REF.:  PTDC/CTE-GIX/116814/2010

BUDGET (TOTAL/UALG-CIMA): 105’000,00/105’000,00 €

STARTING DATE: 21th March 2012

ENDING DATE:  20^th March 2015

COORDINATOR: Ana Matias

DOMAIN:  Earth and Space Sciences – Internal and External Geodynamics

 

ABSTRACT:

The primary goals of this proposal are to understand the evolution of swash runup to overwash (in a 2D framework), to evaluate the role of longshore morphological variations in overwash (in a 3D framework) and to develop a three-dimensional conceptual model of overwash. There are challenging scientific and methodological issues addressed by this proposal. First of all, in-situ field measurements of overwash are limited (only 6 datasets available, but most lack detail) due to difficulties in fieldwork planning (overwash occurrence is infrequent and irregular) and execution (overwash occurrence is hazardous to people and equipment). Secondly, this proposal links knowledge from marine environments (nearshore, beach) to coastal/terrestrial environments (car parking, dune, backbarrier). Thirdly, differences in overwash hydraulics and sediment transport over natural and artificial beds are quantified. The fourth and more challenging issue of this proposal is to combine 2D and 3D framework measurements as a strategy to define fundamental variables of overwash.

Data collection includes hydrodynamic variables, including waves, tides, currents, swash runup spectra and overwash hydraulics; and bed properties variables including topography, bathymetry, porosity, and grain-size. Fieldwork will be divided in a 2D framework (repeated 1 day intensive measurements across a barrier profile during overwash) and a 3D framework (repeated 3 days topo-bathymetric surveying pre- and post-overwash). Hydrodynamic measurements in a 2D framework will be undertaken by a set of equipment deployed from offshore to the backbarrier and by video imagery; and bed properties will be followed by barrier profiling and sediment sampling. Hydrodynamic measurements in a 3D framework will involve modeling offshore waves until the nearshore/breaking zone; and morphological measurements comprise topo-bathymetric surveys and tracking of key alongshore alignments (such as swash lines, overwash lines, barrier crest). Processing all datasets will result in detailed time-series of forcing variables (hydrodynamic measurements) and response variables (bed properties measurements), that will be the basis of the overwash tri-dimensional conceptual model. Project deliverables will be transmitted both to the scientific community as to the general public trough a dissemination plan that includes a webpage, papers in international journals, communications in conferences, and participation in events of science dissemination to the general public.