AMNA NAWAZ: The deadly wildfires that tore through Maui just over three months ago destroyed thousands of structures and killed 100 people, but they also reignited a long-simmering concern among Native Hawaiians over who controls one of their most precious natural resources, water.

Here now is William Brangham again, who was in Maui to report this story recently.

WILLIAM BRANGHAM: This modest little stream trickling through the Waikapu Valley in Central Maui represents one small victory in a generations-long struggle, because, for years, there was no water.

HOKUAO PELLEGRINO, Farmer: These streams dried up overnight, and not by Mother Nature, but by the hands of men.

WILLIAM BRANGHAM: But now freshwater from the mountains freely flows down to Hokuao Pellegrino's ancestral farm.

With that water, this educator and farmer can now grow taro, or kalo, a crop that has deep cultural and historical meaning on these islands.

HOKUAO PELLEGRINO: We believe that we come from this plant, that it is our elder brother, and we will do anything and everything in our power to protect it.

WILLIAM BRANGHAM: For more than 100 years, growing kalo here was nearly impossible because, in the 19th century, sugar plantations founded by Americans and Europeans diverted streams across the island to irrigate their fields.

HOKUAO PELLEGRINO: When the streams were diverted by the sugar plantations, the traditional irrigation systems went dry.

The land cracked literally in all these... WILLIAM BRANGHAM: From dryness.

HOKUAO PELLEGRINO: From dryness, yes.

And those plants died.

NARRATOR: Sugarcane needs water.

It's a thirsty crop.

The planter's solution, burrow tunnels through the mountains, build siphons, raise flumes, and dig ditches, miles of them.

WILLIAM BRANGHAM: What did that do to the Native people who were living here?

HOKUAO PELLEGRINO: Besides taking away their food source, it was their livelihood, it was their traditions, their language.

WILLIAM BRANGHAM: In a matter of decades, to feed the booming sugar industry, much of Maui was transformed, including the town of Lahaina.

It was once known as the Venice of the Pacific, with lush forests, wetlands and ponds, a vision that's hard to imagine now after this summer's inferno burned so much.

I'm standing in one of the many fields in Lahaina that burned, and in addition to the historic water diversions that went on here, the fight over water is now also complicated by climate change and reduced rainfall and increased drought.

KAPUA'ALA SPROAT, University of Hawaii at Manoa: In an area that was already water-scarce, over a century of plantation mismanagement has really created a tinderbox.

WILLIAM BRANGHAM: University of Hawaii Law Professor Kapua'ala Sproat has helped Native Hawaiians reclaim some legal control of the island's precious fresh water.

KAPUA'ALA SPROAT: In these incredibly isolated island communities, water was and remains the source of all life.

In many ways, I mean, this is a fight for the soul of Hawaii.

WILLIAM BRANGHAM: Hawaii's Constitution protects water as a public trust, but, today, some of Maui's water systems, including three-quarters of West Maui's, remain under control of water and development companies, some of which are direct descendants of plantations.

KAPUA'ALA SPROAT: These plantations are no longer the backbone of the economy, but, at the same time, they continue to take almost all of the water resources from our streams and communities for their private commercial gain.

HOKUAO PELLEGRINO: Sugar plantation is gone, right?

But it's only been replaced with lawns and golf courses and hotels and large water users.

WILLIAM BRANGHAM: Sproat helped successfully represent Pellegrino and other Native Hawaiians in part of an almost 20-year legal fight to restore water to four historic streams.

HOKUAO PELLEGRINO: That was really truly a David versus Goliath.

Me, personally, I really just wanted to grow kalo and feed my family.

WILLIAM BRANGHAM: As simple as that?

HOKUAO PELLEGRINO: Very simple.

But we knew it was going to take time.

WILLIAM BRANGHAM: His group's victory was part of a steady progress made by Native Hawaiians over the years.

But when the wildfires swept through Lahaina, killing 100 people and destroying thousands of buildings, some raised questions about whether those legal fights over water made this disaster worse.

During the fire, the administration of Hawaii's Democratic governor, Josh Green, suspended the state's water code and, with it, protections for Native farmers water rights.

The next day, a major real estate developer, the West Maui Land Company, asked state officials if it could permanently reduce the amount of water it had to provide those farmers.

West Maui made the request for - - quote -- "fire suppression in our community."

Soon after, Governor Green seemed to echo those concerns.

GOV.

JOSH GREEN (D-HI): There has been a great deal of water conflict on Maui for many years.

It's important that we're honest about this.

People have been fighting against the release of water to fight fires.

WILLIAM BRANGHAM: Advocates say they have never opposed diverting water needed to fight fires and argue they're not to blame for this tragedy.

HOKUAO PELLEGRINO: This idea that we're pinning one side against the other is just a continued false narrative.

Putting water in the stream ensures that we have water in our tap.

By protecting this resource, it would protect all of us, not just Hawaiians.

KEKAI KEAHI, Farmer: Almost arrogantly, they refuse to listen to the law.

WILLIAM BRANGHAM: Kekai Keahi, a Native Hawaiian farmer and leader, has long advocated for increased oversight of the West Maui Land Company.

The company and its subsidiaries have been fined repeatedly for breaching water laws, including taking too much out of a stream.

KEKAI KEAHI: I think West Maui Land Company used this tragic time and people's hurt and pain, thinking that we'd be distracted, to try and push their agenda of trying to regain this water that they lost, and Josh Green helped them out.

WILLIAM BRANGHAM: West Maui Land Company rejects those assertions.

In a statement to the "NewsHour," it said it simply wants to guarantee that enough water is available to fight fires when needed.

Several weeks after the fires, officials reinstated the state's water code.

But many in Lahaina and across Maui remain outraged.

MAN: Water is life.

Life comes from water.

But what happens when that life-giving source is mismanaged?

WILLIAM BRANGHAM: Water rights have become a rallying cry for locals and Native Hawaiians as the state continues the rebuilding process.

Last month, hundreds attended a state water commission meeting, demanding an overhaul of how water is managed in Lahaina.

MAN: I truly believe that the homes of my ohana and all of us here that have lost would still be there had there been responsible management of our water resources.

WILLIAM BRANGHAM: Back in Central Maui, past his kalo patch, in the stream that his legal battle helped restore... HOKUAO PELLEGRINO: Let's see how lucky we are.

WILLIAM BRANGHAM: ... Hokuao Pellegrino says bringing water back to Lahaina's streams will not only revive traditional farms; it could also help heal long-damaged ecosystems.

HOKUAO PELLEGRINO: And here it is.

There it is.

WILLIAM BRANGHAM: It did just that in his own backyard.

These Native freshwater snails, now common here, could not survive without this water.

HOKUAO PELLEGRINO: Imagine, these have to go all the way down to the ocean to spawn.

WILLIAM BRANGHAM: These guys?

HOKUAO PELLEGRINO: Yes.

When you start to see things like this, then you know it makes it all worthwhile, because these guys don't have a voice.

They require us to speak up for them.

WILLIAM BRANGHAM: In the wake of those devastating fires, a growing chorus of Native Hawaiians seem to be doing just that.

For the "PBS NewsHour," I'm William Brangham on Maui, Hawaii.