Danube Tributaries 1
7
FIGURE 6 The Flood-Minus-Low Water Fluctuations Along the Delta
1 9
FIGURE 7 Sideways Distribution of Highest and Lowest Marks on
Water 20
FIGURE 8 Daily and Seasonal Upper (Vienna) and Lower (Reni)
Danube Run-OffFluctuations 2 1
FIGURE 9 Geographic Settings of Hungarian Plains 23
FIGURE 10 Relationship Between the Sediment Load and Danube
Run-Off 27
FIGURE 11 Hydropower Plants and Sforage of Danube Watersheds 3
1
FIGURE 12 Gabsikovo-Nagymaros Hydropower Scheme 34
FIGURE 13 Austrian Hydropower Stations 56
FIGURE 14 Schematic Profile of the Danube Slope, Discharges and
Energy PotentialUlm City to the Black Sea (Modified Affer Fekete,
1980) 57
FIGURE 15 Existing and Planned Inner Sfates and International
Shipping Canal sin Central and Eastern Europe 60
FIGURE 16 The Locations of the Four Alternative Routes of the
Danube -Dniester-Dnieper Canal Along the Coast of the
NorthwesternBlack Sea (NWBS) 62
FIGURE 17 The Major Hydropower Plants of the Black and Azov
Seas' Watershed 72
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LIST OF TABLES
TABLE 1 The Main Characteristics of the Danube River Subdivided
by Navigatio nStretches 8
TABLE 2 The Major Tributaries of the Danube 9
TABLE 3 Characteristics of the Danube Flow 25
TABLE 4 Extreme and Average Discharges Along the Danube Course
25
TABLE 5 Some Multilateral and Bilateral Agreements Having an
Impact on th eDanube 30
TABLE 6 Major Pollution Sources Along the Entire Danube 33
TABLE 7 Bacteriological Water Quality 36
TABLE 8 Danube Organic Discharges to the Black Sea and Fish
Catch 36
TABLE 9 Some Indicative Hydrochemical Parameters of the Danube
Water . . 38
TABLE 10 Average Seasonal Distribution of Phosphates and
Nitrates Near the Danub eDelta 3 9
TABLE 11 Water Consumption of Danube Riparian Countries 45
TABLE 12 Land Resources and Their Utilization 4 6
TABLE 13 Existing and Planned Hydropower Stations in the Danube
Basin 53
TABLE 14 The Water Storages of the Danube Watershed 54
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ACKNOWLEDGMENT
The author would like to thank first of all the National Council
for Soviet and East Europea n
Research for the funding and patience that allowed him to
initiate and carry on the study . The author
would like to extend his appreciation to Dr . Robert Randolph,
Dr . Vladimir Toumanoff (NCSEER)
and Dr . Dalton West for their thoughtful support of this study
. The author would also like to expres s
his thanks to the United States Global Strategy Council who
supported this project .
He would like to express special thanks to his assistant, Mr .
Elena London, M .S ., whos e
enormous help made this study complete .
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Regional and International Aspects of Strategic Water
Development in Riparian Countries of th eDanube Watersheds
Dr. Michael A. Rozengurt
I .
INTRODUCTION
The demand of policy makers and managers to find environmentally
sound and sustainabl e
economic development requires the interdisciplinary analysis of
versatile systems consisting of natural ,
economic, and social elements of the environment .
The formulation of environmentally sound management policy for
land-use and wate r
resources development requires the reliable prediction of the
impacts of different human interventions
in order to mitigate conflicts between population and
infrastructure, and to preserve the quality of lif e
(Alheritiere, 1985 ; Salewicz, et al ., 1990) .
In this respect, the Danube watershed comprises all
controversial features because of : 1) the
international character of the river (there are eight riparian
countries and four others sharing a smal l
part of the catchment; Benedek and Lászlo, 1980) ;
2) extensive utilization of water (impoundment, canalization,
transboundary pollution, seasonal wate r
shortage); and
3) the self-centered efforts of the riparian countries for water
resources development within their
respective parts of the basin (e .g ., an upstream water use
ignoring the needs of downstream
countries) .
The Danube River crosses the borders of eight European countries
with different politica l
regimes, levels of economic development and ethnic
characteristics (Figure l) . Three of the riparia n
states (Austria, Hungary, and Romania) lie completely within the
Danube catchment area . Here the
water-related sectors of the economy and large-scale ecosystems
are entirel y
dependent upon the water resources of the Danube or its
tributaries . Even the countries which li e
along only short stretches of the Danube or touch the river
marginally (Czechoslovakia, Bulgaria . and
the former U .S .S .R.) have introduced large-scale schemes for
extensive exploitation of the Danub e
via diversions or hydroenergy projects .
Rapidly increasing demands for multipurpose exploitation of the
river calls for environmental-
ly-sound, coordinated international management compatible with
national development schemes . Thi s
trend in international cooperation is buttressed by growing
concern over degradation of diverse natura l
ecosystems closely related to complex surface and groundwater
settings (Linnerooth, 1988 ; Domokos
and Saas, 1986: Sokolovsky, 1988, 1991) . In recent years,
national integrated river basin develop -
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P O L E N
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ment schemes have been marked by enthusiasm at the prospect of
generous revenues from the touris t
industry and from improved and expanded navigation through the
Rhine-Main-Danube and th e
Danube-Labe-Elbe (ECE, 1980 ; Fekete, 1980; Information 1976).
In addition to the construction o f
numerous impoundments and flood control facilities on the
tributaries and the river itself (Matrai ,
1975), large-scale irrigation and drainage schemes have become
one of the major priorities of th e
Danubian countries. Among them, Moldova and South Ukraine are
the two countries whose interes t
in Danube water utilization makes other countries, especially
Romania and Bulgaria, very suspiciou s
and resentful .
The southwest area of the former Soviet Union, which gravitates
to the Dniester and Danub e
basins, is of critical importance to the Moldovan and Ukrainian
economies . It produced 25% of the
former Soviet food supply and 30% to 50% of Soviet iron, steel,
and machinery . The region also
lies in a vital path of commerce, infrastructure, and
environment of other central European states an d
trade with the outside world .
The Southwestern Economic Region (SWER) of the former U .S .S .R
. contains over 3,000
natural lakes of 2,000 km 2 surface area and over 18,000
reservoirs that have inundated 8,000 km 2, or
18% of the total reservoir-flooded area in the old Soviet Union
. The SWER is drained by 23,00 0
streams and rivers with a combined length of 90,000 km . Of
their total runoff, 62% ultimately drain s
to the Black Sea, 27 .7% through the Dnieper (54 km 3 ) and 23
.7% via the Dniester (10 .2 km 3), and
9 .3% via the South Bug (8 km 3 ) . The Danube River's current
regulated run-off equals 170 to 200
km 3 per year .
The SWER is about the size of Texas and slightly larger than
France . Over 71% of the total
area of 60 .4 million hectares is agricultural . The region has
the densest irrigation network in th e
former Soviet Union, consuming 60% to 85% of its total water
resources . Almost 5 .5 million
hectares (nearly 25% of all Soviet irrigated land) spread over
the northern Crimea, Dnieper-Donbas ,
Dnieper-Krivoy-Rog, and Danube-Dniester regions . In 1987, the
53 million people of the SWE R
produced over 26% of the former Soviet Union's wheat, 32% of its
corn, 58% of its sugar beets ,
42% of its sunflowers, 38% of its vegetables, 23% of its milk,
30% of all cattle and hogs, and 20% -
25% of the nation's wine. Rich "chernozem" (black earth) soils
support the densest farmin g
population found anywhere in the former U .S .S .R . and include
patches of its most bountiful farmlan d
(Gerasimov, 1972 ; Stolylik, 1987) .
The cascade of ten hydropower plants (two on the Dniester, and
eight on the Dnieper) jointl y
represent the single greatest power generation network in the
European portion of the forme r
U.S .S .R. (Baksheyev and Laskavyi, 1983) . Still, these plants
produce almost 30% less power than
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anticipated due to the lack of adequate flow to reservoirs to
drive these plants . In addition, they give
up 20% of water to evaporation and 15% to 40% to the
agricultural drainage network, thereb y
exacerbating the regional water shortage . Heavy impoundment of
numerous rivers has retarded th e
hydrological processes, stimulating eutrophication and leading
to increased pollution in the majority o f
water bodies and ground water of the SWER. Atomic and thermo
power plants heat the streams with
their coolant discharge and represent a continuing threat to
Southwest population and environment .
Thus, the quality of freshwater intakes serving nearly 60
million people is affected . Regional losses
to the fishing industry amount to several hundred million rubles
annually (Braginsky, 1986 ; Rozen-
gurt, 1991) .
On the average, annual per capita water consumption in the
Soviet Union is 20,000 meters 3 ,
while in the SWER consumption varies between 1,100 meters 3 in
the north and 226 meters 3 in the
south of the region .
A provocative circumstance is that this chronic water shortage
occurs in close proximity to th e
Danube, for less than 1% of Danube run-off originates from
Soviet land and the river skirts only 13 4
km of Soviet territory (about 4 .7% of the stream's total
length) . Yet Soviet planners have proposed
withdrawing up to 28 km 3 annually from the Danube to irrigate
an additional 1 .5 million hectares of
the SWER arable land for this area faced with a dire water
shortage for irrigation, industry, power
generation, and drinking (Zvonkov and Turchinovich, 1962) .
