Current River Runoff Distribution in the Volga Delta: Analysis and Modeling

Abstract— The Volga delta is a large, dynamically changing water object. Its regime is determined by both natural water balance components and artificial streamflow regulation by the Volga hydroelectric power plant. The paper provides a brief overview of the studies of the Volga delta delta water regime and runoff distribution among the Volga delta branches, including those dealing with the runoff parametrization and computation. It also discusses the works on modeling the runoff distribution. The HEC-RAS software has been used to develop a one-dimensional hydrodynamic model of the Volga delta from its top (the Volga/Verkhnelebyazh’e gauging station) to the Astrakhan–Krasnyi Yar gauge line. The model calibration has been performed using in situ measurements in the delta in 2019 and network gauging data, the validation has been carried out based on the network gauging data for 2015, 2017, and 2018. Modeling results have shown that the contribution of runoff flowing to the Buzan branch source has slightly increased as compared to the period of 2001–2012.