This paper presents the findings of laboratory and field studies undertaken to assess the feasibility of in situ management of contaminated sediments in Port Hope harbor. The contaminated sediments stem from historic releases from an adjacent radium and uranium refinery, and uranium, arsenic, and radium are the most abundant contaminants. With improved emission controls, currently accumulating sediments have much lower levels of contamination, and the harbor waters currently meet water quality limits for the contaminants of concern. Within a few years, however, the continuing sedimentation will render the harbor unusable. Field tests have confirmed that dredging will result in incomplete removal of the contaminated sediments and that sediment suspension and the release of pores waters during dredging will produce harbor water contaminant concentrations that would require the treatment of large volumes of water. In addition, no remedial work can start until a site for the dredged material can be found. The local community inquired whether in situ burial of the sediments and abandonment of the harbor would provide safe disposal. Removing the sediment by conventional dredging methods would leave approximately 5% of the contaminants in the harbor and result in possible mobilization of the contaminants so that a method of further isolating the contaminants in place is investigated. The use of a geotextile (filter fabric) is central to the concept of being able to consolidate the sediment in place by decreasing the water content of the sediment during the application of fill material while confining the contaminated sediment.