Written by: Yuliya Denkova Parvanova, e-mail: firstname.lastname@example.org
English teacher, Maths and Science High School „St. Kl. Ohridski“
Download: Presentation in MS PowerPoint .PPT format [2,1 MB]
Slide1 Only three percent of the water on Earth is fresh water in nature, and about two-thirds of this is frozen in glaciers and polar ice caps.
Most of the rest is underground and only 0.3 percent is surface water. Several million kilometres of flowing waters and more than a million lakes cover the European continent. Each body of water has its own characteristics, such as clarity and biodiversity level, and faces its own specific environmental problems.
In the lesson Fresh waters of Europe we will learn about the present water condition of the continent and some of the main problems related to the water supply.
Slide 2 The hydrosphere originates from the bowels of the Earth through the volcanic gorges. It is close related to the processes in the atmosphere.
Slide 3 There are two types of waters: surface and underground waters.Rivers and lakes belong to surface waters. Underground waters are devided into four groups:grunt, artesians, karsts and mineral waters.
Slide 4 Grunt waters – this is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. It can be a long-term ‘reservoir’ of the natural water cycle. Groundwater makes up about twenty percent of the world’s fresh water supply, which is about 0.61 percent of the entire world’s water supply.
Artesian – waters between two waterproof layers
Karsts – underground waters reach of CaCO³
Mineralwater – naturally impregnated with mineral salts or gasses
Slide 5 A river is a system comprising both the main course and all the tributaries that feed into it; the area that the river system drains is known as the catchment. The main characteristic of rivers is their continuous one-way flow in response to gravity.
Due to variations in physical conditions, such as slope and bedrock geology, rivers are dynamic and may change form several times throughout their course. For example, a fast-flowing mountain stream may develop into a wide, deep and slow-flowing lowland river.
When assessing river characteristics and water quality, it is important to bear in mind that a river comprises not only a main course but also a vast number of tributaries. For example, the main course of Europe’s largest river, the Volga, is 3500 km long. In addition, it receives water from ten tributaries of over 500 km in length and more than 151 000 tributaries of over 10 km in length.
Slide 6 Although there are numerous European river catchments, they are relatively small and their rivers are short. About 70 European rivers have a catchment area which exceeds 10 000 km2. Only rivers arising deep inside the continent are relatively large. Europe’s 31 largest rivers (all of whose catchments exceed 50 000 km2) drain approximately two thirds of the continent and include:
- The major rivers flowing north into the Barents Sea and White Sea – the Severnaya, Dvina and the Pechora.
- The Volga, the Ural and the Kura drain into the Caspian Sea while the Dnepr and the Don drain south into the Black Sea.
- The largest river to discharge into the Black Sea – the Danube . Its catchments lie in 16 countries of central Europe and the Balkans. The main rivers discharging into the Baltic Sea are the Neva , the Wisla, the Oder and the Neman.
- Ten rivers with catchments larger than 50 000 km2 drain into the Atlantic and the North Sea – the Rhine, the Elbe, the Loire and the Douro/Duero being the largest.
- The European rivers draining into the Mediterranean – the Rhone, the Ebro and the Po.
Over half of these rivers have their catchment area in the European part of the former Soviet Union.
Europe’s three largest rivers, the Volga (1), the Danube (2) and the Dnepr (3), drain one quarter of the continent. However, they are relatively small by world standards; their catchments ranking 14th, 29th and 48th, respectively.
Slide 7 Lakes are usually bodies of standing freshwater, though they may also be brakish, i.e. slightly salty. They are characterised by the physical features of the lake basin, such as lake area and water depth, as well as the characteristics of the catchment area, such as size and topography.
Slide 8 Types of lakes Classification according lakes’ origin
Endogenic is a geologic term that refers to processes and phenomena that occur beneath the Earth’s surface – or any other celestial body.
Exogenic refers to external processes and phenomena that occur on or above the Earth’s surface.
- tectonic lakes-resulting from structural deformation of the earth’s crust.
- Crater: A lake which forms in volcanic calderas or craters after the volcano has been inactive for some time. Water in these types of lakes may be fresh, or highly acidic, and may contain various dissolved minerals.
- Coastal lakes: near or bordering on a coast
- Oxbow: A lake which is formed when a wide meander from a stream or a river is cut off to form a lake. They are called oxbow lakes due to the distinctive curved shape that results from this process.
- Glacial lake: a lake with origins in a melted glacier.
- Karsts :An area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns.
