Background information for the Danube river TDA workshop
1. Features of the Danube Basin
This background information was prepared for the transboundary Diagnostic Analysis (TDA) workshop for the Danube river pollution reduction progamme. The information is intended to provide concise overview of the status of conditions in the Danube river basin, that relate to water quality and pollution and that are relevant for the TDA. The information is based primarily on the findings reported in the National review reports (prepared by 13 countries having large territories within the basin) as summarized in summary report for parts A and B of the reviews. Supplemental information is provided from-other reference documents to elaborate or summarize basinwide phenomena which are not addressed in the reports the respective countries. The 13 countries are Germany, Austria, Czech Republic, Slovak Republic, Hungary, Slovenia, Croatia, Bosnia and Herzegovina. Yugoslavia Romania, Bulgaria, Moldova and Ukraine). Four countries with small territories in the basin are not included in the programme and did not submit reports. They are Switzerland, Italy, Poland and Albania.

1.1 Physical and Geographic
The national review reports describe the features of Danube Basin within their respective countries. Concise summands of overall basin features are available from a number of reference documents including Encyclopaedia Britannica (1993). In this section excepts have been used liberally as indicated

The Danube river rises in the black forest mountains of Germany, flows 2850 km to the black sea, drains 817000 km2 and includes about 300 tributaries, of which 30 are navigable. "These sections are discernible in the river's basin. The upper course stretches from its source to the gorgon, called the Hungarian gates, in Austrian Alps and the Western Carpathian Mountains. The middle course runs from the Hungarian gates to the Iron Gate Gorge in the southern Romanian Carpathians. The lower course flows from the Iron Gate to the deltalike estuary at the Black sea" Some descriptions recognize the delta as a separate fourth section of the basin.

A sketch of Danube river basin is presented in Figure 1.1-1. The longitudinal profile of the Danube river is presented in Figure 1.1-2. A diagram of the Danube river basin is presented in Figure 1.1-3 which shows the area of tributary basins on the horizontal axis and the sequence and distance from the river mouth on the vertical axis. Discharges are also presented for selected larger rivers. Profiles of Danube river Tributaries are presented in figure 1.1-4 and 1.1-5

Transboundary relationships in the basin are summarized in a series of tables. Table 1.1-1 is a matrix of direct transboundary relationship within the basin. Table 1.1-2 is a matrix of direct and indirect transboundary relationships. Table 1.1-3 summarizes direct transboundary relationships by country and river. Table 1.1-4 summarizes direct transboundary relationships by river and station

Table 1.1-5 summarizes the distnbuon of territories within be Danube basin and reveals how the area of the basin is widely distributed among 17countries. On the basis of land area within the basin the dormant country is Romania with more than 232.200 ha covering more than 28 percent of the basin. The country with the largest percentage of its area within the basin is Hungary (100 percent).

Table 1.1-6 summarizes the distribution of Danube basin land use, rainfall, and population by country. Romania has largest population in the basin and by far the largest land use in the basin in all categories. Austria appears to have the highest precipitation.

Table 1.1-3. direct transboundary relationships by country and river
Direct transboundary relationship
Germay to Austria
Austria to Germany
Austria to Slovak Republic
Austria to Hungary
Austria to Slovenia
Czech republic to Austria
Czech republic to Slovak Republic
Slovak republic to Czech Republic
Slovak republic to Austria
Slovak republic to Hungary
Hungary to Slovak republic
Hungary to Croatia
Hungary to Yugoslavia
Slovaenia to Hungary
Slovenia to Croatia
Croatia to Hungary
Croatia to Bosnia and hercegovina
Croatia to Yugoslavia
Bosnia and Hercegovina to Croatia
Bosnia and HERCEGOVINA TO Yugoslavia
Yugoslavia to Bosnia and Hercegovina
Yugoslavia to Romania
Yugoslavia to Croatia
Yugoslavia to Bulgaria
Bulgaria to Yugoslavia
Bulgaria to Romania
Romania to Hungary

