INTRODUCTION 



BACKGROUND 



Assessing the impacts of navigational dredging and the disposal of 

 dredged material is a controversial exercise; the viewpoints and approaches 

 are endless. Without question, dredging can devastate fish and wildlife 

 resources; however, in the absence of definitive information, impacts are 

 sometimes more imagined than real. The attempt of this review is to bring 

 some order to the situation by summarizing the pre-1973 literature and the 

 results of new research since 1973. The chief source of the new information 

 is the Dredged Material Research Program (DMRP), a 5-yr Army Corps of Engi- 

 neers program that began in 1973. This program was administered by the U.S. 

 Army Engineer Waterways Experiment Station (WES), Vicksburg, Mississippi. In 

 addition to the DMRP, other recent significant studies have been included in 

 this review. A partial list includes: 



a. Report, International Working Group on the Abatement and Control of 

 Pollution from Dredging Activities. 1975. 



b. Impacts of Construction Activies in Wetlands of the U.S. United 

 States Environmental Protection Agency. 1976. 



c. Dredging and Its Environmental Impacts. American Society of Civl 

 Engineers. 1976. 



d. Dredging in Estuaries, a Guide for Review of Environmental Impact 

 Statements. Oregon State University. 1977. 



e. San Francisco Bay and Estuary Dredging Disposal Study, Corps of 

 Engineers, San Francisco District. 1974 through 1979. 



Boyd et al . (1972) summarized the state of knowledge and unanswered ques- 

 tions just before the beginning of the DMRP in 1973. In addition, one of the 

 better compilations of the older literature was a thesis by James W. Morton 

 which was later published (Morton 1977) by the United States Fish and Wildlife 

 Service (FWS). This report includes most of the literature through 1974 and a 

 portion of the 1975 literature, providing good coverage of dredging impacts in 

 marine waters, but containing little information on impacts to freshwaters. 



In our review we compared the recent (1973 to 1979) literature with the 

 older literature and, if sufficient information was available, we attempted to 

 form a consensus about dredging and disposal impacts on the basis of the 

 available information from both periods. Unless the authors listed in the 

 Literature Cited sections are cited or are directly quoted in the text of this 

 document, the opinions expressed are our own. This literature review is not 

 meant to reflect FWS policy. 



CONTENTS 



A brief sketch is provided about dredging equipment currently used in the 

 United States or potentially available for use (Part I). The type of equipment 

 used determines, to a great extent, the viable disposal alternatives, the type 

 and magnitude of potential impacts, and the potential for habitat development. 

 A brief discussion of characteristics of dredged material is provided in Part 

 II. Characteristics of the material to be dredged strongly influences the 

 available disposal alternatives and pollution potential. 



