The LAKE of BELARUS
One of the main natural resources of the Republic are lakes, water resources – water resources suitable for use in the household. The quantity and quality of resources is determined by the availability of a lakes capacity of lake basins, volume of flow formed in the catchment and runoff from the lake, the difference between precipitation and evaporation from mirror lake and the value of withdrawals and discharges of water used for domestic purposes.
The total volume of water lakes of the country, according to NILE lakes is estimated at approximately 5880 million km3. Administratively, the main part of the volume of lake water is concentrated in lakes of the Vitebsk region (about 85% of all lakes in Belarus) occupying a total area of 970 km2. Followed by Minsk (11.4 percent) and Brest region. Lakes are the most lacking in Mogilev region. More than 84% of the volume of water the lakes are concentrated in the basin of the Western Dvina and its major tributaries of the Disna (13% of the total); Drisi (9.7 per cent).
The largest volume of water enclosed in basins of the Western Dvina (72%) in the Neman basin it decreases to 20%, the rest falls on the pools of the Pripyat river (155 mm3), Dnieper (50,6 million m3) and other rivers. About 30% of the volume of water of all water bodies in lakes with gradation of capacity from 40 to 100 million m3 and the lowest – in the lakes, having a volume less than 1 mm3. The largest volume of water resources has the Vitebsk region (3380 million m3), most of which are located in Braslav district. Among the lakes are reservoirs with capacities ranging from 20 to 40 million m3 and the lake, having a volume more than 100 mm3. Good availability of water is characterized by Chashniki (290 million m3), Rosson, Lepel districts.
The most numerous reservoirs with water volume up to 5 million m3. which holds about 10% water. Major ponds a little, but they hold almost 1/4 of the water resources of the Republic.
The presence of a large amount of factual material and data on chemical composition of water resulting from multi-year surveys of the lakes of the Republic, allowed to identify a number of priority indicators that are representative in the assessment of water quality and lake to divide Belarus into 3 groups.
Group I lakes (about 10% of patients), has a slow water exchange, considerable depth and a large volume of water. Lake groups are characterized by high water quality, which can be used for domestic water supply, industrial processes, breeding of valuable fish species.
Group II – this includes the majority (about 70%) of lakes of Belarus. Lakes of different genetic types distinguished by different degree of trophicity (mildly, this highly eutrophic, distrofia, shallow and superficial with different area). Water classes are “clean”, “small and moderately-polluted”.
Group III includes minor (10%), the number of lakes with water of poor quality, lost natural resources from pollution and depletion of waters under the influence of intensive economic activities on the catchment. This lake different genetic class that has lost its original water quality.