KAILUA — Parts of Kawai Nui Marsh waterway are clogging with debris and trash, some of which is moving toward Hama-kua Marsh and Kaelepulu Stream.

"Even just the normal winter rain is going to unleash all this into the Kaelepulu Stream, and it's going into Kailua Bay," said Shannon Wood, with the Windward Ahupua'a Alliance.

In an effort to avoid that, tomorrow morning the private, nonprofit alliance, in partnership with government agencies, businesses and volunteers, will scoop trash out of the water and haul material from the shoreline, which runs parallel to a flood-control dike in the marsh. Problems will be assessed from boats while workers remove the litter from the water and banks, Wood said. Volunteers must pre-register to take part.

The cleanup effort is part of the ongoing Get the Drift and Bag It campaign. A second round of cleanup is set for Oct. 28 as a Make a Difference Day event.

Decades of mangrove growth along the Kawai Nui Canal have trapped thousands of bottles, pieces of plastic, styrofoam containers, paper and cans, which are visible from a Kailua Road bridge. The banks are littered with furniture, tires, a bowling ball, a bicycle, cushions and a motorcycle, among other things.

The debris problem was exposed during the summer when a city contractor cleared mangrove from the overgrown waterway, said Larry Leopardi, chief of the Road Maintenance Division. While the city does remove trash from waterways, the Kawai Nui Canal is not a current priority, he said.

"We're still taking tons and tons of silt, black sand and other things that came down from Tantalus, and that's only one stream," Leopardi said, referring to the ongoing cleanup in the aftermath of a six-week stretch of heavy rains and flooding earlier this year. "There's a whole bunch of other streams that we're trying to get in condition for the winter rains."

City road maintenance workers will be on hand tomorrow to haul away the trash and assist with assessment matters, Leopardi said. The state Department of Land and Natural Resources will also take part. The state owns the Hamakua Marsh, and trash in the canal impacts the state's preserve, said David Smith, DLNR wildlife manager for O'ahu.

Smith hopes the cleanup will prompt an effort to maintain the mangrove. "Hopefully, this volunteer group can keep up with it," he said. "It's hard for the city guys because they have so much stuff already."

The future of the canal and marsh area is in limbo because of a longstanding impasse over a plan to transfer land from the city to the state. At issue is the upkeep of the flood-control project that includes the dike and the canal. The state is willing to take control of the marsh, but not the flood-control project.

Libby Tomar, president of the Coconut Grove Community Association, said cleaning the canal could eventually lead to expanded use of the waterway, including the addition of hiking trails, water access to the ocean and canal-area seating at restaurants.

She said the land transfer dispute is holding up other projects, such as a multimillion-dollar water bird restoration project. "I would love to see the city and state work together to turn over the ownership or management so we can get the money for the water birds," Tomar said.

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.