Natural fluctuations in nearshore turbidity and the relative influences of beach renourishment

Abstract

Turbidity is a measure of the clarity of water. Turbidity depends upon the scattering and absorption of light by suspended particles. The focus of this study was to obtain quantitative measurements of turbidity in the nearshore zone, along with measurements of associated wave parameters and currents occurring naturally and during a beach nourishment project. The objectives were to make quantitative and qualitative comparisons between natural events and those induced by the dredge and fill operations, as well as assess the long term effects of the nourishment, upon turbidity. In-situ measurements of turbidity and wave climate were obtained at two shore normal sites off the coast of Hollywood, Florida, from January, 1990 to April, 1992. The beaches adjacent to the communities of Hallandale and Hollywood were renourished during the summer of 1991. Thirty minute in-situ observations were recorded in burst mode every four hours at a frequency of four hertz. Analysis of the data resulted in descriptions of the wave climate as well as statistics of turbidity for each observation.