Dewatering and crust management of confined disposal areas in Galveston Bay, Texas

This paper discusses the technical and economic issues involved in the management of fine-grained maintenance dredging materials in confined, upland disposal areas. An essential part of a crust management program consists of the creation of a network of trenches on the surface of the placement area in order to expedite the removal of precipitation and to maximize evaporation of water from the dredged material. The dried material is used to raise the containment dikes. Four important benefits result from such a program: 1. Site volume is maximized by the evaporation of water from the dredged material. Desiccated material will typically have a volume in the placement site of less than 50 percent of its in-situ channel volume. 2. Dried dredged material is an economical source of material for raising containment dikes. 3. New upland disposal areas at a 50 million cubic meter scale have been built in the past decade for about $1 per cubic meter. Currently sites are likely to cost up to $5 per cubic meter. 4. Possibly more important than cost savings resulting from the changed management practice is the fact that the life of almost irreplaceable sites site is increased by allowing a greater volume of dredged material to be placed below a given dike elevation