The U.S. Army Corps of Engineers guidelines require contaminant testing before disposal of dredged materials. If the material does not test positive for certain contaminants, it may be disposed of at upland locations or returned to a waterway to disperse freely in the current. Contaminated sediment disposal offers fewer options. The material can be placed in properly confined upland areas. Or, it may be placed in holes or cavities under water, then covered with clean material that seals the contaminants in place. This is considered a secure and cost-efficient disposal method.