Evaluation of along-channel sediment flux gradients in an anthropocene estuary with an estuarine dam

초록

While estuarine dams can develop freshwater resources and block the salt intrusion, theycan result in increased sediment deposition in the estuary. The mechanism of increasedsediment deposition in an estuary with an estuary dam is not well understood. To fill thisknowledge gap, 7 ADCP measurements of flow and suspended sediment concentration (SSC) were collected along-channel in an estuary with an estuarine dam over a neap-spring cycle. Flow and SSC were used to calculate the sediment flux and sediment flux gradients. Theresults indicated that the cumulative sediment fluxes at all stations were directed landward. The along-channel sediment flux gradient was negative, which indicated deposition alongthechannel. The landward mean-flow fluxes were dominant in the deep portion of the channel near the estuary mouth, whereas landward correlation fluxes were dominant in the shallowportion of the channel near the estuarine dam. The tides were the dominant forcing drivingthe sediment fluxes throughout the estuary.