The settlement of a long-standing dispute over the diversion of water from four Maui streams sends a gratifying message to all concerned about Hawaii’s commitment to manage its water supply as a precious public resource.

The accord was sought by the environmental law agency Earthjustice, which represented community groups Hui o Na Wai Eha and Maui Tomorrow Foundation; the Office of Hawaiian Affairs also was a party to the case.

The bottom line is that the agreement doubles the total minimum volume of stream flow to be required for all four streams from where an earlier ruling had set it, improving prospects for taro cultivation, regeneration of stream habitats and other environmental benefits.

That is a clear victory in the quest for a fairer system of allocating water resources, but the work is not finished, not by a long shot. What must happen now is the development of a permitting system that will turn the legal language into the reality of sustainably managed surface water.

At issue was the distribution of water once used for sugar cultivation by Hawaiian Commercial and Sugar Co. and Wailuku Sugar. The latter company sold its plantation lands to developers and became Wailuku Water Co., with a new business model based on the control, development and selling of land and water.

The plaintiffs rightly countered that this ran afoul of laws governing water use. In 2010, the state Commission on Water Resource Management decided to restore 12.5 million gallons a day to two of the streams Waihee River and Waiehu Stream but none to Iao and Waikapu streams.

Earthjustice appealed to the state Supreme Court, which overturned the decision. The settlement was reached in mediation before the water commission was to rehear the case: The Waihee and Waiehu minimum flow levels were retained, with the additional restoration of 10 million gallons a day to Iao and 2.9 million gallons a day to Waikapu.

Isaac Moriwake, Earthjustice attorney, said that whatever entities seek a water permit should expect to bear the burden of proving the need for the resource and show they have explored alternative sources and eliminated excess wasting of the water.

The state courts have recognized the value of preserving existing water uses, such as the ability of taro farmers to cultivate their crop. Moriwake said Hawaii has a 2000 high court ruling, the landmark Waiahole water case, to thank for that, as well as the reaffirming decisions that followed.

These have included the recent Supreme Court case, Kauai Springs v. Kauai Planning Commission, he added, which reinforced principles that water is a public trust and that private parties profiting from it must justify additional diversions of the resource.

These decisions should matter greatly to every resident of Hawaii; while the preservation of the livelihood of small farmers is very important, they are not the only beneficiaries here. Preserving minimum flow of surface water reinvigorates stream habitats but it also helps to recharge the underground aquifer of drinking water.

In years of drought and Maui has been one island that has experienced this the threat to the potable water supply undermines the security of the entire community.

Hawaii has been richly endowed with water and, more to the point, with the foresight to recognize the crucial need to treat it as a limited resource. Lawmakers have enacted a strong water code, and the Judiciary has upheld it. The next steps in the restoration of these four Maui streams Na Wai Eha should follow the path marked by these actions.