BENTHIC FAUNA OF AN OFFSHORE BORROW AREA 

 IN BROWARD COUNTY, FLORIDA 



by 

 David B. TuTbeville and G. Alex Marsh 



INTRODUCTION 



Beach erosion is a serious problem nationwide, with approximately 

 43 percent of America's shoreline, .excluding Alaska, undergoing 

 significant loss (Callahan, 1980). In southeastern Florida, more than 

 half of the 166.8 kilometers of recreational beach in Palm Beach, 

 Broward, and Dade Counties is listed by the Florida Department of 

 Natural Resources as being in a "critical state of erosion" (Marsh, 

 1980). This problem has necessitated periodic beach restoration and 

 maintenance projects, generally involving the dredging of sand from 

 offshore deposits called borrow areas. Sand from a borrow area is 

 pumped through pipes onto the beach and bulldozed in place. Although 

 many feel that the millions of dollars spent each year in southern 

 Florida to restore degraded beaches are not cost effective since the 

 sand will be lost eventually, others feel that the economic benefits 

 through increased tourism and protection from storm and hurricane surge 

 justify the expense. 



Numerous studies have been conducted on the environmental effects 

 of dredging and filling, although most of the research has centered on 

 bays and estuaries. In Florida, the Tampa and Boca Ciega Bay areas 

 have been studied extensively for the effects of oystershell dredging, 

 canalization, and landfilling (Taylor and Saloman, 1968; Taylor, Hall, 

 and Saloman, 1970; Saloman, 1974; U.S. Army Engineer District, 

 Jacksonville, 1974; Simon and Doyle, 1974a, 1974b; Simon, Doyle and 

 Conner, 1976; Conner and Simon, 1979). 



Relatively little research has been conducted on the environmental 

 impact of offshore dredging for beach restoration. Cronin, Gunter, and 

 Hopkins (1971) reviewed potential effects of various engineering 

 activities, including dredging, on coastal ecosystems, but included no 

 quantitative data in their report. They felt that, "In many, perhaps 

 most, coastal areas, the sand removed from the nourishment zone will be 

 replaced by littoral drift, and the biological population will probably 

 recover in a relatively short period of time." They also felt that the 

 effects of borrowing and redistributing sediment would be greater in 

 bays and estuaries than in the open ocean. In contrast. Dr. Robert 

 Dolan, a University of Virginia authority of barrier beaches, stated 

 that "the assumption that pits cause no permanent environmental 



