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about half of- the earth's surface is covered by ocean water 2000 or more 
meters deep. 
It would seem that a good case can be made for disposing of dredged materi- 
al of many types in the open ocean. Let us now examine why the ocean is so 
capable of assimilating dredged material and then we shall discuss what 
values are to be protected by using special care in the dredging/disposal 
process. 
OCEAN DISPOSAL APPEARS TO BE A GOOD SOLUTION 
On the basis of the above considerations, it is evident that the ocean can 
be a better receiving environment for dredged material than the land. Cer- 
tainly the ocean has a tremendous capacity for assimilating sediments with- 
out measurable ill effects. It has been receiving sediments from rivers 
for millenia. The amount of sediment that man will ever have to dispose in 
the ocean in a given year is but a small fraction of what it has been 
receiving annually via rivers. For instance, Holeman (1968) estimates a 
world annual river runoff of sediment of 18 billion metric tons. About 40 
percent of this is being carried by about a dozen major rivers, of which 
the largest by far is the Yellow River of China (Table 1). It may have 
come aS a matter of surprise that the Mississippi River transports on 
average some 0.3 billion metric tons of sediment to and beyond its delta 
each year. This amount approximates the total of material produced in one 
year by maintenance dredging in the entire USA. It is remarkable, there- 
fore, that between 20-25 percent of the total fish tonnage landed annually 
in the USA comes from the region around the Mississippi Delta where Shepard 
(1960) estimated much of the above sediment drops to the bottom. In view 
of this, it is difficult to believe that well-managed disposal of dredged 
material will seriously impact the marine environment. Even so, it is im- 
portant that we give consideration to the ocean values that we shall be 
able to protect from serious impacts by using extraordinary care in dispos- 
ing of some dredged material. 
