The present invention relates to an installation for dredging or deepening a bottom in or of a body of water. The installation comprises: at least one float (2); a dredger crane (8) or a suction pipe; and a screen which in use can be positioned adjacently of an operational area of the dredger crane (8) or the suction pipe or at least upstream thereof relative to a flow direction in or of the body of water, and in use prevents the dispersal of bottom material dislodged during dredging with the dredger crane (8) or suctioning with the suction pipe or deepening of the bottom. The float (2) is selectively lowerable and dimensioned to be lowered onto or into the bottom of the body of water, and in lowered position forms the screen.