FRACTAL GEOMETRY OF IN-SITU FLOCS IN THE ESTUARINE AND COASTAL ENVIRONMENTS

One- and two-dimensional fractal dimensions of in situ flocs were dete rmined from the dependence of the area and perimeter of projection of the flocs on their greatest length, using an underwater camera and ima ge-analysis system. Values for the fractal dimensions of flocs in the Elbe estuary and the North Sea varied among the samples: D-1 in the ra nge of 1.03 to 1.14 and D-2 in the range of 1.41 to 1.81. D-2 as obtai ned here represents the three-dimensional fractal dimension of flocs, which has been obtained in previous studies from the dependence of set tling velocity or porosity of flocs on their characteristic length. Co mparisons of environmental factors showed no relationships between the fractal dimension and fluid shear. Salinity effects on the fractal di mension were probably also insignificant in our samples. The relations hip of D-1 with the concentration of suspended matter was fairly convi ncing and suggests that the flocs had a rougher edge of projection at high than at low concentrations.