KAUAʻI—Designing a culturally and environmentally sensitive system for treating sewage from the restrooms at popular Keʻe Beach is proving to be a challenge for the State Division of Parks, which is preparing to release an Environmental Assessment on a plan to use an innovative “constructed wetlands” approach.
The project was proposed in response to concerns about the current septic system for the restrooms that were recently constructed in Haʻena State Park, which is heavily used by tourists and marks the start of the Kalalau trail. Community members objected because the leach field for that system flows over the foundation of what is believed to have been an aliʻi’s house, as well as other cultural sites, and a burial is nearby.
Although the state has been working with area residents for nearly three years on the project, lingering concerns remain about how the system will hold up under Haʻena’s heavy rains, as well as possible contamination of the adjacent wetlands, which include a fishpond and taro fields (loʻi kalo).
At an informational meeting held this week in Hanalei, project planners explained the concept, which is being used at a slaughterhouse at Kapolei, on Oʻahu, but is new to the state parks system. If it works, it could be implemented at other park facilities around the islands, according to Russell Kumabe of the division of state parks.
Chad Durkin, project manager for Strategic Solutions Inc., said the system was designed to withstand rainfall from a 100-year flood. However, in a worst-case scenario, partially treated wastewater could overflow into the wetlands, loʻi and fishpond.
That prospect worries Kaʻimi Hermosura and Kaʻili Chandler, who grow kalo in the loʻi there and have hopes of putting the fishpond back into production.
“You’re talking about the contamination of our food,” Chandler said. He is also concerned that persons working in the loʻi could become ill from bacteria and viruses still present in water released from the existing system and proposed facility.
The project, which would be wedged in between “wetlands and an area of intense archaeological importance,” is extremely challenging because of “locational, cultural and environmental” issues, Kumabe said. However, he said it has been redesigned four times based on community input.
“It’s not perfect, but it’s a heck of a lot better than dumping effluent on a sacred site,” said Chipper Wichman, director of the National Tropical Botanical Garden, which has a satellite garden nearby and provided funding for a feasibility study for the project.
Durkin described the process: Solids from the restroom would flow into two above-ground detention tanks, where a bacterial system would eat most of the waste. The tanks also would be pumped periodically, like a septic tank. Liquids would flow into a 5,000-square-foot “constructed wetlands” comprising a plastic liner filled with gravel or cinder and planted with native vegetation. The liquid would be cleaned as it runs through the rocks and plant roots, a process that takes about five days, and from there it would flow into an absorption bed some three feet below the surface, where it would gradually be adsorbed into the environment.
“Ninety-five percent of what goes on in the treatment is a bacterial process,” Durkin said. The system will not generate any of the foul odors often associated with wastewater treatment facilities because the subsurface flow would not be exposed to air as it moves through the plants, he said.
Durkin said the constructed wetlands would be fenced, which raised some concerns about aesthetics in the park, although he said it could be obscured through plantings. The existing septic system would be kept as a backup, which raised the issue of whether the State would be diligent in keeping that system functioning. Durkin said the detention tanks also would need to be maintained to prevent sludge from building up and blocking the system.
The system, which has a life span of 25 to 30 years, is designed to handle about 3,600 gallons of wastewater per day, the maximum that could be generated by the existing restrooms. Community members had previously resisted attempts to expand the restroom facilities due to concerns about overuse of the park.
Hermosura expressed concerns about burials that might be uncovered when excavating some four feet of topsoil to install the plastic liner. But state parks archaeologist Alan Carpenter said no burials were found when test pits were dug on site. Hermosura was also worried about moving rocks during the excavation, saying some of them serve as drains for water coming down from the mountains.
“You can’t just go moving rocks around because they’re all there for a purpose,” he said. Hermosura said kupuna from the area had told him the area in question previously was a river, so he was worried about placing the heavy, gravel-filled liner on land that could be unstable.
After the meeting, Hermosura expressed continuing reservations about the project, saying it didn’t belong in a sacred area like Keʻe and was incompatible with the cultural restoration now under way. “They’re just trying to accommodate the tourists,” he said. “It all comes down to the overuse of Keʻe.”