| Abstract: | An attempt has been made to ascertain the structure of water masses of the Kuibyshev reservoir, one of the largest in Europe, using mathematical techniques and results of long-term observations (1958-84) of the hydrochemical regime (a gaseous regime, biogenic and organic substances) in the reservoir. The principal features of the structure obtained appeared to be its well-defined two-vector pattern describing two directions of changing water masses along the former bed of the Volga river, as well as the stability of this system in time. Regionalization of the reservoir's water area has yielded five zones differing in water quality. The long-term observationshave enabled the establishment of a certain trend in biogenic concentrations showing their increase since the end of the 1970s and continuing at the present time. This is believed to result primarily from increasing water volume in the Volga river and accelerating anthropogenic pressure upon the reservoir. |
