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that it can be categorically dismissed from consideration. Put in different terms, 
there is no inherent effect or characteristic of an alternative that rules it out of con- 
sideration from a technical standpoint prior to specific on site evaluation. This holds 
true for open-water disposal, confirmed upland disposal, habitat development, or 
any other alternative. 
Specific on-site evaluations mean that each project must be considered on a case- 
by-case basis. It is not technically sound, for example, to make the general state- 
ments that ocean disposal must be phased out or that all material in the Great 
Lakes classified as polluted must be confined behind dikes. To do this would be con- 
trary to research results that have indicated that there can be situations where 
there is greater probability of adverse environmental impacts from confined disposal 
than from open-water disposal. Yet, in other situations such as when certain types 
of contaminants are present, confined disposal may provide the greatest amount of 
environmental protection. 
Implications of this conclusion from a management point of view are fully recog- 
nized. Case-by-case evaluations are time consuming and expensive and may serious- 
ly complicate advanced planning and funding requests. Nevertheless, from a techni- 
cal point of view, situations can be envisioned where tens of millions of dollars may 
have been or could be spent for alternatives that contribute to adverse environmen- 
tal effects rather than reduce them. 
The second basic conclusion is that environmental considerations are acting more 
strongly than possibly any force to necessitate long-range regional planning as a 
lasting, effective solution to disposal problems. No longer can disposal alternatives 
be planned independently for each dredging operation for multiple projects in a 
given area. While each project may require a different specific solution, the interre- 
lationships must be evaulated from a holistic perspective and thought given to when 
particular disposal alternatives may have to be replaced with others as conditions 
change. Regional disposal management plans not only offer greater opportunities 
for environmental protection ultimately at reduced project cost, but also meet with 
greater public acceptance once they are agreed upon. 
Considering first the specific findings with regard to the effects of open-water dis- 
posal, the physical effects—the logical and easily predicted physical effects—are 
with few exceptions more important than chemical or biological effects. Physical ef- 
fects include the smothering of a clam bed, the disruption of a flow pattern, a 
change in salinity, or a similar effect. These possible consequences of disposal oper- 
ations are persistent, often irreversible, and compounding. However, they are infre- 
quent and can be avoided with the judicious application of evaluative procedures 
available under guidance for the Section 404 and 103 programs. More intense evalu- 
ations of physical impacts traditionally have relied on physical hydraulic models, 
but the DMRP developed mathematical models that can also be used for certain 
needed predictions. Specifically, a partially verified and tested math model is now 
available to predict the short-term fate or dispersion of barge and hopper dredge 
dumped material as well as pipeline dredged material in ocean, estuarine, lake, and 
river environments. An unverified sediment transport model for the long-term and 
ultimate fate of these deposits is now available. 
Contrary to much public, scientific, and governmental opinion, the deep ocean, 
when analyzed in a detailed objective fashion, is not everywhere a fragile environ- 
ment totally unacceptable for dredged material disposal. A significant contract 
study concluded that, should the economic and technological aspects be favorable, 
extensive deep ocean areas are more environmentally acceptable for disposal than 
are aus highly productive continental shelf areas, especially for contaminated ma- 
terials. 
Turning to inland and coastal areas, the DMRP achieved definitive results that 
soundly substantiate that most widely held fears over the short-term release of con- 
taminants to disposal site waters are unfounded. As long as the geochemical envi- 
ronment is not basically changed, most contaminants are not released from the sedi- 
ment particles to the water. However, in contrast, upland disposal often does result 
in a change in the geochemical environment that can lead to contaminant release. 
Some nutrients such as ammonium and manganese and iron are released in open- 
water disposal, but in most cases enough mixing is present to rapidly dilute these to 
harmless concentrations. Situations where toxic effects could occur would most 
likely be where pipleline dredges are discharging large volumes of material into 
very shallow estuarine waters. 
The difficult problem of the effects of turbidity or suspended sediment particles on 
both water quality and aquatic organisms was addressed with significant results. It 
was found that, except in unusually environmentally sensitive areas such as coral 
reefs, turbidity is primarily a matter of aesthetic impact rather than biological 
