The state will reopen Kamehameha Highway at Waimea Bay in both directions Monday, following two weeks of work to remove boulders and debris and install new protective measures in the wake of an April 7 rockslide.

The cost of the work came to $750,000, said Scott Ishikawa, spokesman for the state Department of Transportation.

The DOT will have to close the road in both directions one last time to remove concrete barriers from 10 p.m. Sunday to 4 a.m. Monday.

Contraflow will remain in effect until Sunday night as crews finish installing a temporary protective fence and barrier along the highway.

Both lanes will be opened at 4 a.m. Monday.

The state must still install permanent fencing. But that work isn't expected for about five months while the state waits for special-order replacement material to arrive, Ishikawa said.

On April 7, tons of boulders and debris fell on to Kamehameha Highway at a time when no traffic was on the road. A steel-ring fence installed seven years ago was able to hold back the worst of it, protecting the road from serious damage and making cleanup easier.

Business owners said they were glad to hear the highway was going to fully reopen so soon and were grateful the DOT moved so quickly. But they called for the state to do more to protect the only thoroughfare through Waimea Bay.

"We hope this situation will expedite the project for the rockfall mitigation for the Hale'iwa side of Waimea Bay," said Antya Miller, executive director for the North Shore Chamber of Commerce. "They have the funding available to do rockfall mitigation, and it's considered the second most critical spot on the Island for potential rock fall."

In seven years, the area has had two slides, and because it's a narrow road, any massive slide could shut the whole place down, Miller said.

Ishikawa said the state is mindful of the problem on the Hale'iwa side of the entrance to Waimea Bay Beach Park but a major hurdle is holding the project back. The road is so narrow and the wall of the hillside so close to the highway that traffic can't bypass any work done there, Ishikawa said.

"We're looking at it, but the obstacle we're trying to overcome is whether we can provide an access road," he said.

When the state made improvements to the highway seven years ago to mitigate slides, it was able to redirect traffic across the beach during construction. There's no room to channel traffic and conduct a construction project on the Hale'iwa side of the bay, Ishikawa said.

During the most recent work, several people praised the way police kept traffic moving through the contraflow area, and Miller said the state did an excellent job of handling the situation.

"We really appreciate the fact that they basically worked around the clock to get the problem solved," she said. "We thank them for getting it open as quickly as they did and keeping it open as much as they did throughout the project."

Things could have been worse for businesses and never reached the scale of lost revenue when the state closed the highway seven years ago after another slide, but businesses did suffer, Miller said. In 2000, the road was closed for 95 days to conduct mitigation work that included moving the highway and installing the barrier fence.

The recent project went faster than anticipated, and Ishikawa said all the praise goes to the DOT staff and the contractors. They cleared about 700 tons of boulders and debris and installed barriers and about 100 feet of steel-ring fence on top of the barriers, he said.

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.