Abstract

BELLIGOTTI, Fábio Mayo  and  MUEHE, Dieter. Measuring Shoreface Profiles with a Kayak and Handheld Depth Finder. RGCI [online]. 2012, vol.12, n.2, pp.257-262. ISSN 1646-8872.

The extension of topographic beach profiles toward offshore is limited to the depth the level rod can be read as also the ability to carry the rod through the surf and breaker zone. To avoid the high cost of a bathymetric survey by a conventional boat in order to extend the profiles to the entire shoreface, the survey may be done using a kayak, which can be launched directly in the research area with measures made using a handheld fish finder together with a hand held GPS. The measurements are made on previously defined waypoints along a line perpendicular to the shoreline with subsequent correction of deviations through the projection of each segment between waypoints to the direction of the profile in order to avoid distortions in length and declivity. In spite of the imprecision of the positioning as also the depth measurement due to the influence of waves, the method is sufficiently accurate to allow the comparison between profiles and the characterization of the morphology of the shoreface in terms of bathymetric gradients and comparison with the equilibrium profile.

Keywords : Echo-bathymetry; shoreface; kayak.

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