Intersectoral assessment of the Volga-Kama cascade of hydropower plants operating at existing and design water levels

Introduction. The study aims to assess the effectiveness of raising the Volga-Kama cascade to its design levels. The relevance stems from the need to provide a basis for management decisions aimed at achieving sector-wide effects. The scientific novelty of this research lies in a comprehensive comparative analysis of various aspects of the project. The aim of the study is to determine the feasibility of raising water levels in the Cheboksary and Nizhnekamsk reservoirs to their design levels. The study examines the project’s effectiveness in terms of key benefits and costs, with a quantitative assessment of these across different scenarios.

Materials and methods. The source materials used include data from the technical and economic assessment of the completion of the Cheboksary Hydroelectric Power Station, official information on the operation of the Volga-Kama cascade, as well as regulatory, legal and strategic documents. Methods of economic evaluation of investment projects, scenario analysis and discounting were applied.

Results. The results demonstrate that restoring design water levels leads to a significant increase in hydropower generation and available installed capacity, removal of navigation depth constraints on the Unified Deep-Water System, reduction of recurrent dredging expenditures, and improvement of hydrological and ecological conditions in the reservoirs. For all considered scenarios, the aggregated intersectoral effect remains positive and substantially exceeds the outcomes associated with continued operation at non-design water levels.

Conclusions. The findings of the study indicate that raising the reservoirs to their design levels will have positive cross-sectoral effects. The project is feasible and should be implemented.

1. Upadhyay D., Bhatia U. Designing Resilient Multi-purpose Reservoir Operation Policies in Presence of Internal Climate Variability. Water Resources Research. 2025; 61(7). DOI: 10.1029/2024WR038160. EDN YQYISQ.

2. Ni X., Dong Z., Jiang Y., Xie W., Yao H., Chen M. A subjective-objective integrated multi-objective decision-making method for reservoir operation featuring trade-offs among non-inferior solutions themselves. Journal of Hydrology. 2022; 613:128430. DOI: 10.1016/j.jhydrol.2022.128430. EDN XFYEEA.

3. Jiang M., Qiao C., Lu F., Zhu K., Zhu C. The impact of reservoirs with seasonal flood limit water level on the frequency of downstream floods. Journal of Hydrology. 2024; 644:132009. DOI: 10.1016/j.jhydrol.2024.132009. EDN PRNSQU.

4. Fang G., Zhang C., Wu Z., Tan Q., Gu G., Yan M. Research on Multiobjective Optimal Scheduling of Reservoir Based on Ecological Flow-Process Level. Journal of Water Resources Planning and Management. 2023; 149(11). DOI: 10.1061/jwrmd5.wreng-6075. EDN OMZEMJ.

5. Song Y. Hydrodynamic impacts on algal blooms in reservoirs and bloom mitigation using reservoir operation strategies : а review. Journal of Hydrology. 2023; 620:129375. DOI: 10.1016/j.jhydrol.2023.129375. EDN GENMDZ.

6. Ma X., Liao S., Liu B., Zhao H., Cheng C., Su H. Multi-objective solution and decision-making framework for coordinating the short-term hydropeaking–navigation–production conflict of cascade hydropower reservoirs. Journal of Cleaner Production. 2023; 422:138602. DOI: 10.1016/j.jclepro.2023.138602. EDN HQXYBF.

7. Larabi S., Schnorbus M.A., Zwiers F. Diagnosing the ability of reservoir operations to meet hydropower production and fisheries needs under climate change in a western cordillera drainage basin. Climatic Change. 2023; 176(12):161. DOI: 10.1007/s10584-023-03632-y. EDN MDWBIF.

8. Sunil A., Singh R., Molakala M. Adaptive (re)operations facilitate environmental flow maintenance downstream of multi-purpose reservoirs. Journal of Hydrology. 2024; 644:132123. DOI: 10.1016/j.jhydrol.2024.132123. EDN ONULBH.

9. Li D., Chen Ya., Lyu L., Cai X. Uncovering Historical Reservoir Operation Rules and Patterns: Insights From 452 Large Reservoirs in the Contiguous United States. Water Resources Research. 2024; 60(8). DOI: 10.1029/2023wr036686. EDN XIWVUG.

10. Zhezmer V., Dudakov N. Influence of the Volga-Kama cascade of reservoirs on the hydrological regime during the flood and the quality of the spawning cycle of fish in the Lower Volga. E3S Web of Conferences. 2023; 454:02007. DOI: 10.1051/e3sconf/202345402007. EDN LCRQFK.

11. Gavrilko D., Zhikharev V., Zolotareva T., Kudrin I., Yakimov B., Erlashova A. Biodiversity of zooplankton (Rotifera, Cladocera and Copepoda) in the tributaries of Cheboksary Reservoir (Middle Volga, Russia). Biodiversity Data Journal. 2024; 12. DOI: 10.3897/bdj.12.e116330. EDN DIOEMR.

