Scale of water resources development and sustainability: Small is beautiful, large is great (Invited)
D. Koutsoyiannis, Scale of water resources development and sustainability: Small is beautiful, large is great (Invited), LATSIS Symposium 2010: Ecohydrology, Lausanne, doi:10.13140/RG.2.2.20564.40320, Ecole Polytechnique Federale de Lausanne, 2010.
In our postmodern culture, political correctness, in which “green” political views dominate, has become a euphemism, if not a synonym of irrationality. Engineering means for the development of water resources and prevention of flood disasters have been severely criticized as “offensive” to the environment and damaging to ecosystems—as if people did not matter and their habitats were not part of the ecosystems. In particular, large scale projects such as dams, large hydropower projects, interbasin water transfer projects and irrigation systems are regarded as evil constructions and are virtually prohibited in many countries, including most of Europe. Only small-scale constructions, such as small hydropower projects and waters tanks, are regarded as politically correct. On the other hand, our societies supposedly seek sustainability, which includes investing in renewable energy, sufficiency of, and equity in, food and water supply, and quality of life and of the environment. These pose a dilemma on whether water resources development should be undertaken or not in areas of the world not already developed, as well as some questions about the appropriate scale of development. Some facts may help study these questions:
- The world population, from 1.65 billion in 1900, now approaches 7 billion and many predict it to be 9 billion by 2050 (a middle scenario).
- Virtually all of the population growth is expected to be concentrated in the urban areas of the world; megacities and megalopolitan conurbations with 10 million or more residents are becoming more numerous, predominantly in developing countries.
- Water is the element that makes cities livable and is also the basis for food production.
- Disparities in water supply among different areas in the globe are marked: More than a billion lack access to safe drinking water; and half of the urban population in Africa, Asia, and Latin America suffers from diseases associated with inadequate water and sanitation. While in developed countries any person has water supply through house connections and consumes 150-200 L/d or (much) more, in developing countries it constitutes merely an objective to provide 20 L/d per person at a distance of less than 1 km.
- Availability of water is by definition sustainable, due to the natural hydrological cycle, and largely exceeds human and environmental needs; however its spatial and temporal distribution is incommensurate to the water needs and this creates problems, which could be coped with engineering means.
- Among the renewable energies, the hydroelectric from large scale projects is the only reliable and available on request, while all others are highly variable, unpredictable and uncontrollable.
- With current technological means, large-scale energy storage, which should be necessary to manage uncontrollable renewable energies, is provided only by pumped storage in large reservoirs.
- Both cost and energy efficiencies increase with the increase of scale of the project.
Based on these facts, the discussion of the questions is illustrated with some examples from the world with particular focus on Greece, whose water resources are only partly developed.
Course bibliography: Water Resources Management,