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The fine fraction of the sediment had the most promising set of tracers. Overall, 

 the biological indicators were statistically more robust than the mineralogical 

 indicators. 



The statistical analyses showed that tracers successfully identified disposed 

 dredged material layers taken from different regions of an esmary, but material 

 from the middle reach had many overlapping characteristics that complicated the 

 interpretation. 



The overlap of the pseudo-UDM and CDM samples collected in cores and grabs 

 from the disposal mound in statistical analysis was consistent with the sequence 

 of disposal operations. 



Because historical dredged material shares biological characteristics with both 

 native, ambient sediment (recolonization by benthic species, settling of 

 planktonic species), and with recent dredged material (presence of freshwater 

 species), it theoretically can be identified. Limiting the presence of historical 

 dredged material in a project area, however, would decrease the possibility of 

 inaccurate identification. 



The tools used for the Royal River project each proved useful for different types 

 of analysis; single-beam bathymetry was noted to be the most problematic due to 

 the complex topography of the survey area. 



Overall, the Portland Disposal Site Capping Demonstration Project demonstrated 

 that dredged material can be effectively placed, capped, and monitored at a deep 

 water site. 



The Portland Disposal Site Capping Demonstration Project, 1995-1997 



