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Woods Hole Gr UP <br /> 4A.2 Sediments <br /> Sediments within the {project site have been analyzed tough a detailed sediment <br /> sampling and anaiysis program. A. sediment sampling plan was developed by the VMC <br /> and approved by the Massachusetts Department of Environmental Protection (DEP) and <br /> the US Array Corps of Engineers (USAGE) in November 2000 (Section 7.0 . This <br /> sampling plan called for the collection and analysis of teen 1 sediment cores to the <br /> depth of proposed dredging,plus one foot of allowable oerdepth dredging for a total of— <br /> 4 ft MLW. <br /> The sediment cores were collected on December 13, 2000 using a push core system <br /> operated from a boat. The boat was equipped with a DGPS and a water depth recorder so <br /> that the core locations and elevations could be recorded. A. total of 10 cores were <br /> collected in the locations shown in Figure 7. The cores were stored on ice and brought <br /> back to the WG for sub-sampling. Detailed logs were recorded fpr each core, showing <br /> the sediment type and elevation(Figure 8 . Representative sections of cares 2,4,6,8, and <br /> to were sampled to ft MLW for laboratory analyses of VOCs. All other sampling <br /> was conducted by collecting composite samples From two adjacent cores to—4 ft MLW. <br /> Thus,composite samples from.cores 1 and 2,3 and 4, 5 and 6,7 and 8, and 9 and 10 were <br /> collected for grain size and chemical testing. Duplicate samples were collected in each <br /> case;one sample for analysis and one sample for archive. <br /> Laboratory results from the grain size analyses are included in Section 5.1 and <br /> summarized in Table 1. The data show that the Mashpee River sediments from Stations <br /> 0+00 to 30- 00 (Cores 2, 4, and and Station 9+00 to 50. 50 (Core 1 are primarily <br /> fine-grained, containing less than 10 % sand, and more than 90% silts and clays. <br /> Sediments in the Vicinity of Stations 37+00 to 41+00 (Core are coarser, containing <br /> approximately 55%sands and 45%silts and clays. <br /> TABLE L <br /> SUMMARY of GRAIN SIZE ANALYSES FOR MASHPEE RIVER <br /> SEDIMENTS, <br /> % Coarse % Medium Flo Fine <br /> Core No. Sand Sand Sana %Silt %Clay <br /> 2 0.00 1.61 4.84 55.55 38.00 <br /> 4 0.00 0.98 2.42 56.09 40,50 <br /> 0.00 2.42 5.87 55.71 36.00 <br /> 0.25 21.42 34.22 19.61 24.50 <br /> 10 0.00 1.14 4.33 38.53 56.00 <br />