The projected appalling destruction of soil, ground water
supply, fisheries, and othe r
resources in the previously healthy Romanian productive coastal
zone has stirred up a vigorou s
political and environmental campaign of protest from the
Romanian authorities and scientifi c
community . (Oddly, under the shadow of environmental and
economic disasters in Soviet Centra l
Asia, and despoliation of Aral Sea, the environmental problems
of the Black Sea and the southwes t
region of the former U .S .S .R. have largely escaped
international scrutiny . )
At the same time, independent Romania has its own plan for water
and other river resources .
Romanian riparian claims stem from the natural course of the
Danube River--40% of the Danube' s
length lies in Romania as well as over 80% of its residual
run-off and most of the Danube Delta . The
Danube serves 60% of the irrigated land in Romania, 85% of its
valuable fisheries, and internationa l
shipping. Moreover, Romania is planning to provide a significant
amount of water to Bulgaria
(Rojdestvensky, 1979) .
As a result, the rising conflicts between national and
international interests concerning wate r
allocation between the infrastructures of neighboring countries
have reached alarming proportions .
To cope with a formidable array of diverse problems, the Danube
Committee was created in the late
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1960s . The rationale for this committee was to get actively
involved in environmental, political, an d
economic issues of acute consideration (such as water
availability versus economic development ,
pollution, and indiscriminate exploitation of the Danube Delta),
to seek alternative environmenta l
policy measures designed to mitigate the distortion of natural
resources, and to preserve a "brother -
like" relationship between neighboring countries . However,
almost two decades of uncertainties i n
economic priorities and in the political fate of the leadership,
as well as rival interests of upper ,
middle, and lower river development, have downgraded the
effectiveness of many programs addresse d
to the restoration and preservation of natural values of water,
fish, and soil in the different parts o f
the river course . Some of these problems of resources
utilization are examined in this projec t
(Al'tman, 1982; Salewicz et al ., 1990) .
The economic activities in the Danube basin are documented in
numerous publications an d
initial appraisals were prepared for basic water projects
(Zvonkov and Turchinovich, 1962 ; Fekete ,
1972) . However, the man-induced modifications in volume and
flow patterns of the Danube at it s
exit to the Black Sea have been subjected to superficial
evaluation . The same is true for the complex
interactions between various surface and underground water
systems along the river. In addition, the
water consumption records have not ordinarily made distinctions
between the Danube and its tributary
basins, particularly for the countries with multi-basin
hydrography . As a result, the accumulation o f
uncertainties coupled with the construction of barrages have
raised serious environmental concern s
among riparian countries (for example, in Hungary and
Czechoslovakia in connection with th e
Gabsikovo-Nagymaros barrage system now under construction
[Appendix III) . The problems o f
upstream and middle Danube have been further complicated by the
degradation of the Danube delta .
Note that the Delta functions as a huge hydraulic and chemical
plant which redistributes the rive r
discharge, affects sediment transport and resuspension, and
transforms the chemical makeup of th e
Danube water by biochemical interactions between fresh and sea
waters and their rich vegetation ,
river borne organisms, and brackish water biota (Almazov, 1962 ;
Simonov, 1969 ; Tolmazin et al . ,
1977) .
In this regard, particular emphasis is given in this report to
those regions and activities which
have reduced water availability either through negative
hydraulic reshaping of the basin, or wher e
negative trends in chemical composition of run-off can be traced
. Information on the various aspects
of the Danube regime and related activities has been generalized
from scientific reports, pres s
releases, and other documents written in the languages of the
riparian countries (German, Hungarian ,
Czech, Slavic, Bulgarian, and Romanian), as well as in English
.
There are three annexes to this report : the first is the
Declaration by the riparian countries
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signed in December 1985 ; the second is a summary evaluation of
the environmental impac t
assessment of the Gabsikovo-Nagymaros barrage system ; and the
third provides a historical view of
water development in the Danube watershed .
In the Declaration, representatives of the eight riparian
countries recognized that the obstacle s
hindering the reasonable utilization of water resources could be
removed only by joint efforts . They
also reached understanding concerning the institutional
framework of the programs to be implemente d
in the fields of water quality control, flood protection, and
general water management among th e
relevant authorities of the eight countries .
The following description of the entire Danube drainage system
is intended to identif y
vulnerable spots where the flow characteristics are most prone
to anthropogenic modifications .
II. WATER RESOURCES OF THE DANUBE BASIN
A .
Geographical and Geophysical Settings
The Danube is the 21st longest river in the world and the second
longest in Europe . Its basin
of 817,000 km 2 represents 8% of the area of Europe (Figure 1) .
The creeks Breg and Brigach, with
their springs in the Black Forest at a height of 1078 m get a
new name--Danube--downstream of thei r
confluence at Donaueschingen . Between this point and the Delta
the elevation difference is 678 m
and the length of the river is 2857 km. Figure 2 . shows the
bottom slope conditions of the rive r
Danube .
About 120 rivers flow into the Danube (the most important
tributaries are given in Table 2) .
The Danube is divided by mountain ranges into three sub-basins :
The Upper Danube, for the
headwaters to the mouth of the Morava River ; the Middle Danube,
from the Morava mouth to th e
Iron Gate Gorge; and the Lower Danube, from there to the Black
Sea .
The Danube receives waters from high mountains and their
foothills, from highlands, plains ,
lowlands, and depressions. Therefore, its character varies from
a high-mountainous stream to a
lowland river (Table 1) .
The Upper Danube basin covers the territory from the source
streams in the Black Fores t
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FIGURE 2
Bottom Slope Conditions of the Danube
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TABLE 1The Main Characteristics of the Danube River :
Subdivided by Navigation Stretches
Stretches ofthe Danube
Distancefrom the
Lengthof the
Width (m) Current velocityat
Numberof
Minimum depth(m)
mouth in stretch river-bed at Low Nay .river km in km navig .
Highest Nav, WL Bridges WL at Lowest
channel Low Navigabl eWater Level
(km/h)
Locks Water Level
Regensburg - 2379 - 153 150-300 10,30-4.60 13 1 .85-2 .00Passau
-2226 40-100 4 .70-2 .80 1 1 .20
Passau - Linz 2226 - 91 200-400 11 .60-6.60 4 2 .00- 2135
120-150 6 .30-4 .20 3 2 .00
Linz - Vienna 2135 - 206 250-400 11 .60-11 .30 14 2 .00- 1929
120-150 7 .20-6 .30 3 1 .30
Vienna - Gönyü 1929 - 138 300-500 11 .40-7.00 10 2 .50- 1791
75-150 7 .10-3 .90 - 1 .30
Gönyü - Budapest 1791 - 144 350-600 7 .80-6 .70 6 2 .50- 1647
100-180 3 .90-3 .10 - 1 .30
Budapest - 1647 - 599 600-1300 7 .80-5 .69 12 2 .50Moldova Veche
- 1048 100-180 3 .67-2 .72 - 1 .60
Moldova Veche - 1048 - 117 600-1300 6 .19-0 .96 1 3 .50Drobeta -
Turnu - 931 100-180 2 .39-0 .87 1 3 .50Severin
Drobeta - Turnu 931 - 761 600-800 8 .85-4 .25 3 2 .50Lower
Severin - Braila - 170 150-180 3 .60-1 .83 l .80
Braila - Sulina 170 - 170 800-150* 6 .98-6 .34 - 7 .30- 0 1i
J-60* 2.81-1 .94 7 .30
* Sulina-Canal
SOURCE :Annuaire statistique de la Commission du Danube pour
1976, Commission du Danube . Budapest - 1977 .
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TABLE 2The Major Tributaries of the Danube (RZdD, 1986)
Mouth at Danube kin Side Length km Catchment area A, km 3
Iller 2,588 right 172 2,125
Lech 2,497 right 254 4,12 5Altmühl 2,411 left 224 3,25 6
Naab 2,385 left 191 5,508
Regen 2,379 left 191 2,874
Isar 2,282 right 283 8,964
Inn 2,225 right 515 26,130
Traun 2,125 right 146 4,277
Enns 2,112 right 349 6,08 0
Ybbs 2,057 right 131 1,293
Kamp 1,981 left 147 2,13 4
March/Morava 1,880 left 329 26,658
Mosonyi Duna (Lajta, 1,794 right 18,06 1Raba, etc . )
Val 1,766 left 378 10,64 1
Hron 1,716 left 284 5,46 5
Ipel' 1,708 left 233 5,15 1
Sid 1,497 right 190 14,72 8
Drau/Dráva 1,384 right 707 40,150
Tisza/Tisa 1,215 left 966 157,220
Sava 1,171 right 940 95,71 9
Temes 1,154 left 371 16,224
Velika Morava 1,103 right 245 37,444
Timok 846 right 184 4,630
Jiu 692 left 331 10,07 0
Iskar 637 right 368 8,646
Olt 604 left 670 24,01 0
Jantra 537 right 286 7,86 2
Vedea 526 left 215 5,45 0
Arges 432 left 327 12,59 0
lalomita 244 left 400 10,43 0
Siret 155 left 726 47,61 0
Prut 134 left 967 27,540
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Bottom Slope Conditions of the Danube Mountains down to the
Devin Gate eastward from Vienna . I t
includes in the north the territories of the Swabian and
Falconian Mountains, parts of the Bavarian
Forest and Bohemian Forest down to the Austrian Mühl and
Waldviertel, and the Bohemian-Moravia n
Uplands .
