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Experimental investigations on wave reflections, run-up and run-down and wave pressures on plane, dentated and serrated seawalls were carried out for a wide range of wave heights, wave periods, seawall slopes and in a constant water depth of 0.7 m. Based on the measurements, predictive equations are proposed. A total performance evaluation is carried out on each seawall. The improved performance of the serrated seawall compared to plane seawall is brought out. It is found that closer to deep water condition, the reflection coefficients from the serrated and the dentated vertical seawalls are only about 0.5 and 0.6 respectively compared to the fully reflecting plane vertical wall. Sloped serrated seawall is capable of dissipating the wave energy almost two times that of the sloped plane seawall. Closer to still water level, the normalized wave pressure value (ratio of maximum wave pressure to static pressure due to the water column equal to incident wave height) for 2% exceedence is 0.9, 1.1 and 1.15 for the serrated, dentated and plane seawalls. The measured relative run-up value (ratio between the maximum run up to the incident wave height) for 2% exceedence is 1.30, 1.5 and 1.6 for serrated, dentated and plane seawall respectively. Hence, the design crest level of the serrated seawall can be at a lower level than that of the plane seawall. Overall, it is found that the serrated seawall is about 20% to 40% better than the plane seawall for reducing the wave pressure, reflection, run-up and rundown. The results can be used for better hydrodynamic design of coastal structures with vertical face (like quay walls in harbors, vertical seawalls and caisson type breakwaters) and sloped structures (like seawalls, dikes, sea side sloped caissons).

An X-band nautical radar system was employed to examine wave run-up during a typhoon around the research pier HORS in Hasaki, Japan. Analyses on radar echo images were done to estimate the spatio-temporal variation of water fronts by manually digitizing cross-shore time stack images. Digitized instantaneous water fronts were validated with wave gauge measurements with an acceptable agreement. Longshore distribution of mean shoreline positions and inter-tidal foreshore slopes were then estimated using time-averaged images. Run-up, the height of discrete water level maxima, was estimated from the digitized water fronts with the help of foreshore profile. Run-up variations under dissipative condition were parameterized with surf similarity parameter. Low frequency variances in the run-up motion were observed, which travelled in the longshore direction.

A simple empirical model is proposed for predicting extreme wave run-up on natural beaches during severe wave events (deep water wave heights H₀ ≳8 m or return periods of about 50 years). The new model departs from traditional approaches that use the slope of the beach face β_f and the Iribarren number ξ₀ as parameters for predicting run-up and instead uses the distance offshore x_h to water depth h to estimate a near-shore profile slope as S = h/x_h, where the depth of closure is the proposed choice for h. Extreme run-up R_x is then expressed in terms of S as R_x/H₀ = CS^2/3. Observations from recent severe storm events in South Africa are used to estimate the dimensionless coefficient C≃7.5. The data are also compared with those of Holman [1986] and the results verify his regression equations and confirm they are valid for significant wave heights extending to 8.5 m for beach-face slopes around 0.1. The run-up predictions of Holman [1986], Nielsen and Hanslow [1991] and Stockdon et al. [2006] are compared to those of the proposed new model. The results suggest that the new model reduces the uncertainties in predicting wave run-up on natural beaches compared with previous models, and thus enables improved estimates of extreme wave run-up and the upper limit of beach change for coastal planning and management.

In this study, a numerical model was employed to determine the optimal location for vegetation as an environmentally friendly method of attenuating tsunami waves. The governing equations are shallow water equations solved using shock-capturing schemes with second-order accuracy model. This simulation was validated using experimental data and another numerical model for simulating the propagation of tsunami waves on a vegetated horizontal bed and vegetated sloping beach. The parameters of wave damping rate, maximum velocity, and height for the plant area at various locations and vegetation zone lengths were investigated using numerical models. By increasing the length of the plant zone, the height and velocity of the tsunami wave were reduced, and the wave damping was increased. The examination of various locations and lengths of the plant area demonstrated that the plant area’s distance from the shoreline is a significant factor in coastal protection. The results exhibit that the location of the forest area has a great impact on the control of destructive factors along the beach. As a result, this study provides some information for designing a tsunami-resistant forest area.

In the present paper, the experimental data on wave run-up on slender monopiles from recently published small and large scale tests are reanalyzed using different methods for the wave analysis. The hypothesis is that the post processing has an impact on the results, due to depth limited and highly nonlinear waves in many of the tests. Thus, the identified maximum waves by a zero-down crossing analysis are highly influenced by the reflection analysis method as well as by bandpass filtering. The stagnation head theory with the run-up coefficient is adopted and new coefficients are presented. The hypothesis is verified, and the applied bandpass filter is identified as a large contributor to conservatism in previous studies, as the steep, nonlinear waves that produce the highest run-up can be heavily distorted by the bandpass filter.

In the recent years, various geo-synthetic components find an extensive application in civil and coastal engineering practice. Commonly, geo-synthetics have a wide application for secondary or tertiary purposes, such as filtration, separation, barrier, reinforcement, whereas, they can be potentially exploited for various other applications in the coastal engineering practice. A sustainable seawall cross-section comprising different geo-synthetic products was proposed to be erected along the Pallana Beach ($19^{\circ }17^{\prime }55.19^{\prime \prime }$ N and $76^{\circ }23^{\prime }18.55^{\prime \prime }$ E), located in Alleppey district of Kerala along the south-west Indian coastline. Since the subsoil at the location is poorly graded, it was decided to replace the conventional materials like rock boulders and concrete armour units with geo-synthetic products. A comprehensive physical model study was conducted to assess the hydrodynamic performance (i.e. reflection, run-up, and pressure distribution) of the geo-synthetic seawall cross-section for a wide range of random wave characteristics and two water depth conditions. The relative overtopping rates for the seawall at varying water levels are computed conservatively from the guidelines prescribed by the EurOtop Manual and XGB Overtopping model.