It may seem counter-intuitive to imagine that a coal-fired power plant is more beneficial to sea life than a sugar mill. But in the years since Hilo Coast Processing Company stopped using bagasse and started using coal, corals in the waters that receive discharges from the plant are healthier and more numerous than they’ve been since monitoring began.
The reasons for the improvement in coral density has, in fact, little to do with the transition to coal from bagasse. Most of it may be attributed to the fact that after the sugar mill ceased operating, the massive discharges of muddy water from the plant (allowed by a congressionally authorized exemption to Clean Water Act regulations) also stopped.
The improvement shows up dramatically in coral-monitoring reports that HCPC is required to file annually with the Department of Health. In the immediate area of the main outfall, coral cover of the ocean floor went from less than 1 percent in 1995 to 17.5 percent in 2002. Half a mile from the discharge, coral cover went from 17.9 percent in 1995 to 37.6 percent in 2002. At distances of 1, 1.5, and 2 miles, similar increases were seen.
By another measure, however – that of species diversity – the corals seem to have lost ground in the last decade, especially at the more distant sampling areas. Whether this loss has anything to do with the HCPC plant is not known.
— Patricia Tummons
Volume 13, Number 10 April 2003