Romania to Yugoslavia
Romania to Bulgaria
Romania to Moldova
Romania to Ukraine
Moldova to Ukraine

Ukraine to slovak republic
Ukraine to hungary
Ukarine to Hungary
Ukraine to Romania

Ukraine to moldova

Major transboundary rivers
Danube
/inn
/inn/Salzach
/inn
/inn/Salzach
Danube
/March [Morava]
/Drava
/Drava/Dyje
/Morava
/Morava/Dyje
/Morava
Danube
/Morava
Danube
/Vah
/Hron
/Ipal
/Uzh
/Tisza
/Tisza/Bodrog
/Tisza/Mornad
/Tisza/Sajo
/Tisza/Hernad

Danube
/Drava
/Drava/Mura

Danube
/Tisza

Drava/Mura

/Drava
/Drava
/Drava/Mura
/Sava
Kolpa

/Drava
/Drava/Mura

/Sava
/Sava/Una

Danube
/Drava
/Sava

/Sava
/Sava/Una
/Sava/Bosna
/Sava/Vrbas

/Sava/Drina

/Sava/Drina

Danube

Danube
/Sava

Danube
/Velika Morava
/V. Morava/Nisava

Danube
/Iskar
/Vu
/Osam
/Yantra
/Rus Lom

/Tisza/Smoes
/Tisza/Crasna
/Tisza/Berettyo
/Tisza/Crisul Negro
/Tisza/Crisul Alb
/Tisza/Mures

Danube
/Timis
/Tisza/Boga

Danube
/Jiu
/Olt
/Arges

/Prut

/Danube
/Siret

/Prut

/Cahul
/ahul
Lalpug

/Tisza
/Uzh

/Tisza

Danube
/Siret
Prut

/Prut

Note: Asterisk (*) denotes minor tributaries or side flows

Table 1.1-4. direct transboundary relationships by river and monitoring station*
Country relationships
Germany to Austria
Austria to Slovak r
Slovak R to Hungary

Hungary to Yugoslavia

Croatia and Yugoslavia
Yugoslavia to Romania
Yugoslavia to Bulgaria

Yugoslavia and Romania
Bulgaira and Romania

Romania to Bulgaria
Ukraine and Romania

Danube to Black sea

Germany to Austria
Austria to Germany

Cross-Border stations
D02, Jochenstein, (km 2204)
A01, Jochenstein (km 2204)
Felsen hutt, Austria (km 2209)?
A04, Wolfstahl, (km, 1873)
SK01, Bratislava (km 1869)
SK02, Medvedov/Medve (km 1806)
SK03, Komarno/Komarom (km 1768)
H01, Medve/Medvedov (km 1806)
H02, Komarom/Komarno (km 1768)
H03, Szob (km 1708)
H04, Dunafoldvar (km 1560)
H05, Hercegszanto (km 1435)
HR01, Batina (km1424)
HR02, Borovo (km 1337)
RO01, Bazias (km 1071)
RO02, Pristol/Novo Selo Har (km 834)
BG01, Novo selo Harbour/Pr (km 834)
RO02, Pristol/Novo Selo Har (km834)
BG01, Novo Selo Harbour/Pr (km 834)
BG02, us Iskar-Bajkal (km 641)
BG03, Downstream Svishtov (km 554)
BG04, us, Russe (km 496)
RO03, us, Arges (km 432)
RO04, Chiciu /Silistra (km 375)
BG05, Silistra/Silistra (km375)
RO02, Pristol/Novo Selo Har (km 834)
BG01, Novo Selo Harbour/Pr (km 834)
UA01, Reni-Kilia/Chilia arm (km 132)
RO05, Reni--Chilia arm (km 132)
UA02, Vilkova-Kilia/Chilia arm (km 18)
RO06, Vilkova-Kilia/Chilia arm (km 18)
Reni (km 163& 136)?
Ismail, Ukraine (km 115&99)??
UA02, Vilkova-Kilia/Chilia arm (18)
RO06, Vilkova-Kilia/Chilia arm (18)
RO07, Sulina-Sulina arm (km 0)
RO08, Sf, Gheorghe/Ghorghe are (0)