Southward from the Danube extends the Swabian-Bavarian-Austrian
foothill belt, comprisin g
major parts of the Alps up to the watershed of the Central Alps
.
a. The Upper Danube forms a narrow valley across the wooded
slopes of the Bavaria n
plateau and the Austrian Alps . Tributaries, particularly the
Inn (Figure 1) cause the river to swell .
Climatically, the upper reaches in the Federal Republic of
Germany and in Austria lie in a transitio n
zone between the maritime north-west of Europe and the
continental masses of the former U .S .S .R. .
The average annual temperature in the valleys ranges between 7°C
and 10°C ; in the mountains it may
drop to below -6°C . The snow cover lasts from 30 to 90 days in
the valleys ; in the mountains th e
snow does not melt before the first summer month .
b. The Middle Danube basin, a magnificent and unique geographic
unit, spreads fro m
the Devin Gate, dividing the last promontories of the Alps
(Leitha Mountains) from the Littl e
Carpathian where the confluence of the March/Morava and Danube
takes place, to the mighty faul t
section between the Southern Carpathians and the Balkan
Mountains near the Iron Gate Gorge . The
Middle Danube sub-basin is the largest ; it is confined by the
Carpathians in the north, by th e
Karnische Alps and Karawanken, Julische Alps in the east and
southeast, and by the Dinari c
Mountains in the west and south . This closed circle of
mountains embraces the South Slovakian an d
East Slovakian Lowland, the Hungarian Lowland, and the
Transylvanian Uplands . This agricultural
land is known as the Little Hungarian Plain ("Kissaföld") . From
there the river passes through a
gorge between the Western Carpathians and the Transdanusian
Mountains (near Nagymaros) onto th e
Great Hungarian Plain .
The Danube, meandering through the Hungarian plains, has caused
the flooding of their low -
lying shores . Approaching the Iron Gate Gorge, the volume of
the Danube flow is increased by run -
offs of the Sava, Drava (from the Dinaric Alps), and Tisza (from
the Carpathians) .
The Drava (Drau, the Italian Alps) drains the slopes and
glaciers of the Austrian Alps ; i t
provides a natural border between Yugoslavia and Hungary . This
river empties into the Danube at
the lower end of the Great Hungarian Plain .
The Sava (933 km long) originates near the Yugoslavian-Italian
border and drains portions o f
the Dinaric Alps and the mountainous slopes of Bosnia and
Herzegovina. This river is the larges t
Danubian tributary below its confluence with the Drina, which
drains the southernmost parts o f
1 0
-
Yugoslavia . The Mediterranean climate of this region is
characterized by average summer tempera-
tures of 22-25°C, and 7-11°C in winter . The total average
annual rainfall over Yugoslavia equal s
975 mm, but its distribution is irregular and erratic (Figure 3)
. Frequent droughts occur in th e
plains .
The Tisza receives its water from the Upper Western Carpathians
and from numerou s
tributaries lying to the east along the course of the river
.
The Danube valley has a mostly continental climate influenced by
air currents from th e
Atlantic Ocean and the Mediterranean Sea . The weather is marked
by significant interannual
variations in humidity . Wet periods of three to four years may
be followed by subnormal or dr y
periods of seven to nine years, including two to three extremely
dry years . However, the Danub e
run-off may not follow these climatic variations since most of
its water originates from upper reache s
of the Danube network .
The annual mean air temperature within the plains is about 11°C,
ranging from minus 8°C i n
January, to 30-35° in July - August . The average value of the
evapotranspiration is 600-700 mm pe r
year, and in dry periods may rise up to 1,000 to 1,500 mm . The
average precipitation ranges from
550 mm ± 300 mm/y in the plains to 800 mm in the hilly area west
of the Danube, of which abou t
8% originates from snow . The amount of precipitation rapidly
increases southwest in the mountain s
of Yugoslavia .
The average precipitation over the Danube basin is as much as
1,200 mm, but it is typified b y
large spatial variations . The highest rainfall is observed in
July and August . In Moravia (Czechoslo-
vakia) the climate is more continental with average rainfall of
about 500 mm . Here the rainfal l
season is spring .
c .
The Lower Danube basin is composed of the Romanian-Bulgarian
lowland, the Sire t
and Prut river basins, and the surrounding upland plateaus and
mountains . It is confined by the
Carpathians in the west and the north, by the Bessarabian upland
plateau in the east, and by th e
Dobrogea and the Balkan Mountains in the south . At the Prut
mouth the Dobrogea promontorie s
project into the Bessarabian upland plateau .
The lower Danube crosses the lowlands of the Wallachian Plain
which constitutes about 33 %
of Romanian territory . The elevation increases to the north,
forming hills and tablelands . The deep
interior depression of Transylvania has an average altitude of
400-600 m and is bounded to the nort h
by the Carpathian Mountains (altitudes over 2,500 m) . South
Transylvania is separated from th e
lowland by a belt of low hills less than 1,000 m in height .
There are several rivers which drain to
1 1
-
FIGURE 3
Precipitation Over the Danube Watershe d
1 2
-
1 3
-
FIGURE 3 (P2) the west into the Tisza . Large tributaries -- the
Siret, Bistritsa, and Prut -- join th e
Danube at its final turn to the Black Sea . Smaller rivers such
as Jalomita, Arges, Olt, and Jiu
originate in the hilly belt . To the south of the Lower Danube
is the hilly Danubian plain with
altitudes ranging from 100 to 600 m, but further south the
height generally increases up to 2,900 m
(fhe Balkan Mountains) . From the northern, Bulgarian side, the
principal tributary is the Iskar River .
After turning north from the Romanian-Bulgarian border, the
Danube divides two tablelands ,
Dobrodgea to the east and the Moldavian tableland to the
northwest . Below confluence with the las t
tributary, the Prut, the river again turns east . The Danube is
crowned by a huge delta of 5,460 km 2
where three major tributaries direct the Danube water to the
Black Sea (Figure 4) .
The lower Danube has a temperate continental climate of a
transitional type, with sligh t
oceanic influences from the west, Mediterranean influence from
the southwest, and continenta l
influence from the north . The summer is milder than in the
Hungarian Plains with average tempera-
tures of 22°C to 24°C in July and August . In winter, the
average temperature drops below minu s
3°C . The annual average temperature ranges are 10° to 11°C in
the plains, 7° to 10°C in the
foothills, and less than 6°C in the Carpathians . The hilly and
mountainous regions in Bulgaria are 2 °
to 4° warmer than in Romania .
The average annual precipitation steadily increases from the
lowlands 400-600 mm to 800 -
1400 mm. The bulk of precipitation falls from October to June .
Many areas experience an annua l
drought because of the uneven precipitation pattern and
increased evapotranspiration in the summer .
The distribution of the Danube among its riparian countries is
as follows :
In the Federal Republic of Germany, from the confluence of the
streams Brigach and Bre g
down to the Austrian border, the Danube flows a distance of 550
km . A reach about 180 km long i s
narrows where the Danube cuts its way through mountain ridges .
On a stretch about 400 km long ,
the Danube passes through wide valleys (RZdD, 1986) .
The Austrian Danube is about 350 km long, including a 21 km
frontier reach with the FR G
and one of about 8 km with Czechoslovakia. About 150 km in
sections are narrows in which th e
Danube cuts its way through mountains . About 200 km of the
Danube pass through the valleys o f
four large basins . The descent of the Danube in Austria is
about 150 m .
The Czechoslovak portion of the Danube on the left (northern)
river bank reaches from th e
mouth of the Mach/Morava River about 172 km downstream to the
mouth of the Ipel'/Ipoly . The
Czechoslovak section of the right (southern) river bank is only
22 .5 km long, the remainder being an
8 km frontier with Austria, and a 142 km border with Hungary
.
The Hungarian Danube reach is 417 km long, including 142 km of
the border wit h
1 4
-
FIGURE 4
Hydrographic Network of the Lower Danube and its Delta
27°E
28°E
29° E
27°E
28° E26° E
-
Czechoslovakia . The Danube starts on the mighty alluvial fan of
the stream at the upper margin o f
the Pannonian Basin and extends as far as the center of this
basin .
The Yugoslavian Danube is about 587 km long, with 358 km in the
Pannonian Basin . Along
this first reach, the slope of the river is only 0 .05-0.04 per
mile . Upstream from the fault gorge
section at the Iron Gate, close to the mouth of the Nera River,
it creates a common border wit h
Romania and remains a frontier river down to the Timok mouth,
about a 229 km stretch . In the
downstream direction, the Danube is a frontier river between
Romania and Bulgaria on a 472 km
reach. The Romanian Danube flows through a 1075 km reach of the
country, starting in the middl e
Danube above the mountainous reach of the Iron Gate and
extending to the Black Sea ; therefore ,
Romania occupies the largest portion of the Danube course . Out
of this total length, 229 km border s
Yugoslavia between the Nera and Timok rivers, and the 472 km
long section is the border with
Bulgaria . Downstream from the Prut, the Danube forms the border
with the former Soviet Unio n
(about 80 km down to the bend of the Kilia branch of Danube
Delta and thence to the Black Se a
estuary . (RZdD, 1986) .
