KAILUA — The state's $5.8 million project to prevent falling rocks near the entrance to Kailua will enter its final phase next week as workers begin restoring part of Kailua Road to its original configuration.

With the bulk of the rockfall mitigation done, workers will begin changing lane patterns, landscaping a median strip and installing new curbing and gutters. Drivers should expect some delays in the area over the next two months as finishing touches are put on the project, said Transportation Department spokesman Scott Ishikawa.

"We just want to give people a heads up as we move into the final phase," Ishikawa said.

Work on the emergency project started two years ago following a series of landslides on the steep hillside overlooking the road and Kawai Nui Marsh. The area had been listed in an earlier DOT report as one of O'ahu's 10 most dangerous rockslide locations.

Mitigation efforts included a variety of measures such as tying down large boulders, metal nets draped over the steepest parts of the hillside, creation of a large swain to catch falling rocks, installation of a rockfall protection fence and construction of concrete water drains to prevent additional erosion.

"It wasn't just one fix that was needed. It was a mix of lots of things," Ishikawa said.

At the peak of the work, the contractor, Prometheus Construction, used drills to anchor 30-foot-long bolts into the rock and attach the wire mesh.

Passing motorists could see workers scrambling up and down the nearly vertical hillside on specially engineered contraptions that combined winches and pneumatically powered drills the size of a small car.

As part of the project, crews removed a planted median strip in Kailua Road and realigned the highway to keep traffic away from the construction area. While the traffic pattern changes created a slight detour for Kailua-bound passengers, they also allowed the state to keep all four lanes of the busy road open during the construction.

With the hillside work finished, the state will now restore the highway and its plantings to their original condition — and then some.

"It was too bad it had to be done before, but we're delighted that the median strip will be fully restored and extended farther up the highway," said Sharon Geary, head of the Lani-Kailua Outdoor Circle.

Ishikawa said the state will replant original loulu ferns and naupaka bushes in the new median strip.

Many of the full-sized ferns have been kept safe in a nursery during the construction, he said. New water sprinklers will also be installed.

The Outdoor Circle worked with the city to come up with a plan that would minimize traffic delays and eventually add to the scenic beauty of the approach to Kailua.

"Compared to some construction, like the Kalaheo sewer project, this one went very smoothly," Geary said.

Next year, the state plans to begin rockfall mitigation on three more of the most dangerous spots near highways, Ishikawa said.

They include a stretch of Kalaniana'ole Highway between Castle Junction and Castle Medical Center, and two areas of Kamehameha Highway near Wahiawa, he said.

Reach Mike Leidemann at mleidemann@honoluluadvertiser.com.