D03 Kirchdorf, (km 195)

1.2 Hydrological
"The upper Danube… has a considerable average inclination of the riverbed (0.93 percent) and a rapid current of two to five miles per hour [three to eight km per hour]. Depths vary from three to 26 feet (one to eight meters)…

"in the middle course the Danube looks more like a flatbed river, with low banks and a bed that reaches a width of more than one mile [1.6km] . Only in two sectors-at Visegrad (Hungary) and the Iron Gate-does the river flow through narrow, canyon like gorges.. the Danube enters the little Alfold plain immediately after emerging from the Hungarian Gates Gorge near Bratislava, Czech. There the river stream slows down abruptly and loses its transporting capacity, so that enormous quantities of gravel and sand settle on the bottom. A principal result of this deposition has been the formation of two islands, one on the Czech side of the river and the other on the Hungarian side, which combined have an area of about 730 square miles [1869km2] that support some 190,000 inhabitants in more than 100 settlements. The silting hampers navigation and occasionally divides the river into two or more channels. The Danube then flows past Budapest and across the vast great Alfold plain until it reaches banks. River accumulation has built a large number of islands, including terraces stretch along both banks. River accumulation has built a large number of islands, including Csepel Island near Budapest. In this long stretch the river takes on the waters of its major tributaries-the Drama, the Tisza and the Save-which create substantial changes in the river's regime…

"Beyond the Iron Gate the lower Danube flows across a wide plain, the river becomes shallower and broader, and its current slows down. The tributaries in this section are comparatively small and account for only a modest increase in the total runoff. They include the Old, the Sired and put. The river is again obstructed by a number of islands. Near Tulsa, some 50 miles [80 km] from the sea, the river begins to spread out into its delta.

"The river splits into three channels-the Chilia, which carries 63 percent of the total runoff, the Sulina, which accounts of 16 percent, and the Sfintu Gheorghe (St. George,) which carries the remainder. Navigation is possible only by way of the Sulina Channel, which has been straightened and dredged along its 39-mile [62-km] length. Between the channels, a maze of smaller creeks and lakes are separated by oblong strips of land. [which] are arable and cultivated, and some are overgrown with tall oak forests. A large quantity of reeds that grow in the shallow-water tracts are used in the manufacture of paper and textile fibers. The Danube Delta covers and area of some 1600 square miles [4100km2] and it a comparatively young formation. About 6500 years ago the delta was a shallow low cove of the black sea coast, but it was gradually filled by river-borne silt; the delta continues to grow seaward at a rate of 80 to 100 feet [24 to 30m] annually.

The different physical features of the river basin affect the amount of water runoff in its three sections. In the upper Danube the runoff corresponds to that of the Alpine tributaries, where the maximum occurs in June when melting of snow and ice in the Alps is the most intensive. Runoff drops to its lowest point during the winter months.

In the middle basin the phases last up to four months with two runoff peaks in June and April. The June peak stems from that of the upper course. Reaching its maximum 10 to 15days later. The April peak is local. It is caused by the addition of waters from the melung snow in the planns and from the early spring rains of the lowland low mountains of the area. Rainfall is important. The period of low water begins in October and reflects the dry spells of summer and autumn that are characteristic of the low plains. In the lower basin all alpine traits disappear completely from the river regime. The runoff maximum occurs in April, and the low point extends to September and October (Encyclopaedia Britannica, 1993).