The Danube Delta, covering an area of 5640 km 2 . is the second
largest one in Europe (Figure
4). Eighty percent of it belongs to the former Soviet Union and
20% to Romania .
B.
Flow Characteristics
The Danube basin exhibits a large variety of topographic
features that affect the regimes of it s
watercourses . The abundance of water in the dense and branching
river network is guaranteed by a
snowpack over high elevations in the Bavarian plateau, the
Austrian and Dinarie Alps, and th e
Carpathian Mountains to the north . These mountains solicit
moisture from the cyclonic atmospheri c
patterns of an adjacent part of the Atlantic Ocean and the
Mediterranean which frequently pas s
Southeast Europe . The Danube basin contains about 300
tributaries . Mountainous flows contribute
up to 66% of the total river run-off . The right-shore
tributaries provide more than two-thirds of th e
total flow (Figure 5) .
Although the range of instantaneous river run-off may vary
considerably ,
the interannual variability in the total river discharge is
relatively small . For the period 1861-1975 ,
the mean value was 6283 m 3 /s (198 km 3/yr), the minimum value
was as low as 3340 m 3 /s (105
km2/yr) in 1863, and the maximum reached 9540 m 3 /s (301 km 3
/yr) in 1915 (Almazov, 1967;
Reimers, 1988) .
The Danube water regime due to its alpine character is
relatively balanced . The rates of the
extreme discharges are 1 :40 at the upper section, 1 :15 at the
middle (Budapest), and 1 :8 - 1 :9 at the
downstream reaches. The annual historical run-offs equal 44 km 3
at Passau,
1 6
-
FIGURE 5
Left/Right Run-Off Inputs by Major Danube Tributarie s
1000 Cubic Meters Per Second
17
-
74 km 3 at Budapest, and 200 to 209 km 3 at the Black Sea (as
computed for 55 to 60 years of
unimpaired run-off conditions) . The difference between the
extreme water stages is about 8 to 9 m
along the river .
Water exchanges between surface and ground waters in the Danube
basin determine losses o f
water via evaporation and evapotranspiration . These processes
largely affect the seasonal run-of f
fluctuations, which are by themselves topographically dependent
. An example of observed seasonal
fluctuations along the Danube (Figure 6) shows that the highest
fluctuations in the alpine section o f
the river (between Ulm and Linz) is clearly related to rapid
changes in flow rate in the mountainous
rivers . The floodwater is substantially lower and less variable
along the stretch downstream o f
Bratislava to Komaron for here, immediately below the Hungarian
Gates Gorge near Bratislav a
(Czechoslovakia), the Danube enters the Little Hungarian plain
.
After emerging from the Visegrad Gorge between the foothills of
the Western Carpathian an d
the Transdanubian mountains, the Danube flows along the western
margin of the Great Hungaria n
Plain. Along this reach, water level fluctuations are relatively
small . Further south, flux of the thre e
major tributaries, the Sava, the Drava, and Tisza, in
combination with the constriction at the Iro n
Gates, causes the local development of typical seasonal
fluctuations (Figure 7) .
In the course of the 800-kilometer lower stretch of the Danube,
floodwater heights above th e
low water are essentially uniform ; downstream from Braila and
to the delta, floodwaters can b e
affected by the wind-induced surges along the coast .
The flood-minus-low water curve along the river length (Figure
6) is nicely complemented b y
the curves of sideways spreading of water during the highest and
lowest waters (Figure 7) . Two
constrictions at Visegrad and at the Iron Gates clearly separate
three flatland regions, the Little an d
Great Hungarian Plains, and the Wallachian Plain where the width
of the river changes dramaticall y
with the seasons .
Patterns of flow variability by time at different stretches of
the river can be exemplified b y
comparison of year-round daily fluctuations of run-off in
various places . At a site near Vienn a
(Figure 8) the flow still preserves its original alpine
characteristics (sharp fluctuations, non-unifor m
nature) . Near the delta (Reni), the seasonal run-off pattern is
greatly modified by topographical an d
hydraulic features of the tributaries . In the lower Danube,
day-to-day variations are much smaller
than upstream, but the seasonal character is well-pronounced
.
1 8
-
FIGURE 6
The Flood-Minus-Low Water Fluctuations Along the Delta
-
FIGURE 8
Daily and Seasonal Upper (Vienna) and Lower (Reni) Danube
Run-Off Fluctuation s
Discharge in 10 3m 3/s
-
Little and Great Hungarian Plains
After the Danube enters the Little Hungarian Plain (Figure 9)
the velocity of its run-off is
significantly reduced . Along the 10 km common
Czechoslovakian-Hungarian stretch, the botto m
slope decreases from 4 cm/100 m to 1 .5 cm/ 100 m and becomes
nearly constant at 0 .6 cm/100 m
near Komaron . The flow transport capacity abruptly decreases,
so that gravel and sand settle on th e
bottom . As a result, the river divides into three branches .
(Note that this site has a shallo w
underground reservoir of 10 to 12 km 3 which occupies about 1620
km 2 near Zitni Ostrov [Benedek
and Lászlo, 19801 . This storage recharges the Danube in the
summer and provides a domestic supply
for the nearby settlements at a rate of 17 m 3 /sec . )
Below the Budapest metropolitan area the meandering Danube flows
across the vast Great
Hungarian Plain . The riverbed is shallow and marshy because of
erosion . This aggravates navigation
and necessitates intensive dredging (Matrai, 1980) .
The southernmost flow regime of the middle course is controlled
by the hydroenergy comple x
built near the Iron Gates (Janko, 1978) . The backwater from the
dam reaches upstream as far as
Belgrade . The dam reduced annual suspended sediment loads from
23 .8 x 106 tons to 3 .5 x 106 tons .
These sediments fill the numerous potholes in the bed of the
reservoir . Prior to control, thes e
sediments were deposited on the Wallachian Plain or the seaward
edge of the delta .
The Lower Danube
The lower Danube is mostly controlled by the run-off from the
Carpathian reach of Romani a
and to a much lesser degree by run-off from the Bulgarian side .
Romania has 115,000 km of natural
waterways, equivalent to a density of 0 .49 km/km 2 of
territory, but the figure falls to 0 .27 if
consideration is restricted to the 66,000 km of rivers exceedin
g
5 km in length. In general, this density varies across the
country from 0 .50-1 .30 in the mountains to
0.30 between the Siret and Prut and falls below 0 .1 in the
Wallachian plains . The total flows of th e
interior rivers (excluding the Danube) average approximately
1,200 m 3/sec (38 km 3 /yr) . With the
Danube water supply, the total increases to 5,450 m 3/sec (172
km 3 /yr) . However, a significant
volume (nearly 85%) of renewable water gravitates to the main
course of the Danube (norther n
Romania) . Substantial water deficits are obdserved in all
counties of southern and eastern Romania .
Romania's considerable fresh ground water surplus equals 8 .5 km
3 /yr, of which 4 .5 are
economically exploitable . Such waters are of crucial importance
for Dobrogea where they provide fo r
the sharply-rising demands of Constanta and the Black Sea
holiday resorts . However, the rest of the
ground water surplus (nearly 75% of the total) consists mainly
of highly mineralized waters wit h
22
-
FIGURE 9
Geographic Settings of Hungarian Plains
-
curative properties, arising from contact with salts and gas
emanations at depth .
The Danube Delta
The Danube Delta covers 5,640 km 2 . This area is divided into
the fluvial delta (47 .5%), the
fluvio-marine delta (30 .2%), and the southern Razelm-Simoe Lake
complex (20 .3%) (Figure 4 in
circles 7 and 8) .
Much of the delta consists of artificial canals, small lagoons,
ponds with dense vegetation, an d
many sandbanks which support inner delta agriculture and
settlements (Shvebs, et al ., 1988) .
The branching point of the delta, where the river divides into
the Chilia and the Tulcea arms ,
lies several kilometers upstream . The Chilia arm, in turn,
ramifies into several arms of which the
Dehakov and Haro-Stanbul arms are the largest . One of fhe arms,
the Prorva, has been converted b y
Soviet authorities into a navigation channel .
In the upper reaches the Chilia arm is 400-600 m wide and 18-26
m deep, but become s
shallower (4-6 m) and narrower seaward . The Tulcea channel is
also large (300-500 m wide an d
about 7 m deep) . About 17 km downstream the Tulcea arm
bifurcates into the Sulina and the St .
George arms . The Sulina arm of 69 km length and 120-200 m width
is the major navigation route i n
the delta; its 8 m depth is maintained by dredging . Jetties
extending into the Black Sea provide saf e
entrance into the Sulina branch . These were some of the major
shipping branches in 1950 through
1960 .
The St. George (Sfintu Gheoghe) is the most sinuous arm in the
entire delta. It is 109 km
long and 300-400 m wide . The depth steadily decreases from 5-8
m in the upper and lower reache s
to 1 .5 m in the mouth .