On the pictures -tectonic- Lake Balaton(Hungary); volcanic-Lake Albano near Rome (Italy); coastal – Lake Bourgass( Bulgaria), Oxbow-Lake Srebarna ( Bulgaria), glacial and karsts –lakes in Rila( Bulgaria)
Slide 9 Many natural European lakes appeared 10 000 to 15 000 years ago; being formed or reshaped by the last glacial period. The ice sheet covered all of northern Europe. However, in central and southern Europe ice sheets only stretched as far as mountain ranges. Norway, Sweden, Finland and the Karelo-Kola part of Russia have numerous lakes that account for approximately 5 % to 10 % of their national surface area. Large numbers of lakes were also created in other countries around the Baltic Sea, as well as in Iceland, Ireland and the northern and western parts of the United Kingdom.
In central Europe, most natural lakes lie in mountain regions. Lakes at high altitude are relatively small whereas those in valleys are larger, for example Lac Léman, Bodensee, Lago di Garda, Lago di Como and Lago Maggiore in the Alps and Lake Prespa and Lake Ohrid in the Dinarian Alps. Two exceptions are the large lakes lying on the Hungarian Plain— Lake Balaton and Lake Neusiedler.
Slide 10 European countries which were only partially affected by the glaciation period (Portugal, Spain, France, Belgium, southern England, central Germany, the Czech Republic, the Slovak Republic and the central European part of Russia) boast few natural lakes. In these areas man-made lakes, such as reservoirs and ponds, are often more common than natural lakes.
Slide 11 Reservoirs are human-made lakes created by the damming of rivers to serve one or more purposes, such as hydropower production, water supply for drinking, irrigation and flood protection.
Slide 12 Dams have been built in Europe for over hundreds of years. The oldest still in activity are Cornalbo, Proserpina and El Belcial in Spain, which have been in operation since the 2nd century. The reservoirs resulting from the dams that were built before 1800 were relatively small and were used mainly for domestic water supply, crop irrigation, energy production and canal operation. During the last two centuries there has been a marked increase in both size and number of large storage capacity reservoirs, especially with the development of hydropower and large basin management. There are currently about 7000 large dams in Europe. In addition, there are thousands of smaller dams
The total number of dams in Europe is now growing very slowly, as suitable sites becomer fewer and environmental concerns become greater.
The total European reservoir surface area covers more than 100 000 km2; 50% of which lies in the European part of Russia. Although there are only a few reservoirs in this area, they are very large. The six largest reservoirs are located in the Volga river system in Russia.The Kuybyshevskoye (6450 km2) and Rybinskoye (4450 km2) are the two largest reservoirs. Of the 13 European reservoirs with an area exceeding 1000 km2, only the Dutch reservoir Ijsselmeer lies outside Russia and the Ukraine.
The member state with the largest number of reservoirs is Spain (approx. 1200), Turkey (approx. 610), Norway (approx. 364) and the UK (approx. 570). Other countries with a large number of reservoirs are Italy (approx. 570), France (approx. 550) and Sweden (approx. 190). In Bulgaria there are approximately 2000 large and small reservoires.
Slide 13 Overall, the region abstracts a relatively small portion of its total renewable water resources each year.
Total water abstraction in the region is about 350 km3/year. In other words, approximately 10 % of Europe’s total freshwater resource is abstracted annually.
To ensure water supply many countries have built reservoirs. Three countries – Spain, Turkey and Romania – are able to store more than 40 % of their long-term annual available (LTAA) resource, but also countries such as Cyprus, Bulgaria, Ukraine, Sweden and the Czech Republic have high storage capacities. Although such structures are beneficial for securing supply at critical moments, they adversely affect the regional water cycle and sediment transport. Moreover, they act as barriers for migrating aquatic species, e.g. salmon and sturgeon.
In Europe, there are eight countries that can be considered water-stressed (Germany, England and Wales, Italy, Malta, Belgium, Spain, Bulgaria and Cyprus), representing 46% of Europe’s population. Only in Cyprus does the WEI exceed 40 %. However, it is necessary to take high water abstraction for non-consumptive uses (cooling water) into account in Germany, England and Wales, Bulgaria and Belgium. Most of the water abstracted in the other four countries (Italy, Spain, Cyprus and Malta) is for consumptive uses (especially irrigation) and there is therefore higher pressure on water resources in these four countries.
Slide 14 All economic sectors need water; agriculture, industry and most forms of energy production are not possible without water.
Navigation and a variety of recreational activities also depend on water. The most important uses, in terms of total abstraction, have been identified as urban (households and industry connected to the public water supply system), industry, agriculture and energy (cooling in power plants). On average, 44 % of total water abstraction in Europe is used for agriculture, 40 % for industry and energy production (cooling in power plants), and 15 % for public water supply. The main water consumption sectors are irrigation, urban, and manufacturing industry.
