PART III: DATA ANALYSIS AND RESULTS 



25. The behavior of New Bedford Harbor sediments at slurry concentra- 

 tions equal to those expected for inflow to a confined site is governed by 

 zone settling processes. As expected for saltwater conditions, the sediments 

 exhibited a clear interface between settled material and clarified superna- 

 tant. The settling test data were analyzed using the Automated Dredging And 

 Disposal Alternatives Management System (ADDAMS) (Hayes et al. , in prepara- 

 tion) . This system is a family of computer programs developed to assist in 

 planning, designing, and operating dredging and dredged material disposal 

 projects. 



Compression Settling Tests 



26. For the compression tests, the initial slurry concentration and 

 and the height and depth to interface versus time were entered (Tables 1-3) . 

 The ADDAMS program uses the initial slurry concentration and height to deter- 

 mine the solids concentration at a given time. A plot is generated showing 

 the relationship between solids concentration (grams per litre) and retention 

 time (days) . The ADDAMS also develops a regression equation for the resulting 

 power curve relating solids concentration to time. Regression equations for 

 the hot spot, upper estuary composite, and potential capping samples are as 

 follows: 



_ T 0.1097 

 C HOT ~ 178 T 



where 



C = solids concentration, g/ H 

 T = time, days 



27. Slopes of the solids concentration versus time curves for all three 

 sediment samples were similar (Figure 2). However, the solids concentration 



13 



