The Cities And Ecosystems Of The Lower Dniester: Problems Of Rational Water Management
The cities and ecosystems of the Lower Dniester: problems of rational water management
A.V. Krivenko1, A.B. Fiodorov2, V.G. Fomenko1
1T.G. Shevchenko Dniester State University, Tiraspol, Moldova
2National Museum of Ethnography and Natural History of the Republic
of Moldova, Chisinau, Moldova
The Dniester River serves as the accumulator and the transit passage of ecologically dangerous industrial and municipal sewage wastes, which eventually enter the Black Sea basin. The nature of the environmental impact on the riverine ecosystem has undergone significant changes during the past decade. The anthropogenic pressure on the Dniester River has been redistributed in “favor” of urban settlements because of the sharp reduction of agroindustrial production in the states located in the watershed of the Dniester.
If the organoleptic and the sanitary - chemical parameters of the Dniester water have lately had the steady tendency to improvement, the bacterial pollution remains rather high. Emergency discharges of industrial wastewaters coming from the cities of the region have had a particularly significant impact on the riverine ecosystem. The maximum anthropogenic load on the ecosystems of the Dniester and its tributaries has been produced within the boundaries of the Tiraspol-Bendery metropolitan area. The water of the Dniester River is not used for drinking purposes in the aforementioned urban area because of the availability of significant reserves of confined underground waters, and, also, because the serious bacterial pollution of river water requires its superchlorination and other additional purification measures, which could sharply decrease the drinking quality of water. In general, water abstraction and the subsequent wastewater discharge is carried out for the needs of industry and agriculture.
The number of small tributaries of the Dniester piercing the Tiraspol and Bendery municipal areas are actually used as natural sewers. Their sanitary - epidemiological condition is unsatisfactory. Industrial and municipal sewage wastewaters, construction waste, and household garbage are dumped into the
Dniester tributaries. In spring, they become a source of epidemiological hazards associated with abounding pathogenic microflora and microfauna. In spring and autumn, heavy rains result in the emergency discharges of the tributary waters into the Dniester, which is an additional source of the disruption of the ecological balance of the river. As the result, the content of surfactants, yeasts and molds, different bacteria including the bacterium Vibrio cholerae and the eggs of the parasites of humans and animals sharply increases. In hot weather, 60-70% of the Dniester water samples contain the bacterium Vibrio cholerae. In some years, this parameter exceeds 80%, which upsets the normal functioning of urban beaches, direct irrigation of agricultural crops with river water, and the local fisheries. During the last several years, the growth of child and adult morbidity, particularly due to intestinal infections transmitted through the river water, has been observed. As the consequence of the aforementioned factors, the Dniester water downstream begins to bloom, which leads to sharp deficiency of oxygen and, as the result, to a massive loss of riverine and coastal flora and fauna, fish kills, breaking of food chains in the ecosystem of the river.
Storm discharge is particularly destructive for the ecological balance of the Dniester. It results in serious flooding, waterlogging of farmland, improper functioning of municipal sewage systems, washout of toxic substances from streets and industrial zones. Thus, some individual analyses show the excess of the maximum allowable concentration of nitrites, nitrates and ammonium nitrogen, heavy metals, petroleum substances (0.08mg/l), fats, alcohols e.g. phenols (0.02 mg/l), iron compounds, surfactants e.g. detergents (0.06mg/l), and suspended matter (365‑578 mg/l in the Olanesti section) in 2-3 times. In comparison with the 1950s, the mineralization of Dniester water has increased by 50%. The autonomous character of municipal water supply systems reduces the threat of the deep-seated underground water pollution. Water supply in the cities of Tiraspol and Bendery is ensured by 80-90% at the expense of artesian wells, i.e. does not depend on the Dniester water, as it is in Chisinau. With the diurnal average water consumption of 200-250 liters, direct water losses make up about 50 liters and the other 30 liters of drinking water leaks away into the municipal sewage system because of the deterioration of water-conducting pipelines. Individual segments of municipal water piping are characterized by the infiltration of domestic wastewaters in the ground, which creates a direct threat of groundwater pollution.
Another factor of the disturbance of the ecosystem of the Lower Dniester basin is the degradation and uncontrolled felling of the water-protecting riparian woody vegetation along the artificial levee separating a riverbed from a partially ploughed up and built up floodplain of the river. The contemporary condition of a levee is inadequate and is giving rise to anxiety. Serious floods have been destroying its first line because of the weakened-forested strip. The anthropogenic impact on the last remaining patch of floodplain forest in the Lower Dniester basin, the Chitcani forest, is serious. Despite the reforestation practices, the forested area is being damaged by regular overgrazing, uncontrolled illegal cutting, the expansion of area under private orchards and vegetable gardens, forest fires caused by human negligence, piles of domestic garbage, which has been collected in the area for decades. The fragile forest ecosystem has been losing its ability to regenerate and its recreational potential, so valuable considering its vicinity to the downtown of Tiraspol.
In the contemporary situation, the development of the effective long-term sustainable environmental / natural resources management program directed towards the normalization of the ecological situation in the Lower Dniester area is required. It should include the following measures:
1. Further strengthening of the coordination of efforts of various governmental, non-governmental, educational, business, and other organizations of the Dniester Region, Moldova, and Ukraine dealing with the water resources management issues.
2. The creation of a system of interstate environmental monitoring and assessment of the Lower Dniester basin.
3. The increase of efficiency of the environmental control over the state of the water supply sources.
The following individual measures permitting to improve the environmental situation in the Tiraspol-Bendery metropolitan area are proposed:
1. The construction of filters of the appropriate capacity for the storm water drainage systems located in the cities of the metropolitan area.
2. The organization of rehabilitation works in the water-protecting riparian-forested areas.
3. The improvement of a sanitary regime in the small tributaries of the Dniester.
4. Tightening of the control over the quality of water in recreational zones.
5. Further improvement of the efficiency of environmental / natural resources management education of the population in the region.
References
1. Annual reports of municipal and regional committees on ecology for the 1996-1999 period (in Russian).
2. Paliy T.Z., Kishlyaruk V.M., et al. Gigiyenicheskaya Otsenka Vody Reki Dnestr v Cherte Goroda Tiraspolya [Hygienic Assessment of the Water of the Dniester River within the Boundaries of the City of Tiraspol] // Collected articles Kachestvo Vody i Zdorovye Cheloveka [Quality of Water and Human Health]. Odessa: OTSNTEI, 1999; p.p. 39-42 (in Russian).
3. Topchiyev A.G. Geoecologiya: Geograficheskiye Osnovy Prirodopol’zovaniya [Geoecology: Geographical Principles of Natural Resources Management]. Odessa: Astroprint, 1996, p. 392 (in Russian).
4. Fomenko V.G., Dobynda K.G., et al. Ecologicheskiye Problemy Vodopol’zovaniya Gorodov i Syol Pridnestrovya [Ecological problems of Water Resources Management in the Cities and Villages of the Dniester Region] // Collected articles Kachestvo Vody i Zdorovye Cheloveka [Quality of Water and Human Health]. Odessa: OTSNTEI, 1999; p.p. 292-297 (in Russian).
5. Republica Moldova. Mediul Inconjurator: Starea si Dinamica [The Republic of Moldova. The Environment: State and Dynamics]. Chisinau: Institutul de Geografie al Academiei de Stiinte a Republicii Moldova, 1997 (in Romanian).
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