The impact of suspended sediments on exchange flow in a macrotidal, hyperturbid estuary
Abstract
This study investigates the sensitivity of the total exchange flow (TEF) with regard to suspended sediment concentrations (SSC) in water density calculations. We consider two scenarios of an idealized model based on a macrotidal, highly turbid estuary: one where density depends on both salinity and SSC and another where density depends only on salinity. These models are used to understand how TEF volume inflow ( Q in ) varies along the estuary over fortnightly and monthly time scales. The bulk values of TEF inflow between the two model scenarios show small differences (less than 4 %) over 5 months. However, differences in TEF bulk volume inflow reach 7 % downstream of the estuarine turbidity maximum (ETM), 22 % at the ETM, and nearly 70 % upstream of the ETM when quantified only over spring tides. The gradient Richardson number indicates that sediment-induced stratification suppresses shear production ∼ 30 km further upstream when suspended sediments are an active tracer. The most profound impact on TEF occurs during spring tides at, and upstream of, the ETM where sediment contributions to density exceed those from salinity. The sediment contribution leads to increased stratification in the upper reaches of the estuary, effectively reducing the longitudinal density gradient and therefore the exchange flow as much as 2000 m 3 s −1 , indicating a dominant role of suspended sediments in attenuating exchange in hyperturbid estuaries. The results from this work highlight the importance of SSC on density calculations in estuarine studies of the exchange flow.
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BibTeX
@article{rojas2026impact,
title = {{The impact of suspended sediments on exchange flow in a macrotidal, hyperturbid estuary}},
author = {Cristian M Rojas and Lauren Ross and Betty John Kaimathuruthy and Isabel Jalón-Rojas and Aldo Sottolichio and Nicolas Huybrechts},
journal = {Ocean Science},
year = {2026},
month = oct,
doi = {10.5194/os-22-1311-2026},
url = {https://hal.science/hal-05789826v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The impact of suspended sediments on exchange flow in a macrotidal, hyperturbid estuary
AU - Cristian M Rojas
AU - Lauren Ross
AU - Betty John Kaimathuruthy
AU - Isabel Jalón-Rojas
AU - Aldo Sottolichio
AU - Nicolas Huybrechts
PY - 2026
DA - 2026/10/09
JO - Ocean Science
DO - 10.5194/os-22-1311-2026
UR - https://hal.science/hal-05789826v1
AB - This study investigates the sensitivity of the total exchange flow (TEF) with regard to suspended sediment concentrations (SSC) in water density calculations. We consider two scenarios of an idealized model based on a macrotidal, highly turbid estuary: one where density depends on both salinity and SSC and another where density depends only on salinity. These models are used to understand how TEF volume inflow ( Q in ) varies along the estuary over fortnightly and monthly time scales. The bulk values of TEF inflow between the two model scenarios show small differences (less than 4 %) over 5 months. However, differences in TEF bulk volume inflow reach 7 % downstream of the estuarine turbidity maximum (ETM), 22 % at the ETM, and nearly 70 % upstream of the ETM when quantified only over spring tides. The gradient Richardson number indicates that sediment-induced stratification suppresses shear production ∼ 30 km further upstream when suspended sediments are an active tracer. The most profound impact on TEF occurs during spring tides at, and upstream of, the ETM where sediment contributions to density exceed those from salinity. The sediment contribution leads to increased stratification in the upper reaches of the estuary, effectively reducing the longitudinal density gradient and therefore the exchange flow as much as 2000 m 3 s −1 , indicating a dominant role of suspended sediments in attenuating exchange in hyperturbid estuaries. The results from this work highlight the importance of SSC on density calculations in estuarine studies of the exchange flow.
SN - 1812-0784
SN - 1812-0792
ER -