Spatially Resolved Salt Intrusion Mechanisms in a Tidal Estuary and the Impact of Channel Deepening

Rummel, K., Gräwe, U., Klingbeil, K., Kolb, P., Li, X., Reese, L., & Burchard, H. (2025). Spatially resolved salt intrusion mechanisms in a tidal estuary and the impact of channel deepening. Journal of Geophysical Research: Oceans, 130(6), e2024JC022073. https://doi.org/10.1029/2024JC022073

Estuarine salinity dynamics are driven by river discharge, tides, and human interventions like channel deepening. This study utilizes a high-resolution numerical model of the North German Weser River Estuary to analyze salt transport mechanisms. We identified an alternating dominance between subtidal shear transport and tidal pumping. By applying a novel two-dimensional decomposition method, we demonstrated that traditional cross-sectional analysis often underestimates transport strength due to opposing flows between channels and shoals. Furthermore, simulations of channel deepening reveal increased subtidal shear transport in dredged areas.

These findings clarify the spatial complexity of salt dynamics and the environmental impact of anthropogenic modifications.