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The Honolulu Advertiser
Posted on: Monday, December 2, 2002

Study finds Waimanalo runoff hurting reefs

By Eloise Aguiar
Advertiser Windward O'ahu Writer

WAIMANALO — Preliminary research on Waimanalo Stream and the effect of its runoff on coral reef show that something must be done to improve the waterway, but a state official says the community and government lack the will and resources needed for such a large project.

Waimanalo Stream has been called one of the most seriously polluted bodies in Hawai'i, with an estimated 42 percent of its stream bed choked with dense grass and a significant portion hardened with concrete.

Ed Laws, a coral reef specialist and professor at the University of Hawai'i, is studying the effects of channel hardening on water quality in the stream, Waimanalo Bay and on coral reefs.

His preliminary results show the flat concrete bottom of the hardened channel heats up and destroys vertebrates and invertebrates that make up part of the stream's life cycle, including degradation of material that makes up the substrate in stream beds, Laws said.

The ecology of the stream is destroyed, he said, so that it no longer behaves like a sponge, soaking up rainwater and releasing it slowly during dry weather. Instead, runoff pushes everything into the ocean, depositing pollutants in near-shore waters and on reefs.

Restoring stream habitat will be essential to eliminate the adverse effect on coral reefs, he said, adding that the study will include recommendations for stream management.

"I'm hoping the data we get out of this will be of use to somebody who can follow up on this in a political way, or perhaps a legal way, to get the authorities to modify the way they're treating these streams," Laws said.

June Harrigan, manager of the state Department of Health's Environmental Planning Office, said getting someone to do something has been a problem for her office, which has begun measuring pollution in streams and drawing up plans to eliminate some of the contributing causes.

Small projects have been done to improve Waimanalo Stream since the state completed a study of nutrient and sediment levels, but the result is essentially cosmetic, Harrigan said. Small-scale solutions by volunteers have improved stream banks, but are not large enough to affect water quality, she said.

Large projects require broader, multi-agency and community partnerships, as they tend to involve multiple landowners, environmental reporting requirements, permits and contract management.

"That's rather daunting for a community group," Harrigan said, adding that such a project could cost millions of dollars.

The Health Department last year documented 111 polluted coastal waters and streams in Hawai'i. These could affect the ocean, beaches and groundwater, she said. Yet Hawai'i does not have laws mandating restoration of water quality for aquatic communities or stream habitat.

"Laws are not always enforced, because there's no will to do so," Harrigan said — or no money.

She said she was not aware of Laws' research, but said such reports begin to educate the public about the issue.

"I think they'll become more visible to people, and hopefully these groups will start to pay more attention to the condition of their streams," Harrigan said.

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com or 234-5266.