THE MEASUREMENT OF PEBBLE IMPACTS AND WAVE ACTION ON SHORE PLATFORMS AND BEACHES - THE SWASH FORCE TRANSDUCER (SWASHOMETER)

An instrument has been designed that can measure pebble impacts and wa ve forces in a harsh, high-energy, turbulent near-shore environment. T he instrument weighs some 50 kg and stands 60 cm in height, and has a pebble sensor head that is interchangeable in that the size and shape can be representative of beach pebbles e.g. discoid, spherical, blade or rod like. Impacts on the sensor are recorded on a computer and the instrument can be programmed to run for varying time periods. Two char acteristic force versus time traces, representing a different wave act ivity are presented. The instrument performed well throughout several tidal cycles and under a variety of energy conditions.