Table 1.2-1 summarizes the Danube river probability of annual runoff at selected stations whose locations were shown in Figure 1.1-3 figure 1.2-1 summarizes the Danube river seasonal pattern of mean monthly discharges for selected stations from the upper basin to the lower basin. Table 1.2-2 summarizes Danube river mean monthly and annual flows for Danube stations and selected tributary to be compared and reconciled with runoff, accounting for more than 2000 m3/s of discharge (more than 29 percent of the basin total). Austria is the second major source, with more than 1500m3/s (more than 22 percent of the basin total).

The river carries considerable quantities of solid particles, nearly all of which consist of quartz grains. The constant shift of deposits in different parts of the riverbed forms shoals. In the stretches between Bratislava and Komarno and in the Sulina Channel, draglines are constantly at work to maintain the depth needed for navigation. The damming of the river has also changed the way in which sediments

The distribution of reservoirs and storage in the basin is summarized in table 1.2-4 which was compiled for the DWQM.

1.4 Demographic, social and economic
present and projected populations for countries and areas within the Danube basin are summarized in table 1.4-1 and Figure 4.1-1 which reveal large differences in total populations, the ratio of rural to urban populations, population density and the fraction of each country's population within the Danube basin. A notable similarity among all countries is the low rate of projected population growth to year 2020.

Main economic indicators (GDP, per capita GDP, inflation and exchange rates) for the DRB countries are summarized in table 1.4-2 and the other countries, in per capita GDP between Germany and Austria and the other countries and high inflation in Bulgaria, Romania, Ukraine and Yugoslavia. In 1997 the GDP of Germany (US$ 2034 billion) was more than 1000 times the GDP of Moldova (US$ 1.9billion). in 1996 and 1997 in Germany and Austria per capita GDP exceeded US$ 25000 while for Moldova it was less than US$ 500. For Ukraine and Bosnia and Herzegovina is was less that $ 1000.

Not yet revealed in these tables is the extent to which activities and production in the agricultural and industrial sectors have declined in the eastern block countries during the economic transition. This information is at least partially available and will follow in table 1.4-3.

Data reported for cargo shipping and passenger transport are very incomplete.

The present and projected percentages of the DRB population connected to sewerage system is presented by country in Figure 1.4-4.

On the basis of limited data, mostly from six countries (Slovenia, Croatia, Czech Republic, Slovak Republic, Hungary and Romania) a particular economic and environmental problem appears to involve unknown dump sites for municipal and non-municipal waste (for which only fragmentary data on waste volume and composition are available ). Waster quality and health risks are increased by the proximity of many of these sites to river banks.

Water mediated health and social problems are summarized by country (excluding Germany and Austria) as follows:
Czech Republic -In 1996 there were no reported cases of water-borne infection from drinking water abstracted by public water supply systems although there were occasional cases of water-bome infections in certain periods from bathing in water courses and reservoirs. Potential hazards may result from accidental pollution of water courses. In 1995, for example, 243 such cases were resources were depreciated, waste water treatment plants flooded and various industrial chemicals and wastes got under water.

Slovak Republic -about 75% of the population are supplied by ground water sources. About 90% of irrigation water is surface water. The primary problems regarding both the surface and ground water are high nitrite, contain nations from agrochemical and untreated waste water discharge. The main problem regarding the surface waters of the Danube river systems are high pollution by nutrients and contamination by different industrial substances, including oil substances . at the time being there are no significant health hazards through pollution of water used for drinking purposes. Diseases caused by hygienic quality of drinking water are not frequent and only in exceptional cases it has come to epidemics.

Hungary-public water supply is principally ensured by ground water. Problems with the quality of drinking water include increased levels of arsenic, bacterial contamination, nitrite and chlorinating by-products. There are occasional epidemics due to bacteriological infections in swimming pools.

Slovenia -surface water is a minor source of public water supply. There are no serious health hazards. Some cases of pollution in water used for drinking purposes include organic solvents, pesticides, heavy metals from industrial spillage and agricultural runoff.

Croatia-public water supply is mainly ensured by ground water (90%). There are no reports of serious problems with water-related diseases except for occasional epidemics of enterocolities and hepatitis a.

