42 



all disposal projects, regardless of the 

 bulk chemistry results. 



Box 3.2 



"Mound Covered?" 



Immediately following completion 

 of a capping operation, physical 

 monitoring is conducted to assess 

 compliance, i.e., has the mound been 

 capped completely with a specified 

 thickness of capping material? This 

 evaluation typically involves a 

 precision bathymetric survey possibly 

 combined with a sub-bottom profiling 

 survey (project conditions usually 

 require a cap thickness of at least 50 

 cm, which is well within the resolution 

 of acoustic measuring techniques). If 

 necessary, the REMOTS® camera can 

 be used to map cap thickness on the 

 mound flanks when the capping 

 material has textural or optical 

 properties (grain-size or reflectance) 

 that are unique from the underlying 

 disposed material. If the cap meets 

 both the thickness and coverage 

 criteria, post-disposal trend monitoring 

 begins in Box 3.4. 



Box 3.3 "Add More Capping Material" 



If the capping operation has failed 

 to cover all of the disposed material 

 with the designated minimum 

 thickness, further capping operations 

 are necessary. This may involve the 

 use of the same capping material as 

 initially used, or the NED may identify 

 another "project-of-opportunity" to 

 complete the capping project. Once 

 the recapping has been completed, the 

 mound is revisited to assess 

 compliance (Box 3.1). If recapping is 

 successful, trend monitoring begins 

 (Box 3.4) 



Box 3.4 "Assess Population Density of 



Stage 1 Organisms ... " 



This task would be carried out 

 exclusively with REMOTS® technology 

 as before because of the quick data 

 return and relative cost savings over 

 traditional monitoring techniques. See 

 the explanation in Box 2.1 in the 

 previous section for further details. 



Box 3.5 "Stage 1 Population Density 



Greater Than References?" 



Once again, the predicted response 

 of ecosystem recovery following the 

 cessation of capping operations would 

 be the colonization of the area by 

 dense assemblages of Stage I 

 pioneering polychaetes. The unstated 

 null hypothesis being tested is: 



H : The population density of 



opportunistic polychaetes on the 

 disposal mound as detected in 

 REMOTS® photographs is not 

 less than that on the ambient 

 seafloor outside the disposal site 

 boundaries. 



Acceptance of the null hypothesis 

 would lead one to Box 3.10; rejection 

 of the null hypothesis would lead to 

 Box 3.6. Other considerations for this 

 particular step are similar to those 

 discussed in the previous section for 

 Box 2.2. 



Underlying Assumptions : If 

 capping has been carried out by 

 placing medium or coarse sand over a 

 silt/clay contaminated mound in an 

 area that is predominantly a muddy 

 seafloor, one would expect to see a 

 different recolonization pattern 



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



