More than two years after Manoa Stream jumped its banks and flooded homes, businesses and University of Hawai'i buildings, a new federal report gives state and city officials suggestions for short-term, relatively inexpensive ways to mitigate the risks of similar floods.

But as Manoa residents are calling for quick action on the study — and with $5 million already available for a mitigation project — the state and city say they are still in negotiations and won't commit to any short-term projects until liability and other concerns are straightened out. They are not working on a time line, but officials say it could take a year or more for the parties to agree on a fix.

Those who live and work in Manoa are frustrated by the pace of flood mitigation efforts.

With a long-term solution decades away, they say something needs to be done in the interim to keep their homes, schools and businesses safe.

"There could have been fatalities in the flood," said David Ulrich, whose basement and car were flooded. "I was lucky. A lot of my neighbors fared worse."

But city Department of Design and Construction Director Eugene Lee said he would be reluctant to go forward with any of the fixes without more study.

"We would be hesitant to go in and do something without knowing what it would do downstream," Lee said.

Lee said all of the proposals in the report, released this week, would require a comprehensive downstream impacts report, which could take a year or longer to complete. And Peter Young, state Department of Land and Natural Resources chairman, said a short-term fix would have to fit into a long-term plan for Manoa Stream.

STREAMBED FINDINGS

The Manoa flood of Halloween Eve 2004, which caused an estimated $85 million in damage, was spurred by a combination of unusually heavy rains and debris-laden streambeds, according to the new U.S. Army Corps of Engineers report. However, the report says some flooding — as far down to the UH campus — still would have occurred even if the streambeds were cleared.

The conclusion raises questions about state and city efforts on stream mitigation over the last 26 months, which include streambed cleaning and dredging portions damaged in the flooding.

Army Corps hydrolics engineer Michael Wong, who co-authored the study, said the overall capacity of the stream needs to be increased — at Woodlawn Drive, especially — to lower the risks of another flood.

"By increasing the capacity, they would get the most benefits for the limited amount of dollars they have now," Wong said yesterday. "So far, nothing has really been done."

The report comes as the Army Corps is also working on a flood zone study for the Ala Wai Canal, which includes an analysis of the Manoa Stream. The report is expected to be released in 2008, and will allow the state to apply for federal matching funds for long-term flood mitigation projects.

Officials say Manoa Stream would likely see a long-term flooding fix in 10 to 20 years.

RESIDENTS ANXIOUS

Duane Preble, a former board member of Malama o Manoa, said there is no consensus among residents about what needs to be done. But there is a strong drive to get something done soon.

"It seems they're (the city and state) moving very slowly," said Preble, who is still a member of Malama, a nonprofit dedicated to preserving historic Manoa Valley. "Two years (since the flood) is a long time. They need to move a little faster, and a little more comprehensively."

Fred Lee, of upper Manoa, said the city and state have not spent enough time thinking about how to mitigate flooding above Woodlawn Drive Bridge. Lee is one of dozens of homeowners whose property lines extend into the streambed. Under law, he is responsible for its upkeep.

"The Corps of Engineers and the city and the state, they're only concerned about the stream below the Woodlawn Drive Bridge," said Lee, whose home was damaged in the flood. "But what about all of us who are above the bridge?"

The Army Corps report gives officials four major recommendations for short-term projects aimed at reducing the risk of floodwaters topping the banks of Manoa Stream.

Cost estimates are not included in the analysis, but Wong said all of the proposals would be relatively inexpensive. The efforts are centered in lower Manoa, where most of the community's homes and businesses are.

State Rep. Kirk Caldwell, who represents Manoa, said he favors a proposal to build a small dam and install floodwalls at Woodlawn Drive Bridge. The system would have prevented flooding at the bridge two years ago, the Army Corps report said, but would not have affected flooding in other parts of the stream.

"It's really good news that we have this report," Caldwell said. "Every time it rains really hard in Manoa, the residents of that valley become deathly scared. ... "

He also said the report is particularly troubling because it calls the 2004 flood a 25-year event, which means the chance of it happening annually is about 4 percent. Earlier, it had been assumed to be a 50- and even 100-year flood.

Also, the study says without any debris blockages, the East Manoa Road and Woodlawn Drive bridges still can only withstand flows of a 10-year flood.

'WE CAN'T SIT AROUND'

The figures, Caldwell said, illustrate why officials need to move quickly on a short-term mitigation effort. He said the state, city and federal government have already pitched in $5 million for a project. The money was made available in the last legislative session, he said.

City Councilwoman Ann Kobayashi, who also represents Manoa, agreed something more needs to be done — soon. She said the state and city should be able to resolve their concerns without months more of study.

"We can't sit around and do nothing," said Kobayashi, a resident of Manoa.

The Army Corps report studying solutions was long delayed.

Wong, of the Army Corps, said he finished the report in January 2006 and transmitted it to the city and state. The city returned comments within a few weeks, but the state did not return its recommendations until October. Young said he could not comment on the delay.

Reach Mary Vorsino at mvorsino@honoluluadvertiser.com.