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The Honolulu Advertiser
Posted on: Saturday, April 24, 2010

Flooding fix not a cure-all

By Eloise Aguiar
Advertiser Staff Writer

Hawaii news photo - The Honolulu Advertiser

Jeff Iwasaki-Higbee, president of project contractor EBD Inc., says cleaning and modifying this concrete transition box is part of the solution for the tidal flooding problem in the Mapunapuna industrial area.

RICHARD AMBO | The Honolulu Advertiser

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Work under way in the Māpunapuna industrial area is intended to end tidal flooding that has swamped intersections here for decades, but the fix paid for by the city and landowner may not address inundations caused by heavy downpours.

The city and HRPT Properties Trust, which owns much of Māpunapuna industrial area, are installing one-way valves designed to stop the high tide flow from entering the city storm drain system.

But the $1.4 million project will only deal with day-to-day tidal events, said Corey Lieber, project engineer for HRPT.

"These valves alone are not going to solve the flooding problem with respect to the big rains that we get," said Lieber, with PBS&J Inc., a civil engineering company based in Florida.

Māpunapuna has suffered from tidal flooding for more than two decades. But when high tide coincides with heavy rain, portions of Māpunapuna get covered with up to 2 feet of water.

Yesterday, standing water from the high tide covered half a lane at the corner of Āhua and Kilihau streets.

Barry Bundy, who stores automobiles at the nearby Diamond Head Self Storage, said he's glad the problem is being addressed. He said he avoids the intersection and goes two miles out of his way to get to the storage facility.

"I don't drive through here because it's just too dangerous," Bundy said. "I've even seen cars get stalled in there."

The salt water is harmful to automobiles and the roads, which have numerous potholes, he said.

Construction on the project began in mid-March and is expected to be completed by mid-May. Work includes cleaning out 300 feet of storm water pipes, removing three feet of muck and debris from a transition box, which will hold the valves, and installing the valves, said Jeff Iwasaki-Higbee, president of EBD Inc., project contractor.

"In order for the valves to work properly this needs to be cleaned out," said Iwasaki-Higbee, pointing to a 30-foot by 25-foot by 9-foot- deep concrete transition box. The box had about 6 feet of water in it, brought in with the tide from Ke'ehi Lagoon.

Work also includes raising the height of the concrete wall on the 'ewa side of the transition box, adjusting the inlets and closing an old storm drain that led to flooding on Awa'awaloa and Āhua streets.

Debris buildup that prevented previous valves from working properly contributed to the flooding problem, said Jan Yokota, vice president for the Pacific Region of HRPT Properties Trust.

The area has had the problem since the mid-1980s. When HRPT purchased the property in 2003, officials decided to find the cause of the flooding, spending $800,000 just for the engineer consultant's work.

"If this solves the flooding tidal issue, it's worth it for us," Yokota said.

The city is paying $600,000 for the construction, according to Bill Brennan, city spokesman.

Several people who work in the area questioned whether the project would solve the problem and thought the city should change the elevation of the drain pipes.

This project is a first phase to a multi-phase solution, said Lieber, the engineer, adding that the other phases have not been initiated.

"They'll need to remove and rehabilitate several storm drains that are in the area," he said. "There's areas that are lower than sea level, so some of that may need to be drained down and pumped out. Ultimately there's work that needs to be done on the river that's over there."