scholarly journals The role of the reef–dune system in coastal protection in Puerto Morelos (Mexico)

2018 ◽  
Vol 18 (4) ◽  
pp. 1247-1260 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellin ◽  
María Eugenia Allende-Arandia ◽  
Christian M. Appendini
Keyword(s):  
Sand Dunes ◽  
Coastal Flooding ◽  
Water Levels ◽  
Coastal Protection ◽  
Dune System ◽  
Fore Reef ◽  
Extreme Water Levels ◽  
Reef Environments ◽  
Storm Impact

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef–dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH). Wave hindcast information, tidal level, and a measured beach profile of the reef–dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore reef slope) is warranted.

scholarly journals The role of the reef-dune system in coastal protection in Puerto Morelos (Mexico)

2017 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellín ◽  
María Eugenia Allende-Arandia ◽  
Bernabé Gómez ◽  
...  
Keyword(s):  
Numerical Model ◽  
Physical Model ◽  
Sand Dunes ◽  
Coastal Flooding ◽  
Coastal Areas ◽  
Coastal Protection ◽  
Coastal Vulnerability ◽  
Dune System ◽  
Storm Impact

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of the barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to investigate the role of the reef-dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea. Firstly, a nonlinear non-hydrostatic numerical model (SWASH) is validated with experimental data from a physical model of a fringing reef. The numerical model predicts both energy transformation and runup statistics as compared with experimental results for two different reef crest geometries conducted in a physical model. Thus, the numerical model is further used to investigate the role of the reef-dune degradation in coastal vulnerability. Wave hindcast information, tidal level, and a measured beach profile of the reef-dune system in Puerto Morelos are employed to predict extreme runup and estimate the storm impact scale for different scenarios. The numerical results show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. This highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term.

scholarly journals The Role of Beach Morphology and Mid-Century Climate Change Effects on Wave Runup and Storm Impact on the Northern Yucatan Coast

2021 ◽  
Vol 9 (5) ◽  
pp. 518
Author(s):  
Gabriela Medellín ◽  
Martí Mayor ◽  
Christian M. Appendini ◽  
Ruth Cerezo-Mota ◽  
José A. Jiménez
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Water Levels ◽  
Transformation Model ◽  
Wave Runup ◽  
Beach Morphology ◽  
Extreme Water Levels ◽  
Storm Impact ◽  
Wave Conditions

Wave runup is a relevant parameter to determine the storm impact on barrier islands. Here, the role of the beach morphology on wave runup and storm impact was investigated at four coastal communities located on the northern Yucatan coast. Current wave conditions based on regional wind simulations, topo-bathymetric transects measured at each location, and a nonlinear wave transformation model were employed to reconstruct multi-year runup time series. Dune morphology features and extreme water levels (excluding storm surge contributions) were further employed to determine the storm impact at each site for different return periods. Despite the similar offshore conditions along the coast, extreme water levels (i.e., runup and setup) showed intersite differences that were mainly ascribed to subaerial and submerged morphological features. Numerical results showed that the average surf zone beach slope, sandbars, berm, and dune elevation played an important role in controlling extreme water levels and storm impact at the study sites under the present climate. Moreover, in order to assess the potential effect of climate change on coastal flooding, we analyzed wave runup and storm impact in the best-preserved site by considering wave conditions and sea level rise (SLR) projections under the RCP 8.5 scenario. Modelling results suggest no significant increase in the storm impact regime between the present and future conditions in the study area unless SLR is considered. It was found that to accurately estimate SLR contribution, it should be incorporated into mean sea level prior to performing numerical wave runup simulations, rather than simply adding it to the resulting wave-induced water levels.

scholarly journals Spatiotemporal Storm Impact on the Northern Yucatan Coast during Hurricanes and Central American Cold Surge Events

2019 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Wilmer Rey ◽  
Paulo Salles ◽  
Alec Torres-Freyermuth ◽  
Pablo Ruíz-Salcines ◽  
Yi-Cheng Teng ◽  
...  
Keyword(s):  
Water Levels ◽  
Coastal Development ◽  
Central American ◽  
Spatiotemporal Variability ◽  
Northern Coast ◽  
Dune System ◽  
Cold Surge ◽  
Storm Impact ◽  
The Impact

