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Routine physical monitoring 

 (repetitive precision bathymetric and 

 REMOTS® surveys to map the physical 

 shape, areal extent, and long-term 

 stability of the disposal mounds) 

 occurs at all the active disposal sites on 

 an annual basis. These activities serve 

 as both compliance monitoring (e.g., to 

 verify all material is within the 

 designated site boundaries and 

 adequate operational control of 

 disposal has been achieved by 

 dredging contractors) and model 

 verification (e.g., mound height, areal 

 extent and long-term stability are as 

 predicted by Corps of Engineers' 

 numerical models). It was the trend 

 monitoring addressing the short and 

 long-term biological resource impacts 

 that was the main focus of the TAC's 

 activities. 



The primary vectors for adverse 

 impacts to organisms at dredged 

 material disposal sites are physical and 

 chemical alterations to the native 

 sediments or the water column. Both 

 of these vectors can be of concern 

 when dredged sediment is involved, 

 because the grain size of the sediment 

 may represent either a very different 

 bottom type than that of the region 

 around the disposal site, or the 

 sediment may contain contaminants 

 that are either acutely or chronically 

 toxic or can be biologically 

 accumulated and transferred within 

 the food web. In these instances, the 

 management objectives are to contain 

 sediments and isolate any associated 

 contaminants within the disposal site 

 so that they are not available to 

 biological organisms in quantities 

 sufficient to cause adverse effects. 



The biological impact component of 

 most monitoring programs often has 

 provided very little information that 

 could be applied directly to the 

 formulation of disposal management 

 decisions. This is not necessarily 

 because the monitoring programs did 

 not or could not detect changes in the 

 environment, but because it was 

 unclear whether detected changes 

 indicated adverse conditions or not. 

 As emphasized earlier, monitoring 

 programs also have failed in many 

 other ways, including lack of clear 

 objectives, inadequate sampling 

 designs, etc. Our objective was to 

 overcome these common inadequacies 

 and address the disposal-related 

 environmental (biological) impacts 

 through a tiered monitoring approach. 

 The steps necessary to achieve this end 

 were: (1) identifying the resources to 

 be protected (being as specific as 

 possible); (2) predicting the processes, 

 specific magnitudes, and areal extent 

 of change that would be necessary to 

 bring about an impact; (3) 

 incorporating monitoring tools with a 

 rapid data return so that field results 

 could be used to make management 

 decisions; and (4) recognizing there are 

 limited resources and a need to 

 develop the most parsimonious 

 monitoring plan. 



It was recognized early on that 

 developing specific categories of what 

 were or were not adverse effects would 

 be a difficult and probably impossible 

 task. This was because of the infinite 

 combinations of situations that could 

 be envisioned, and because of the 

 diversity of scientific opinions that 

 subjectively would judge each 

 condition. Certainly it would be 



An Integrated, Tiered Approach to Monitoring and Management of Dredged Material Disposal Sites 