12. Lazareva V.I., Zhdanova S.M., Sabitova R.Z., Sokolova E.A. Zooplankton of Volga River reservoirs: structure, abundance and dynamics. Inland Water Biology. 2024; 17(1):148-161. DOI: 10.1134/S1995082924010103. EDN PWRCJF.

13. Ilina A.A., Nikonorova I.V., Ilin V.N., Nikitina E.A. Hydrological and ecological problems of Cheboksary and Kuibyshev reservoirs of Cheboksary section of the Chuvash republic. Advances in Current Natural Sciences. 2023; 6:34-39. DOI: 10.17513/use.38050. EDN JFIWHY. (rus.).

14. Shashulovskaya E.A., Mosiyash S.A. Interannual changes in the content of organic matter and biogenic elements in reservoirs of the lower Volga: the influence of climatic transformation. Water Sector of Russia: Problems, Technologies, Management. 2024; 3:83-100. DOI: 10.35567/19994508-2024-3-83-100. EDN DTUNCX. (rus.).

15. Sazonov A.A., Lisina A.A., Erina O.N., Frolova N.L., Lomakov O.I., Platonov M.M. Synchronous studies of the Volga river water quality. Water Sector of Russia: Problems, Technologies, Management. 2024; 5:97-114. DOI: 10.35567/19994508-2024-5-98-114. EDN TJNWSV. (rus.).

16. Bolgov M.V., Belyaev A.I. Water problems of the Lower Volga: main factors and compensating measures. Bulletin of the Russian Academy of Sciences. Geographical Series. 2023; 87(6):862-874. DOI: 10.31857/S2587556623060031. EDN EZEJWU.

17. Poddubnyi S.A., Zakonnova A.V., Tsvetkov A.I., Trofinmenko L.T., Shvets’ N.V. Current hydrological regime of the Volga reservoirs. Water Resources. 2023; 50(3):249-262. DOI: 10.31857/S0321059623030100. EDN DCFTDU. (rus.).

18. Georgievsky M.V., Goroshkova N.I., Eremeeva A.O., Gladkov G.L., Strizhenok A.V., Semenova D.A. Assessment of dangerous hydrological events probability for navigation on the lower Volga and don based on water levels and ice phenomena data. Water Sector of Russia: Problems, Technologies, Management. 2023; 6:44-56. DOI: 10.35567/19994508_2023_6_4. EDN WHLOJO. (rus.).

19. Rodionov A.A., Rumyantzev V.A., Fyodorov M.P., Zinoviev A.T., Krivoshei V.A., Medvedeva O.Ye. et al. Solution options for problems of navigation on a limited section of the Volga river from Gorodetsky hydroelectric complex to Nizhny Novgorod, including taking into account the assessment of the impact on the sanitary-epidemiological and environmental situation in the region. Fundamental and Applied Hydrophysics. 2022; 15(4):109-131. DOI: 10.59887/fpg/abfh-m2n7-9mn6. EDN LPSDZD. (rus.).

20. Seleznev V.A. Inter/annual changes in the Volga river water content under global climate change. Water Sector of Russia: Problems, Technologies, Management. 2024; 6:7-21. DOI: 10.35567/19994508-2024-6-7-21. EDN ZXEOHA. (rus.).

21. Kalugin A.S. River runoff of the European part of Russia under global warming of 1.5 and 2 degrees. Water Resources. 2023; 50(4):451-464. DOI: 10.31857/s0321059623040120. EDN QJXLZE. (rus.).

22. Selezneva A.V., Seleznev V.A. The Kuibyshev Reservoir water level increasing in the context of the climate change. Water Sector of Russia: Problems, Technologies, Management. 2025; 4:25-43. DOI: 10.35567/1999-4508-2025-4-25-43. EDN EXMLTZ. (rus.).

23. Bednaruk S.E., Chukanov V.V., Mastryukova A.V., Chernobrovkin N.N. Development of the Volga-Akhtuba floodplain and the Volga river delta mathematical model as a tool for improving of the lower Volga reservoirs management. Russian Journal of Applied Ecology. 2025; 2(42):51-58. DOI: 10.24852/2411-7374.2025.2.51.58. EDN EVUFJA. (rus.).

24. Gordienko A.N., Rozhko O.I., Petruchenko A.I. Organization of emergency forecasting during the flood period on the example of a pass through the waterworks of the Volga-Kama cascade. Hydrosphere. Hazard Processes and Phenomena. 2025; 6(2):157-168. DOI: 10.34753/HS.2024.6.2.157. EDN QIFEJV. (rus.).