WAIKIKI — A year after 48 million gallons of raw sewage was diverted into the Ala Wai Canal, canoe clubs are returning to their home waters to get ready for the upcoming regatta season.

It's a welcome homecoming for many of the clubs, some of which have called the Ala Wai home for decades. But it's accompanied by an abundance of caution despite assurances from the state Health Department that bacteria levels have returned to pre-sewage numbers.

Last March the contaminated water forced nearly a dozen canoe clubs to move to new practice sites, from nearby Kaimana Beach to Maunalua Bay in Hawai'i Kai.

Some clubs returned to the Ala Wai in August 2006 to finish the long-distance season, which ended in October. But most stayed away.

Now, with this year's regatta season starting in May, a number of displaced clubs have returned, and others are considering whether to come back to the convenient, flat-water location.

"It's no different now than it was before (the raw sewage release)," said Mike Cushnie, head coach of Lokahi Canoe Club, which returned last August after temporarily relocating to Kaimana Beach. "There was a difference when it happened for about six months. Now it's OK."

A year ago Saturday, an aging sewer main ruptured, prompting the city to divert the raw sewage into the Ala Wai Canal rather than risk it backing up into nearby homes, hotels and businesses.

To prevent that from happening again, the city has spent an estimated $38 million to put in temporary lines under Kai'olu Street, where the line cracked last year. The project will include a permanent fix to the aging sewer system.

Bacteria levels in the Ala Wai Canal are back to what they were before the sewage was diverted last year, said state Health Department spokeswoman Janice Okubo. These levels tend to be higher here than in other waterways because the canal is a drainage basin, Okubo said.

As they have for years, warning signs about the contaminated water remain posted along the canal, urging people — including paddlers — to stay out of the water.

Lokahi paddlers started practicing for their regatta season earlier this month. No one from the club has reported becoming sick or getting infections since returning to the Ala Wai, Cushnie said.

"To me, it's how it used to be," said Cushnie, who's been coaching at the club for 27 years. "I don't know if there's any more bacteria. But so far, nobody's gotten more staph or infections than we did before, at least at our club."

Some canoe clubs have not returned to the Ala Wai Canal, citing health concerns.

Last March, Healani Canoe Club relocated to Sand Island.

While some of its youth paddlers may still train at its original site at the Ala Wai, the rest of the crews likely will remain at Sand Island, where the water quality is better.

"It was a tough decision," said head coach Kea Pa'iaina.

While the Ala Wai Canal's location is convenient and the flat water ideal for working on paddling technique, the risk of paddling in contaminated water fueled Healani's decision to stay at Sand Island, at least for this season.

Pa'iaina said if the club had moved back to the Ala Wai last August, he would have lost many of his adult paddlers.

"It's going to be a year-to-year decision, and we'll re-evaluate it again," Pa'iaina said.

Reach Catherine E. Toth at ctoth@honoluluadvertiser.com.