In the north the Danube delta borders the low-lying Budzhak
plateau . Several large lakes
with mineralized waters are hydraulically connected with the
Chilia branch (Figure 3) . These lakes ,
the Yalpukh, Kurgul', Katlabukh and Kitai collect water draining
from the north via a number o f
small streams . The western boundary runs from the branching
point along foothills of the Dobroge a
flatland and includes the Razelm-Sinoe lake-lagoon complex .
Water levels vary with flows (Table 3) . Floodwaters may occur
at any time of the year, bu t
maximum flood usually is in spring and early summer . Minimum
flows occur from October to
January . High water causes flooding over 95% of the delta .
Storm surges play an important role i n
the level regime . Usually their influence is restricted by the
marine edge of the delta . However ,
during low-flow periods, wind-induced oscillations may reach the
delta apex . This effect is particu-
larly pronounced during winter storms .
In the navigational arms of the Prorva and the Tulina, the salt
wedge penetrates man y
24
-
TABLE 3Characteristics of the Danube Flow
MONTHS WITH FREQUENT
REGION RIVER RUN-OFF IN M'/SE C
Low Water
Mean Water
High Water Low Water
High Wate r
The upper course (after the conflu - 850 2050 10900 X - III V -
VIII
ence with the Morana)
The middle course (Iron Gates) 1800 5600 16000 VII - IX V - VI,
X
Before branching in the delta 2000 6430 19200 VII - VIII V-
VI,IV - X
The Chilia arm 4244 VII - VIII V - VI, IX - X
The Sulina arm 386 VII - VIII V - VI,IX - X
The St . George arm 1800 VII - VIII II - VI,IX - X
SOURCE: Atlas (1972-1986) .
TABLE 4Extreme and Average Discharges Along the Danube Cours
e
Q. Min. Q. Average Q. Max .
m 3 / s
Passau 280 1 .470 8 .700Vienna 390 1 .920 10 .500Budapest 650 2
.340 9 .500Belgrade 1 .400 5 .300 13 .500River Mouth 2.000 6 .430
19 .200
25
-
kilometers upstream, particularly in low flow years (Simonov
1969 ; Bondar, et al ., 1973) . The
interface between freshwater and Black Sea water is marked by a
vertical salinity gradient of about 3 -
4 ppt/m .
C .
Sediment Transport and Deposition
The sediment regime of the Danube is typified by two features :
the bed-load at the upper
section and the suspended load at the downstream section .
The annual average bed load is 0 .5 million tons at Linz and 1
.0 million tons at Vienna ;
downstream of Bratislava, on the upper (common
Czechoslovakian-Hungarian) section, 0 .6 million
tons/year of gravel has to be dredged .
Before excessive river impoundment of the downstream section,
suspended load was
predominant. On the middle section, the average annual suspended
load was equal to 5-6 millio n
tons ; at the river mouth it was up to 40-60 million tons/year
(the historical sediment load to th e
Danube Delta and the Black Sea) .
The construction of dams caused considerable changes in the
sediment regime . In the
Austrian and German backwater reaches (the upper section), most
of the bed load now settles, and i s
removed yearly by regular dredging . The current sediment
transport between the middle and lower
Danube has been reduced by 85% . Before 1970, the turbidity and
sediment load were clearl y
correlated with the stream flow (Figure 10) . For the period
1948-1970, i .e ., before impoundment o f
the Danube at the Iron Gate, the mean multiannual value of
suspected silts and clays was 1051 kg/se c
at Orsova and 1428 kg/sec at the branching point . Corresponding
numbers for turbidity were 19 0
g/m 3 and 218 g/m 3 , respectively . After the damming, the mean
values for the period from 1970 t o
1975 were reduced to 414 kg/sec at Drobeta-Turni Severin
(slightly downstream from the Iron Gates )
and 1304 kg/sec at the branching point in the delta . The
suspended sediment concentrations dropped
to 73 g/m 3 or less. The Danube delta experiences ever
increasing erosion by the sea waves, and
significant efforts are required to prevent the Soviet part of
navigational channels from being silted b y
the alongshore sediment transport .
The current total volume of the sediment load is equal to less
than 40% of that of th e
historical norm . The processes of sedimentation in the delta,
vegetation growth and decay, re-
suspension of light material, etc . greatly affect the final
composition of the Danube water entering th e
Black Sea . It is thought that deltaic processes substantially
affect concentrations of trace elements .
The chemical composition of the Danube water is invariably
related to waste discharges into the river .
It has been repeatedly demonstrated by Rojdestvensky (1979) that
concentrations of various nutrient s
is well-correlated with effluent waters passing through the
observation site .
26
-
III. HYDROCHEMICAL REGIME AND WATER QUALIT Y
A.
Water Quality
Numerous studies have been conducted in various Danubian
countries on water pollution .
The upper and middle courses of the river are continuously
monitored, particularly within Austria and
Hungary . This part of the river is considered moderately
polluted . Only a small portion fro m
Vienna to Bratislava is considered heavily polluted, as well as
some tributaries near industrial centers .
Benedek and Lászlo(1980) and Shvebs (1988) demonstrated that
concentrations of toxic elements
including mercury, lead, and cadmium had increased .
International activities for better water quality are conducted
by the Society of International
Limnology and by several neighboring countries according to
bilateral agreements . In 1976, a set o f
water quality criteria for the Danube were established for all
countries upstream from the Iron Gates '
dam .
In the framework of the research activities of SIL (Society of
International Limnology) and it s
national brances considerable research is underway . In Austria
the socio-ecological effects of th e
impoundments are being studied (Oeko ., 1984) . In
Czechoslovakia bacteriological and zooplankto n
research is emphasized (Rotschein, 1976, 1981) . In Hungary,
fish fauna, primary production an d
oxygen balance have been extensively studied by many (Bartais,
1984 ; Geldreich, 1984 ; Toth, 1982) .
In Yugoslavia, saprobiological and fish-faunistical
investigations, and in Bulgaria zooplankton an d
zoobenthos studies, are carried out. Soviet and Romanian experts
had been involved in research o f
the Delta hydrology, its phyto- and zooplankton and reeds, as
well as fish-faunistical investigation s
(Curcin, 1985 ; Simonov, 1969 ; Shvebs, 1988 ; Vinogradov, 1969
; Tolmazin et al ., 1977 ; Topa-
chevsky, 1961 ; Sokolovsky, 1991) .
The activity of SIL in Austria covers the following three fī
elds :
n Description of the main characteristics of the river .
n Continuous survey of the changes in these characteristics
.
n Investigation on the impacts of human activities .
Along most reaches of the Danube, a water quality of biological
grade II ( β-meso-saprobic)
can be measured, but downstream of major polluting discharges,
quality drops to grade III (a-meso-
saprobic) . This indicates that current pollution control
measures are inadequate, which could lead t o
future restrictions on water uses and higher treatment costs
(UNDP/FAO, 1982-1985 ; VGI, 1982 ;
Salewicz et al ., 1990) . Potentially harmful materials
resistant to natural degradation are becomin g
2 8
-
more common constituents of Danube waters from a complex range
of chemicals and by-product s
produced in riparian countries and discharged to the Danube .
However, major bilateral and
multilateral arrangements have concentrated on sharing water
quantity rather than directed t o
controlling water quality (Table 5) .
The multipurpose utilization of the Danube water is of vital
importance to the approximatel y
71 million inhabitants in the river basin . Economic development
in the riparian countries, and th e
increase of navigation accelerated by the Rhine-Main-Danube
canal (which interconnects the two mos t
important transcontinental waterways of Central and Western
Europe, as well as the North Atlanti c
Ocean with the Black Sea), are causing water quality problems .
This in turn considerably affects th e
economics and environment of riparian countries' public health
(Sevrikova, 1988 ; Toth, 1982 ;
Vendrov, 1979 ; WHO, 1976, 1986 ; Beklemishev et al ., 1982)
.
Construction of dams and other regulatory structures
significantly alters the hydrauli c
conditions in a river and has an effect upon the water quality
of aquifers . Reduced velocity in th e
river bed leads to increased deposits of the smaller-grained,
silt-like material, and causes a reductio n
in dissolved oxygen content of the river water . This
subsequently aggravates water quality (solubilit y
of iron and manganese, reduction of sulfates and nitrates,
problems of taste and odor, etc . ; WHO ,
1984) .
The high concentrations of nutrients discharged into the Danube
as constituents of sewage an d
other effluents increase eutrophication, so that much of the
brown color of the river is associated wit h
assimilated brown pigments from diatoms growing on those
nutrients . The effects of biological
growth and decay on the quality of impounded water can influence
the use or the treatment require-
ments of the water (WHO, 1982) .
Bio-resistant materials, persisting in the water, are
accumulated by aquatic organisms or
absorbed on the suspended solids in the water course and are
deposited in the sediments . Upstream
and downstream water diversions and withdrawals exacerbate
cumulative effects of pollutants on bio-
chemical contamination of the river . In addition, the dredging
of shipping channels whose botto m
deposits are saturated with contaminated toxic metals and
organic chemicals, compounded by the lac k
of spring floods, further facilitates the deterioration of water
quality, especially in the Middle an d
Lower Danube . Note that an increase of navigation through the
inter-river canals not only encourage s
urban, industrial, and agricultural development in the river
basin but also increases the risk o f
pollution of the Danube because of a potential risk of shipping
accidents .
