Chow said the federal-state Ala Wai Canal Project seeks public input to make sure residents' concerns are not overlooked in the effort to protect Waikiki and surrounding areas against flooding and to restore the ecosystems of Makiki, Manoa and Palolo streams and the Ala Wai Canal.

In the event of a 100-year storm, there is high potential for flood damage to the densely populated and economically important areas of Waikiki, McCully and Mo'ili'ili, Chow said. The Ala Wai Canal, at its current capacity, has been found to have only marginal ability to handle a 10-year flood event and definitely could not handle a 100-year flood, he said.

Renwick "Uncle Joe" Tassill asked when we can expect the next 100-year flood.

Bruce Tsuchida, with Townscape Inc., the company putting together a report on the project, said the term represents a statistical estimate.

"It doesn't mean a storm that size will only take place once in 100 years," said Tsuchida. "In any year there is a 1 percent chance a storm that size could happen."

The current bank-full capacity of the canal has been estimated at 6,500 cubic feet per second, while the peak discharge rate for a 100-year flood flow is estimated at 22,900 cubic feet per second.

Water would submerge parts of Waikiki, McCully and Mo'ili'ili and cause an estimated $175 million in damage to buildings and their contents, studies indicate, and that's not including damage to cars and the cost of emergency response.

Among the options being considered are constructing flood walls around the canal, widening and dredging the canal, modifying bridges and diverting floodwaters through the Ala Wai Golf Course.

Lauren Roth, a University of Hawai'i graduate student in oceanography, said the day-to-day issues of the watershed are more important.

"I look at our streams now as gutters," she said before the meeting. "People throw trash in there; we have all kinds of contamination issues."

A yearlong $7.4 million dredging of the Ala Wai Canal was completed in October, with 185,801 cubic yards of trash, debris and muck removed.

Dredging of the 2-mile canal to a depth of 6 to 12 feet began on Aug. 22, 2002. Two decades of sediment and debris had left the canal only inches deep in sections.

The Army Corps and the state Department of Land and Natural Resources published a report June 8 on their intention to prepare a required environmental impact statement for the Ala Wai Canal Project which, if approved by Congress, would use 65 percent federal money and the remainder from the state.

The impact statement is expected to be completed by the end of 2005 and a report made to Congress in 2006.

The Ala Wai Watershed covers the most congested urban area in the state, and is home to more than 161,000 people. The watershed's streams, springs and pools flow from an abundance of rain from the Ko'olau mountains, and rainstorms often send debris and runoff into the canal.

With parts of streams covered in concrete, and pollutants from cars and pesticides in the water and the canal, the watershed desperately needs improvement, officials said.

Chow said the waters of the Ala Wai watershed have suffered from significant environmental degradation, including heavy sedimentation, poor water quality, lack of habitat for native species and a prevalence of alien species.

Ecosystem restoration actions being investigated include stream channel reconstruction, stream bank revegetation and reinforcement, sedimentation basin and dam construction, debris catchment and energy dissipation, and better maintenance accessibility.

Sally Moses, a paddler and coach with Hui Lanakila, uses the Ala Wai Canal and hopes more paddlers will take interest in the project.

"This meeting shows us they are listening to our concerns," Moses said before the meeting. "It's more important for me to see something done to keep the watershed clean. We all should pay attention to our environment and what we leave to our children and their children."