Experts traced the flood's cause to a complicated mix of conditions that includes haphazard and rapid development in Manoa Valley, outdated flood control measures and residents dumping debris in the stream.

Add a 50-year rain and it was enough to damage 30 buildings at UH, destroy untold numbers of historic documents and priceless research, and inflict at least $5 million in property losses on more than 150 homeowners.

And it could happen again — any time, said Patricia Cooper, a geologist who studies stream behavior. As interim associate dean of the School of Ocean and Earth Sciences and Technology, she's doing extensive analysis on the flood's causes.

"It was more water than the channel could handle and the debris caught in the bridges made it worse," said Cooper. "But the 'why' is that Manoa is paved now so there's no place for the rain to go except into the stream.

"If it rains steadily all day, the stream channel will accommodate most of the run-off. But if the stream channel is extremely full and there's another big slug of water coming through, yeah, you could have another flood."

Experts are studying how to keep it from happening again.

But it's clear that it will require a massive effort involving city, state and federal agencies, the university and even homeowners. High-priority, shorter-term measures are being weighed to reduce the magnitude of any future flooding, but far-reaching solutions could be years away.

No place to go

A UH-Manoa soil erosion expert says buildings on the campus were built too close to the stream — without adequate flood prevention measures.

"What should have been done before any buildings (were built) was to put drainage facilities beside the stream," said Samir El-Swaify, chairman of the UH Department of Natural Resources and Environmental Management. But El-Swaify also noted that flood-control planning rarely takes into consideration 50-year storms.

Yet, even added drainage may not have prevented the Oct. 30 flood that saw the stream jump its banks farther up Manoa Valley, channeled by debris caught against bridges and chain-link fences, fed by water from new culverts and allowed to flow out of the streambed by alterations to its banks.

Even culverts on the other side of the valley contributed. Homeowner George Endo, who lives on that side of the valley, sees his property flood virtually every time it rains, but said he can't get the city to maintain the ditch entrance across his property, though it maintains the exit.

"It's overwhelming. The pipes cannot handle the volume of water and it just overflows repeatedly. And all of that run-off eventually goes to Manoa Stream."

Endo said when he moved in nine years ago he began worrying about all the new homes being built in Manoa. "Where's the impact statements. How can all these residences be approved without any plans for the run-off?"

Jumbled ownership

Complicating all of this is the confusing patchwork of responsibility for keeping the stream clear, a duty that's shared among the city, state, UH and private homeowners. With at least 50 percent of the stream owned privately, adjacent landowners are responsible for its maintenance to the middle of the stream, say state officials.

"We're constantly telling people 'Don't throw stuff in the streams,' " said city information officer Carol Costa. "This is just what happens. You have heavy weather and all that stuff rushes down and produces a big clog. The downpour caused the banks to overflow but the debris thrown in didn't help.

"You could see the fresh cuts on the logs when they came down," said Costa. "One of those trunks came down like a battering ram and hit the supports for the little pedestrian bridge and the whole thing collapsed into the stream."

Private ownership of the stream extends from the far reaches of the valley to East Manoa Road, where state ownership takes over for two blocks to Woodlawn Drive and on to Kalawao Street. City ownership, meanwhile, covers portions under bridges and some lined channelized areas above bridges created as flood control projects. UH responsibility includes the section flowing through its land.

"All the owners along the stream own half of the stream," said Didi Mamiya, land division administrator at the state Department of Land and Natural Resources. "Whoever owns the stream is responsible for clearing it."

That includes homeowners such as Thomas Yoshioka, who said it hasn't been clear that he's responsible for daily upkeep of the stream, now blocked by boulders where it runs through his land.

"I don't know whose responsibility it is," said Yoshioka. "Maybe it belongs to me. I don't know. But I have been taking care of the stream. My dad and I put walls up ourselves in 1952 or so."

But debris is only part of the picture.

"Even if that stream was spic-and-span, we still would have had run-off," said Civil Defense vice director Ed Teixeira. "When the water overran its banks and the debris got caught on some of the cyclone fences, what essentially happened is it may have channeled the water into areas where we didn't want it to go."

While UH is pointing no fingers, interim President David McClain made it clear he expects the state and city "to take the necessary measures to make sure the stream is as clear as possible.

"It's important to understand that the problem we suffered and its origins are up in Manoa Valley," said McClain, "with the stream and a fair amount of trees that showed up in the stream."

University officials can't yet estimate damage because of the complexity of the losses of research, intellectual property, rare library collections and the time spent getting hundreds of researchers into alternative work space. However, cleanup costs alone by the global recovery company BMS Catastrophe are estimated at $5 million, and at least one renowned researcher has pegged her own laboratory losses at more than $1.5 million.

UH grants at stake

The longer it takes to restore functions such as electricity to make laboratories usable in the Biomedical Sciences tower especially, the greater the potential damage to research efforts that survived the flood — and future grant income on which UH depends heavily.

John A. Burns School of Medicine Dean Ed Cadman estimated that $20 million in research for the National Institutes of Health is being jeopardized if power and air-conditioning aren't restored soon to the tower.

"If you don't perform, they don't give you the money," said Cadman of the multimillion-dollar service contracts. "If we don't get power for two months they will probably stop funding us."

The group Malama 'O Manoa organizes volunteers monthly to clean the stream and a group was out just that morning, and the state does checks twice a year.

Rep. Kirk Caldwell, D-24th (Manoa) wants more attention paid to changes in the stream.

"Anything you do at one part of the stream can affect it farther down," Caldwell said. "For instance, when the elderly housing was built, the bank was raised on that side which forced the water to bounce off the lower bank where all the homes were."

And he suggests even more cooperation between the state and city, even if it means helping out on private property.

"Many of the people are elderly and they don't have the money to have a tree trimmer come and cut a huge log that has fallen," he said. "Most government agencies say it's not government property so we're not going to touch it, yet it has an impact on the public at large. I hope government sees they have a responsibility here. Maybe they can do regular patrols and where they find potential hazards, take action."