Numerical Hydrodynamic Modelling As A Tool For Research And Use Of Tidal Rivers

Tidal estuaries play a crucial role, serving as major hubs for economic activities while also contributing to the preservation of natural diversity and bioproductivity. In Russia, these estuaries are primarily located in remote regions of the European North and the Far East, making them vital for energy and transportation usage as they essentially form the ‘cores’ of territorial development along the Northern Sea Route. To facilitate the development of energy and navigation infrastructure in tidal estuaries, as well as to plan and implement environmental protection measures, it is essential to have a comprehensive understanding of their hydrological regime. Unlike regular river flow, tidal estuaries exhibit more complex hydrodynamics, influenced by both river and marine factors. Due to the considerable challenges of conducting field hydrological studies in remote areas, numerical hydrodynamic modelling has emerged as a valuable method for obtaining information on the flow and water level regime in tidal estuaries. This paper presents an application of one-dimensional HEC-RAS and two-dimensional STREAM₂D CUDA numerical models to investigate the parameters of reverse currents in the hypertidal Syomzha estuary flowing into the Mezen Bay of the White Sea. The limitations and accuracy of the models are discussed, along with the potential for their improvement considering recent advancements in understanding the hydraulics of reverse currents.