Numerical Simulation and Analysis of Joint Multi-Line to Defend Storm Surges Due to a Super Typhoon

This paper aims to the inundated conditions which probably occur in the macro-tidal estuary where the floodplains are lower than the high tidal level. A high Precision two-dimensional numerical model is developed to simulate the inundated degree introduced by storm surges taking the Qiantangjiang estuary coastal area as an example. Except for the sea area, both sides of the floodplains are included in the calculation scope. Meanwhile, the secondary dikes owing to the reclamation projects and some roads which have the effect on tide resistance are considered. In this article, the front dikes damaged scale is determined by Interior Wave Model Experiment[3], Safety Assessment of the Front Dikes’ Ultimate Defense Capability[11]. Using the model, this paper simulated inundated conditions under the typical super typhoon which takes Typhoon No.5612, the most intense typhoon landed in china since 1949, as the controlling conditions. According to the calculated results, this paper analyzed the effects of joint multi-line defense (the secondary dikes and roads) behind the front dikes and obtained action sphere and role of each defense. These results can be applied to direct the defense of storm surges over designed standard occurring in the macro-tidal estuary.

Shore Platform Processes in Eastern Canada

This research is conducted on a mesotidal, argillite shore platform at Mont Louis in Gaspé, Québec, and on macrotidal platforms in the basalts of Scots Bay and the sandstones of Burncoat Head in Nova Scotia. Rock samples have been subjected to wetting and drying and to salt weathering cycles. The platforms were surveyed; rock hardness was determined with a Rock Test Hammer; waves were recorded in the field; and downwearing rates were measured at 56 micro-erosion meter stations over 1 to 3 years. Weathering is the dominant process at Mont Louis, although the horizontal platform may have been cut by waves at the high tidal level. Wave backwearing was much more important than downwearing by weathering during the Holocene at Scots Bay. Wave quarrying only occurs on a few scarps today, however, and without much abrasive material, slow downwearing now dominates over most of the platform surface. Waves probably help to remove loosened sand grains at Burncoat Head, thereby contributing to platform downwearing. Abrasion is also important in places, but the data suggest that backwearing by wave quarrying and probably frost has been a little more important than downwearing by abrasion and weathering during the Holocene.

Structure and growth of a high-level population of Cerastoderma edule (Lamellibranchiata)

The allometric relationships between shell length and shell breadth, shell height, shell weight, wet tissue weight and dry tissue weight are described for a population of Cerastoderma edule living at a high tidal level in the Dovey Estuary, West Wales. Seasonal fluctuations in standard animal values for shell weight and dry weight are interpreted in terms of the cycles of reproduction and food availability; the dangers associated with the use of wet weight in growth studies are demonstrated. The population structure is described using a combination of length-frequency and growth ring analyses and comprised nine year-classes with overlapping size ranges. The growth of the population was very slow and the relative growth rate was almost constant; associated with this slow, atypical growth pattern was considerable longevity and a small maximum size. The reasons for these characteristics are discussed.