29
-
TABLE 5Some Multilateral and Bilateral Agreements Having an
Impact on the Danube (WHO, 1982 )
YEAR
COUNTRIES
TOPIC OF AGREEMENT
1948 (1960-Austria )
1950
1952
1954
1954
1955
1955
1956
1956
1957
1957
1958
1958
1959
1963
1967
1969
1971
(Austria), Bulgaria, Czechoslovakia, Hungary ,Romania, Ukraine,
U.S .S .R ., Yugoslavia
Hungary, U.S .S.R.
Romania, U .S .S .R .
Austria, Yugoslavia
Austria, Yugoslavia
Romania, Yugoslavia
Hungary, Yugoslavia
Austria, Hungary
Albania, Yugoslavi a
Hungary, Yugoslavia
Romania, U.S.S.R.
Czechoslovakia, Polan d
Bulgaria, Yugoslavi a
Romania, U .S .S .R .
Romania, Yugoslavia
Austria, Czechoslovaki a
Hungary, Romania
F.R. Germany, Czechoslovakia
Danube Convention on navigation of R .Danub eConvention to
prevent floods and regulate R.Tisza
Convention to prevent floods and regulate R.PrutConvention
concerning water managemen tquestions relating to R. Drava
Convention concerning water managemen tquestions relating to R .
Mura
Agreement concerning control of frontie rwatersAgreement
concerning water managemen t
Treaty concerning water management infrontier region
Agreement concerning water management infrontier region
Agreement concerning fishing in frontie rwaters
Agreement extending R . Prut convention(1952) to Tisza, Suceava
and Siret, an dother frontier waters
Agreement concerning use of frontier wate rresources
Agreement concerning water managemen t
Agreement extending R. Prut convention(1952) to Danube
Agreement relating to navigation and powe rgeneration Iron
Gates
Treaty relating to management of frontie rwaters
Convention relating to control of frontie rwaters
Local (non-government) commission dealin gwith pollution and
management of frontierwater s
3 0
-
FIGURE 1 1
Hydropower Plants and Storage of Danube Watersheds
-
B.
The Role of the River Impoundment on the Hydrochemical Regime of
the Danube
Austria
At the water intake site of Godworth supplying Linz, upstream
from the power station o f
Ottensheim-Wilheving, the Danube water level has risen by 9 m
above the original level . This has
resulted in reduced flow velocities and an increase in deposit
of organic matter in the riverbed ,
causing blanketing and a subsequent reduced capacity of the
bank-well filtration plant . This has
resulted in oxygen depletion in the upper part of the river and
an increase in organic matter in th e
river sediments that has triggered anaerobic conditions . As a
result, post-extraction treatment t o
produce a drinking water of acceptable quality has been
introduced .
Czechoslovakia and Hungary
The Czechoslovakian part of the Danube basin accumulates
domestic and industrial pollutant s
from Germany and Austria, plus sewage and chemical effluent from
Bratislava itself and its numerou s
factories . This in turn leads to contamination of the Hungarian
Danube . According to Slovak radio
(as cited in Singleton, 1985), nearly half of the republic's
3750 miles of rivers, which drain towar d
the Danube, were significantly contaminated by agricultural,
domestic, and industrial waste . As a
result, many tourist centers have been closed and no swimming or
bathing is allowed . There is
strong opinion among scientists and the population that the
chronic water shortage and eradication o f
fish in over 4,300 miles of streams are strongly correlated with
pollution . Reduced water quality
forced millions to use mineral water for cleaning teeth and to
boil potable water before its utilization .
It has been assumed that full scale operation of the
Gabsikovo-Nagymaros barrage system may
result in further decrease of suspended solids from the present
30% over a river stretch of about 7 0
km downstream from Bratislava to 55% after construction of the
dam (Benedek et al ., 1978, 1980 ;
Benedek and Hammerton, 1985 ; Rothschein, 1976) .
Additionally, the decomposing organic and pathogene
micro-organism content originatin g
from untreated municipal wastes will obviously result in
anaerobic decomposition and consequently a n
oxygen loss in the bottom sediment .
Industrial pollution of the Danube may be potentially more
serious in the upper reach, as
more industrial plants are sited there and lower volumes of flow
are available for diluting th e
resulting effluents (Table 6) .
32
-
TABLE 6Major Pollution Sources Along the Entire Danube (Benedek,
1986 )
2370
2220
2130
2120
1930
Wien/Vienna /A
1880
187 0
180 0
176 0
1650
1250
1170
1170
1100
690
600
530
43 0
With population equivalent of 500,000 or more .
CITIES'
WITHOUT OR WIT HWITH WASTE TREAT- PARTIAL WASTE TREAT -
MENT
MENT
TRIBUTARIES WITH MAJORINDUSTRIAL POLLUTIO N
Regensburg FRG
Passau Region FRG
Linz A
Enns A
March/Morava A/CS
Váh CS
Sava Y U
Bratislava C z
Gyór Region H
Budapest H
Novi Sad Yu
Beograd (Belgrade) Yu
Morava YU
Jiu R
Olt R
Jantra B G
Arges R O
3 3
-
FIGURE 1 2
Gabsikovo-Nagymaros Hydropower Schem e
From Lokvenc andSzanto;1986
-
As a result, in the Hungarian Danube section water quality is
mainly determined by pollutio n
of industrial origin from the upstream countries . Their
discharges are saturated with heavy metal s
and derivatives from oil, paper, iron and steel mills, petroleum
refineries, chemical plants, cement
works, and coal .
The Hungarian Research Center for Water Resources Development
(VITUKI) attempts to
forecast the combined effect of the dams and waste discharges on
chemical properties, primar y
production, and planktonic communities . It was found that the
number of algae and their biomass i s
substantially higher in the Hungarian section than in the upper
Danube . This raises the mesotrophi c
community up to a level typical for an impounded basin and
substantially aggravates the water quality
of the lower stretch of the Danube (VITUKI, 1978, 1986, 1985 ;
Rothschein, 1981) .
One of the biggest pollution sources of the Danube is Budapest
with two million inhabitants
and a rather developed industry, and whose wastewater treatment
is more or less out-of-date .
The ratio of accumulated heavy metals in the bottom deposit in
the Hungarian Danube and it s
tributaries is as high as 2 to 20 times the background values
(Somlyody and Hock, 1985) . As a
result, lignin sulfonic acid and high concentrations of heavy
metals are emptying into the Middl e
Danube .
At the same time, bacterial counts and organic load in the river
exceed the permissible limit s
for irrigation or aquatic recreation (Tables 7 and 8) . The
teriophages and enteroviruses show hig h
survival rates in the Danube and may even resist the water
treatment processes currently given t o
some potable supplies .
Correspondingly, the hygienic situation is rather severe
downstream from major wastewate r
discharge points, such as Bratislava and Budapest . Table 9
shows a typical bacteriological picture of
the Danube at the water intake of Mohács and in the water
distribution system of Pecs for which th e
water is provided by this intake (Geldreich, 1984) .
The common characteristic of Danube cities is that they - with a
few exceptions - do not hav e
sewage and wastewater treatment plants ; or, if they do, the
treatment
efficiency is not adequate . Therefore, the Danube and its
tributaries receive significant organic an d
inorganic loads (Table 10) . Moreover, there is no adequate
warning and emergency system betwee n
the riparian countries ; accidents which result in water
pollution are of particular concern in the mai n
river course and adjacent sea (Tolmazin, 1977 ; Stepanov and
Andreev, 1981 : Singleton, 1985) .
35
-
TABLE 7Bacteriological Water Quality from the Danube Water
Intake at Mohacs
to the Distribution Network of Pecs (Geldreich, 1984 )
TYPE OF WATERCOLIFOR M
TOTAL (PERFECAL
FECALCOLIFORM STREP. (PER CLOSTRID- SPC (37°C) NH; MG/L
100 ML) (PER 100 ML)
100 ML) IA (PER 40 PER MLML )
Danube-Water at Mohács 5200 - 72400 200 - 4600
< 100 - 500 64 - 240 3800 - 98000 0.17 - 1 .32
Clarified Water of Mohács 160 - 1200 210 - 960 0.2 - 0 .9 6
Stored Mixed Water at 40 - 2100 95 - 850 0.04 - 1 .10Pecs
Water Reaching the Active 1 - 200 0 .06-0 .6037- 11 0Carbo n
Purified Drinking Water xx xx 0 .01 - 0 .3 94 - 3 2
Stored Drinking Water xx xx 3-43
-
In the past, the most serious accidental spills occurred in
Vienna, Bratislava, and Vác (40 km
north of Budapest) . In 1976, at the Nussdorf water works near
Vienna, alcylphenols in the wate r
caused a long quarantine of this plant (Frischherz and Bolzer,
1984) ; and in 1980 at Vác, organi c
solvents resulted in the same situation. Significant hazard was
caused to the Bratislava water works
by the leakage of oil resources at a nearby oil refinery (WHO,
1982) . In all these cases the
rehabilitation of the contaminated wells either lasted for an
extended period or the wells had to b e
abandoned .
At the current level of development of nuclear power stations
along the river, there is a
potential danger from radioactive discharges .
