1. Guadiana river (Spain/Portugal)

  2. Belá river (Czech Republic/Poland)

  3. Pasvik river (Norway/Russia)

  4. Nestos river (Greece/Bulgaria)

  5. Sumava catchment (Germany/Czech Republic)

1 - Guadiana river (Spain / Portugal border), with focus on water use and pollution problems:
    This case study represents the typical conditions of an area of arid climate of Southern Europe, with its particular environmental and social characteristics. Climate, soil and hydrogeology have a particular significance on the catchment available resources and they are main factors influencing groundwater recharge, whilst the main human impact driving forces are urbanization, industry and agricultural production. The increase in impervious surface have as effects a decrease of the recharge, and an increasing of the base flow in urban systems, increasing the surface run-off, and changes in river regimes have effects of gaining or losing, with increase or decrease of the available resources. Thoughout history Portugal and Spain had to learn the sharing of transboundary water resources. According to recent data the total needs for irrigation and domestic supply of water from Guadiana basin represent a 19 % in Portugal and a 81 % in Spain, and from the average annual discharge a 25 % is generated in Portugal and a 75 % in Spain. Non point source pollution from agricultural returns and point source pollution from industries, mining, sewage treatment plants, landfills, and others, are identified as major pollution sources and in consequence there is a decreasing of the availability of resources. Political, cultural, industrial and economical factors must be taken in consideration for best environmental management and water regulation.

2 - Belá river (Czech Republic / Poland border), with focus on pollution and flooding problems:
    The selected case-study borderline area includes natural conservation areas in the Czech Republic (the Protected Land Reserve of the Jeseniky Mountains) as well as in Poland (the Protected Park of the Opawskie Mountains) that represent one of the most attractive and valuable reserves of both countries. However, at the same time this area is characterised by impacts of quite inappropriate human interventions into the hydrogeological regime, a dramatic deforestation, large-scale amelioration and de-watering, interventions into vegetation and inappropriate adaptation of basins of local streams.
    From the geomorphological view, the area in question belongs to westernmost portion of Eastern Sudeten, from the climatic point of view it is a slightly warm region. Total annual precipitation is 846 mm, average annual temperature is 7.1 °C. According to the land-use map (collective of authors, 1992), there are 2 types of landscape in the area in question: in the central area, there is forest landscape with pine trees, and in the remaining portion of the area in question, there is landscape with a significant overbalance of grassy growths.

    The area in question is drained northward to the Baltic Sea. From the regionally hydrogeological point of view, there are two hydrogeological regions in the area in question – rocks of the Krystalinikum (crystalline complex) with fissure permeability and glacial-fluvial porously permeable sediments. The environment of two thirds of the region is of great quality; in the remaining one third, the environment is judged as fitting. Agriculture and forestry belong among the most important economic activities of this portion of the region, with a total share of 14% in the volume of business entities. A serious environmental problem of the region is water and wind erosion related to the primary agricultural production, which is cased by greater slope occurrence. A great danger in the region is the threat of floods.
    The Belá river area was selected as a pilot site primarily because the question of common management in this area is quite timely and perhaps even critical.

3 - Pasvik river (Norway / Russia border), with focus on pollution problems:
    Northern territories represent distinctive environmental and social conditions. A cold climate, a very vulnerable countryside and aquatic ecosystems distinguish the environment. Severe pollution problems have been identified. The pollution is caused by two major sources: overgrazing by reindeers on the Norwegian side and air pollution, mainly from the industry in the city of Nikel. This air pollution has caused a “technogenic” desert north and south (prevailing wind direction) of the nickel-smeltery. From the Nikel area large amounts of contaminated water are draining to the Pasvik River. With the new political era, major changes are expected in the region regarding settlement, industrial activity, land use and the standard of living.
    The cultural, political and related industrial and economical changes mentioned above provide an opportunity for land use planning according to best-practice guidelines and safe-minimum standards of environmental regulation, while trying to minimise the costs of achieving the guidelines and standards.

4 - Nestos river (Greece / Bulgaria border), with focus on water use problems:
    The area under study, on the borderline of the Nestos/Mesta River between Greece and Bulgaria is characterized by conflicting water uses. Nestos river is sited at the area of western Thrace and flows through the prefectures of Drama, Xanthi and Kavala, consisting the most important water source of the whole area.
    The river flows from the mountain Rila (2716m) in southern Bulgaria and after a distance of approximately 230Km in both Bulgarian and Greek territories, it discharges into the Thracian Sea eastern of the city of Kavala.
The total river catchment area is 5749 Km2. From this area, 3437 km2 (60%) belong to Bulgaria and the remaining 2312 km2 (40%) belong to Greece. Despite earlier agreements, Bulgaria has been withholding supplies to serve its extended agriculture and industrial activities. Heavy urbanization, industry and agriculture has lead to a significant decrease in the river’s flow affecting especially the Greek part. From 1975 the Nestos flow declined from 1500 million m3 to 600 million m3 resulting to repeated Greek protests. Several series of negotiations since 1965 have resulted in a new agreement between the two countries that however suffer from essential weaknesses. According to the agreement, Bulgaria is obliged to leave downstream 28% of the river discharge, without further specifying however the seasonal variation of this amount of water. Pollution coming from the Bulgarian industry is decreasing in the recent ten years of democratic changes however continues to deteriorate downstream water resources resulting to water quality problems affecting both urban systems and irrigation.An integrated approach of all environmental, political, social, economic and technical aspects of water resources management is needed in order to ensure water preservation and environmental integrity of the region.

5 - Šumava catchment (Germany / Czech Republic border), with focus on water pollution:
    The studied area represents the south-eastern Czech part of the Šumava Mts. and the German trans-boundary region between the cities Rotz, Cham and Zwiesel. The large mountain range of Šumava forms a historical border with Germany and since the World War Two until 1990 it also represented a contact between the Western and Eastern political blocks during the Cold War period. This led to almost complete evacuation of local population and the major part of the range became a military area. Consequently, the whole region remained untouched for long decades and today it may serve as a natural laboratory that can provide data on the development of environment that did not suffer from human activities.
    Two basic areas can be outlined in Šumava. The mountain part with elevations around 1000 m a.s.l. and the foothills. The study area shows two climatic zones. The apical parts belong among slightly cool to cool climate with enhanced precipitation. The majority of hydrogeological data in the Šumava Mts. area come from shallow drilling, which characterize subsurface zone of solid products of weathering and opening of fractures to a depth of 30 to 40 metres. The studied part of Šumava is drained by two important streams, i.e., the Vltava and Otava rivers. From a hydrogeological viewpoint, the circulation of groundwater in one way depends on a thick network of cracks and as well on watering out coatings of gneiss, mica, granite etc. When effected by freezing efflovescence, during the ice age freeze over of Šumava, the decay coating can become tens of meters thick.
    The Šumava region is a very important European region in natural conditions. A National Park has been declared in 1991 in the apical parts of the Šumava mountain range.