From Divers Who Contacted DAN on Both the Einergency and Non
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DANANALYSIS OF RECREATIONALDIVE ACCIDENTS FOR 1988 P. B. Bennett J A. Dovenbarger C. J. Wachhok K S. Corson Divers Alert Network Hyperbaric Center Duke UniversityMedical Center Durham,NORTH CAROLINA 27701U. S.A. TheDivers Alert ¹tN orkisapproaching theend ofits first decade ofservice tothe SCUBAdiving public and medi cine community. One of DAN's primary goals is thecollection of SCUBAinj ury statistics. The kist few years have seen increased effortsto collect more information onthe causes ofinj ury. METHODS In 1988,SS3 diving accidents were reported from hyperbaric treatment facilities and fromdivers who contacted DAN on both the einergency andnon-emergency lines.Accident ReportForms are filled out by the injured divers and by hyperbaric facility staff. Hyperbaric staffprovide information ontreatment while the divers provide information concerning the diveprofile and personal data such as medical history. For clarification andconfirmation, personnelatDAN central contact the treatment facilities and divers byletter and telephone. ByJune of 1989,419 Accident Reports were received. Ofthe 419 cases received, 111were not recreational and40 were incomplete. Thus, 268recreational dive accident cases were analyzed. DIVER AGE Themean age of an accident victim was 34 years with the range being 11-61 years. Table 1 givesa frequencyof agedistribution. Divingfor Science...1990 %bte1. Distrtbotionol' Age of DiveAccideat Victims 10-14 2 4 0.7 15-19 13 20-24 27 10.1 25-29 62 23.1 30-34 64 23.9 35-39 39 14.6 40-44 35 13.1 45-49 19 7,1 50-54 11 4.1 55-59 2 0,7 TOTAL 100.0 SEX Menwere involved in divingaccidents more than three timesas often aswomen. This probablyindicates a largermale diving population but it could reflecthigher risk divinghabits for men. Table2 givesthe sexof the accidentvictim. 'ttabk 2. Sex of the occtdeat victim Female divers 21.6 100,0 CERTIFICATION/EXPERIENCE Forty-ninepercent 31 of 268! of the injured diverswere beginninglevel basicor openwater! SCUBAcertified. The majority 0 of 78! of new diver divers with one yearor lessexperience! injuries occurred in themore serious severity codes, indicating central nervous systemDCS and/or gas embolism. New diver profiles indicate 75 k dived20 timesor less,61% werediving at or deeperthan 80 feet, 50% were diving repetitively, 41% had a rapidascent and 31% were outside the USN dive tables. Bennett er aL Recreational Dive Accidents for 1988 Inthe 78 divers who had been diving one year or less there were 25 gas embolisms. Of the25 new diver embolisms, 16had rapid ascents. These 25 cases represent 32% of all new divers8! butit represents69% of all embolisrn cases 6! analyzedwhich could suggest that lack of experiencemay contribute to the risk of AGE. CASE BREA%MOWN Ofthe 268 analyzed cases,46 were AGE, 60 were DCS Type I,and 162 were DCS Type CONCLUSIONS Accidentsdonot just happen, The 500-600 dive injuries which occur each year can be attributedto nospecific cause, but they are frequently a productof a seriesof events.While theseevents can be differentfor eachdiver, similarities do exist.Certain conditions or behaviors,inparticular, are associated with injury, these include: fatigue, inexperience, and/or drinkingalcohol on the preceding night. Deep diving and repetitive diving are also strongly linkedto decompressionsickness. Inexperience is a majorpredisposing factor for both decompressionsickness and air embolism. New divers are less knowledgeable aboutdiving safetyand may have a tendencytogo along with more experienced divers doing higher risk diving. CHARACTERISTICSAND ASSESSMENTOF DREDGERELATED MECHANICALIMPACT TO HARD-BOTTOMREEF AREAS OFF NORTHERN DADE COUNTY, FLORIDA StephenM. Blair Brian S.Flynn SusanMarkley Restorationand EnhancementSection Metro-DadeDepartment of Environmental ResourcesManagement 111 NW First Street Miami, FLORIDA 33128 U. S. A. Beacherosion control measures have become a necessity along the south Florida coastdue to thecontinued erosional loss of protective beach and dune areas. The pnrruuymethodtodate, for beach reconstructionin southFloridainvolves dredging of sandfrom anoffshore "borrow area" and pumping the sand to theshoreline. Althoughthe method results in a "new"beach with greatly enhanced erosion protectionand recreatiorral use, it is oftennot without impacts both unavoidable andavoidableirnpacts! tothe environment. Inthe summer of1988, Dade County sponsoreda beach erosion control project to renourisha 2.5 mile segment of northernDade County shoreline. ¹ar thetime of completion ofthe project, areas ofmechanicalimpacts tothe reef adj acent to the borrow area were discovered. The physicalcharactenstics ofthe impact indicatedit wasassociated withthe dredging operations.A subsequent