Influencia de la marea en la hidrodinámica del sistema Mecoacán-río González, México

El estado de Tabasco, México, es altamente vulnerable a inundaciones. La más grave de los últimos años fue en 2007 y cubrió el 62% de su territorio. A raíz de este suceso surgió el Plan Hídrico Integral de Tabasco, con el objeto de encontrar soluciones para disminuir la vulnerabilidad de la zona ante eventos extremos.Una de ellas consiste en el desvío de grandes caudales hacia el río Samaria, que desemboca al mar por el río González. Este estudio analiza el comportamiento de los flujos del sistema río González-Mecoacán y el rol de la marea en su regulación. En el río González, el flujo hacia el mar es disminuido de forma considerable en pleamar, llegando a detenerse durante mareas vivas. En el río Hondo (que fluye del río González hacia Mecoacán), el flujo llega a revertirse, mientras que en la boca lagunar está modulado por la marea. Esto sugiere que un aumento considerable en el caudal del río González estaría sujeto a un lento drenaje hacia el mar por efecto de la corriente mareal. Lo anterior causaría un aumento del nivel del río y riesgo de inundación en esa zona durante eventos extremos. Las evidencias de penetración de la onda de marea hasta un sitio alejado de la desembocadura del río sugieren que el flujo río arriba podría también estar modulado por la marea. Además, las observaciones termohalinas indican que la salinidad y temperatura cerca de la desembocadura están gobernadas por intrusión salina, mientras que en sitios alejados dependerían de factores atmosféricos

Partitioning the Extreme Wave Spectrum of Hurricane Wilma to Improve the Design of Wave Energy Converters

Analysis of the omnidirectional energy spectrum from storm wave measurements provides valuable parameters for understanding the specific local conditions that wave energy converters would have to withstand. Partitioning the energy spectrum also helps to identify wave groups with low directional spread propagating in the direction of the dominant waves of the more energetic wave systems. This paper analyzes the partition of the Hurricane Wilma energy spectrum using single-point measurements obtained in shallow water. Hurricane Wilma generated simultaneous crossing wave systems with different significant wave heights and steepnesses. The maximum estimated significant height among the wave groups was 5.5 m. The corresponding height of the partitions and the omnidirectional energy spectrum were 11.0 m (swell) and 12 m, respectively. While linear superposition was the main mechanism responsible for driving the wave groups, at times, modulational instability produced nonlinear wave groups. This is a new finding, since modulational instability is usually considered an open-sea phenomenon. For shorelines with multidirectional wave groups, submerged and semi-submerged devices should be designed to account for changes in wave direction and wave height, although under extreme hurricane conditions, energy harvesting might have to be sacrificed for the benefit of device integrity

Awac data

Data generate by AWAC Nortek at Xcalak Reefs<br

How Effective Were the Beach Nourishments at Cancun?

Beach nourishment is generally seen as the preferred means of rectifying coastal erosion, due to its low environmental impact and natural evolution. The largest beach nourishment project ever carried out in Mexico took place on Cancun beach in 2006, as a response to the most intense hurricane season ever registered in Mexico, in 2005. After Hurricane Dean, in 2009, a second nourishment was conducted, which evidenced flaws in the design and execution of the first project. Previous investigations report that the need for beach re-fills directly correlates with wave energy. However, following a thorough revision of the extreme climatic events that occurred between 1978 and 2018, it has been found that the amount of erosion also depends on the frequency and duration of high energy events. The findings also show that the apparent success of the second nourishment is mainly associated with a decline in the number of extreme wave power events impacting the beach. In the conclusion to this paper, we share the knowledge gained, but not yet applied, in Mexico or elsewhere, regarding beach use, urbanization, and protection in beach planning

Km-scale shoreline sand waves: Numerical modelling and observations

Km-scale shoreline sand waves have been studied with a quasi two dimensional model (Q2D-morfo model) and with observations from a populated coastal zone in Yucatán (México) with frequent human interventions. The model was modified to improve the physics in the case of large amplitude shoreline sand waves that develop due to the high angle wave instability (HAWI). The modified version of the model can better reproduce the formation of large-amplitude shoreline sand waves, compared with the original model. Shorelines of Yucatán, from 2004 to 2012, were digitized and analyzed. Although undulations can be observed, they do not exhibit clear migration or growth, an indication of being in the limit of instability, in accordance with the results of the modelPeer Reviewe

The attenuation of tidal and subtidal oscillations in the patos lagoon estuary

Abstract The single, long and narrow channel that usually connects choked coastal lagoons to the ocean can serve as a natural hydraulic low-pass filter that reduces or eliminates tidal and subtidal effects inside the lagoon. This study proposes an alternative method of estimating the attenuation of the tidal and subtidal oscillations throughout the Patos Lagoon estuary. The attenuation is estimated for conditions of contrasting river runoff and weather (summer and winter). A highpass/ low-pass filter (fast fourier transformation technique – FFT) is applied to time series of sea-surface elevation (SSE) measured at the mouth of the Patos Lagoon. The resulting high-frequency (tidal) and lowfrequency (subtidal) signals are used in independent simulations to force the TELEMAC-2D model. Attenuation of the tidal and subtidal signals throughout the estuary is estimated by applying cross-spectral analysis between the model-generated SSE time series at different locations throughout the estuary and the filtered SSE time series measured at the mouth. Results from the proposed method suggest that: (1) the low-frequency (subtidal) oscillations are less attenuated and propagate further than the high-frequency (tidal) oscillations in the Patos Lagoon estuary; (2) the filtering capability of the Patos Lagoon estuary is expected to follow a seasonal pattern, although further investigations on an interannual time scale are recommended in order to confirm this hypothesis; (3) the influence of the oceanic boundary processes on the SSE dynamics of the lagoon is restricted to the lower estuary. Further inland, the local forcing generated by the wind and freshwater input is likely to be the main forcing effect controlling the dynamics of the system. The proposed method proved to be an efficient and alternative way of estimating the attenuation of energy in the tidal and subtidal bands throughout the access channel of a choked coastal lagoon located in an area of reduced tidal influence

Km-scale shoreline sand waves: Numerical modelling and observations

Km-scale shoreline sand waves have been studied with a quasi two dimensional model (Q2D-morfo model) and with observations from a populated coastal zone in Yucatán (México) with frequent human interventions. The model was modified to improve the physics in the case of large amplitude shoreline sand waves that develop due to the high angle wave instability (HAWI). The modified version of the model can better reproduce the formation of large-amplitude shoreline sand waves, compared with the original model. Shorelines of Yucatán, from 2004 to 2012, were digitized and analyzed. Although undulations can be observed, they do not exhibit clear migration or growth, an indication of being in the limit of instability, in accordance with the results of the modelPeer Reviewe