Modeling of sediment transport and riverbed reformations in the area of the Sormovo water intake in the conditions of high water, low water and during dredger operation

The construction and operation of hydraulic structures has an impact on the environment and nearby objects. The article discusses the Sormovo intake structure and the possible impact on it of the projected Nizhny Novgorod low-pressure hydroelectric complex. The STREAM 2D CUDA software package, based on the original numerical algorithm for solving two-dimensional shallow water equations (Saint-Venant equations) on an uneven bottom, was used as a research tool. To calculate the deformations of the river bottom and siltation of water intake structures, a new physical and mathematical model of sediment transport is used, taking into account the heterogeneous (multi-fractional) composition of the soil, the movement of both traction and suspended sediments, and the reformation of underwater and above-water slopes. Three models were built for the calculations. At the fi rst one, calculations were made for fl oods of rare frequency of 10%, 1%, and 0.1% probability. On the second low water conditions – the navigation period with daily regulation of the above located hydroelectric complex. The third model considered the construction period, when hydro mechanized works are carried out. Based on the calculations obtained, plans for erosion – accumulation, plans for sediment deposition were built, and the masses of sediments entering the Sormovsky intake were determined. The simulation results showed that the bottom deformations in the intake structure area are insignifi cant. Most of the sediment enters the intake structure bucket during the fl ood period. At the same time, the construction of the Nizhny Novgorod low-pressure hydroelectric complex does not change the existing trend much. The main conclusion of the work done is that special additional measures to protect the Sormovo intake structure from sediments during the navigation period will not be required.

1. Certifi cate of state registration of the computer program No. 2017660266. STREAM 2D CUDA software package for calculating currents, bottom deformations and transferring contaminants in open streams using Computer Unifi ed Device Architecture technologies (on NVIDIA GPUs) // Moscow, 2017

2. Aleksyuk A.I., Belikov V.V. Modeling of shallow water currents with areas of shallowing and bottom ruptures. // Computational mathematics and mathematical physics. T. 57. № 2. S. 316-338.

3. Aleksyuk A.I., Belikov V.V. The uniqueness of the exact solution of the Riemann prob-lem for the shallow water equations with discontinuous bottom // Journal of Computational Physics, vol. 390, pp. 232-248, Aug. 2019. https://doi:10.1016/j.jcp.2019.04.001

4. Aleksyuk A.I., Malakhov M.A., Belikov V.V. The exact Riemann solver for the shallow water equations with a discontinuous bottom // Journal of Computational Physics. 2022, vol. 450, p. 110801, 2022, doi: 10.1016/j.jcp.2021.110801

5. Belikov V.V., Aleksyuk A.I. Models of shallow water in the problems of river hydrodynamics: monograph. M.: RAS, 2020.346 p.

6. Belikov V.V., Borisova N.M., Gladkov G.L. Mathematical model of sediment transport for calculating the drift of dredging slots and channel quarries. Journal of the University of water communications, 2010, Vol. 2 P. 105-113

7. Belikov V.V. Use of Accumulation Basins to Reduce Silting of Reservoirs of Hydroelectric Power Plants Located on Mountain Rivers / Aleksyuk A.I., Borisova N.M., Fedorova T.A. // Power Technologyand Engineering, 53(4), 429-439 (2019) doi: 10.1007/s10749-019-01095-9

8. Belikov V.V. Hydraulic substantiation of the project of the Bagayevsky hydroelectric complex using numerical hydrodynamic modeling. / Borisova N.M., Aleksyuk A.I. Rumyantsev A.B. and others. // Hydro technical construction, 2018, No 5, P. 19-35.

9. Krylenko I.N. Analysis of the impact of hydrotechnical construction on the Amur river near Blagoveshchensk and Heihe cities using a two-dimensional hydrodynamic model / Belikov V.V., Fingert E.A., Golovlev P.P. // Water resources. 2018, vol. 45, № S1, S112-S121.

10. Belikov V.V. The use of pit traps to reduce the siltation of hydroelectric power plants reservoirs on mountain rivers / Aleksyuk A.I., Borisova N.M., Fedorova T.A. // Hydro technical construction. 2019. № 6. p. 12-24