Kailua Reservoir to be emptied

An inspection of dams statewide finds the site in Waimanalo poses a flood danger downstream

The state plans to breach the dam at Kailua Reservoir in Waimanalo this week so it will no longer hold water.

"We will do to Kailua Reservoir what we did to Morita Reservoir (on Kauai) and turn it into a stream," Maj. Gen. Robert Lee, state Civil Defense director, said yesterday.

The state broke open Morita Dam last month after seven people were swept away by flood waters that had breached Ka Loko Dam upstream.

The wall of Kailua Reservoir has been weakened by a sinkhole, and the dam could break during the next heavy rains, state officials fear.

"The current condition of Kailua Reservoir is unsafe. And we need to take immediate action to protect the people downstream of that reservoir," said Sandra Kunimoto, state Department of Agriculture director. The department owns the reservoir.

The state Department of Land and Natural Resources and the Army Corps of Engineers are inspecting dams on Oahu and Maui this week. So far, the Kailua Reservoir is the only one that has generated any concern, said Peter Young, DLNR director.

David Kalama, whose family home is below Kailua Reservoir, said he agrees that the state needs to breach the dam, but hopes the breach will be temporary, just long enough so that officials can fix the wall.

"The dam is very much needed for water control," Kalama said.

The dam was built in the 1930s for irrigation. In 1993 the state closed the reservoir and kept the drainage pipe open when Waimanalo Reservoir was completed.

Kunimoto said there are no long-term plans for the reservoir. Six years ago the state completed an environmental assessment on a plan to remove the dam. The state backed off the plan and did more studies after residents objected.

If it is determined the dam is needed for flood control, it will be rebuilt to modern standards, Lee said.

Twelve families in Waimanalo evacuated their homes Sunday as floodwaters threatened to top the dam.

Kalama said he believes the sinkhole loosened a tree that clogged the drain, and that the ground collapsed because the state has not been maintaining the reservoir.

Lee said Kailua Reservoir is among a handful of reservoirs statewide that have basically been abandoned and are recommended to be taken out of service.

Inspection of dams on Kauai is complete, but Lee said he sent the report back with questions. The report should be released to the public by the end of this week or early next week, he said.

The report found none of the Kauai dams poses any immediate danger, Lee noted.

In other storm-related news, the state Department of Transportation is doing assessments of areas that pose risks of rock fall. Two years ago DOT listed the top 10 rock-fall hazards on Oahu.

"We're looking at everything again, because obviously Kailua Road now moves up the list because of the imminent danger of things rolling into the highway and other areas," said Rodney Haraga, state transportation director.

The department closed the right lane of Kailua Road heading into Kailua Town on Monday when overhanging material was noticed during an inspection of the hillside adjacent to the road. The recent heavy rains had washed away soil and exposed rocks on a flat plain above the road, Haraga said.

The lane will remain closed until the department finds a solution.

A portion of Diamond Head Road is expected to remain closed for three weeks as the state removes rocks from the slope of the crater.