Abstract:
This paper describes an application of the
Boussinesq-type COULWAVE model to study the wave
hydrodynamics in the vicinity of a multi-functional artificial
reef (MFAR). This reef is under investigation and consists of
a supplementary protection solution for the Leirosa sand
dune system located at South of Figueira da Foz, on the
PortugueseWest coast. Such installation near the coastline is
expected to contribute to enhance the surfing conditions in
the area, protect the sand dune system in the surroundings of
Leirosa beach, and increase its environmental value.
Numerical calculations with the COULWAVE model were
performed for four test cases, considering two reef geometries
(differing in the reef angle) and two incident wave
conditions (storm condition and a common wave condition).
Comparisons between the results obtained, in terms of wave
heights and breaking line positions allow us to assess the
influence of the reef on the hydrodynamics near the beach
and around the reef. Moreover, the reef performance was
analysed in terms of surfability and coastal protection. The
surfability parameters (breaker height, Iribarren number and
peel angle) were calculated for each test case using the
numerical wave heights, wave directions and wave breaking
positions. Comparisons of parameters allow characterizing
the most appropriate configuration of the reef to improve the
surfing conditions in the study area. A methodology based
on numerical free surface elevations and horizontal velocity
components was developed to calculate wave directions,
since this is not a direct output of the COULWAVE model.
Concerning coastal protection, analyses of the mean currents
around the reef were used together with observations
of the velocity cells near the shoreline as an indication of the
sediment transport.
