Fresh water resources Ukraine
Changing rainfall patterns and runoff indicate that future summer river flows are likely to decrease substantially, by as much as 50%, across central and eastern Europe, including the Ukraine (4). It is likely that the country will suffer increased water stress over the 21st century as severe droughts, classified today as one in 100 year events, are projected to become twice as likely by 2070 (5).
Europe: five lake categories
There are almost one and a half million lakes in Europe, if small water bodies with an area down to 0.001 km2 are included. The total area of lakes is over 200,000 km2; in addition the manmade reservoirs cover almost 100,000 km2. The response of European lakes to climate change can be discussed by dividing the lakes into five categories (3):
Deep, temperate lakes
Typical representatives of this class are e.g. Lakes Maggiore, Ohrid, Geneva and Constance with mean depths of 177, 164, 153 and 90 meters, respectively. Due to the great depth and relatively mild winters, there is usually no ice cover. The future climate change in Europe may suppress the turnover in deep lakes. This implies the enhancement of anoxic bottom conditions and an increased risk of eutrophication. The oxygen conditions can also be anticipated to deteriorate due to increased bacterial activity in deep waters and surficial bottom sediment.
Shallow, temperate lakes
Balaton (600 km2, 3 m) in Hungary and Müritz (114 km2, 8 m) in Germany belong to this class. Increasing water temperatures may result in intensified primary production and bacterial composition. The probability of harmful extreme events, e.g. mass production of blue-green algae, will increase. The impacts may extend to fish life; changes in species composition and reduced fish catches will be anticipated. The use of the expression 'thermal pollution' is well justified for these lakes.
Ladoga (17 670 km2, 51 m), Onega (9670 km2, 30 m) and Vänern (5670 km2, 27 m) are the largest in this class, being also the three largest lakes in Europe. This group includes about 120 lakes with an area exceeding 100 km2. Most lakes of the boreal zone mix from top to bottom during two mixing periods each year. Shortening of the ice cover period will be the most obvious consequence of climate change in these lakes. This could improve the oxygen conditions in winter and spring.
These are mainly small water bodies in northern Scandinavian mountains and in the tundra region. Arctic lakes are generally considered to be particularly sensitive to environmental changes. Melting permafrost may seriously threaten the ecosystems of arctic lakes. In some cases the whole lake may disappear as a consequence of ground thaw and enhanced evaporation.
To this class belong all high altitude lakes in central Europe and also those located in southern Scandinavia. Even if mountain lakes were connected by channels, physical and ecological constraints limit species migration between them. In a warming climate, there is no escape route; the only possibility for survival is adaptation.
In the northern part of Ukraine annual river runoff may rise by 15-25%; winter runoff will increase and spring runoff will decrease. In the southern and southeastern part of Ukraine annual river runoff may decrease by 30-50%. Both drought risk and the frequency and magnitude of extreme floods will increase (2).
The sectors that are most vulnerable to these changes are agriculture in the south and industry and households in the south and southeast. In the south and southeast, surface water quality will deteriorate (2).
The Dnieper is the main river of Ukraine. The river fills water reservoirs that are used for several interests. When there is not enough water in these reservoirs, priorities are made. Four levels are discriminated (1):
- Zone of full provision. All consumers are provided with water without restrictions.
- Zone of economic consumption. All water consumers are provided with water in accordance with norms. Restrictions of auxiliary needs are introduced.
- Zone of strict water saving, when water reservoirs are being drawn down below navigation drawdown level not more than 1 m. Restriction for irrigation systems and for auxiliary needs of industry are introduced. River transportation is restricted to a navigation depth of 2.6 m. Ecological passing may be curtailed to 300 m3/s for short periods. Upon that everyday inspection of water quality is established.
- Zone of all consumers’ restriction. To provide for needs of inhabitants, limits and schedules for strict water supply are established.
Under climate change scenarios that lead to decreased Dnieper water discharge, the quality of surface waters may deteriorate. Therefore, bearing in mind the present high level of Dnieper water contamination, underground deep water horizons are recommended for near future water use to meet the demands for drinking water (1).
Managed aquifer recharge
Comprehensive management approaches to water resources that integrate ground water and surface water may greatly reduce human vulnerability to climate extremes and change, and promote global water and food security. Conjunctive uses of ground water and surface water that use surface water for irrigation and water supply during wet periods, and ground water during drought (6), are likely to prove essential. Managed aquifer recharge wherein excess surface water, desalinated water and treated waste water are stored in depleted aquifers could also supplement groundwater storage for use during droughts (7,8). Indeed, the use of aquifers as natural storage reservoirs avoids many of the problems of evaporative losses and ecosystem impacts associated with large, constructed surface-water reservoirs.
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Ukraine.
- United Nations Framework Convention on Climate Change (1998)
- Manukalo (presentation downloaded from internet on 27-01-2010)
- Kuusisto (2004)
- Oltchev et al. (2002); Eckhardt and Ulbrich (2003), both in: Met Office Hadley Centre (2010)
- Alcamo et al. (2007), in: Met Office Hadley Centre (2010)
- Faunt (2009), in: Taylor et al. (2012)
- Scanlon et al. (2012), in: Taylor et al. (2012)
- Sukhija (2008), in: Taylor et al. (2012)