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Introduction
Published in Dominic Reeve, Andrew Chadwick, Christopher Fleming, Coastal Engineering, 2018
Dominic Reeve, Andrew Chadwick, Christopher Fleming
Beaches are dynamic, changing their profile and plan-form in both space and time in response to the natural forcing of waves and currents, sediment supply and removal, the influence of coastal geological features, and the influence of coastal defences and ports and harbours. Categorisations depend on whether the coastal forcing (waves, tides, wind) or the coastal response (sediment transport, morphodynamics) is the focus of interest. There is no fully agreed classification, but as a general rule time scales range from micro (for wave by wave events) through meso (for individual storms) to macro (for beach evolution over seasons, years and decades). Similarly, space scales have a range of micro (for changes at a point) through meso (e.g., changes of beach profile) to macro (regional changes in plan-form). One categorisation scheme is given in Tables 1.1 and 1.2. The basic theory for waves and their transformation in coastal waters is covered in Chapter 2. The methods for describing the random superposition of waves we experience in the sea and defining wave parameters that can be used for designing coastal and flood defences is covered in Chapter 3. The changes in sea level elevation due to tides and atmospheric variations are described in Chapter 4.
Temporal changes in the ebb-tidal delta bathymetry of Imagire-guchi inlet in Japan
Published in Coastal Engineering Journal, 2018
Stabilization of an inlet mouth by jetty construction confines the direction of ebb-jets. This regulation collapses the inlet system, and then the morphology and hydraulics form a new state (Hinwood, McLean, and Wilson, 2012). Some inlet studies of post-jetty morphologic evolution on longshore sediment transport have reported seaward migration of the ebb shoal with erosion of downdrift beach and updrift beach evolution, using field data such as aerial photos and historical bathymetric maps (Castelle et al., 2007; Garel, Sousa, and Ferreira, 2015). In the Imagire-guchi inlet, there have been the same types of morphologic changes in the delta and adjacent beaches (Kuriyama et al., 2004; Uda et al., 2010). Uda et al. (2010) used the regular bathymetries and indicated linear increase of the delta volume with the lobe progradation after the jetty constructions to 2005. Our results in Figures 6 and 9(d) supported that enlargement of the delta lobe has been maintained even after 2005.
Influence of the construction of the Yantai West Port on the dynamic sedimentary environment
Published in Marine Georesources & Geotechnology, 2018
Jiang Shenghui, Hu Rijun, Feng Xiuli, Zhu Longhai, Zhang Wei, Liu Aijiang
Human activities, especially port construction, have a significant impact on the hydrodynamic environment, sedimentary environment, and ecological environment (Wang and Liu 2011; El-Asmar, Taha, and El-Sorogy 2016). There are significant changes in the geomorphology, coastal sediment transport processes, and beach evolution (El-Asmar and White 2002; El Banna and Frihy 2009; Garel, Sousa, and Ferreira 2015). Moreover, changes in the sedimentary dynamic environment also have a great effect on human activities, such as port development, waterway maintenance, and marine structure construction (Smith et al. 2010). Therefore, investigations should be conducted to determine how port construction changes the dynamic sedimentary environment.
Investigation of proposed countermeasures against coastal erosion and sediment invasion around half-buried floodway
Published in Coastal Engineering Journal, 2020
In Japan, one of the main reasons for the decreasing sediment yield in the coastal zones is the impoundment and deposition of sediments behind dams and reservoirs. Sato et al. (2004) confirmed these claims on their study of the sediment movement and beach evolution around the Samegawa River and Nakoso Coast, on which the reduction of sediments on the coast is of the same order of magnitude as the impoundment of sediments in dams and reservoirs.