Posted on: Saturday, April 23, 2005

Plant cleaning of Ala Wai gets OK

By James Gonser
Advertiser Urban Honolulu Writer

A plan that would use floating platforms covered with plants to clean up urban pollution at the Ala Wai Canal has gotten the go-ahead from the state.

The state Board of Land and Natural Resources yesterday approved a permit for Natural Systems Inc. to begin installing a 3,396-foot long, 5-foot wide platform covered with 'akulikuli plants.

Roots of the 'akulikuli plants will drop down from 3 to 5 feet into the water. Bacteria and microorganisms that colonize the roots will improve water quality by drawing in nitrogen, phosphorus and algae as nutrients.

"In one year, we hope it will demonstrate water quality improvement due to the project," said Chad Durkin, project manager. "We think it is the most cost-effective application to control non-point source pollution."

Non-point source pollution results when rainwater moves over and through the ground, carrying away natural and manmade pollutants such as sediment from construction sites, excess fertilizer, pesticides from lawns, bacteria from livestock and pet wastes that wash into street gutters.

In urban Honolulu, much of that washes directly into the Ala Wai Canal, which has posted warning signs against swimming and eating fish living there.

The platform will be laid out in sections over the next three months stretching from the Manoa-Palolo drainage canal to near the Waikiki-Kapahulu Public Library. A second, 50-foot long platform will cross the canal at the end.

The project is funded with a $500,000 federal grant.

Durkin told the board that water will be tested monthly with the results given to the state Department of Health to document changes in water quality.

Board approval came with three conditions: that the project have no commercial activities, that it is entirely removed at the end of the year and that the company work with canoe clubs that use the canal to ensure they have access to the water.

"I think it is a worthwhile project," said board member Kathryn W. Inouye. "I just want the end result to benefit the state."

The floating platform will be anchored to the bottom and within 20 feet of the mauka bank of the canal leaving room for paddlers to navigate the waterway, Durkin said. He said commercial activities are not part of the project and the grant includes funds to remove the platform.

Phytoremediation is the term used to describe the treatment of environmental problems through the use of plants. Certain plants are able to extract hazardous substances from soil and water, according to Wenhao Sun, vice president of Marine Agritech, a partner in the demonstration project.

The company also is conducting similar demonstration projects in Salt Lake and in Kawa Stream in Kane'ohe, and last week was recognized by the Environmental Protection Agency for a commercial project at the Four Seasons Resort Hualalai on the Big Island.

Sun said the main objective of the Ala Wai project is to clarify the water and improve the growth conditions for submerged aquatic plants. A secondary goal is to restore a sea grass ecosystem and improve the water quality in a sustainable manner.

Durkin said both Marine Agritech and Natural Systems hope the project will help them market their remediation technologies and the state could be a major customer.

"The main goal is to introduce this technology, get it through the door so that whoever wants to work with this will see it's a good way to go," he said.

Previously, Sun had said it would cost between $1 million and $1.5 million to run a platform the length of the canal to keep the water clean on a long-term basis.

Reach James Gonser at jgonser@honoluluadvertiser.com or 535-2431.