Over half the domesticfreight movements, such as this coal laden tow,
carry energy related commodities.
develop attractive recreational areas. On the negative side,
this method of disposal causes a short-term increase in water
turbidity at the discharge point for a short period, tem-
porarily disrupts the local biotic community, and tends to
About 1/3 of our waterway commerce originates or terminates in foreign
cause shoaling which can interfere with lateral drainage and
countries.
natural flows. In regard to the affected biotic communities,
we are aware that changes do take place, but thestate-of-the-
art does not yet permit us to evaluate these changes quan-
titatively with any degree of accuracy.
This inland disposal problem is in sharp focus in the upper
Mississippi River, where off-channel disposal is used exten-
sively. The Corps has maintained navigability of this area
since 1922 by congressional direction.
Maintenance dredging in the channel, along with natural
accretions, has created a series of small islands which act to
reduce the water surface, to narrow existing wetlands and, in
some cases, to cause shoaling. This has caused back channel
drainage problems. As a result, our disposal techniques have
come under sharp criticism from environmental interests in
the adjacent States, where court injunctions have prohibited
all but emergency dredging.
Ocean and other forms of open-water disposal have always
appeared environmentally acceptable and this method has
been used for many years. It avoids disruption of all the
natural values in the coastal zone, including estuaries and
wetlands. Further, the disruptive influence it has in the dis-
charge area is so small in comparison to the vast and
dynamic influence of the surrounding waters that the net
effect should be minimal. On the other hand, some marine
scientists contend that the long-term cumulative effects of
ocean water disposal could have serious adverse conse-
WATER SPECTRUM
Previous Page
