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3.7 Sediment Coring Collection 



3.7.1 Royal River Survey 



Thirty vibracores (RR-1 through RR-30) were collected in the Royal River in 

 August 1995 from the base of the falls at the Interstate-95 highway overpass to Parker 

 Point (Figure 2-4). The cores provided deep cross sections of the material to be dredged 

 from the Royal River (Table 3-3). Sediment cores were collected to a depth of 

 approximately 2.5 m with a custom, concrete compactor-type vibracore unit, deployed 

 from a shallow draft vessel. The sediment core was retained within a rinsed polyethylene 

 core liner, capped, and stored vertically during field operations. Twice a day, cores were 

 transported from the vessel to refrigerated storage containers on shore. Following the 

 survey, the cores were relocated to a refrigerated storage facility at the University of 

 Rhode Island's Graduate School of Oceanography (GSO), and stored for later analysis. 



SAIC processed the Royal River vibracores at the GSO coring laboratory in 

 September 1995. Core liners were split lengthwise using a hydraulic core splitter, and 

 nylon wire was used to divide the sediment samples. One-half of each core was 

 photographed, visually described, and archived for potential future analyses. A subset of 

 eleven core halves were selected and sampled for use in the identification of tracer 

 components for the Portland Disposal Site Capping Demonstration Project. Sediment 

 samples were collected from Cores RR-7, RR-8, RR-10, RR-12, RR-15, RR-18, RR-21, 

 RR-22, RR-26, RR-28, and RR-29. The composited sediment samples were placed in a 

 70% methanol/seawater solution. After the meiofauna had been preserved, the samples 

 were washed, sieved, and dried. Eleven samples containing the fine fraction, particles 500 

 /xm to 63 jLtm in size, were sent to the Micropaleontology Laboratory at Wesleyan 

 University. 



3.7.2 Postcap Survey 



As part of the January 1997 CDM survey over the Royal River Project Area, nine 

 gravity cores were collected to verify the presence of a pseudo-UDM/CDM interface 

 within the capped mound (Figure 3-6). Nine stations were selected over the project area 

 based on the pattern of pseudo-UDM accumulation (Table 3-4). The target location for 

 Core A was established over the PDA 96 buoy position. The remaining core locations 

 were strategically placed relative to the morphology of the pseudo-UDM deposit. Cores E 

 and G were situated over the thicker portions of the mound. Cores D and F were located at 

 the margins of the detectable mound, and Cores B, H, and I sampled the apron of the 

 deposit. Core C was collected away from the accumulation of Royal River pseudo-UDM 

 to characterize the thin strata of dredged material, as well as to ensure penetration into 

 ambient sediments. 



The Portland Disposal Site Capping Demonstration Project, 1995-1997 



