The Portland Disposal Site (PDS) is located in the waters off the coast of Maine. It
covers a 3.4 square kilometer (1 square nautical mile) area of the seafloor centered at 43° 34.105' N, 70° 01.969' W (NAD 83), approximately 13.2 kilometers (7.1 nautical miles) east of Dyer Point, Cape Elizabeth, Maine. The topography at PDS is characterized by a rough, irregular bottom, a prominent northwest-southeast trending trough, and areas of soft sediment accumulation in the basins among bedrock outcrops. Water depths across the site range widely, from 37 to 71 meters (121 to 230 feet). The various bedrock ridges surrounding deep basins provide a measure of protection from wave energy and subsurface currents, and thus act to contain the deposited dredged material. Dredged material disposal operations have specifically targeted these natural basins to enhance containment of dredged material.

Additional information about the monitoring and management of PDS, including the current Site Management and Monitoring Plan (SMMP), can be found on the EPA Region 1 Ocean Dumping web page.