Yugoslavia and Romani a
The role of the Iron Gate dam (Djerdap) on the environment of
the Yugoslavian-Romanian
stretch of the Danube can be summarized as follows :
n The turbidity in the lacustrine part of the reservoir has
decreased and there has been intensiv e
sedimentation of suspended organic and inorganic particles ;
n The temperature stratification became relatively stable in
summer (August) ;
n The oxygen deficiency was higher in the lacustrine part than
in the fluent area ; available
oxygen is lacking for the decomposition of organic matter ;
n There is an increase in the content of soluble organic matter
;
n The phosphate and ammonia content as well as the concentration
of total solubles were als o
higher in the lacustrine part of the reservoir than in the
fluent part ;
n Vertical stratification in the distribution of phosphates,
ammonia, dry residuals, and sulfate s
has occurred .
In the Romanian stretch of the Danube most major polluting
enterprises discharge their waste s
into tributaries, particularly into the Tisza; only a few enter
the Danube directly . In the 1960s ther e
were more than 1,500 point sources of pollution ; in the 1970s
industrial discharges had increased by a
factor of 4 .2 but there were only 100 treatment works and these
were mostly overloaded .
37
-
TABLE 9
Some Indicative Hydrochemical Parameters of the Danube Wate
r
Near Russia During Various Periods
PERIOD 02 mg/L 02 % OXIDATION SUSCEPTIBILI-
TY mg OIL
Max Min Average Max Min Average Max Min Average
1966-1972 10 .26 4 .64 7 .06 135 .0 74 .9 90 .6 7.12 2.73 4
.15
1973 8 .73 5 .09 6 .75 98 .5 71 .8 86 .5 5.86 2.00 4 .3 3
1974 9 .04 4 .57 7 .21 114 .1 64 .6 93 .0 7 .67 2.90 4 .90
1975 10 .02 4 .36 7 .15 126.0 67 .9 92 .9 6 .27 1 .68 3 .90
PERIOD NO- 3 mg/L NH- 4 mg/L Po --4 mg/L
Max Min Average Max Min Average Max Min AverageAverage Discharge
m 3/sec
1966- 20 .00 0.35 7.52 1 .20 0.01 0.15 7 .60 0.00 0.19 618 1
197 2
1973 15 .00 2 .50 0.35 0.04 0.11 1 .00 1 .00 0 .00 0.16 5910
1974 11 .00 1 .20 6.04 0.30 0.05 0.10 1 .25 0 .01 0.34 7150
1975 10 .50 2 .00 4.29 0.35 0.04 0 .14 1 .45 0 .00 0.35 7940
Source : Rojdestvensky (1979)
3 8
-
TABLE 10
Average Seasonal Distribution of Phosphates and Nitrate s
Near the Danube Delta
10 N MILES FROM THE DELTA
20-50 NMILES FROM THE DELT A
Depth Winter Spring Summer Fall Yearly Depth Winter Spring
Summer Fall Yearly
m Aver-
age
m Averag e
Phosphates (P'mg/ n3 )
0 115 .1 13 .0 1 .5 53 .6 48.3 0 40 .4 3 .1 1 .3 15 .2 15 .0
5 123.6 8 .2 3 .3 19 .0 38 .5 10 51 .6 7 .8 0.3 13 .7 18 . 4
10 30.7 2.5 1 .6 30 .0 16 .2 25 17 .4 3 .1 1 .8 8 .3 7 . 7
15 28 .4 1 .6 13 .1 37 .5 20.2 50 32.1 7 .8 9 .3 0 12 . 3
25 58.9 2 .3 19 .6 16 .3 24 . 3
Nitrates NO -3
0 569.4 136 .0 35.3 73 .5 203 .6 0 39 .4 3 .4 1 .4 77 .8 12 .
8
5 57 .9 45 .2 4.5 2 .9 27.6 10 9 .6 2 .7 0.5 0 3 . 2
10 41 .8 2.3 2 .3 2 .5 12 .5 25 10 .2 1 .4 1 .3 0 3 . 2
15 10 .0 0.6 1 .1 1 .7 3 .4 50 11 .8 2 .8 1 .6 0 .5 4 . 2
25 7 .7 1 .1 0 .6 5 .0 3 .6
After Rojdestvensky (1979)
39
-
Former U.S.S .R.
Limnological investigation of the Danube, conducted by the
Institute of Hydrobiology of th e
Academy of Sciences of the Ukrainian SSR in 1958-1988 throughout
the Soviet section of the rive r
from the confluence of the Prut to the mouth of the Danube,
yielded data for the determination of th e
degree of contamination of the water (Almazov, 1962; Nikiphorova
and D'iakonov, 1963 ; Simonov ,
1969 ; Shvebs, 1988) .
Of the 202 species and varieties entering into the composition
of the phytoplankton of th e
river, 47 species (or 23 .2%) were so-called significant
organisms .
Of these only one species (Oscillatoria tenuis Ag.) proved to be
a-mesosaprobic, 19 wer e
β-mesosaprobic, and the other 27 were oligosaprobic .
The total content of bacteria and their biomass, the quantity of
saprogenic and phosphorus -
mobilizing bacteria showed that the quantity of bacterioplankton
in this region was very high an d
fluctuated from 2 to 45 .5 million cells per mL. The biomass of
the bacterioplankton equalled 0 .5 to
17 mg per liter . The monthly bacterial discharge varied from 14
to 103 thousand tons . A study o f
the dynamics of the quantity of bacterioplankton showed that it
depended chiefly on the content o f
suspended alluvium and organic substances .
The distribution of saprogenic bacteria fluctuated from 300 to
3000 cells per mL . In the bay s
of the Kilia fore-delta, the number was as high as 8 to 11
thousand cells per mL . The number o f
bacteria depended on the content of organic nitrogen, the
temperature, and the discharge of water .
Thus, the degree of contamination of the river may be defined as
oligo-mesosaprobic . The
highest degree of contamination of the river water occurred
during early autumn and winter . An
investigation of waters flowing from the sections of Danube
above the borders of the former U .S .S .R .
showed considerable contamination, which was β-mesosaprobic and
determined the degree o f
contamination of the Soviet section of the river .
The total microbe count and the con index were fairly high,
which is explained by contami-
nated water coming from the higher reaches of the river .
Hydrochemical Regime of the Lower Danub e
Prior to construction of the Iron Game dam, average mineral
concentrations of the Danubian
water showed gradual increases . Average concentrations during
1950-1954, 1954-1961, and 1962 -
1965 were respectively 292, 318, and 321 mg/L, most likely due
to increasing sulfates and chlorides .
Nitrate concentrations also rose during the same period . River
pollution caused fluctuations i n
ammonia (NNH +), decreases in dissolved oxygen and increases in
BOD 5 (Tables 8, 9, and 10) .
40
-
The effects of the Danube's outflow on nutrients in the Black
Sea are revealed in Tables 8 and
10 . Concentrations of P and NO- at the surface near the Danube
is elevated if compared with water
samples taken from the deeper layers or at greater distances
from the shore (Table 10) .
Since 1973, the coastal areas north of the Danube delta have
been struck by acute oxyge n
deficit (Atsikhovskaya, 1977 ; Tolmazin, 1977, 1985) because the
lack of run-off and insufficien t
mixing, which in concerf have triggered catastrophic
eutrophication. The coastal waters south of th e
Danube delta are polluted by agricultural discharges, in
particular (Braginsky, 1986) .
The Upper Danube exhibits a reasonable self-purification
capacity for polluting discharges, at
least with respect to degradable materials . However, the middle
and lower Danube suffer fro m
pollution, especially in the winter when ice cover and low
temperatures reduce the rates of oxidatio n
and different kinds of organic and inorganic materials
subsequently affect the taste and odor o f
potable water supplies derived from the river .
The presence of high concentrations of ammonia has also been
identified as a possible facto r
endangering the use of some reaches of the Danube as sources of
potable water supply . The
maximum ammonium-ion concentrations occur in winter when the
water temperature is low and th e
nitrification processes are suppressed, while striking nitrate
concentrations are typical in early sprin g
owing to the high surface run-off from cultivated areas ( Lászlo
and Homonnay, 1985) .
IV. INTERNATIONAL IMPORTANCE OF THE DANUBE BASIN
As was said, the eight riparian countries share the Danube
waters, a small part of whic h
originates from the non-riparian countries : of Italy,
Switzerland, Poland, and Albania . In addition ,
the Danube connects the two different socio-economic groups of
West and East European countries .
A.
The Major Natural Resources of the Danube Basi n
Federal Republic of German y
Southern Bavaria possesses natural gas, oil, brown coal, and
forest resources . In the vicinity
of the Czechoslovakian border pyrite, lead, zinc, tin, and brown
coal are found . Agriculture assets
include meadow, ploughland, grassland, and livestock breeding
.
Austria
The nation has brown and black coal, various metals, natural oil
and gas, and significan t
forest resources . Crop lands occupy the Vienna Valley and the
southeast zone of the country . Non-
fertile areas are confined to the Alps where snow and ice
prevail all year around .
