This paper investigates the engineering feasibility of cage aquaculture in the offshore wind farm area of Changhua, Taiwan. Two types of net cages commonly used in Taiwan are compared under typhoon wave and monsoon wave conditions to determine the suitable one. The submersible function of the selected cages to reduce the typhoon wave effect is analyzed. The yearly probability of the remaining volumes of the selected cages (deformed volume/undeformed volume) under a wave scatter diagram combined with a tidal current of the study area are analyzed and discussed. The influences of water depth on the selected cages for the site selection are investigated. Regarding the seabed sand waves in the study area, two potential disasters of mooring line failure and anchor sinking on the selected cages are considered and discussed. Both issues are a concern for the wind farm developers, fishery groups, and government authorities. According to the results, the selected cage aquaculture is feasible from an engineering standpoint in the case study area.

Numerical and physical experiments on bichromatic wave trains were conducted in deep water. The evolution of wave trains and corresponding spectra were investigated in this paper. The results indicate that the evolution of bichromatic wave trains strongly depends on the wave steepness and frequency difference between the imposed wave components. The evolutions of wave trains including breaking and non-breaking types were analyzed for different combination of wave steepness and frequency difference. Specifically, for non-breaking cases, the wave trains evolve modulation and demodulation periodically in the experimental data. This phenomenon can be better predicted by the nonlinear Schrödinger (NLS) equation. However, for the free surface displacement, the multi-layer Boussinesq model gives better phase agreement with experimental data. For breaking case, the amplitude of lower sideband frequency is selectively amplified through the breaking process, which can be qualitatively simulated in the NLS model by adding an additional proper damping function. The experimental data also show weak evolution of induced bound long wave during the breaking process

Barrier change is a complex process of evolution of coastal topography, which is related to the interaction of driving forces such as waves, tides and sea level rise (SLR) with beaches. The Waisanding Barrier (WSDB) in Taiwan has suffered from continuous beach erosion in recent decades. Some short-term studies have been carried out to understand the characteristics of the barrier change to provide a reference for future barrier protection. In this paper, the digital elevation model (DEM) measured by LiDAR (Light Detection and Ranging), over nearly two decades was used to analyze the morphological changes, the land area and volume. The changes in the morphology, including the whole shoreline, duneline height, width of forebeach and backbarrier, are investigated. The WSDB’s land area and land volume were analyzed to show a continuous decrease by a rate of −0.418 × 10⁶ m²/year and −3.96 × 10⁵ m³/year, respectively. The corresponding average land volume (LV) decrease in elevation can be estimated to be −0.0286 m/year. The changes in these features are discussed and relate to land subsidence, sea level rise and large waves induced by typhoons passing near WSDB.

Storm tides, surges, and waves associated with typhoons/tropical cyclones/hurricanes are among the most severe threats to coastal zones, nearshore waters, and navigational safety