A Wahiawa rockfall project tumbled from No. 10 to No. 42 on a list of most hazardous sites, leading the state to delay mitigation there and raising concerns among local residents.

The slope just past the Karsten Thot Bridge, heading out to the North Shore, had alarmed consulting engineers enough in 2003 to place it at No. 10 on a list of the 66 highest-risk rockfall slopes on O'ahu of more than 400 sites evaluated.

The bridge, on Kamehameha Highway, is along a main route to the North Shore and Waialua, where more than 2.5 million tourists visit each year. The other route is Kaukonahua Road, known for its curvy and deadly turns.

After the state announced that it would fix the problems at Karsten Thot Bridge this year, the community learned that state engineers had determined that the slope north of the bridge is a soil erosion problem rather than a rockfall hazard, said Tammy Mori, state Department of Transportation spokeswoman.

Mori said the determination was made in 2004, and it included the slope on the other side of the bridge that was listed as No. 7 and is now rated as No. 25.

The consultant included landslide potentials in the report, but the state now wants to focus on surface instabilities of rocky slopes and rock formations, she said.

"After our specialized geo-technical engineers conducted further evaluation, they reclassified this site," Mori said. "It was determined that the Karsten Thot slope has the potential for surface erosion, but not a potential for surface instabilities or rockfalls."

Residents are not happy about the state decision and say it is taking advantage of Wahiawa's easygoing nature.

"We take it slow and easy," said Ben Acohido, chairman of the Wahiawa Neighborhood Board. "We would wait a year (to get a problem fixed). Hawai'i Kai would get reaction almost immediately."

Acohido doesn't dispute that erosion is taking place there. The walkway from Whitmore Village to Wahiawa town is blocked by falling dirt, he said, adding that people have to cross to the other side of the road where there is no walkway.

"One of these days, one of the pedestrians is going to get hit," Acohido said.

Mori said the consulting engineer made a mistake when he included the site on the rockfall list, but the DOT has mulched and planted grass in the area to help with the erosion.

Waialua resident Tim Haverly strongly disagrees about the hazard there. Haverly drives to Honolulu every day to go to work and said boulders are hanging over the road, and every once in a while rocks end up on the highway.

"This grass isn't going to hold them," Haverly said. "It's not going to stop anything."

Acohido and Joe Francher, a Wahiawa Neighborhood Board member, met with the director of the DOT in June. Francher said the director told them that all of the sites were re-evaluated, and others were found to be more urgent.

Francher said he's not an expert, but there are problems at the bridge.

"I see exposed tree roots out there, and there are rocks in the whole area," he said. "I feel a little bit slighted that Karsten Thot bridge was demoted."

Mori said the original 2003 list was part of a report, and that the full study will be out next year.

Since the list was released, the state has completed several projects on its top 10 sites, including Makapu'u, Waimea, Kipapa Bridge and Kailua. The DOT is also working on slopes on Kalaniana'ole Highway near Kapa'a Quarry Road in Kailua.