USE OF FLUORESCENT TRACERS TO DETERMINE FORESHORE SEDIMENT TRANSPORT, SANDY HOOK, NEW JERSEY.

Each of four size classes of foreshore sand from Sandy Hook, New Jersey, was color coded with daylight and ultraviolet fluorescent coating material. These tracer particles were introduced at mid-swash line on the foreshore surface at Kingmill Beach, Sandy Hook, two hours prior to high tide. During the test Atlantic Ocean waves approaching at an angle of approximately 5 degrees to the shoreline caused 5.3-second breakers of 2.4-foot maximum height. A sampling line transverse to the foreshore was established 100 feet downdrift from the point of introduction. In a time-integration procedure samples were obtained by scraping a 0.10-foot deep and 0.18-foot wide channel a distance of 10 feet upslope from the backwash limit. Sub-samples of the 18 samples taken during the 69.7 minutes after marked particle introduction were examined for tracer particle content. Recovery data indicate particles in the smallest size class 0.701d0.589 mm began arriving at sampling line 38.9 minutes after introduction equivalent to 2.6 ftmin maximum transport velocity. Particles in the next largest size class began arriving 50.0 minutes after introduction equivalent to 2.0 ftmin maximum transport velocity. However, a maximum number of marked particles in both size classes was found in a sample taken 62.3 minutes after introduction.