Native Hawaiians and environmentalists have won a significant court challenge of a diversion of water from a river and three streams known as "the four great waters of Maui." The state Supreme Court has ordered the state water commission to require companies to restore enough water to the public without necessarily forcing them to close shop — a ruling that sends a timely, critical message to public agencies charged with stewardship of Hawaii’s natural resources.

The lawsuit was against the state Commission on Water Resource Management and its decision that only 12.5 million gallons of water daily from the four waters be restored by Wailuku Water Co. and Hawaiian Commercial and Sugar Co., leaving two of the four streams dry. That is far less than the 34.5 million gallons per day —about half the amount that had been diverted — that the commission’s hearing officer had recommended in its 2010 ruling.

Two community groups and the Office of Hawaiian Affairs alleged that the environmental impact statement for the water project failed to give enough details about the source of the water and its cultural and environmental effects on the West Maui Mountain streams.

The Supreme Court’s decision means that more water that had been diverted for the sugar industry will be restored, said Isaac Moriwake, the Earthjustice attorney for the two community groups, Hui O Na Wai Eha and the Maui Tomorrow Foundation.

The groups have a legitimate need for more water to flow for taro cultivation and the restoration of the natural habitat. Even then, the court’s decision should be weathered by the companies, which want the diversion of water to eventually develop thousands of acres of agricultural land for residential and commercial uses.

Rick Volner, Hawaiian Commercial general manager, said the commission’s ruling returned "substan- tial water" to the streams, giving the company "a fighting chance for survival."

He remains "optimistic" that the commission will "strike an appropriate balance" among the needs of the company, the community and stream uses.

The high court found that the commission erred in calculating Hawaiian Commercial’s acreage and failed in holding it and Wailuku Water’s "burdens of proof regarding losses" from diversion of water, instead "choosing a number that appears to be arbitrary." The court said the commission also failed to adequately consider "traditional and customary native Hawaiian practices" in the four waters.

Essentially, it said the commission’s work failed to "display a level of openness, diligence and foresight" required under state law.

The high court’s decision does not direct the water commission to make particular findings about the exact level of water to be restored, but rather, to greatly improve its calculations.

Water use and other resource impacts will continue to be a key discussion as more developments come to fruition throughout the islands. The high court’s ruling in this Maui dispute faulted the water commission for inadequately factoring alternative water sources such as recycled water and nonpotable wells. Such viable options cannot be overlooked for resource efficiency when future developments come calling for project permits.

With this ruling, the court issued an important reminder that any commission with such hefty responsibility must perform its duties with utmost care and thorough examination toward a comprehensive conclusion.

Other county and state commissions should take note.