Dole Food Co. of Hawaii officials have slowed the loss of water in Lake Wilson in Wahiawa by partially closing a broken valve, raising hope the state’s largest freshwater reservoir will avert a fish die-off.

But despite Dole closing the outlet valve by two-thirds yesterday, state officials continued to monitor the wildlife there, including fish and birds.

"It’s pretty dramatic as far as how low it’s become," said William Aila Jr., interim chairman of the state Board of Land and Natural Resources.

Aila said the oxygen level in the water is "pretty good" and that there is no threat of a fish die-off at this time.

Dole, operator of the reservoir, said the good news is that there might be more water rushing into streams that feed Lake Wilson, with rain expected tomorrow.

"We’ve stabilized the level of the reservoir, and we’re expecting it to go up with the rains," said Daniel Nellis, Hawaii operations director for Dole Foods.

Aila said he hopes Dole will be able to fully close the valve outlet.

"We don’t want the water level to drop any further at this point," he said.

He said the company is working on the problem and that it is doing an initial assessment of what actions are needed to fix the problem.

Aila said the company has been unable to pull out the malfunctioning valve, and he doesn’t know the cause of the problem.

"We haven’t got the full engineering report," he said.

He said the water level, usually somewhere between 70 and 80 feet, was at 57 feet at the spillway.

He said the water has gone down as far as the 40-foot level in the past.

Aila said if the water goes down further and threatens the health of the fish, the state can use pumps to aerate the water to provide oxygen for the wildlife in the lake.

The company said it has been working on the problem for the past week and a half.

Aila said he was notified of the problem Saturday.

Lake Wilson has a capacity of 3 billion gallons, a shoreline of 20 miles and is home to a variety of fish, including bass.

The source of the water is the watershed in the west Koolau Mountains, from which the north and south forks of Kaukonahua Stream feed into the lake.

The valve feeds into a tunnel that leads to irrigation fields or below the lake to another part of Kaukonahua Stream.

Dole has said due to the lack of rain in the past week and a half, much of the water has been directed to irrigating crops.