Modelling Wave Transformation Across a Fringing Reef Using Swash

Zijlema, Marcel

doi:10.9753/icce.v33.currents.26

Cited by 25 publications

(24 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to validate XBNH and the parameter settings for wave transformation and runup on a fringing reef, the model was tested against the Demirbilek et al () laboratory‐derived experimental data set of cases without wind, similar to the data sets used by Nwogu & Demirbilek (), Zijlema (), and Shimozono et al () to validate their numerical models.…”

Section: Results and Analysismentioning

confidence: 99%

A Bayesian‐Based System to Assess Wave‐Driven Flooding Hazards on Coral Reef‐Lined Coasts

et al. 2017

View full text Add to dashboard Cite

Many low‐elevation, coral reef‐lined, tropical coasts are vulnerable to the effects of climate change, sea level rise, and wave‐induced flooding. The considerable morphological diversity of these coasts and the variability of the hydrodynamic forcing that they are exposed to make predicting wave‐induced flooding a challenge. A process‐based wave‐resolving hydrodynamic model (XBeach Non‐Hydrostatic, “XBNH”) was used to create a large synthetic database for use in a “Bayesian Estimator for Wave Attack in Reef Environments” (BEWARE), relating incident hydrodynamics and coral reef geomorphology to coastal flooding hazards on reef‐lined coasts. Building on previous work, BEWARE improves system understanding of reef hydrodynamics by examining the intrinsic reef and extrinsic forcing factors controlling runup and flooding on reef‐lined coasts. The Bayesian estimator has high predictive skill for the XBNH model outputs that are flooding indicators, and was validated for a number of available field cases. It was found that, in order to accurately predict flooding hazards, water depth over the reef flat, incident wave conditions, and reef flat width are the most essential factors, whereas other factors such as beach slope and bed friction due to the presence or absence of corals are less important. BEWARE is a potentially powerful tool for use in early warning systems or risk assessment studies, and can be used to make projections about how wave‐induced flooding on coral reef‐lined coasts may change due to climate change.

show abstract

Section: Results and Analysismentioning

confidence: 99%

A Bayesian‐Based System to Assess Wave‐Driven Flooding Hazards on Coral Reef‐Lined Coasts

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The method automatically detects discontinuities in solution and introduces nonlinear dissipation to suppress nonphysical oscillations arising from them. The validity of this approach for wave breaking over fringing reefs was confirmed in previous studies [ Roeber and Cheung , ; Zijlema , ]. However, the shock‐capturing methods are, in general, too diffusive when applied to short wave propagation and thus cannot accurately reproduce wave steepening to the breaking point.…”

Section: Numerical Modelmentioning

confidence: 99%

Combined infragravity wave and sea‐swell runup over fringing reefs by super typhoon Haiyan

et al. 2015

View full text Add to dashboard Cite

Super typhoon Haiyan struck the Philippines on 8 November 2013, marking one of the strongest typhoons at landfall in recorded history. Extreme storm waves attacked the Pacific coast of Eastern Samar where the violent typhoon first made landfall. Our field survey confirmed that storm overwash heights of 6–14 m above mean sea level were distributed along the southeastern coast and extensive inundation occurred in some coastal villages in spite of natural protection by wide fringing reefs. A wave model based on Boussinesq‐type equations is constructed to simulate wave transformation over shallow fringing reefs and validated against existing laboratory data. Wave propagation and runup on the Eastern Samar coast are then reproduced using offshore boundary conditions based on a wave hindcast. The model results suggest that extreme waves on the shore are characterized as a superposition of the infragravity wave and sea‐swell components. The balance of the two components is strongly affected by the reef width and beach slope through wave breaking, frictional dissipation, reef‐flat resonances, and resonant runup amplification. Therefore, flood characteristics significantly differ from site to site due to a large variation of the two topographic parameters on the hilly coast. Strong coupling of infragravity waves and sea swells produces extreme runup on steep beaches fronted by narrow reefs, whereas the infragravity waves become dominant over wide reefs and they evolve into bores on steep beaches.

show abstract

“…Results show that XBnh+ can predict the wave heights across the reef reasonably well (Figures e– g). The coefficient of determination ( R 2 ) was estimated equal to 0.73–0.83 at the two transects, the scatter index (Zijlema, ) to 0.22–0.26, and the relative bias (Rel.Bias) to ±0.01 for total (Figure e), SS (Figure f), and IG (Figure g) significant wave heights. Estimates of mean water level were even more accurate with R 2 =0.96, scatter index =0.07, Rel.Bias =0.02 (Figure h).…”

Section: Results and Analysismentioning

confidence: 99%

Impact of Coral Reef Mining Pits on Nearshore Hydrodynamics and Wave Runup During Extreme Wave Events

et al. 2019

View full text Add to dashboard Cite

Small island developing states are among the most vulnerable areas to the impact of natural hazards and climate change. Flooding due to storm surges and extreme waves, coastal erosion, and salinization of freshwater lenses are already a serious threat and could lead to irreversible consequences in the coming decades. Reef flat mining is one of the most common practices to source the required material for the implementation of coastal protection measures, but concerns remain that partial removal of the protective reef could increase wave loading on the islands. However, the available data and knowledge on the effects of these mining pits are currently very limited. This study provides new insights on the effects that pits may have on nearshore hydrodynamics and wave runup. Results are based on a large numerical data set of fringing reefs, derived using the validated XBeach nonhydrostatic+ process‐based model. Model results indicate that excavation pits cause a decrease in infragravity wave energy around the fundamental mode of the reef, which is partly caused by reduced wave transmission. Additionally, changes in sea and swell wave energy are attributed to reduced transmission, a decrease in wave dissipation, and (triad) wave–wave interaction. Furthermore, in 13% of all modeled cases, an increase in wave runup is observed, mainly due to more sea and swell wave energy reaching the shoreline. This probability is lowest for narrow pits relative to the reef flat width or pits located further from shore.

show abstract

Modelling Wave Transformation Across a Fringing Reef Using Swash

Cited by 25 publications

References 17 publications

A Bayesian‐Based System to Assess Wave‐Driven Flooding Hazards on Coral Reef‐Lined Coasts

A Bayesian‐Based System to Assess Wave‐Driven Flooding Hazards on Coral Reef‐Lined Coasts

Combined infragravity wave and sea‐swell runup over fringing reefs by super typhoon Haiyan

Impact of Coral Reef Mining Pits on Nearshore Hydrodynamics and Wave Runup During Extreme Wave Events

Contact Info

Product

Resources

About