Modelação do impacte do prolongamento do molhe norte da embocadura do rio Mondego nas praias adjacentes a sul

21/10/2016

The need to protect coastal populations and mitigate the shortage of sediments and the consequent erosive effect observed in the Portuguese west coast, led to the massive construction of groynes and revetments along the study area, a coastline extension of 30 km south of Figueira da Foz. This study characterizes the wave climate and the induced potential sediment transport south of the Mondego river inlet, from 1952 to 2010. Based on the statistical analysis of a wave parameters’ time series (hindcast), a wave climate with high interannual and seasonal variations and highly energetic, with 40% of Hs occurrence greater than 2 m and a mean wave direction of 299.5ºN, was identified. The calculated potential longshore sediment transport (LITDRIFT) revealed highly variable annual figures, ranging between 580-1500 x103m3.year-1, with south directed drift averaged 385 x103m3.year-1 during 78% of the study period. The cross-shore distribution of the longshore transport was identified in the active zone, with variable length (~2000 m). Between 2008 and 2010 the north jetty of the Mondego river’s inlet was extended about 400 m, motivating the main goal of this study: to evaluate the impact of this extension on the southern beaches, using numerical modelling (LITLINE). The coastline evolution model was calibrated for the period 1996-2001 and validated for the period 2001 2008, based on measured coastlines and synoptic wave climate data. The predictions for the 12 subsequent years to the extension point out a widespread retreat of the coastline, enhanced downdrift of the existing groynes.

Autores da comunidade :

• 

  J

  João Nuno Correia Oliveira

  ist162904

Orientadores desta instituição:

• 

  A

  António Alexandre Trigo Teixeira

  ist11951

civil-engineering - Engenharia Civil

por - Português

Instituto Superior Técnico