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In response to misinformation in previous articles and opinion pieces regarding the condition of coral reefs off of Kahekili Beach Park in Kaanapali, we have scientific evidence of the negative impacts that the wastewater injected into the ground at the Lahaina Wastewater Reclamation Facility (LWRF) has had and is having on the adjacent coral reef. The science is part of the public record.
The results reported here are based on research conducted by dozens of scientists with greater than 50 years of combined person-time working on the coral reefs of Kahekili Beach Park. It is critical to understand that the wastewater effluent is entering the ocean where people swim and that the reef is degrading because of it -- data from the Division of Aquatic Resources and the University of Hawaii have shown significant declines in the coral over the past 20 years.
At Kahekili, dead coral occurs in distinct patches that are nicknamed "dead zones." It was erroneously reported in a previous article that they are found where the waves break. Dead zones are actually found across the reef in depths ranging from 5 to 40 feet, well below the effects of waves and in habitats where coral normally thrive.
Ranging in size from 15 to 45 feet in diameter, the dead zones contain heavily eroded dead coral skeletons overgrown by turf algae. Turf algae are small, fine algae that aggressively compete with coral for space on the reef. Algae can grow over the coral and kill it or grow into spaces where coral has died. If a reef is not growing, it is eroding. Erosion and algal growth like this are consistent with the effects of excessive nutrient input.
After numerous freshwater seeps -- visible discharges of water from the seafloor -- were discovered at various locations around the reef, studies were undertaken by UH and the Environmental Protection Agency to investigate their source and composition. Researchers introduced fluorescent dye into the LWRF's injection well, which was later detected in the freshwater seeps on the reef, demonstrating the presence of effluent originating from the LWRF.
The water coming out of the seeps at Kahekili is warm, acidic, high in nutrients, and lacking oxygen. Any one of these things alone is bad for corals so there is no doubt that the combination of all of them together is harming the reef, especially since this water is seeping through the reef structure, literally eroding it from the inside out.
Further research by the U.S. Geological Survey found that corals in the area affected by seep water, containing 50 times as much nitrate (a nutrient found in sewage) as surrounding ocean water, suffered increased erosion from sponges, worms and urchins. A follow-up study also demonstrated that high nutrient levels caused the corals' skeletons to dissolve and lose strength. New research led by University of California, Santa Cruz discovered the sewage nutrient fingerprint in coral skeletons, dating back to 1995 when the county began biological nutrient removal.
In response to the decline of the reef at Kahekili, an Herbivore Fisheries Management Area was implemented in July 2009. The goal was to increase the number of fishes and sea urchins that graze on the algae fueled by the nutrient-rich water. This has had significant positive impacts on the herbivore fish population, as well as early signs of benefiting the reef itself.
However, research from Scripps Institution of Oceanography has shown that existing populations of these fishes are not enough to control all of the algae. Rather, it could take 30 years for fish to graze the algae down. Therefore, fisheries management alone will not solve the problems created by the excess nutrients from wastewater injection wells; we need to directly address the sources of this pollutant.
Decades of rigorous scientific research has improved our understanding of the impacts of wastewater upon the coral reef ecosystem. There are many factors affecting coral reef health. All of these must be dealt with to reverse the reef's decline, and addressing the effects of wastewater effluent is a critical part of protecting our coral reefs. Our goal is to present the wealth of evidence available, so that efforts to conserve these resources will be effective, appropriate, and guided by good science.
* Emily Kelly, Megan Ross and Jennifer Smith are scientists involved in studies of the effects of injection wells on coral reef health.