For decades, residents on the west side of Kauaʻi have watched the water level drop in Waimea River, the region’s biggest and most important natural river system.

John Aʻana, a 58-year-old taro farmer, used to take his son swimming in the Waimea River. They would jump from a swinging bridge into a swimming hole 15 feet deep. Now, the water depth is less than a foot.

“For a long time we’ve known there’s something wrong with this picture,” says Aʻana, who helped found a local group called Poʻai Wai Ola to restore the Waimea River as a public trust for future generations.

Starting in the 1920s, industrial sugar barons massively diverted the Waimea River to water their sugarcane, one of the thirstiest crops on earth. The crops consumed 50 million gallons per day, enough water to fill 75 Olympic-size swimming pools. But the plantation era in Waimea ended in 2001. Today, only a fraction of the fields are planted with corn and other crops, which sip water instead of gulping it.

Yet bizarrely, corporate water users continue to divert nearly as much water as before without using it. And rather than remove the system of dams and ditches that have nearly sucked the river dry, the state Agribusiness Development Corporation has been rebuilding it.

Where does all the excess river water go? Earthjustice attorneys David Henkin and Isaac Moriwake investigated a tip from Poʻai Wai Ola and were shocked to find freshwater being dumped over cliffs and flung into dry gullies.

Someone has gone to great lengths to avoid replenishing the Waimea River, says Henkin. “They have virtually no use for this water. There’s no justification for continuing to keep the tap running like this,” he says.

In late July of 2013, Earthjustice filed a legal petition on behalf of Poʻai Wai Ola, asking the state Commission on Water Resource Management to set higher base flow levels in the Waimea River. The petition may forestall more intensive legal proceedings if the ADC acts swiftly to cut back on the excessive diversions and stops dumping water, says Henkin.

Hawaiʻi law enshrines water resources as a protected public trust. That includes protections for Native Hawaiian traditional practices and for wildlife, both of which depend on a healthy watershed.

Today, the Waimea River is so choked with silt that it often no longer reaches the ocean; contractors must open the sandbars at the river mouth with excavators. Slimy pools of algae stagnate in the sun. ʻOʻopu, a native freshwater fish once plentiful in the river, are now scarce.

Locals like Aʻana suspect the state is hoarding the water for development schemes like hydropower projects, or growing houses instead of sugarcane.

“The cycle is broken,” he says.

Published in the Fall 2013 issue of the Earthjustice Quarterly Magazine.