Model Based Assessment of the Reflection Behavior of Tidal Waves at Bathymetric Changes in Estuaries

Abstract

Estuaries are often modified by human activities. Adjustments in the morphology of an estuary have a potential impact on the hydrodynamics and on the reflection behavior of the tide. The influence of such system changes on the complex tidal regime with a large number of superimposed tidal constituents is not fully understood yet. The reflection properties of estuaries that are characterized by abrupt changes in geometry are systematically investigated on the basis of simplified estuary model approaches to improve the understanding of the oscillation and reflection behavior of tidal waves in estuaries. The reflection coefficients at abrupt cross-sectional changes are determined by two different methods, i.e., an analytical energy-based approach and a hydrodynamic numerical (HN) model. Comparisons indicate a high agreement of the results of the different methods when evaluating the reflection coefficient. The tidal constituents are reflected at partial and total reflectors and amplified by shoaling depending on the water depths, the height of the bottom step and the horizontal constriction. A harmonic analysis of simulated water level data partly shows the formation and amplification of higher harmonic components as a result of shallow water effects. The interaction with reflectors results in an increasing amplification of the tidal constituents and the tide.

Mathematical Modeling of the Phytoplankton Populations Geographic Dynamics for Possible Scenarios of Changes in the Azov Sea Hydrological Regime

“…The three-dimensional mathematical model of biogeochemical cycles, combined with the model of hydrodynamics, used in this work, makes it possible to predict the spatialtemporal dynamics of the main phytoplankton populations more accurately compared to the two-dimensional models discussed above [12,13,15,16], taking into account the changing hydrological regime, their consumption of nutrients, the transition of nutrients from one form to another. In contrast to the two-dimensional model used in [14], the three-dimensional model of hydrodynamics makes it possible to more accurately model wave processes under conditions of a complex, dynamically changing the geometry of the reservoir, friction on the bottom and wind stress on the free surface, turbulent and advective heat and mass transfer in three coordinate directions, Coriolis forces, river flows, precipitation and evaporation, heat and salt transportation.…”

“…In work [14], the hydrodynamic characteristics and tidal phenomena in estuaries are investigated. The study uses a simplified estuary model to improve the understanding of oscillation and tidal wave reflection behavior in estuaries.…”

A framework for estuarine future sea-level scenarios: Response of the industrialised Elbe estuary to projected mean sea level rise and internal variability

“…The channel network of the inland delta was also simplified through engineering over the centuries and consists of two major branches today, both of which route tides, freshwater and ship traffic. Between 1958 and1960, a tidal weir was built at km 586 (see Figure 1B) limiting tidal influence upstream and acting as a total reflector of tides and surges propagating further upstream (Sohrt et al, 2021). A major deepening campaign that concluded in 1970 established a design depth of 12 m downstream of the port of Hamburg.…”

A Novel Framework for Parametric Analysis of Coastal Transition Zone Modeling

“…Many published works feature case studies that examine coastal models' sensitivities to input parameters in specific regions (e.g., Garzon and Ferreira 2016; Sohrt et al 2021). Akbar et al (2017) examined the effects of variations in bottom friction on water levels during a landfalling hurricane in the Gulf of Mexico.…”