Swash zone velocity and volumetric measurement using a simple video technique

A geographic information system (GIS) method for measuring two-dimensional laboratory swash characteristics using data recorded with standard video cameras at 25 frames per second is used to test the predicted shoreline velocity, water surface shape, elevation and swash volume over a single swash event. A time-varying record of the swash event covering the full swash extent at a spatial resolution of 2 mm is used to compare observed measurements to those predicted using the Shen and Meyer (1963) model for uprush following bore collapse show significant over-prediction of the maximum shoreline position, swash period and swash height. This is consistent with the findings of Hughes (1992). Observations of the video record suggest that turbulent flow continues within much of the uprush and backwash phases of the swash. A 'flow reversal' phase similar to that seen by Larson and Sunamura (1993) was also observed.