We investigate the storm impact associated with historical events in the northern Yucatan Peninsula. The study area is prone to coastal flooding due to both its geographical location and low-lying areas. Extreme events associated with tropical cyclones and Central American cold surge (CACS; locally known as Nortes) are ubiquitous in this region, and coastal development in the study area has exacerbated the erosion of the sand beach-dune system. This study aims to assess the impact on the northern coast of Yucatan associated with different types of storms and to investigate the role of the dune in its spatial variability. Nearshore hydrodynamics, associated with hurricanes (Gilbert: 14 September 1988; Isidore: 22 September 2002) and energetic Nortes (Norte A: 12 March 1993; Norte B: 25 December 2004), were computed using a numerical model. The beach and dune characteristics were extracted from a LIDAR flight with a spatial resolution of 1 m conducted in 2011. Furthermore, the extreme water levels and the spatiotemporal variability of the storm-impact regime (swash, collision, overwash, or inundation), along a 41.5 km stretch of coast, were derived using both runup parametrizations and the modeling results. On the one hand, the predominant storm impact regimes for Hurricanes Gilbert and Isidore were inundation and overwash, respectively. The flood that propagated from east to west in the northern Yucatan was due to westerly-directed hurricane tracks. On the other hand, for the Norte events, the predominant impact regimes were collision and overwash for Nortes A and B, respectively. This difference in the impact regime between Norte events can be ascribed to tidal differences. Moreover, during the passages of Nortes A and B, the flood was propagated from west to east in the northern Yucatan, consistent with cold-front paths. The results suggest that the western part of the study area presented a stronger impact regime due to the dune degradation caused by coastal infrastructure and settlements established in those areas. This work highlights the important role of sand dunes in providing natural coastal protection during Norte events.

scholarly journals Can Managed Realignment Buffer Extreme Surges? The Relationship Between Marsh Width, Vegetation Cover and Surge Attenuation

2021 ◽  
Author(s):  
Joshua Kiesel ◽  
Leigh R. MacPherson ◽  
Mark Schuerch ◽  
Athanasios T. Vafeidis
Keyword(s):  
Sea Level ◽  
Vegetation Cover ◽  
Coastal Wetlands ◽  
Water Levels ◽  
Coastal Protection ◽  
Return Periods ◽  
Managed Realignment ◽  
Extreme Water Levels ◽  
The Relationship

AbstractManaged realignment (MR) involves the landward relocation of sea defences to foster the (re)creation of coastal wetlands and achieve nature-based coastal protection. The wider application of MR is impeded by knowledge gaps related to lacking data on its effectiveness under extreme surges and the role of changes in vegetation cover, for example due to sea-level rise. We employ a calibrated and validated hydrodynamic model to explore relationships between surge attenuation, MR width(/area) and vegetation cover for the MR site of Freiston Shore, UK. We model a range of extreme water levels for four scenarios of variable MR width. We further assess the effects of reduced vegetation cover for the actual MR site and for the scenario of the site with the largest width. We show that surges are amplified for all but the largest two site scenarios, suggesting that increasing MR width results in higher attenuation rates. Substantial surge attenuation (up to 18 cm km−1) is only achieved for the largest site. The greatest contribution to the attenuation in the largest site scenario may come from water being reflected from the breached dike. While vegetation cover has no statistically significant effect on surge attenuations in the original MR site, higher coverage leads to higher attenuation rates in the largest site scenario. We conclude that at the open coast, only large MR sites (> 1148 m width) can attenuate surges with return periods > 10 years, while increased vegetation cover and larger MR widths enable the attenuation of even higher surges.

scholarly journals A NEW STORM IMPACT MATRIX COMBINING BOTH COASTAL FLOODING AND EROSION HAZARDS

2020 ◽  
pp. 6
Author(s):  
Christopher Leaman ◽  
Mitchell Harley ◽  
Kristen Splinter ◽  
Mandi Thran ◽  
Michael Kinsela ◽  
...  
Keyword(s):  
Wave Energy ◽  
Early Warning ◽  
Early Warning Systems ◽  
Coastal Flooding ◽  
Water Levels ◽  
Warning Systems ◽  
Coastal Zones ◽  
Windows Of Opportunity ◽  
Erosion Hazards ◽  
Storm Impact

Coastal zones are often threatened by storms that elevate water levels and increase the wave energy impacting the shoreline. These storm conditions result in coastal flooding and erosion hazards for communities, threatening lives, properties and infrastructure. Coastal impact Early Warning Systems (EWSs) are currently used to alert authorities of potential impacts prior to advancing storms. Effective EWSs provide important windows of opportunity to undertake mitigating actions to minimize the damage caused by a storm.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/-U6uEHfLizA

scholarly journals Effect of Variations in Water Level and Wave Steepness on the Robustness of Wave Overtopping Estimation

