Measuring depth of water above layer of silt in e.g. river, by measuring depth position of body being moved along boundary between silt layer and water above it

摘要

A body (5) which is freely movable between a position in the water and a position in the silt layer is immersed in the water and then moved at a given speed in a direction parallel to the silt layer so that it adopts an equilibrium position at the boundary between the water and silt layers. The depth of the body at the equilibrium position is measured and the depth of the water is determined on the basis of this depth position. The body is moved by towing it with a cable from a boat and includes a hydrofoil (7) for generating a lift and a keel (8) for stabilizing the body as it is towed through the water. The depth position is measured using a pressure sensor.