461 
To accomplish this objective simply involves establishing several release 
points within the dumpsite. The polluted dredged material is then released 
for, say, three days or so at release point No. 1, then at No. 2, etc. un- 
til the polluted material has been dredged out of the harbor. This in- 
series dumping will permit the longshore current to carry the finest part 
of the dredged material across the site without materially affecting adja- 
cent release points. Meanwhile the organisms downstream of release point 
No. 1 are able to depurate before accumulating large quantities of serious 
pollutants. fi 
The rest of the procedure involves the location and time sequence of the 
dredging process. As shown in Figure 7, the first dredging is done around 
docks or near point source releases of pollutants where "hot" sediments 
will occur (H in Figure 7). This enriched material is then dumped in 
series at the release points, while the dredging continues down the channel 
toward the harbor mouth where generally the sediments should be relatively 
clean (C in Figure 7). This clean material is then dumped in series at the 
release points with sufficient precision to accomplish a normal capping 
operation. 
A Theoretical Example 
¢ 
There are no known examples of this modification of the CMC approach. For 
purposes of exemplification, consult Figure 7 and note that the dumpsite 
has six release points that are 1.25 nautical miles from each other and 
from the dumpsite's side boundaries. The longshore current is flowing 
about parallel to shore at a rate of 0.1 knots. Since a 1 kt current 
covers 1 n mile in an hour, it will take a 0.1 kt current 12.5 hours to 
carry sediment to the site's downstream boundary. Thus, much of the 
material will have settled to the bottom within the site. If we assume 
that the dredging of the contaminated parts of the channel and turning 
basin take 18 days, then organisms downstream of any given release point 
will have been exposed to fine material for only 3 days rather than 18 if 
