476 
Environmental Soundness 
One outstanding advantage of these island pits is absence of the fear of 
ground water contamination. The islands could also serve as excellent open 
habitat for many birds, such as the Least Tern that nest in sand, whose 
former breeding grounds are being overrun by man. The part of the island 
bearing plant cover would provide habitat for various other species of sea 
birds. 
Obviously, the islands would have to be sized and positioned so as to not 
interfere with navigation and with the normal longshore water circulation. 
Also, careful positioning and thoughtful design should preclude the chance 
of their being washed out. 
DISPOSAL BELOW THE ZONE OF MAXIMUM PLANKTON PRODUCTIVITY 
Description of the Technique 
In areas where disposal of dredged material must be carried out during 
periods of maximum phytoplankton production, it should be possible to 
ameliorate impacts by shunting dredged material below the zone of maximum 
production. 28 
As noted earlier, the lower part of this zone in temperate regions is no 
deeper than 15 or so meters. It may be feasible to pipe material for that 
depth from a sea-going barge. 
SPECIAL CARE DREDGING MEASURES 
PUMPING FROM HOPPER DREDGES TO SEA-GOING BARGE 
When hopper dredges are used more environmental concern is expressed over 
the dredging than the disposal process. This is due to the great amount of 
fine material released as the hoppers are overfilled in order to obtain as 
much sediment per shipload as possible. The turbid slurry that overruns 
