NUUANU, OAHU (HawaiiNewsNow) - Tropical Storm Olivia dumped 8 inches of rain on Nuuanu Wednesday night, rapidly increasing the depth of the Nuuanu Reservoir Number 1, and bringing the water to within 18 inches of its spillway.
On Thursday the Honolulu Board of Water Supply and Honolulu Fire Department used five portable pumps to drain the excess water.
"If the levels drop down say another 15 feet from where it is today, I'd feel more comfortable," BWS manager and chief engineer Ernie Lau said.
Through a press release early in the day the water company floated the possibility of an evacuation of about 10,000 residents down slope of the dam.
"It's kind of scary, especially not being prepared for it or even knowing what could happen," Stephanie Furuno said.
Her house is right next to the reservoir.
"You see how close we are? The reservoir is right where that fence is," her neighbor Alvin Chung said.
The Board of Water Supply later said there was never a need to evacuate residents.
"The public was not in any danger," Lau said.
But people who live close to the reservoir were understandably alarmed.
"It surprised us. I didn't know there was a dam up there to begin with," Heather Hirata said.
"We didn't get any notification that there was the possibility of the dam breaking or overflowing," Jonny Hirata said.
"I think they would warn us before they call the fire department, or at least have someone come over and say, 'This is what we're doing,'" Chung said.
Lau said BWS will immediately look for better and faster ways to alert the community to situations at the reservoir.
"There could be another storm in a week or two weeks. We'll bring that water level down," Lau said.
Furuno said people who live in areas that could be endangered by a dam breach need a lot of lead time.
"Last minute we wouldn't have anyplace to go," she said.
The reservoir was built in 1905.
The Board of Water Supply is studying how it could use the 30 million gallons it holds to recharge a groundwater aquifer.