Navy ends coral work at USS Port Royal grounding site
The Navy has halted additional coral stabilization and rubble removal at the site where the USS Port Royal ran aground in February, the U.S. Pacific Fleet announced today.
The work was suspended because of high surf this summer, with a commitment from the Navy to reassess after the high surf season. Recent assessment dives by marine biologists indicate that the initial coral stabilization efforts were successful. Additionally, they found that the ocean dispersed most of the remaining rubble without additional damage. The underwater environmental experts now conclude that continued stabilization efforts would likely cause more harm than good.
"The results of the recent assessments are very encouraging," said Rear Adm. Scott Van Buskirk, deputy commander of the U.S. Pacific Fleet. "This, combined with Mother Nature's work during the summer months, has convinced the experts and us in the Navy that the best course is to let the environmentally impacted area continue to take care of itself. All signs indicate that is the responsible thing to do."
Port Royal ran aground the night of Feb. 5, and was freed early on Feb. 9. Immediately, the Navy began working on assessing and minimizing damage to the environment. Navy divers from Mobile Diving and Salvage Unit 1 did the initial work, reattaching some coral colonies and moving rocks that might cause further damage in high surf conditions.
After a detailed underwater assessment, contractors reattached nearly 5,400 coral colonies and righted eight large boulders. In addition, contractors used a barge-mounted, environmentally sensitive bucket system to remove 250 cubic yards of rubble created by the grounding. The Navy waited for two weeks for the high surf to subside before finally suspending work in late June. By then, the Navy had spent more than $7 million on the coral stabilization.
A series of assessment dives last month found that high spots and rubble berms that were created in the area of direct impact by Port Royal were greatly reduced. Most of the estimated 2,350 cubic yards of remaining rubble had been dispersed by waves and tides without creating any apparent further damage to the ecosystem. The marine biologists who did the assessment also saw evidence of natural recovery in the form of coralline algal growth, which helps by cementing the rubble in place and restores aquatic life in the reef.
The dives were conducted in August and September to check on the rubble and to locate and assess the viability of the reattached coral. About 96 percent of the reattached coral colonies encountered were still alive and in place. The remaining 4 percent is within the expected mortality rate of naturally occurring coral.
"The state of Hawaii appreciates the effort that the Navy has put into stabilizing this damaged ecosystem," said DLNR Chairwoman Laura Thielen in the Pacific Fleet press release. "We look forward to a continuing constructive dialogue regarding long-term monitoring of this site, and other mitigation measures to offset the aggregate coral reef loss sustained during the grounding."
"This was a big summer for south shore surf," said Van Buskirk. "Despite the high surf, the scientists saw nothing to suggest the rubble created by the grounding became mobilized to cause additional damage. In fact, nature's healing powers were clearly in evidence. We regret the grounding and the damage it caused and we are convinced we have taken all reasonable steps to stabilize the reef."
He added, "We remain in close coordination with Hawaii state officials on all matters and specifically this ongoing effort."