In suspension, fine grained sediment may shadow areas over a time span, which can be critical for the survival of light-depending benthic flora and fauna. It may also deposit in areas where deposition is unwanted, for instance harbour inlets. Furthermore, pollutants are prone to adhere to cohesive sediment. If deposited in ecologically sensitive areas, it may affect the local flora and fauna and water quality in general. MIKE 21/3 MT can be used to analyse the effect of sedimentation on vegetation, biology and sediment inhomogenity to mitigate these concerns.