Dewatering Bags are used for collecting silt and debris from water being pumped from ditches, runoff collection ponds, and drilling before it is allowed to leave a construction site and are designed to replace expensive retention basins and to hasten the dewatering process. Dewatering bags are the most effective when there is not a good open pit solution. This method allows the material to be pumped into bags which retain the sediment but allow the water to exit and return to the source clean.