MODELING OF WATER TURBIDITY DISTRIBUTION IN THE KUJBYSHEV RESERVOIR
The concentration of suspended solids (or water turbidity) in a reservoir determines the transparenc y of water and, as a consequence, the penetration of light, the intensity of heating, as well as sorpt ion processes and photosynthesis intensity. All this determines the importance of the study of spatial-temporal re gularities of turbidity distribution during the different phases of water regime, as well as under the adverse meteorological phenomena. While it is important to monitor water turbidity and reservoir bottom reshaping, field ob servations in large reservoirs are often extremely difficult and expensive. In this case, numerical modeling of hydrodynamic processes in a reservoir, that describes two-phase mass transfer over the water area, may be relevan t. The object of the study is the Kujbyshev reservoir, the largest one in the Volga cascade. The mathem atical modeling is based on the 3D hydrodynamic model «Wave» developed by A.V. Rakhuba and integrated analy tical formulas for the flow rate of sediment and the transport capacity of the flow suggested by M. V. Shm akova. It is obvious that the distribution of suspended matter in a reservoir is determined by its morphome try, the location of tributaries and runoff, the intensity of solid matter inflow with tributaries, and t he meteorological conditions. Specific configuration of the Kujbyshev Reservoir and its longitudinal ex tension cause the uneven distribution of water turbidity and specific sediment discharge in the water area. The values of suspended matter concentration in the northern and southern parts of the reservoir vary by three or more times, and the specific sediment discharge under strong winds - by an order of magnitude. The map of distribution of maximum water turbidity in the Kujbyshev reservoir presented in the paper is compiled under the hypothetical initiation of bottom soil agitation processes over the wate r area. The result is particularly valuable for the low-water period, which is characterized by the lowest d epth of the reservoir, and therefore the highest values of turbidity. The resulting map of the maximum turbi dity distribution makes it possible to assess water areas with the most unfavorable hydrodynamic conditio ns, which can become the basis for further recommendations on the activities related to dredging.