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Estuarine salinity response to freshwater pulses

Authors :
Biemond, Bouke
de Swart, Huib E.
Dijkstra, Henk A.
Díez-Minguito, Manuel
Sub Physical Oceanography
Marine and Atmospheric Research
Sub Physical Oceanography
Marine and Atmospheric Research
Source :
Journal of Geophysical Research: Oceans, 127(11), 1. American Geophysical Union
Publication Year :
2022
Publisher :
Wiley, 2022.

Abstract

Freshwater pulses (during which river discharge is much higher than average) occur in many estuaries and strongly impact estuarine functioning. To gain insight into the estuarine salinity response to freshwater pulses, an idealized model is presented. With respect to earlier models on the spatiotemporal behavior of salinity in estuaries, it includes additional processes that provide a more detailed vertical structure of salinity. Simulation of an observed salinity response to a freshwater pulse in the Guadalquivir Estuary (Spain) shows that this is important to adequately simulate the salinity structure. The model is used to determine the dependency of the estuarine salinity response to freshwater pulses for different background discharge, tides, and different intensities and durations of the pulses. Results indicate that the change in salt intrusion length due to a freshwater pulse is proportional to the ratio between peak and background river discharge and depends linearly on the duration of the pulse if there is no equilibration during the pulse. The adjustment time, which is the time it takes for the estuary to reach equilibrium after an increase in river discharge, scales with the ratio of the change in salt intrusion length and the peak river discharge. The recovery time, that is, the time it takes for the estuary to reach equilibrium after a decrease in river discharge, does not depend on the amount of decrease in salt intrusion length caused by the pulse. The strength of the tides is of minor importance to the salt dynamics during and after the pulse.

Details

ISSN :
21699275
Database :
OpenAIRE
Journal :
Journal of Geophysical Research: Oceans, 127(11), 1. American Geophysical Union
Accession number :
edsair.doi.dedup.....3afef55becae3a7c7bca83829b788389
Full Text :
https://doi.org/10.1002/essoar.10511020.1