cost varies over a wide range and is 

 rising steadily. The dredging and dis- 

 posal cost is highest in New England, 

 nearly $5/yd 3 . The cost in the Lower 

 Mississippi Valley is lowest, just under 

 SCMO/yd 3 . Note that this is an inverse 

 situation from the total amounts of 

 dredged material listed above. Thus, the 

 scope of the problem, in an economic 

 context, does not correlate proportion- 

 ately to the quantities. In some loca- 

 tions, the cost has risen to over $10/ 



yd 3 . 



The tremendous range of dredging 

 and disposal costs is due to several 

 factors. A large percentage of dredged 

 material is fine-grained sediment and, 

 as a consequence, it is a natural sink 

 for contaminants resulting from urban 

 and agricultural runoff, domestic and 

 industrial sewage, and other polluting 

 sources. Sediments dredged from water- 

 ways once were most commonly disposed of 

 in open water or on marshes. But now, 

 because of some known consequences of 

 dredging and disposal, and a concern 

 over the unknown consequences of such 

 actions, the general practice has been 

 to confine contaminated materials on 

 land behind dikes. In many areas, this 

 has increased the cost of the operation 

 by a factor of at least 10. 



In 1970, Congress passed legisla- 

 tion that called for an interim 10-yr 

 program of building confined disposal 

 facilities to retain all contaminated 

 material from the harbors in the Great 

 Lakes. With the anticipated cost of 

 this program for this one region of the 

 U.S., estimated at approximately a quar- 

 ter of a billion dollars, Congress rec- 

 ognized a need to understand far better 

 what are truly the environmental effects 

 of dredged material disposal. Conse- 

 quently, the same legislation that man- 

 dated the Great Lakes diking program in- 

 cluded authorization for a comprehen- 

 sive, nationwide research program to 

 provide much needed answers. Hence, the 

 DMRP was established as a multi-objec- 

 tive research plant that would require 5 

 yr and $30 million to complete. The 

 program began in 1973 and was completed 

 in March 1978. 



Insofar as environmental effects 

 are concerned, the DMRP is as concerned 

 with disposal in upland and wetland 

 areas as it is with open-water disposal. 



It is concerned with the productive use 

 of both the dredged material and the 

 disposal sites. Principal emphasis is 

 on marsh and habitat development as the 

 most promising productive or beneficial 

 disposal alternatives. Realizing that 

 confined land disposal is a viable al- 

 ternative, the DMRP is concerned with 

 improving the effectiveness, acceptance, 

 and environmental compatibility of con- 

 fined disposal and making it more econo- 

 mical. The program has been divided into 

 four project areas: the Environmental 

 Impacts and Criteria Development Project, 

 the Disposal Operations Project, the 

 Productive Uses Project, and the Habitat 

 Development Project. I will briefly 

 touch on the first three projects and 

 then proceed to a more detailed discus- 

 sion of the Habitat Development Project. 



ENVIRONMENTAL IMPACTS AND 

 CRITERIA DEVELOPMENT PROJECT 



The Environmental Impacts and Cri- 

 teria Development Project is the focal 

 point for research about the effects on 

 water quality and aquatic organisms of 

 both land and open-water disposal as 

 well as land containment of dredged 

 material . 



Aquatic Disposal Field Investiga- 

 tions are a principal concern of this 

 project. Four major field investigations 

 of the physical, biological, and chemi- 

 cal impacts of open-water disposal are 

 being conducted in the Pacific Ocean off 

 the mouth of the Columbia River, Oregon; 

 the Gulf of Mexico off Galveston, Texas; 

 Lake Erie off Ashtabula, Ohio; and an 

 estuarine site near the Duwamish Water- 

 way in Elliott Bay, Seattle, Washington. 

 To date, the baseline research and con- 

 trolled disposal investigations are com- 

 pleted and the post-disposal monitoring 

 is currently underway at all four sites. 



Another concern of this project is 

 the short- and long-term movements of 

 dredged material in open water. A math- 

 ematical estuarine dispersion model has 

 been developed and is presently being 

 field verified. The objectives of the 

 field study are to quantitatively define 

 the physical processes by which dredged 

 material released from a barge, hopper- 

 dredge, or pipeline is conveyed to, and 



119 



