1.0 INTRODUCTION 



The Portland Disposal Site (PDS) is located in Bigelow Bight, 7.1 nmi east of Dyer 

 Point on Cape Elizabeth, Maine (Figure 1-1). It is one of ten regional dredged material 

 disposal sites in New England managed by the US Army Corps of Engineers, New England 

 Division (NED), as part of the Disposal Area Monitoring System (DAMOS) Program. The 

 Portland Disposal Site was first used for the disposal of dredged material in 1979. Since 

 then, it has been periodically monitored as part of the DAMOS Program. The site is a 1 nmi 

 square with sides running true north-south and east-west, centered at 43°34.100' N, 

 70°02.000' W, North American Datum 1927 (NAD 27). It is characterized by a flat, sandy 

 valley, surrounded by rocky outcrops. Water depths range from 42 m on the hard rock 

 ridges to 64 m in the valleys. 



In January 1989, a bathymetric survey and a REMOTS® survey were conducted at the 

 site. From January 23, 1989 to November 15, 1990, 14,810 m 3 of dredged material was 

 released near the PDS buoy location (43°34.270' N, 70°01.968' W). Most of this material 

 came from the Portland International Terminal and the Royal River Boatyard. On 

 January 31, 1989, one barge load of material (412 m 3 ) was recorded as being released at 

 43°34.100' N, 70°01.900' W. The next series of disposal events, from March 18 to 

 April 30, 1991, (6,193 m 3 ) was also released near 43°34.100' N, 70°01.900' W. 

 Navigational charts and the USCG light list do suggest that a buoy may have been at that 

 location during these disposal events. 



In October 1991 a capping project was begun at PDS. This project at PDS set a 

 precedent among DAMOS capping projects since the water depths at the site are much 

 greater than 20 m (20 m is the average water depth for Long Island Sound sites). From 

 October 1991 through January 1992, 13,270 m 3 of material that was determined to be 

 unsuitable for unconfined open ocean disposal was released at or near the buoy 

 (43°34.270' N, 70°01.968' W). One barge load of this material (625 m 3 ) was reported 

 released at 43°34.100' N, 70°01.900' W on November 8, 1991. All material unsuitable for 

 unconfined open water disposal came from the US Coast Guard (USCG) project in South 

 Portland and consisted of 75-86% silt/clay contaminated with moderate to high levels of 

 metals. 



In January 1992, Science Applications International Corporation (SAIC) conducted 

 postdisposal, precapping bathymetric, and REMOTS® surveys at PDS for C&B Marine. The 

 results of these surveys were used to map the location of the dredged material and to 

 determine disposal points for subsequent cap placement. 



Capping began in January 1992 and was completed in June 1992. The cap material 

 (37,761 m 3 ) consisted of fine-grained material from other portions of the USCG project 

 (19,451 m 3 ) and sandy material (70-86% sand) from the Northeast Petroleum project 



Monitoring Cruise at the Portland Disposal Site, July 1992 