survey ofthe reefs bordering theborro~ area identified ninesites of impact. At eachsite physical evidence was found consistent with the dredgrngequipment making contact with and scraping thereef. Two of the nine locationsexhibited substantial i e., orders ofmagnitude greater in size! and severe impact.These sites were chosen for detailedassessment. Theassessment involved mappingthe extent and magnitude oftheimpacted area via evenly spaced transects whichwere evaluated bybiologists using scuba 7he assessed impact at the two siteswas spread over an area of 2.2acres. Appraxirnately 1.5acres of benthic hard-bottomcommunities withinthe impacted areawere destroyed destruction of 75-100%ofthe benthic organisms!. It was estimated that over 25,000 hard coral coloru'es,24,000 soft coral colonies andover 2,000 barrel sporrges wereamong the organismsdestroyed bythe dredging equipment. 77us destruction represents a significan~tract to the hard-bottom comrrutnity within the region byreducing habitatquality, density of organrsms,reefstructural complexity and the overall productivityof the area. Divingfor Science...19Ã INTRODUCTION DadeCounty, Florida has approximately 21miles of ocean shoreline. Severe erosion alongthe shoreline, hasresulted inreduced storm protection and loss of a recreationaland economicresource. Metropolitan DadeCounty iscommitted toenhancing, restoring and revitalizingthecoastal beach and dune systems, to provide enhanced storm protection for barrierisland residents andrecreational opportunities forcounty residents and visitors. The County'sbeach projects are administered through the Department ofEnvironinental Resour- cesManageinent DC-DERM!. Todate, 15.4 miles of eroded beach front have been restored. Unfortunately,therestoration ofthe County's beaches hasnot been without impact tothe nearshorehabitats Marszalek 1981,Goldberg 1989!. Ofspecific concern tothis report isthe impactcaused byphysical contact ofdredging equipinent withthe hard-bottom live-bottom! reefareas adjacent tothe dredging site e.g., borrow area!. Although other modes ofimpact canoccur and can be of equivalentor greater concern, only the effects of themechanical impactswill be discussedhere. Duringthe summer June through early October! of 1988DC-DERM served as the localsponsor fora federallyfunded beach restoration project along 2.5 miles of shoreline in SunnyIsles Figure 1!.The dredging inethod employed utilizes a "hopper dredge". This type ofdredge has arms mounted onthe sides ofthe dredge. The dredging end of the arm is lowered tothe bottom where the material i.e., sand! issuctioned upthe arm and into the "hoppers" onthe dredge. Theship moves along within the borrow area, dragging thesuction arin or "drag head"on the bottom Figure 2!. On August W, 1988, DC-DERM personnel noted mechanical impacttoa portionofthe third reef, adjacent to the borrow area. The location and charac- teristicsofthe impact indicated thatit hadbeen caused bythe contact ofthe hopper dredge's HopperDredge LONG ISLP&D! drag head with s! the reef. Subsequently, a surveyof the reefssurrounding theborrow area was conducted byDC-DERM biologists todetermine the extentand degree ofthe impact. Nine separate areasof impact were identified. This report detailsthelocation ofthe areas, characteristics ofthe impact and method used toquantify the areaof hardbottom impacted at twoof thenine locations. Thegeneral geological and biological features ofthe reefs found off the southeastern coastofFlorida have been described byGoldberg 973!, Jaap 984! and Shinn 988!. The geologicalandbiological features ofthe reefs off northeastern DadeCounty are siinilar to thosedescribed bythe above cited authors, butdiffer with respect tothe depth offormations, and,toa lesserdegree, withthe biotic components ofthe reef. A brief suminary ofthe specific featuresfound off Sunny Isles ispresented here,outlining thepertinent topographic features and biotic communities. Qgg4Cy.Three distinct reef platforms, or terraces, are foundbetween 0.5 and 2.0 milesoff the Dade County coast Figure 1!. The reefs are formed ofpleistocene reefrock witha "cap",upto eight feet thick, of geologically recent coral reef Shinn 1988!. Shoreward ofthe first westernmost! reefis a largesand area with scattered patch reefs. The first reef is a lowprofile, non-continuous reefbelieved tobe formed bythe convergent growth ofsmaller patchreefs Goldberg 1973!. The second reefis relatively narrow 25-200 m wide!,andcrests Blairet al Hard-BottomReef Breeze Off M DadeCo.,FL at11 to 13 m. The western edge ofthe second reef shows a mild relief of 1 to1.5 in, rising out of'a sandplain at a depthof14 to 15 m. The eastern edge shows a greater andsteeper relief dropping1 to 3.5 in to a depthof17 m ontoa sand plain which makes upthe borrow area. The westernedge of the third reef, adjacent tothe borrow