|Hydromorphological transformation and environmental problems of the Dnieper reservoirs — see everything from space|
|News Waterfall - News Waterfall #4|
|Friday, 07 September 2012 16:00|
In Soviet times, the main river of Ukraine — Dnieper was transformed by dams into a cascade of six reservoirs. During the last ten years attention of ecologists and public was attracted to the formation of new deltas in the upper parts of reservoirs, where the Dnieper river flows into the reservoirs. In previous time only problem of silting of the reservoir was in focus of the research, but the actual process is more complicated and substantial. In these “new” deltas the hydromorphological landscapes are developing with a unique vegetation and soil cover as a result of overgrowth. New relief elements are formed due to the accumulation of sediment runoff, banks transformation, regressive erosion, organic matter accumulation.
Already 3 years author of this article, professor of the National University of life and Environmental Sciences of Ukraine is conducting a field studies and monitoring the changes of the newly formed landscapes using satellite images “Landsat”. It is shown that new landscapes (including the new land) are formed with highest rate in the shallowest Kiev reservoir, which is the upper reservoir of the cascade. Here the rate of increasing area overbrowned by macrophytes: Scírpus, Týpha and especially — macrophytes with floating leaves (Trápa nátans, Núphar lútea, Nymphaéa, etc.) is about 1,000 hectares per year. It creates difficulties for navigation, fisheries and degrades the quality of water used for drinking water supply.
In Kanev Reservoir, located down stream Kyiv, in its upper (river) part the natural formation processes of hydro-morphological landscapes are supplemented with the man-made landscapes by using dredges in the water area. During 1985–2011 years more than 1,000 hectares of land were built and sold for private cottage construction in this area of Kanev Reservoir.
Now the area of new deltas is rapidly growing in the Kremenchug reservoir too, where the growth rate is 231 ha per year.
The general area of hydromorphic landscapes exceeds 35 000 ha throughout the cascade, including Dneprodzerzhinskoe and Kakhovka reservoirs, the new Deltas occupy about 70 000 hectares including water surface.
Scientists believe that the wise use of these new landscapes can reduce significantly their negative impact. At the same time it is necessary to take into account the positive value of the “new Deltas” to enrich the biodiversity of the region and increase the recreational resources of the Dnieper cascade.
However, the main threat to the quality of the Dnieper water is discharges of polluted water from industrial and utility companies. Moreover, these discharges are often carried out in shallow tributaries of the Dnieper, affecting dramatically their ecological status. This is the case in the estuary of the river Sula — left-tributary of the Dnieper at Kremenchug reservoir. The contaminated water flows into reservoirs, intense “blooming” and deterioration of water quality of the Dnieper reservoirs can be clearly seen on Satellite images. On the attached photo made by satellite Terra on September 3, 2012 clearly shows that the main sources of pollution of the Kremenchug reservoir are the rivers Sula and Tyasmin and enterprises of cities Svetlovodsk and Cherkassy.
Since this polluted water is used as sources of drinking water for the cities: Kremenchug, Komsomolskaya and others, located downstream, this satellite images and information was sent to the local authorities of these cities.
Taking into account that the water from Dnieper is the source of drinking water supply for 70% of the country population, now a determined action against discharging of not treated, polluted wastewater into rivers must become a priority for ecological restoration of the Dnieper River Basin.
This article prepared by Vladimir Starodubtsev, professor of the National University of life and Environmental Sciences of Ukraine, Env. NGO “EKO-Svit”, Kyiv , Head of the Working Group on ecological- Hydromorphological research of reservoirs to the Dnieper River Basin Council.
To read more in Russian: http://nd.nubip.edu.ua/2012_4/12svm.pdf.