4 1
-
Czechoslovakia
Oil and natural gas exist along the lower reach of the
March/Morava River, and in the Hro n
and Váh Rivers' watersheds various metal ores, natural gas, and
brown coal are found . The valley o f
the Morava River and the southern part of Slovakia are the major
ploughland regions . Forests with
pastures and meadows are typical for two-thirds of Slovakia
.
Hungary
A typical agro-industrial country, Hungarian valleys produce
wheat, maize, sugar beets ,
potatoes, grapes for wine, fruits, fodder, vegetables, and
livestock . Mining and mineral resources
include bauxite, brown coal, natural gas and oil, lignite,
uranium, bentonite, gravel, and pyrite .
Yugoslavi a
Coal and ore resources are abundant (copper and bauxite being
the most important), while oi l
and gas resources are scattered. Cropland culture dominates in
the north, and grassland and pastur e
in the south . Forests cover the land at higher elevations .
Romania
Still possess significant amount of oil (Ploesti region) and
black coal . The major part of the
country is cropland . The mountainous regions of the Carpathians
and the Transylvanian Middl e
Ranges are covered with forests and extensive pastures . In this
area non-ferrous metals can be foun d
at several locations .
Bulgaria
The nation consists mainly of agricultural land . In the
vicinity of Sofia brown coal, and along
the north-west border, black coal resources, can be found .
Forests cover the ridges of the Balkan
Mountains along the basin .
Former U.S.S.R.
Most of this part of the Danube basin belongs to the catchment
of the Prut river, and i s
mainly agricultural land . There are no significant mineral
resources .
Cities and Town s
Along the banks of the Danube, there are ten major cities with
populations exceedin g
100,000: Regensburg (125,000), Linz (260,000), Vienna
(1,650,000), Bratislava (250,000), Budapes t
(2,000,000), Novisad (170,000), Beograd (1,100,000), Braila
(120,000), Galati (150,000), and Rus e
(176,000) . Other major cities of over 100,000 inhabitants in
the Danube basin are Munich ,
Augsburg, Innsbruck, Salzburg, Graz, Miskolc, Debrecen, Szeged,
Pecs, Györ, Nyiregyháza ,
Székesfehévár, Kecskemét, Zagreb, Osijek, Subotica, Bucaresti,
Brasov, Cluj-Napoca, Timisuara ,
Iasi, Craiova, Oradea, Arad, Sibiu, Bacau, Pitesti, Tirgu-Mures,
Baie Mare, Satu Mare, Sofija, an d
42
-
Pleven (Radó, 1985). In the former U .S .S .R., Izmail, Reni,
and Vilkovo have populations 100,000 .
Other
In the Danube basin, tourism also represents a significant
economic factor and
among the water users, fishery plays an important role with a
total catch of 4,400 tons/year (Table 8) .
A further 45,000 tons/year are taken from ponds in the
floodplains and the delta (Gerasimov et al . ,
1969 ; Liepolt, 1973) .
B.
Utilization of Danube Water Resources
The multi-purpose utilization of the Danube includes :
n Municipal, industrial, and agricultural ;
n Flow regulation and flood control ;
n Sediment and ice control ;
n Hydroelectric power generation (a total capacity of 7900 MW)
;
n Local and international shipping between Danube and the Black
Sea (The opening of th e
Rhine-Main Danube Canal will extend the waterway to the Atlantic
Ocean with a total length
of 3500 km) ;
n The irrigation of about 4 million ha, with up to a planned 5
million ha ;
n Processing of drainage discharges from the watershed or
pollution control ; and
n Recreational and commercial fishery, parks, and preservation
zones .
Water management of the Danube basin is determined by : 1)
geographical location of each
riparian country ; 2) the degree of economic development ; and
3) efficiency of the implementatio n
of major objectives of the Danube Commission among these
countries . In the upper part of the basin ,
morphological and climatic conditions limit the development of
irrigation . In this region, the major
uses of water are industrial and drinking water supply and
hydroelectricity generation (Figure 11) .
Dams, canals, and regulated water elevation facilitate the
utilization of the continuously renewin g
energy of the river, improve navigation, and reduce the risk of
floods .
The same is true for the middle and lower reaches of the Danube,
where flood protection ,
river regulation, and agricultural, industrial, and domestic
water supply are the dominant water uses .
The water demand data within the basin estimated for the year
1980 and predicted for 200 0
are summarized in Table 11 (Information, SEV, 1976 ; Kovács, et
al ., 1983) . Note that the predictio n
assumed an annual increase of 4-6% in water demand . Considering
the world-wide economi c
recession which has strongly affected this region, the estimated
increase might be exaggerated . The
most important demands are : 1) rivers should be navigable by
larger ships independently from wate r
43
-
availability, 2) the inundation of valleys, developing
settlements, and arable land should b e
eliminated, 3) continuous and safe supply of water of suitable
quality for communities, industry, an d
irrigation should be warranted, 4) the river energy output
should be thoroughly utilized, and 5 )
since rivers are recipients of wastes their self-purification
capacity should be maintained . However ,
long before these goals were outlined, a large number of
hydrotechnical constructions and wate r
conveyance systems had already been put into operation (Annex
III) . Consequently, river beds ,
suspended sediment and bedload transport, the water quality, and
even the flow discharges have bee n
changed considerably along several stretches . Dams and water
transfer facilities have large radii o f
influence; therefore, their cumulative impacts are interwoven .
Unfortunately, this interrelation wa s
realized by the neighboring countries only after a significant
delay . As a result, the middle and lowe r
Danube, its delta, and the coastal ecosystem of the Black Sea
are suffering a great deal of losses i n
water quality, fishery, and optimal utilization of fresh water
intakes (Baidin, 1980 ; Al'tman and
Panayotov, 1988 ; Shvebs et al ., 1988) . This in itself has
already contributed considerably toward
creating a new consciousness of interdependence and cooperation
among the Danube countries at
present and in the future (RZdD, 1986) .
Flood Control
Historically Danube basin development has not been in close
accord with the hydrologica l
regime of the Danube watershed . Riparian countries used their
natural resources to their advantag e
and sometimes caused substantial changes in flow characteristics
. The strengthening of river beds ,
deforestation of the slopes, and the desiccation of large areas
by local dams significantly jeopardize d
large tracts of fertile lands and surrounding cities and
villages .
Federal Republic of German y
Flood protection levees built in 1849-1897 from 2,540 km
(Dillingen) to 2,510 km (Don-
auwörth) hindered thenceforth the floods from overflowing the
banks and inundating an area of about
115 km 2 . Flood protection levees from 2,460 km (Ingolstadt) to
2,427 km (Fining) were built i n
1913-24 and reinforced in 1965-75 . They protect an area of 80
km 2 . Flood protection levees fro m
2,376 km (Regensburg) to 2,256 km (Hofkirchen) were constructed
in 1930-56, protecting an area o f
about 120 km2 , but giving only partial protection for the
territory between Regensburg and Strau-
bingen . On the basis of experiences gained during the floods in
1954 and 1965, these levees and th e
inland drainage were reinforced .
44
-
TABLE 1 1Water Consumption of the Danube Riparian Countries
(OMFB, 1975 ; Kovacs, et al., 1983)
1980 (10' m 3 /year) 2000 (10' m 3 /year )
Communal CommunalCOUNTRIES and Irriga- Fisheries Total and
Irriga- Fisheries Total
Industrial tion Industrial Lion
FRG 170 - - 170 303 - - 303
Austria 120 237 - 357 207 682 - 88 9
Czechoslovakia 220 1970 12 2202 591 3740 12 4343
Hungary 411 4710 265 5386 729 9297 282 10308
Yugoslavia 224 1220 95 1539 381 4056 95 4532
Romania 595 12760 623 13979 984 26934 698 2861 6
Bulgaria 148 5680 - 5828 201 8608 - 8809
U .S .S .R . 82 1029 18 1129 85 1738 20 1843 x
TOTAL 1970 27606 1013 30589 34.81 55055 1107 59643
45
x Without the Danube-Dniester-Dnieper Canal .
-
TABLE 12Land Resources and Their Utilization (Thousand Hectares
)
Aus-tria
Czechoslova-kia* (1980)
Hunga-ry (-
Bulgaria Romani a(1979) (1980)
(1978) 1978 )
Land Area 8,272 12,552 9,303 11,070* 23,034
Arable Land 1,547 5,112 5,423 4,400* 9,834
Permanent Crops 98 134 1,574 N/A 66 3
Permanent Pasture 2,071 2,071 1,307 N/A 4,46 7
Under Irrigation 46 244 450 1,182* 2,30 1224* *
Under Irrigation in 1990 N/A 525 N/A 1,700 -2,300
Total Irrigation Potential 200 1,366 .4 N/A N/A 5,400
Under Drainage 120 755 4,113 128** 39 0
Water Used for Irrigation 106m'/yr 350 500 -600 3,200* 3 .60
0600**
*
Including basins of all rivers .**
From the Danube alone .
Sources : Tumock (1979), Ponomarenko (1980), Tivko (1983), and
Annex III .
46
-
Numerous completed dams and impounding reservoirs took over a
part of the flood protectio n
by lowering flood peaks (Bayerisches, 1972 ; Danecker, 1981,
DoKW, 1985 ; Kresser, 1984) .
Austria
Subsequent to flood disasters in 1830 and 1864, the first more
extensive measures for