Effects of Underwater Demolition on the Environment in a Small Tropical Marine Cove
NAVAL UNDERWATER SYSTEMS CENTER NEWPORT RI
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Construction in a small cove on Cross Cay, a small island located off eastern Puerto Rico, necessitated the use of 4000 lb of explosives to clear a beach area for use as an access road and remove underwater and awash coral heads and boulders to create a boat lane. In order to assess the impact of the blasting on the environment, acoustic-pressure levels and the effect of the demolition on marine life were measured. Three separate charges were positioned so that a large portion of the energy was dissipated skyward. As a result of the precautions taken to minimize the damage to the environment, at a distance of 350 yd from the demolition area, the largest of the three blasts produced a pressure level of only 9.15 lbfsq in, considerably less than expected. Air- bladdered fish that were suspended in cages 175 and 350 yd from the center of the demolition area remained alive and healthy.