area's finfish, have apparently not been altered at stations where large 

 amounts of spoil are not present. 



112. MORTON, J.W., "Ecological Impacts of Dredging and Dredge Spoil Disposal: 

 A Literature Review," M.S. Thesis, Cornell University, Ithaca, N.Y., 

 1976. 



A comprehensive review of literature on the physical, chemical, and bio- 

 logical impacts of dredging and spoil disposal in estuaries and the identifi- 

 cation of alternative spoil disposal methods is presented. Although direct 

 burial and habitat destruction are the most obvious biological impacts of 

 dredging and dumping, these impacts can be minimized by careful timing and 

 placement of the dredging and disposal operations. A critical problem requir- 

 ing further study is the uptake, accumulation, and recycling of contaminants 

 associated with polluted dredge spoils by marsh vegetation, phytoplankton, 

 zooplankton, benthos, and fish. 



113. MORTON, J.W., "Ecological Effects of Dredging and Dredge Spoil Disposal: 

 A Literature Review ," Teohniaal Papers of the United States Fish and 

 Wildlife Service, No. 94, 1977. 



This study is a comprehensive review of the literature on the physical, 

 chemical, and biological effects of dredging and spoil disposal in estuaries 

 and identifies alternative spoil disposal methods. The specific objectives 

 were to identify the most critical problems relating to dredging and spoil 

 disposal and to summarize the progress made to date. 



An important physical effect of dredging and open-water spoil disposal 

 is the alternation of circulation patterns. A second important effect is the 

 uncontrolled redistribution of sediments. Changes in the chemistry of the 

 sediments at the dredging and disposal sites and of the water overlying these 

 areas are likely to result from dredging and dumping. Although direct burial 

 of organisms and destruction of the habitat are the two obvious biological 

 effects of dredging and dumping, the effects can be reduced by careful timing 

 of the dredging and placement of the spoil. 



114. MORRIS, L.A., et al . , "Effects of Main Stem Impoundments and Channelization 

 Upon the Limnology of the Missouri River, Nebraska," Transactions of the 

 American Fishery Society, Vol. 97, No. 4, Oct. 1968, pp. 380-388. 



Rigid control has been imposed on the Missouri River by impounding more 

 than one-half of the upper 1,500 miles and by channeling most of the remaining 

 river within permanent, narrow banks. These controls have caused environmental 

 changes in the lower Missouri River of adjacent, unchannelized and channelized 

 sections of river below the main stem impoundments. Impoundments have regulated 

 flow discharges and improved the downstream water quality. In addition, the 

 impoundments have contributed a limnetic cladoceran, Leptodora kindti , to the 

 drift and have affected the distribution of benthos through the modification 

 of turbidity. 



Channelization of the river has reduced both the size and variety of the 

 aquatic habitat by destroying key productive areas. The average standing 

 crops of benthos were similar in the unchannelized and channelized river, but 

 the benthic area was reduced 67 percent by channelization. There was little 



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