As a “marine ecological engineer”, the oyster reefs not only perform important ecological functions, but also reduce the damage caused by waves to protective structures such as seawalls. However, oyster reefs in shallow water change the nonlinear characteristics of waves and affect sediment transport and coastal evolution. Based on Fourier spectrum and analysis of Wavelet Transform, the influence of artificial bag oyster reefs on the energy and nonlinear phase coupling of irregular waves are studied through physical experiment. The results show that oyster reefs have a substantial effect on the energy of primary harmonic, which transfer to higher harmonics through triad interactions, and a considerable reduction in primary harmonic energy and an increase in higher harmonics energy are reflected in the energy spectra. The transmission spectrum behind the oyster reefs shows three peaks at primary, secondary and third harmonics. The bicoherence spectrum indicates that the peaks at secondary and third harmonics mainly result from the self-coupling of the primary harmonics and phase coupling between the primary and secondary harmonics respectively. As the water depth increases, the degree of nonlinear coupling between wave components decreases, which leads to the energy of wave components at different frequencies increases. With increasing top width, the length of the shoaling region increases, and the growth of triad nonlinear interactions are observed in wavelet-based bicoherence spectra, resulting in the spectral peak energy decreasing while the secondary harmonics energy increasing in the spectrum. Finally, the potential application of an ecological system composed by “oyster reefs + mangroves” is discussed. As the effect of water depth on wave energy is much greater than that of top width, in artificial oyster reef construction, it is recommended that keep the oyster reefs non-submerged in terms of wave dissipation. Further studies should take the dynamic growth effect of oyster reefs into account.
In the coastal ecological project aimed at wave attenuation through mangroves, incorporating oyster reefs as a complementary component to establish an “oyster reefs + mangrove” wave attenuation system could enhance the survival probability of mangrove, as well as improve the overall effectiveness of wave dissipation. This study investigates this innovative combined wave attenuation system consisting of oyster reefs and mangroves with various configurations. Laboratory experiments were conducted in a wave flume using artificial models of mangrove and oyster reefs to examine the impact of the system on the wave attenuation effect, thereby providing a scientific foundation for coastal ecological restoration projects. The results indicate that the wave attenuation coefficient increases with the incident wave height, decreases with water depth and period, and enhances with the height of oyster reefs and the density of mangroves. Notably, oyster reefs play a dominant role in wave attenuation within the system. The system’s maximum wave attenuation coefficient of 0.42 is achieved when three layers of oyster reefs are combined with staggered dense mangroves. Moreover, although the summed wave attenuation coefficient of individual mangrove and individual oyster reefs is higher than that of the system, it is noteworthy that the overall wave dissipation exhibited by the system exceeds that of either individual component alone. Additionally, incorporating oyster reefs within individual mangrove structures significantly enhances wave dissipation capacity by up to 0.26. In coastal ecological restoration projects, to enhance wave energy reduction, maximizing the height of oyster reefs in areas with low water depth and pairing them with the staggered dense arrangement of mangroves is recommended. For areas with high water depth, the most effective wave reduction can be achieved through a combination of taller oyster reefs and either staggered or tandem clusters of dense mangroves.
Integrated water resource scheduling is a key strategy for controlling river floods as well as for promoting the benefits and abolishing the harmful aspects of water conservancy projects. It is necessary to explore an effective development mode to address the current issues of long development times and poor outcomes for integrated water resource scheduling models. Drawing on the concept of software reuse, a development mode for an integrated water resource scheduling model is offered based on “platform system + model plug-in”, the cores of which are plug-in modules and interface integration. The boundaries and connection relations of each plug-in module are formed based on the logical analysis of the model plug-in. A web application mode is used to implement a standardized interface, which can be quickly and seamlessly connected to the system platform. The model is explored and applied in the Wudu diversion and irrigation area in China. The generated model is eventually verified using data obtained from two flood periods. According to the simulation results, the gate operation will be convenient, and the target water level will be attained in the allocated time with a satisfactory peak-clipping effect. It shows both good coordination and great utilization value of the plug-in modules. The concept of designing a plug-in database is eventually taken into consideration for combining and generating an optimization model of each river.
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