Video measurement of swash zone hydrodynamics

A new technique for recording two-dimensional uprush and backwash depth profiles using standard analogue camcorder technology is introduced. This technique has the potential to provide low cost, high frequency, high resolution measurements of individual swash events. Analogue to digital data conversion using multimedia software is discussed, as is the derivation of metric data via image processing and geographical information systems techniques. A series of field and laboratory experiments are described which provided an opportunity to refine and test the technique. Data from the laboratory video record are compared against measurements from standard surface piercing resistance type wave gauges, and an assessment made of the next steps required for the enhancement of the technique. The comparison between video and probe data indicates that the technique shows promise as a means of deriving two-dimensional profiles of swash lens; however, further development and testing are necessary. (C) 1999 Elsevier Science B.V. All rights reserved.