Tidal and subtidal transport in short, tidally-driven estuaries with low rates of freshwater input

Ross, Lauren; Alahmed, Sohaib; Smith, S. M.; Roberts, Gwyneth

doi:10.1016/j.csr.2021.104453

Cited by 6 publications

(1 citation statement)

References 33 publications

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“…In the base simulation, residual current magnitudes are strongest (0.3 -0.5 m/s) in the vicinity of major channel bends and headlands (i.e., Fort Point and General Sullivan Bridge regions, Figure 7A). In these areas, residual currents are generally strongest over the shoals with opposing directions over each shoal, indicative of differential advective accelerations driven by cross-channel variability in maximum flood and ebb currents (e.g., Ross et al, 2021). Away from these regions, residual currents are of order ~0.1 m/s, landward directed in the center channel of Great Bay, and seaward directed over the remainder of the main Piscataqua River channel (Figure 7A), matching past work in the estuary (Ip et al, 1998;McLaughlin et al, 2003).…”

Section: Currents: Spatial Variability and Turbine Effectsmentioning

confidence: 99%

Tidal energy extraction modifies tidal asymmetry and transport in a shallow, well-mixed estuary

Spicer,

Yang,

Wang

et al. 2023

Front. Mar. Sci.

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Tidal energy extraction is increasingly being studied as a potential renewable energy resource in estuaries worldwide. Although it is understood that energy extraction via tidal stream turbines can modify currents and transport within estuaries, it is not clear how the underlying nonlinear physical mechanisms dictating tidal hydrodynamics are modulated. This research investigates the influence of a hypothetical tidal stream turbine array on barotropic tidal processes in a shallow, well-mixed system: the Piscataqua River – Great Bay (PRGB) estuary, using a numerical model. The modeled turbine farm includes 180 turbines which would extract an estimated 44.7 GWh of energy, annually. The tidal hydrodynamic model for the existing condition is validated with in-situ observations of currents and water level before analyzing tidal asymmetry and transport with and without tidal turbines. Results indicate that the tidal turbine array will decrease tidal elevation and current magnitudes system-wide, but generally reduce ebb currents and transport more than flood over most of the estuary footprint, thereby diminishing tidal asymmetry. The smaller asymmetric distortion compared to the no-turbine case is attributed to reductions in the storage volume of water over the estuary’s extensive tidal flat regions between low and high waters which decreases the associated nonlinear intertidal storage mechanism up to 25%. This leads to weakened ebb dominance over estuary sections from the mouth to mid-reaches, where depths are deep enough to keep the combined nonlinear shallow water and frictional effects from asserting control over the storage mechanism. Even in upstream shallow regions where depth-dependent friction controls asymmetry in both cases, the frictional mechanism is reduced only by 10% with turbines. Some environmental considerations of this work are discussed, with focus on sediment transport, water quality, and ecology.

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Section: Currents: Spatial Variability and Turbine Effectsmentioning

confidence: 99%