Bosnia and Herzegovina- as a consequence of the war, public water supply and sewerage system are damaged or partly under construction. Only the thirds of the population is currently supplied with hygienically correct potable water. In 1996, 14 infection and parasite epidemics (including 4 epidemics of enterocolitis and 2 epidemics of hepatitis a ) were recorded. Presently the situation has improved but still has to be considered as unstable.

Federal republic of Yugoslavia-problems include inadequate water quality in larger municipal water supply systems from inferior raw water quality, inadequate water treatment and disinfecting. About 50 municipal water supply systems (for which microbiological inadequacy is higher than 5% and physical and chemical inadequacy higher than 20%) do not use water from watercourses or impounding reservoirs, but ground water from different water bearing strata. In a large number of small settlements the quality of drinking water is not satisfactory due to the absence of water treatment and casual disinfection on one side, and worn-out piping and periodic supply interruptions, on the other. Most frequent causes of inadequate water quality are elevated contents of iron, manganese and organic matters, the absence of residual chlorine, an increase in the total number of bacteria, and period increases in coliform bacteria, including e coil. The number of epidemics contagious diseases peaked in 1995 when there were reports of 396 epidemics involving 6850 affected persons, and appears to be decreasing since that time.

Romania-surface water can principally not be used for drinking purposes without proper treatment. Water quality of shallow wells and boreholes is considered a serious health problem in rural areas due to the high nitrite concentration usually exceeding 50mg/l. Significantly increased occurrence of diseases mediated by water from the Danube river system or groundwater sources is reported for:
Infant methemoglobinemia (caused by nitrite intoxication);
Communicable diseases such as dysentery, acute diarrhea, cholera, viral hepatitis (due to microbial contamination of surface water and water from shallow aquifers and rural wells);
Communicable diseases (due to water shortage, respectively periodic intermittence of tap water supply combined with fecal contamination);
Diseases due to intoxication from industrial and agrochemical substances in water used for drinking purposes either from permanent pollution or from occasional accidents and spillage,) and
Diseases from elevated content of toxic cyanobactena in surface waters.

Bulgaria-public water supply is mainly ensured by ground water (81%) about 75% of water from the public water supply systems is not treated. Elevated levels of iron and manganese are found in water from the public water supply systems (due to worn-out piping systems) as well as contamination of water sources with ammonia, petroleum products and chromium-6+, elevated levels of coliform bacteria in most towns of the DRB and elevated nitrite levels in different areas of the DRB.

Moldavia-public water supply is mainly ensured by ground water (80-85%). There are elevated levels of hydrocarbons, sodium and fluorides in water from public water supply systems. Water from shallow wells is often polluted with nitrogen compounds. On average 38% of centralized water supply sources do not meet sanitary-chemical standards and 11% do not correspond to microbiological standards. Of the decentralized water supply sources, 70% do not meet sanitary-chemical standards and 12% do not meet microbiological standards. There are significant incidences of hepatitis A, dysentery and enteritis. Exact data on water-borne diseases are, however, not available.

Ukraine-Regarding centralized water supply systems about 18% of water quality tests did not meet sanitary-chemical standards and about 15% of the tests did not meet bacteriological standards (figures for Odessa Region, 1996). At the time being there are no exact data on health hazards mediated by surface or ground water utilization in DRB part of Ukraine. A recognized problem is the use fo hypo chlorinated water with high concentration of heavy metals and other toxic substances, which are supposed to lead to endocrine system diseases, metabolism disturbances, nervous system diseases, etc.

1.3 Ecological
1.4 Much of the pertinent ecological information for the TDA is being developed by the wetlands study for which a report and maps were not yet available at the time of writing of this background document.

Selected statistics on fisheries in the Danube river basin are presented in table 1.3-1.

Data on wetlands and floodplains was summarized from the national review reports for the Danube water quality model in previously cited table 1.2-4.