Researchers to look at how residential sewage systems impact Kahalu‘u Bay waters

If the waters at Kahalu‘u Beach Park have a tint of green over the weekend, don’t be alarmed.

From Aug. 9-12, researchers from University of Hawai‘i at Hilo will be dropping a small amount of the dye, fluorescein, into sewage disposal systems of residences upstream to see where sewage water travels and if it’s entering the bay.

“By observing whether the dye travels to the shoreline and how long it takes, researchers can learn more about the impacts onsite sewage disposal systems may have on water quality and marine life,” Parks and Recreation officials stated in a press release Wednesday.

Hawai‘i County officials say the dye is non-toxic.

Cindi Punihaole, director of the Kahalu‘u Bay Education Center, a program of the Kohala Center, said the organization supports the research.

“Kahalu‘u is a wahi pana,” Punihaole said. “It’s very sacred and growing up in this ‘aina it’s so important that we really look at taking care of this place.”

Punihaole said the data being researched will help decision-makers understand what’s happening in the bay.

“We want to make sure how we move forward is pono. We do this work for our children so they have a place to have a clean and resourceful bay,” Punihaole said.

Punihaole said she’s grateful that researchers picked Kahalu‘u to do this study as it allows them to move forward in a strategic way not a haphazard way.

“Growing up in Kona the oceans were so bountiful and clean and we have a chance to clean it again,” Punihaole said.

“Together with our community partners, the Department of Parks and Recreation is committed to protecting and restoring beautiful Kahalu‘u Bay, and this research supports that effort,” said Maurice Messina, Director of Parks and Recreation. “We want the public to be aware this testing is taking place and know it is being done safely, using methods approved by both the Hawai‘i State Department of Health and U.S. Environmental Protection Agency.”

The research is part of a larger project funded by the Pacific Islands Climate Adaptation Science Center, which is a collaboration between the U.S. Geological Survey, UH Mānoa and UH Hilo.

Kahalu‘u Bay is home to an important and unique coral reef ecosystem and is also one of the most popular snorkeling locations in all of Hawai‘i. The bay is closed regularly throughout the year to allow for coral spawning.

Punihaole said it’s important to know what’s happening in the bay, especially when looking at coral growth.

“We have hundreds of coral growing in the bay but we also know there are pollutants that are causing damage to the coral,” Punihaole said, adding they hope to see more coral growing.

Punihaole expects to see results in a month or so.

Each year, over 400,000 people visit this shallow, nearshore reef to view its diverse marine life, colorful fish and ancient coral colonies.