Simulation of Skimming Flow over Moderate Stepped Spillways Using Smoothed Particle Hydrodynamics

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Morphodynamics of sandy beaches under the influence of storm sequences: current research status and future needs

This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences. The paper reviews how the three main research methods, field investigations, numerical modelling, and physical modelling, have been used to study beach morphodynamics during storm sequences. Available quantitative definitions of storm sequences at different sites are presented and discussed. It is shown that the definition of storm sequences is site-specific and requires knowledge of the storm climate, beach characteristics, and the temporal scale of beach recovery. Subsequently, the paper brings together currently available approaches aimed at describing the effect of storm sequences on beach erosion in a general way. The importance of storm chronology and the effects of an extreme storm within a sequence of storms are highlighted. Following that, the more poorly studied aspect of beach recovery in between storms within a sequence is discussed. Three indicators for defining beach recovery, namely the shoreline location, sediment volumes, and the beach state, are identified and compared. Finally, important research needs, including the need for detailed physical modelling, are identified.Peer Reviewe

Storm sequencing and beach profile variability at Hasaki, Japan

Beach profile evolution under storm sequence forcing presents an emerging research topic that has only been investigated at a limited number of sites. The occurrence and effects of storm sequencing on beach profile evolution are studied at Hasaki Beach, Japan, using weekly beach profile and two-hourly offshore wave measurements. During the 25-year study period, the supratidal beach at Hasaki is subjected to long-term accretion and steepening while the shoreline shows a long-term oscillation. In addition, oscillations of the supratidal beach volume and the shoreline at semi-annual and annual intervals are identified, which are largely controlled by the variability of the wave height. Hasaki Beach is subjected to frequent storms that often cluster in sequences, especially during the extra-tropical cyclone season (January to March). The majority of storms and sequences generate erosion of the beach above the low water level but some also lead to recovery. Despite a tendency for storms and storm sequences with larger power to cause more erosion, the present data does not demonstrate increased beach erosion by storm sequences. Following these findings, the tendency of the beach to evolve towards equilibrium and the importance of the antecedent beach morphology are demonstrated