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Peró coastal plain vulnerability26960 mm, occurs between June and September whilethe rainy season starts in December, with decreasingamounts of rain up to March. Winds are predominantlyfrom northeast during the whole year alternatingwith short periods of winds from southeast andsouthwest associated to the arrival of cold fronts.Wind velocities usually stay between 4 and 6m/s;higher values are observed during the winter.The present study seeks to identify presentdaymorphodynamic processes and the possibleeffects of climate change on them.MethodologyMonthly topo-bathymetric profiles weremeasured over twelve months in three positionsalong the beach arc and along the longitudinal axisof three parabolic dunes; the main goal was tocharacterize the topography of the foredunes and toassess the mobility of the beach and shoreface aswell as that of the parabolic dunes of the deflationplain (Fig. 3).Topo-bathymetric profiles were measured atpositions P2, P5 and P7 (Fig. 3), and adjusted to theaverage sea-level on the basis of the predicted tidesfor the Porto do Forno (Arraial do Cabo), followingthe methodology described by Muehe et al. (2003)and Muehe (2004). The profiles extended from theback of the foredune field (profiles P5 and P7) andfrom the public walk (profile P2), up to the outerlimit of the surf zone through conventionaltopographic leveling. The profiles were extended togreater depths, for the determination of the depth ofclosure and sediment sampling, with a kayak, aportable echo sounder a hand-held GPS, inaccordance with the methodology developed byBelligotti & Muehe (2007).In accordance with the studies undertakenby Belligotti (2009), the depth of inflection of thebathymetric profile was considered for thedetermination of the depth of closure, the depth atwhich vertical variations of topography arenegligible (Hallermeier 1981), as a more practicalalternative in view of the enormous discrepancybetween the values obtained with the differentequations proposed in the literature (Hallermeier1981, Birkemeier 1985, Houston 1995, Wang &Davis Jr 2007) which are, in their turn, greatlyinfluenced by the wave parameters adopted.The determination of the shorefaceequilibrium profile, for purposes of comparison withthe measured profile, was obtained with the use ofDean’s equation (1991) expressed by the relation:z x= Ax2 / 3where the depth “z” at a distance “x” from thecoastline is defined as a function of the mediandiameter of the sediments or of the correspondingsettling velocity of (ω s ), expressed by the scaleparameter “A”, determined in its turn by the relation:A =0.440,0067⋅ωsFor a rough assessment of a potential retreatof the coastline corresponding to a given rise in sealevelthe equation of Bruun (Bruun, 1962, 1988) wasemployed:SLGR =hwhere:R = erosive retreat of the coastline due to rise in sealevel(m)S = rise in sea-level (m)L = length of the active profile (m)h = height of the active profile (m)G = proportion of eroded material which ismaintained on the active profileThe height of the active profile isdetermined by the sum of the land height (sandbarrier, terrace, foredune) and the depth of closure,and the active length is the horizontal distancebetween the land height and h. The proportion ofmaterial retained on the profile (G) is considered tobe 1, because of the difficulty of assessing thequantity of material made available by erosion andretained on the submerged profile. This is certainlyone of the sources of error in the assessment of theamplitude of the retreat.Sediment traps were installed at a fewselected locations (Fig. 3) for the assessment ofsediment transport from the foredunes to thedeflation plain and were monitored during the periodof the surveys. The traps were constructed inaccordance with Leatherman (1978) and consisted ofa 100 cm long PVC tube whose upper half wasprovided with two openings on each side, one ofthem being closed with a silk-screen in order toretain the sediments but still allowing the passage ofthe wind. The lower part was buried and served assupport for an acetate cylinder in which the grainscollected by the trap were retained. The traps wereplaced with the opening in the direction of theprevailing wind, of about 60º, well defined insatellite images by the tracks of the trajectory of thesedimentary transport.Sediment samples were collected for grainsize analysis at each of the traps and along thebeachface (Fig. 3), where the sampling was carriedout at 500 m intervals on the top of the foredune, ofthe berm and on the beachface. For an adequaterepresentation of the berm sediments 30 cm deepPan-American Journal of Aquatic Sciences (2010), 5(2): 267-276