When the city developed a strategy in the mid-1990s to deal with spills from O'ahu's aging sewer system, it included a contingency plan to temporarily dump raw sewage into the canal running through the heart of Hawai'i's main tourism district.

The contingency was put in place to handle a worst-case scenario: A spill so massive that other options, such as trucking wastewater to treatment plants, weren't deemed feasible.

When a 42-inch pressurized underground pipe broke during heavy rains last month along Kai'olu Street in Waikiki, that worst-case scenario became reality.

Over several days, 48 million gallons of untreated sewage were diverted into the Ala Wai Canal, forcing the closure of some of Waikiki's most famous beaches and giving the state's No. 1 industry an international black eye as news footage quickly disseminated showing tourists unwilling to even wade offshore. The beaches have since reopened.

Critics say dumping into the Ala Wai never should have been considered an acceptable option when the contingency plan was established in 1996, especially given that the city has long known of the need to develop a backup system to the so-called Beach Walk force main that runs for more than a mile in Waikiki.

"There should have been a completely different alternative drawn up a long, long time ago," said Daniel Spears, a University of Hawai'i assistant professor of hospitality management, noting the lingering effects the spill is expected to have on the tourism industry.

"Whoever thought of that contingency plan obviously wasn't thinking of the impact on the economy and people in Waikiki," said attorney Lea Hong, who represents several groups that have taken the city to court over the pace of making improvements to the sewage system.

The city says dumping raw sewage into the Ala Wai no longer is an acceptable option, but that it had no other choice — short of letting the untreated wastewater back up into homes and hotels in Waikiki — when the rupture happened March 24.

"We had indicated to the EPA before my administration came on board that this would always be a last resort — a last option," Mayor Mufi Hannemann said at a press conference yesterday.

"After exhausting what we felt was every other possible remedy, this was the last course of action. To have done otherwise ... the effect on our tourism economy and our quality of life would have been far more devastating and catastrophic."

But because the city's long-standing plan to build a replacement line isn't expected to be completed for roughly three more years, officials are looking at the feasibility of constructing a temporary fix to tide the system over in the interim. That evaluation began after last month's break.

"Now we're starting to question whether this pipe will hold up three more years," said Eric Takamura, the city's environmental services director.

PREVIOUS MAIN BREAKS

The city has raised such concerns because the March 24 break was the third over the past several decades along the Beach Walk force main, the technical name for the pressurized line. In the 1980s, a break resulted in sewage being dumped into the Ala Wai, but Takamura on Friday didn't know the amount or other details. A smaller Beach Walk break occurred in the '90s, but that was repaired without having to resort to dumping in the canal, according to Takamura.

Before the city developed its contingency plan in the 1990s, the public health effects of dumping sewage into the Ala Wai were compared with the cost of installing a backup system at the time, and that cost apparently was deemed too high, said Takamura.

"They chose to live with dumping into the Ala Wai" in case of a worst-case scenario, he said. "We know that's not acceptable anymore."

The city has come under fire for releasing such massive amounts of raw sewage into the Ala Wai. A man who was pushed or fell into the sewage-tainted canal died last week, though it's unclear whether the polluted waters caused or contributed to the bacterial infection that led to his death.

Kathi Moore, manager of the U.S. Environmental Protection Agency's compliance office for the Clean Water Act, said her agency in recent years has encouraged the city to improve upon the mid-'90s plan, which generally called for dealing with spills by dumping into local waterways. She said technological improvements since then have created more effective options.

Moore, based in San Francisco, said her agency never approved a plan that dealt specifically with dumping sewage into the Ala Wai. She acknowledge that last month's spill, the largest in the state, presented a difficult challenge to the city.

"This would have overwhelmed any municipality in the country," Moore said.

But she said she's not certain that the EPA completely agrees that the city had no choice but to dump 48 million gallons into the canal.

"Maybe there's a way that some of it could have been contained or controlled or treated before entering the waterways," she said.

OPTIONS CONSIDERED

Takamura said the city looked at other options but couldn't find one that could handle an emergency of that magnitude. The Beach Walk force main normally handles about 15 million gallons on average daily from Manoa, Mo'ili'ili and Waikiki, but heavy rains during late March pushed the rate to much higher levels. The estimated flows on March 24 totaled close to 35 million gallons.

Takamura said the city sometimes can run a temporary bypass sewer line above ground as it has done in other construction projects. And with smaller wastewater flows, the city can pump sewage into tanker trucks for transport to treatment plants or can divert the flow to another point in the collection system.

But none of those options were feasible with Beach Walk, he said.

Even assuming more typical flow rates, for instance, some 108 tanker trucks would have to be parked over manhole covers in Waikiki for the roughly 20 minutes needed to fill the trucks, then be driven to the plants to dump the loads, then immediately returned to start the process again, Takamura said. That process would continue uninterrupted for days until the main line could be fixed, he said.

There aren't even that many tanker trucks on O'ahu, and even if there were, that option "would create a humongous traffic mess," he said.

Building a temporary bypass would've taken longer than repairing the existing line, and the bypass would have been so large it would've created a traffic hazard and other problems, he added.

And disinfecting the sewage with chlorine before dumping it in the canal was not feasible given the huge amounts of chlorine that would have been required and the widespread environmental damage, including massive fish kills, that would have resulted from the chemical treatment, Takamura said.

PREVIOUS WARNING

The Beach Walk site was one of seven force mains that a city consultant determined in October 2004 were in "very critical" condition and should be considered for replacement.

Since Hannemann took office in January 2005, the city has moved as fast as possible, given budgetary constraints and other factors, to move along the plans to replace Beach Walk with a new line, Takamura said. Some $30 million has been appropriated for the project.

But construction isn't expected to start until the first half of next year, with a minimum of 2 1/2 years needed to complete the line, according to Takamura.

Because the project is expected to take so long, the city is evaluating how much it would cost to install a temporary bypass system that would remain in place until the permanent line is completed. The existing line would be upgraded and would become the backup to the new line.

"I don't think we can take the risk of just sitting around and not having another contingency (besides dumping in the Ala Wai) for three more years," Takamura said.

Dean Otsuki of the O'ahu chapter of the Surfrider Foundation, a nonprofit group dedicated to the preservation of the world's oceans and beaches, criticized the city's handling of the sewage disaster.

"I think it was irresponsible of the city not to have a decent backup plan," he said. "Who's going to come to Hawai'i if they think the water's polluted?

Reach Rob Perez at rperez@honoluluadvertiser.com.