Abstract: Beaches along the Rio Grande do Sul (RS) coast are fully exposed with the exception of the extreme northern end where a rocky headland composed of sandstone, basalt and volcano-clastic sequences provide a small degree of protection to coastal dynamics. The beaches generally consist of fine quartz sand with a low gradient swash zone usually containing low-relief beach cusps. Beaches range between intermediate and dissipative, with beach state controlled in part by grain-size variations through the contribution of shell fragments, gravel and coarse quartz sand. This wave-dominated coast is episodically exposed to storm waves, which favors the formation and maintenance of two to three shore parallel sand bars. Most of the beaches possess distinct hazard to bathers associated to their beach state and hazard rating. The longshore bar and trough (LBT) and rhythmic bar and beach (RBB) states are very common and the troughs are usually deeper than the height of the bathers. The combination of higher beach population during summer seasons and rip-dominated intermediate beaches result in the most hazardous beaches along the northern littoral and in the extreme south. Other beach hazards are related to the presence of washouts and flooding, as well as, to episodic deposition of fluid mud at the surfzone and beach as a result of anthropogenic influence. Approximately 80 % of the coastline is undeveloped and the main impacts are associated to car traffic and litter represented by solid waste and plastic beads. Foredunes along the littoral are affected by changes in coastal orientation in relation to the prevailing northeast winds and beach morphodynamics and range from well-developed to non-existent.
Publication Year: 2016
Publication Date: 2016-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 14
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