1. Building dams upstream is an essential condition for the operation of a large hydropower station.
2. The environmental consequences of large-scale dam building are insignificant.
3. Salmon is among the species most affected by the dam construction.
4. Groundwater levels are not influenced by the water regulation of this sort.
5. Small-scale hydropower plants have become obsolete and do not operate any more.
Text 4.1.2. Dam building
A large hydropower station requires a large dam upstream to provide a better fall height and a more controlled and continuous supply of water. The effects on the rivers are therefore threefold: a reduction of the seasonal variation; the permanent formation of large dams, even enormous lakes, upstream; and often a considerable reduction of water volumes downstream.
The environmental consequences of this are dramatic. The seasonal flooding of flood plains disappears, and with them a whole biotope. Species dependent on seasonal variation are affected as are migrating fish such as salmon, which no more is able to go upstream rivers to spawn. In addition, large aesthetic values are lost. The romantic and comparatively unaffected scenery of water-falls, streams and desert-like areas where the old riverbed lays barren substitute flood plains. Changes in water flows may have negative consequences for groundwater levels, which affect the local water supply and irrigation.
The social and economic effects are also substantial. Valuable farm- and forest-lands may be lost when the dams constructed block the water reservoirs. Sometimes whole valleys are set under water and homes and even entire villages may have to be relocated. These effects have, however, to be compared to the benefits the hydropower plant brings, such as electrification and regulation of the river flow to protect from devastating floods.
A relevant alternative to large-scale hydropower production can be small-scale hydropower plants, i.e. power plants with a capacity below 5MW. Although in the past 50 years the number of small-scale hydropower plants in industrialized countries has declined as power companies have invested in larger, more profitable electricity production systems. However, the conditions for small electricity generation are slowly improving again in Europe. One reason for this is change is the deregulation of the electricity market. Another reason is a revived interest in developing domestic energy sources in order to reduce the dependence for electricity imports.
Task 7. These are the answers to the questions about the text, make up the questions
1. Because it is necessary to provide a better fall height and a more controlled and continuous supply of water.
2. No, the environmental consequences are significant.
3. They are mostly species of fish and birds.
4. No, they are not always beneficial.
5. Yes, there is an alternative for large-scale hydropower production.
6. There are two reasons for small-scale electricity production. They are .
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Task 8. Read the extract and fill in the gaps with the appropriate word
The technology of hydropower
Hydroelectric power is __________ and in this way presents a sustainable source of_____, in contrast to combustion of oil____ and coal which dominates the electricity production in the Baltic_____.
An important advantage of hydropower plants is that they can be used to _____energy. Water is stored in dams as a reserve energy source to meet sudden changes in _______. In Northern Europe water is typically stored during spring and _____, when electricity demand tend to be lower, and is used to produce power later in the winter when electricity demand is _____.
Summer, store, gas region, demand, high, renewable, energy
Module 2
Task 1. Read the effects of regulation of watercourses, can you think of any other?
Effects of regulation of watercourses
1. Different obstacles block the way for salmon and other migrating species;
2. Varying water level removes large parts of beach flora, bottom vegetation and bottom fauna;
3. Increased isolation reduces biological diversity.
