The subsoil dredge is a dredge which removes the sand underneath a soft top layer. This way of dredging leaves most of the top soil undisturbed. Therefore the subsoil dredge leaves living organisms undisturbed and also contamination of the soil are retained at there location. When the dredge is used to remove the sand underneath the top layer a portion of the sand can be placed back on top to improve bottom structure. For peat soil the sand placed back on top immobilizes the peat and improving water quality.