HAU'ULA — Windward resident Chris Guerrero envisions the worst whenever rain is in the forecast: flood waters overflowing a nearby clogged stream, gushing through his yard and pouring under his house, undermining its foundation.

"This is a tragedy waiting to happen," Guerrero said. "Luckily, we haven't had much rain, but when it rains, we will have another major flooding."

Last spring's 40-plus days of rain created a dam under one span of the bridge, an island of boulders downstream and a boulder-strewn streambed.

Memories of the constant rain that flooded many Windward areas and filled streambeds with dirt, debris and rocks has Guerrero and his neighbors worried about their property. The stream went from 35 feet wide to 140 feet wide, covering more than half his and his neighbors' property.

For years, rocks and debris collected under the Kaipapa'u Bridge, and one side of the bridge is completely blocked.

Guerrero said he has been after the city and state for more than two years about the problem.

Help is on the way, but the earliest it can arrive is the beginning of next year, said George Abcede, state Department of Transportation maintenance engineer for the O'ahu District.

The project is complicated and requires getting an excavator of some kind to pull material from under the bridge. The state doesn't have the equipment so it must hire outside help, Abcede said. Several contractors inspected the site and one agreed to do it, but pulled out after a second look, he said.

The DOT was hoping to get the debris removed for less than $25,000 because work could be done immediately. Any cost higher than $25,000 would require the DOT to go through an extensive procurement process that would take even longer, he said.

The bridge is scheduled for replacement in 2008 and that would make removal simpler, but Abcede said the material has to come out sooner.

"I think we have to do whatever we can for under $25,000," he said.

Like many of the older bridges in Hawai'i, Kaipapa'u Bridge doesn't meet state and federal bridge and roadway standards. The 74-year old bridge is structurally deficient and is one in a series of state bridge replacements, according to a draft environmental assessment of the project. The bridge doesn't meet design standards for highway speed, load, sight distances, guard rails and pedestrian accessibility.

It also seems to trap debris, causing rocks and dirt to accumulate under the spans. In a heavy storm, the blockage could cause the stream to overflow and where the water would go is anyone's guess, said David Bangert, who lives on the stream.

"Our fear, of course, is it will go through our yard and take out our house, take out part of our yard," said Bangert, recalling how a Manoa flood two years ago caused by a clogged stream damaged many buildings on the University of Hawai'i campus, where he is a business professor.

Guerrero, a disabled veteran, and Bangert, who also is a licensed civil engineer, called the city and state, only to be told that the stream is privately owned and the state is only responsible for keeping the waterway clear under the bridge.

Bangert said he's also worried that the new bridge project will make flooding worse because the plan calls for a wall across the stream from his home that would force the water toward his property and be a choke point for the outflow of water.

"The wall would protect another home on the other side of the stream, but it's going to change the flow of the stream and every time you do that, there's a concern," he said.

The state Department of Transportation Highways Division and the Federal Highway Administration will install a pre-stressed concrete girder bridge 110 feet long by 57 feet wide.

The design includes two 12-foot lanes, two 8-foot-6-inch shoulders, two 5-foot pedestrian walkways/bikeways, guard rails, and drainage features. The bank of the stream beneath the bridge abutments will be stabilized with concrete to maintain the integrity of the embankment.

But before the $11.55 million project gets under way in 2008, Guerrero wants the state to clear under the bridge. And so do his neighbors.

"I'm 100 percent disabled veteran and all my life savings are in this house," he said.

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.