Hawaii Island residents are invited to discuss how best to preserve the fragile coral ecosystems of Kahalu‘u Bay.

The U.S. Army Corps of Engineers, in partnership with the Hawaii County Department of Parks and Recreation and the Kohala Center’s Kahalu‘u Bay Education Center, will hold a public meeting on Thursday, Dec. 12, to discuss an ongoing study that will investigate methods to restore the bay’s marine environment, which has become degraded due to human impact and changing weather patterns caused by climate change.

The study — called the Kahalu‘u Bay Aquatic Ecosystem Restoration Study — will determine the factors that are contributing the bay’s ecological degradation and recommend measures that can mitigate the damage, according to the Army Corps of Engineers.

“The bay itself, it’s such a beautiful place,” said Cindi Punihaole, director of the Kahalu‘u Bay Education Center. “But it has a lot of stressors, especially because of climate change. We’re dealing with sea level rise, high surf, tides … and there’s sewage, cesspools along Ali‘i Drive, that we need to address.”

The bay, located about five miles south of Kailua-Kona village, is attractive to tourists, divers and fishers thanks to its coral reef ecosystem, but is also particularly susceptible to climate-related impacts. In 2015, marine heatwaves caused a catastrophic mass coral bleaching event in West Hawaii, leading to the death of about 90% of the area’s population of cauliflower coral.

An Army Corps fact sheet about the study notes that, during storms, runoff deposits sediment from the shore onto the coral reef, smothering the corals and other marine life that lives there, and inhibiting photosynthesis. Storm runoff also brings toxins and heavy metals from the nearby parking lot into the water.

“But we also see hope here,” Punihaole said. “We asked Parks and Recreation in 2018 to close the bay for coral spawning, and they allowed it.”

Each year since 2018, the bay has been closed in tandem with the coral’s natural spawning cycle, allowing the species to reproduce undisturbed — to great results.

Punihaole said there were six viable coral heads in the bay after the mass bleaching in 2015. Today, she said, there are about 47,000 living coral heads in Kahalu‘u.

Despite this rebound, Punihaole said other help for the bay has been slow to come. She said it has taken years to bring county and federal leaders together to develop the restoration study.

Parks and Recreation spokesman Thatcher Moats said via email the study will cost $1.02 million, split evenly between the Army Corps and the county. The study is underway, but an estimate for its completion could not be confirmed Wednesday.

Punihaole said next week’s meeting is important to gather the community’s mana‘o about the importance of the area and what should and should not be considered for any plans to address its problems.

She said the education center’s public outreach has significantly contributed to the bay’s improvement, explaining that “about 99%” of visitors to the bay want to be respectful toward the reef and are willing to change their behaviors when asked.

In addition to soliciting public feedback, the meeting also will provide additional background information and answer questions about the study.

The meeting will take place 5 p.m. to 6:30 p.m. Dec. 12 at the West Hawaii Civic Center in Kailua-Kona. Doors will open at 4:30 p.m. Virtual attendance will be possible at tinyurl.com/4a229hr6.

Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.