CASI data utilized for mapping suspended matter concentrations in sedimentplumes and verification of 2-D hydrodynamic modelling

A combined tunnel and bridge between Denmark and Sweden, The Oresund Link, is presently under construction (1995-2001). The dredging spills and enviro nmental effects are monitored continuously. The monitoring involves the sim ulation of suspended matter concentrations in sediment plumes from dredging operations using 2-D hydrodynamic modelling (MIKE 21 PA/MT). A Compact Air borne Spectrographic Imager (CASI) acquisition was used to map suspended ma tter concentrations in a plume from 10 June 1997. Suspended matter concentr ations were in the range of 1-30 mg l(-1) with background concentrations ar ound 1-3 mg l(-1), while concentrations in the plume were 3-30 mg l(-1). A map of suspended matter concentration was derived from an empirical algorit hm between in situ irradiance reflectance at 550 nm and suspended matter co ncentration determined from water samples taken both inside and outside the plume. The map was used to verify the results derived by the 2-D hydrodyna mic model. A comparison of the concentration variations derived using the t wo methods presented here shows a reasonable agreement, in spite of the fac t that the remote sensing data have far more spatial details than the MIKE 21 simulation.