Blair,-S.M.; Flynn,-B.S.; Markley,-S. Characteristics and assessment of dredge related mechanical impact to hard- bottom reef areas off northern Dade County, Florida. DIVING-FOR-SCIENCE-1990.-PROCEEDINGS-OF-THE-AMERICAN- ACADEMY-OF-UNDERWATER-SCIENCES-TENTH-ANNUAL-SCIENTIFIC- DIVING-SYMPOSIUM,-OCTOBER-4-7,-1990,-UNIVERSITY-OF- SOUTH-FLORIDA,-ST.-PETERSBURG,-FLORIDA. Jaap,-W.C.-ed. 1990. pp. 5-14. The primary method to date, for beach reconstruction in south Florida involves dredging of sand from an offshore "borrow area" and pumping the sand to the shoreline. In the summer of 1988, Dade County sponsored a beach erosion control project to renourish a 2.5 mile segment of northern Dade County shoreline. A subsequent survey of the reefs bordering the borrow area identified nine sites of impact. At each site physical evidence was found consistent with the dredging equipment making contact with and scraping the reef. Two of the nine locations exhibited substantial (i.e., orders of magnitude greater in size) and severe impact.