2020 ◽  
Vol 8 (2) ◽  
pp. 63
Author(s):  
Nils B. Kerpen ◽  
Karl-Friedrich Daemrich ◽  
Oliver Lojek ◽  
Torsten Schlurmann
Keyword(s):  
Water Level ◽  
Wave Spectrum ◽  
Water Environment ◽  
Physical Modelling ◽  
Storm Surges ◽  
Water Levels ◽  
Coastal Protection ◽  
Wave Steepness ◽  
Wave Overtopping

The wave overtopping discharge at coastal defense structures is directly linked to the freeboard height. By means of physical modelling, experiments on wave overtopping volumes at sloped coastal structures are customarily determined for constant water levels and static wave steepness conditions (e.g., specific wave spectrum). These experiments are the basis for the formulation of empirically derived and widely acknowledged wave overtopping estimations for practical design purposes. By analysis and laboratory reproduction of typical features from exemplarily regarded real storm surge time series in German coastal waters, the role of non-stationary water level and wave steepness were analyzed and adjusted in experiments. The robustness of wave overtopping estimation formulae (i.e., the capabilities and limitations of such a static projection of dynamic boundary conditions) are outlined. Therefore, the classic static approach is contrasted with data stemming from tests in which both water level and wave steepness were dynamically altered in representative arrangements. The analysis reveals that mean overtopping discharges for simple sloping structures in an almost deep water environment could be robustly estimated for dynamic water level changes by means of the present design formulae. In contrast, the role of dynamic changes of the wave steepness led to a substantial discrepancy of overtopping volumes by a factor of two. This finding opens new discussion on methodology and criteria design of coastal protection infrastructure under dynamic exposure to storm surges and in lieu of alterations stemming from projected sea level rise.

scholarly journals Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

2015 ◽  
Vol 15 (7) ◽  
pp. 1533-1543 ◽  
Author(s):  
P. Dissanayake ◽  
J. Brown ◽  
H. Karunarathna
Keyword(s):  
Extreme Event ◽  
Morphological Changes ◽  
Water Levels ◽  
Storm Event ◽  
Dune System ◽  
Morphological Response ◽  
Cumulative Impact ◽  
Dune Erosion ◽  
Sequence Of Events ◽  
Storm Impact

Abstract. Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/2014 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper-beach profile. The sequence of events impacting the size of this ridge–runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number of the storms. This model application provides inter-survey information about morphological response to repeated storm impact. This will inform local managers of the potential beach response and dune vulnerability to variable storm configurations.

scholarly journals TIME-VARYING EMULATOR FOR SHORT- AND LONG-TERM ANALYSIS OF COASTAL FLOODING (TESLA-FLOOD)

2018 ◽  
pp. 4
Author(s):  
Dylan Anderson ◽  
Peter Ruggiero ◽  
Fernando J. Mendez ◽  
Ana Rueda ◽  
Jose A. Antolinez ◽  
...  
Keyword(s):  
Sea Level ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Water Levels ◽  
Sea Level Anomalies ◽  
Extreme Water Levels ◽  
Flooding Risk ◽  
The Individual ◽  
Flooding Events

The ability to predict coastal flooding events and associated impacts has emerged as a primary societal need within the context of projected sea level rise (SLR) and climate change. The duration and extent of flooding is the result of nonlinear interactions between multiple environmental forcings (oceanographic, meteorological, hydrological) acting at varying spatial (local to global) and temporal scales (hours to centuries). Individual components contributing to total water levels (TWLs) include astronomical tides, monthly sea level anomalies, storm surges, and wave setup. Common practices often use the observational record of extreme water levels to estimate return levels of future extremes. However, such projections often do not account for the individual contribution of processes resulting in compound TWL events, nor do they account for time-dependent probabilities due to seasonal, interannual, and long-term oscillations within the climate system. More robust estimates of coastal flooding risk require the computation of joint probabilities and the simulation of hypothetical TWLs to better constrain the projection of extremes (Serafin [2014]).

scholarly journals Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

2015 ◽  
Vol 3 (4) ◽  
pp. 2565-2597 ◽  
Author(s):  
P. Dissanayake ◽  
J. Brown ◽  
H. Karunarathna
Keyword(s):  
Extreme Event ◽  
Morphological Changes ◽  
Water Levels ◽  
Storm Event ◽  
Dune System ◽  
Morphological Response ◽  
Cumulative Impact ◽  
Dune Erosion ◽  
Sequence Of Events ◽  
Storm Impact

Abstract. Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/14 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross-section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number of the storms. This model application provides inter-survey information about morphological response to repeated storm impact. This will inform local managers of the potential beach response and dune vulnerability to variable storm configurations.

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