Open AccessSURF ZONE MEASUREMENTS OF SUSPENDED SEDIMENT
Author(s) -
Timothy W. Kana
Publication year - 1978
Publication title -
proceedings of conference on coastal engineering/proceedings of ... conference on coastal engineering
Language(s) - English
Resource type - Journals
eISSN - 2156-1028
pISSN - 0589-087X
DOI - 10.9753/icce.v16.104
Subject(s) - circuit breaker , surf zone , elevation (ballistics) , sediment , geology , breaking wave , wave height , inlet , hydrology (agriculture) , wind speed , significant wave height , wind wave , sediment transport , geotechnical engineering , geomorphology , oceanography , wave propagation , geometry , physics , mathematics , quantum mechanics
Suspended sediment concentration was measured in approximately 250 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. As many as 10 instantaneous 2-liter water volumes were obtained in each wave for a total of 1500 samples. Concentrations of suspended sediment were determined at fixed intervals of 10, 30, 60 and 100 cm above the bed for various surf zone positions relative to the breakpoint. The majority of waves sampled during 22 days in June and July, 1977 were relatively long crested, smooth, spilling to plunging in form, with breaker heights ranging from 20 to 150 cm. Surf zone process variables measured included breaker height and depth, breaker type, wave period, surface longshore current velocity, wind velocity and direction. Scatter plots of mean concentration against various process parameters indicate the amount of sediment entrained in breaking waves is primarily a function of elevation above the bed, breaker type, breaker height and distance from the breakpoint. Concentration ranged over 3 orders of magnitude up to 10 gm/1, but varied less than 1 order for samples collected under similar conditions with regard to elevation and breaker type. Plunging breakers generally entrain 1 order more sediment than spilling breakers equal in height. Despite considerable scatter, these data indicate concentration decreases with increasing wave height for waves 50 to 150 cm high, suggesting that small waves can be important in the transport of sand on gently-sloping open coasts.