Southern European countries use the largest percentages of abstracted water for agriculture. This generally accounts for more than two-thirds of total abstraction. Irrigation is the most significant use of water in the agriculture sector in these countries.
Central European and the Nordic countries use the largest percentages of abstracted water for cooling in energy production, industrial production and public water supply.
Slide 15 There are three main problems. The first one is droughts. Large areas of Europe have been affected by droughts over the past 50 years, and pressures on European water resources have increased in the past decades.
Therefore, future conflicts between human requirements and ecological needs are likely to increase. These conflicts are most critical and intensify during severe and extensive droughts. The primary cause of any drought is a deficiency in rainfall, but also increased human demand for water is an important factor.
Slide 16 Droughts can be divided into meteorological droughts, agricultural droughts and hydrological droughts.The main impacts of droughts include water supply problems, shortages and deterioration of quality, intrusion of saline water in groundwater bodies and increased pollution of receiving water bodies and drops in groundwater levels. Droughts have major economic impacts.
The latest climate change scenarios suggest significant summer drying across many parts of Europe, especially in the south. These scenarios also suggest lower rainfall in other seasons and increased variability. These patterns of change suggest that over the coming decades Europe is likely to suffer more frequent meteorological droughts. Policy measures are needed.
- The use of economic instruments, such as water pricing and metering
- Water-reuse and recycling
- Increased efficiency of domestic, agricultural and industrial water use
- Water saving campaigns supported by public education programmes
Slide 17 Catastrophic floods cause human tragedy, endanger lives and bring heavy economic losses.
In addition to economic and social damage, floods can have severe environmental consequences, for example when installations holding large quantities of toxic chemicals are inundated. The coming decades are likely to see a higher flood risk in Europe and greater economic damage.
During the last five years Europe has suffered over 100 major damaging floods, including the catastrophic floods along the Danube and Elbe rivers in summer 2002, in northern Caucasus in July and August 2002, in the Alps in summer 2005 and along the Danube in spring 2006. Since 2000, floods in Europe have caused at least 700 deaths, the displacement of about half a million people and at least EUR 25 billion in insured economic losses.
Some areas have been more affected than others. Between 1998 and 2005 north-western Romania, south-eastern France, central and southern Germany, northern Italy, and eastern England experienced the highest concentration of repeated flooding.
Slide 18 Almost all human activities can and do impact adversely upon the water. Water quality is influenced by both direct point source and diffuse pollution which come from urban and rural populations, industrial emissions and farming. Diffuse pollution from farming and point source pollution from sewage treatment and industrial discharge are principal sources. For agriculture, the key pollutants include nutrients, pesticides, sediment and faecal microbes. Oxygen consuming substances and hazardous chemicals are more associated with point source discharges. The diagram illustrates the many sources of nitrogen pollution in water. Generally, a distinction can be made between:
point sources, such as discharges from urban wastewater, industry and fish farms; diffuse sources, such as background losses (e.g. forests), losses from agriculture, losses from scattered dwellings and atmospheric deposition on water bodies (e.g. marine areas or lakes).
Slide 19 Over the past three decades, several pieces of EU legislation and international agreements have addressed the pollution of aquatic ecosystems.
These include the Urban Wastewater Treatment Directive (91/271/EEC), the Nitrates Directive (Directive 91/676/EEC) and IPPC Directive (96/61/EC), the Bathing Waters Directive (76/160/EEC & 2006/7/EC), and, more recently, the Water Framework Directive (WFD; 2000/60/EC).
The WFD requires all inland, transitional and coastal waters to reach good ecological and chemical status by 2015. Based on a review at river basin scale, all pollutants and their associated anthropogenic activities must be addressed to ensure that good status is attained and maintained.
Under the 1991 Urban Waste Water Treatment (UWWT) Directive, the standards for collection, treatment and disposal of wastewater required at each works depends on two factors:
- size of the urban area.
- classification of the receiving waters, i.e. sensitive or non-sensitive to eutrophication.
Many EU-15 countries have not yet complied fully with the directive. They have not yet installed the sewage treatment capacity that the directive required by 1998 and 2000. Others are seeking postponements to requirements in order to extend sewage treatment to smaller urban areas by 2005.
Some countries have shown that both successful implementation of the UWWT Directive and subsequent significant improvements in water quality are possible. These countries include: Austria, Denmark, Germany and the Netherlands. In France, only 40 % of sewage discharges to sensitive areas meet the required standard. In Spain, supported by substantial subsidies from the EU Cohesion Funds, 55 % of the population is connected to public sewage treatment plants.