Coral at Kahekili alive and well


Over the nearly 40 years that the Lahaina Wastewater Reclamation Facility has been operating, some of the recycled water that is disposed of into deep injection wells has reached the ocean through small “seeps” near the shoreline. However, data we have collected reveals no dead zones of coral on the reef off of Kahekili Beach that are related to the seeps.

In 2014, I and Dr. Eric Hochberg, Ph.D., professor of oceanography at the Bermuda Institute of Ocean Science, conducted an extensive survey of the reef at Kahekili (Airport Beach) for the County of Maui. Our goal was to use research tools developed for NASA to create maps of the biological structure of the entirety of the Kahekili Beach coral reef, and not just the small area where the freshwater seeps occur. To do this, 71 sites were investigated, extending from the shoreline to the offshore limit of coral coverage along the entire length of Kahekili Beach.

The maps created using these tools show that the coral cover is low at the shoreline throughout the survey area, both where the seeps occur and where they do not. Put simply, corals don’t typically grow near the shoreline where wave action and sand scour occur. The abundance of coral increases with distance from shore. At about 30 feet offshore, ocean conditions become less stressful and healthy corals are abundant.

From the maps we created it is apparent that there are no abnormalities in the coral reef community offshore of the freshwater seeps. Should the groundwater/recycled water exiting from these seeps be causing harm to the coral, one would expect to see “halos” of reduced coral coverage around the seeps. No such halos were observed.

To set the record straight, none of the data collected by Earthjustice provides a comprehensive picture of the entirety of the reef off Kahekili Beach. The data that was collected in the comprehensive study that was undertaken by myself and Hochberg is the only information to accurately evaluate the effect of the seeps on the coral reef community structure in this entire area.

The NOAA “Baseline assessments for coral reef community structure and demographics on West Maui: data report, 2017” concludes that “With mean coral cover ranging between 30 percent and 58 percent, the Wahikuli and Honokowai Watersheds contain the greatest extent and concentration of coral-rich habitat in West Maui, with relatively well developed, spur-and-groove coral reef complexes off Canoe Beach, Kahekili Beach Park, and Honokowai Point.” There is no mention in the NOAA report of impacted corals at Kahekili Beach. (repository.library.noaa.gov/view/noaa/14801).

Another often mentioned, but never documented, assertion is that algal blooms are caused by the recycled water from the county’s Lahaina facility. Under the auspices of an EPA grant, extensive studies were conducted to determine causal effects of algal blooms that occurred in West Maui in the 1990s. One of the major conclusions of this study was that nutrient enrichment from sugar cane production provided the most likely driver for algal blooms. No algal blooms have occurred at or near the seeps since they have been under investigation. Our comprehensive field investigations of the entire reef at Kahekili show no discernable effects to coral attributable to the recycled water exiting through the seeps.

Data from other governmental scientific agencies indicates that the reefs at Kahekili are among the best in the area with no evidence of damage from the seeps. As the LWRF has been in operation for about four decades, negative effects to reef structure would be clearly apparent, which has not been demonstrated. There is no data to support the occurrence of any such negative impacts to the reef at Kahekili.

* Steven Dollar, Ph.D., is president of Marine Research Consultants and Clean Water Act National Pollutant Discharge Elimination System permit monitoring for the Kauai and Hawaii counties and the U.S. Navy.


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