A fire that has scorched 6,700 acres of North Shore land was nearly extinguished yesterday, but the barren fields left in the blaze's wake already have residents and legislators concerned about pending environmental impacts.

The Waialua wildfire will enter its seventh day today.

Late yesterday afternoon, the fire was 90 percent contained. However, persistent gusts and rocky hillside terrain make it difficult for firefighters to completely extinguish the flames, said Capt. Frank Johnson, spokesman for the Honolulu Fire Department.

Yesterday the department relied on six helicopters to douse flames in hard-to-reach areas. The crafts — one from the police, one from the state, two from HFD and two from the military — stopped working at night. Some 30 firefighters hosed down the hot spots, and the department expected to spend another night monitoring the blaze.

Firefighters also tackled brushfires near Kahuku Hospital at 2:08 yesterday afternoon and had it out by 3:49 p.m. About an acre burned, Johnson said. Several units were dispatched to a wildfire in Mokule'ia near YMCA Camp Erdman at about noon yesterday, and they were still there at 4 p.m., he said, adding that he couldn't tell yet when that fire would be contained.

PREVENTIVE ACTION

Officials have not yet determined what started the Waialua fire. It is still under investigation, Johnson said.

Once the Waialua brushfire is out, residents and lawmakers worry that the next heavy rain could sweep those fields clean, carrying topsoil and soot into the streams and down to the ocean, polluting the water, the coral beds and the near-shore ecosystem.

But with cooperation of the landowners, the city and the federal government all of that can be averted, said City Councilman Donovan Dela Cruz.

While it's still summer and there's no threat of a downpour, government and land-owners have time to correct the problem if they act now, Dela Cruz said.

"As soon as the fire is out, there's other work to be done, because if there's any heavy rain within the next couple months, we'll probably see a lot of topsoil heading into Kaiaka Bay," he said.

As was done in 2003 after a big fire in Waialua, Dela Cruz is counting on landowners, the city and the federal government to help replant the burned fields to prevent run-off or flooding.

First, "the mayor has to call a state of emergency so we can qualify for the funding," Dela Cruz said. "Then the city just has to bring in (matching money)."

The September 2003 wildfire burned about 1,000 acres of land along the Poamoho Stream and Poamoho Stream Watershed. At one point, residents were evacuated. That fire came within a couple hundred feet of homes on Hukilau Loop, the same community threatened this week.

COMBINED EFFORT

The revegetation involved the U.S. Department of Agriculture Natural Resources Conservation Services, land-owner Castle & Cooke and the city.

The NRCS provided the majority of the money and Castle & Cooke kicked in the required 25 percent matching money for the $21,053 project to reseed the affected land.

Jeff Mikulina, executive director for the Sierra Club Hawai'i Chapter, said revegetation is important for erosion control and to replace endangered plants that were burned in the fire.

"Not that nature wouldn't do it herself," Mikulina said. "The problem is the opportunistic weeds would probably take over."

Mikulina suggested using native plants that are fire tolerant because when left alone, the fields would be taken over by invasive plants that are known to be flammable.

"It's not just a matter of the environment and creating an ecosystem, but it is a matter of future fire protection, too," he said.

Altogether, the fire-prone area in Waialua along Kaukonahua Road and the Poamoho Gulch has resulted in threats to homes on Hukilau Loop three times in recent years — in 2003, 2005 and again this year.

CRITICAL NEED

Jacob Ng, who lives on Hukilau and is a member of the North Shore Neighborhood Board, said the revegetation is critical and corrective action is necessary to avoid flooding and soil erosion.

Dela Cruz has called for a meeting Aug. 22 to discuss the issue with landowners, North Shore and Waialua residents, and state, city and federal representatives.

Ng hopes the appropriate parties will seed the burned-out fields and that the federal government will help.

"They did it in the upper land as well as in gulches and that helped a lot," Ng said. "If it doesn't happen, all the ash and soil is going to wash down into the rivers and into the ocean."

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.