The Use of Hydrodynamic Models in the Determination of the Chart Datum Shape in a Tropical Estuary

Abstract

Estuaries are transitional environments with ideal conditions for port construction and navigation. They represent a challenge to hydrographic services due to the dynamics of the seabed and the tidal wave deformation. The bottom slope, the convergence of the channels, and the nonlinear effects produced by the bottom friction produce variation in both the tidal range and the location of the chart datum (CD). In this study, sea level data series obtained from the nodes of the mesh of a hydrodynamic model (virtual tide gauges) were used to calculate the harmonic constituents, form factor, asymmetry, and estuary type. The final chart datum surface, obtained from the hydrodynamic model, was used to determine the separation values between zones and also the number of tidal zones in an estuarine system. It was found that in a complex hydrodynamics scenario, the use of the ellipsoidal referenced surveying (ERS) method is more convenient than traditional tidal zoning survey. In the ERS method, once the CD model is complete, it must be attached to the ellipsoid directly. Finally, the variation of the CD in different scenarios (due to anthropogenic action) was assessed.

Carbon dynamics and CO2 and CH4 exchange in the mangrove dominated Guayas river delta, Ecuador

“…We recognise that ideally a 25 h measuring campaign allows to capture potential day and night cycles in the measured variables. However, because of practical and logistical constraints, we conducted our temporal sampling only during daylight time for 13 h. This sampling is still appropriate to capture variability over a single semi-diurnal tidal cycle, as here in the Guayas river delta, tides do not exhibit a significant diurnal inequality, and rather show a clear and consistent semi-diurnal tidal pattern (Zapata et al, 2019). These characteristics result in minimal changes in tidal amplitudes and phases between successive tides, provided similar meteorological conditions.…”

An Operational Framework for Urban Vulnerability to Floods in the Guayas Estuary Region: The Duran Case Study

“…In combination with the tides, Duran and its natural channels and lowlands are strongly affected by the streamflow of the Babahoyo and Guayas rivers. Human settlements in Duran are threatened by a process of increasing sedimentation which appears to be occurring in the estuary resulting in high tides and faster river currents that increase flood risk for low lying areas around the margins of the river [16][17][18][19]. Duran's climate and environment is linked to the Guayas Estuary ecosystem and its geographical position in the coastal region.…”

Zonation of Positively Buoyant Jets Interacting with the Water-Free Surface Quantified by Physical and Numerical Modelling

“…CE was employed for two major reasons: (1) it is very commonly used in river and estuary model applications [52][53][54][55][56], and (2) [57] CE is also found to be the best objective function for reflecting the overall fit of a model output.…”