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Drought puts a stop to artificial floods that have helped restore habitat

MARY LOUISE KELLY, HOST:

As the American Southwest suffers its worst drought in 1,200 years, there is a lot less water in Lake Powell on the Colorado River. That means a longstanding effort to restore habitat downstream in the Grand Canyon is in jeopardy. From member station KNAU in Flagstaff, Ariz., Melissa Sevigny reports.

MELISSA SEVIGNY, BYLINE: The Grand Canyon starts 15 miles downriver from Lake Powell at a place called Lees Ferry. It's where boats launch for trips through the canyon. As well as navigating sometimes scary rapids, boaters like these also have to find a place to camp every night. The best spots are sandbars that form from the rise and fall of the river, says scientist and longtime river guide Katie Chapman.

KATIE CHAPMAN: You have to go bushwhacking to find a place to camp.

SEVIGNY: Sandbars were once common in the canyon, built by the sand, washed down in annual spring and summer floods. Then in the 1960s, the dam was built, and beaches started to vanish. Chapman says that's a problem not just for river runners but also native plants and animals.

CHAPMAN: There's kind of some calm areas. And the back of the eddy is kind of tucked in behind the sandbars, called backwaters or return channels, that are a critical habitat for a bunch of the native aquatic species.

SEVIGNY: That includes four endangered native fish. In the '90s, Federal river managers started to experiment with artificial floods, ramping up the water released from the dam over several days. These floods are small compared to what used to come down the river but four or five times higher than typical dam releases. It worked. Here's engineers cheering as an artificial flood is released from the dam in 2016.

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UNIDENTIFIED GROUP: Woo (ph).

SEVIGNY: Beach-building floods happened most autumns between 2012 and 2018.

PAUL GRAMS: And then we hit these drought conditions.

SEVIGNY: Paul Grams is a hydrologist with the U.S. Geological Survey. With Lake Powell lower than it's ever been and hydropower at risk, the flood program is in trouble.

GRAMS: So we have a condition now where it's been - it's now four years since the last high flow, and the sandbars have eroded a lot.

UNIDENTIFIED PERSON: One.

(SOUNDBITE OF METAL CLANGING)

UNIDENTIFIED PERSON: Two.

(SOUNDBITE OF METAL CLANGING)

UNIDENTIFIED PERSON: Three.

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SEVIGNY: This group of boaters at Lees Ferry are actually scientists, heading out on their yearly trip to document that erosion. Karen Koestner is part of the team.

KAREN KOESTNER: We are going to be mapping sandbars. And we'll have crews looking at vegetation on sandbars. And essentially, we're monitoring change.

SEVIGNY: She's seen that change firsthand on dozens of river trips.

KOESTNER: You see banks breaking off, cut banks forming.

SEVIGNY: Some scientists want to switch artificial floods from fall to spring, when snowmelt bolsters Lake Powell's level. That could help balance the need for floods with the demand for hydropower. Decisions about river management are made by the U.S. Bureau of Reclamation with a diverse group of advisers, among them Matt Rice of American Rivers.

MATT RICE: If we fail, you know, the Grand Canyon could go dry.

SEVIGNY: If Lake Powell drops to deadpool, no water can pass through the dam. That's not expected to happen within the next five years. But Rice points out in a climate-changed world, the drought may never end.

RICE: Ultimately, you know, I think we have one tool, right? It's like, we have to use less water.

SEVIGNY: Rice says his goal is to make sure the pain of water shortage doesn't fall unfairly on plants and animals in the canyon.

RICE: I think about the Colorado River and the Grand Canyon every morning when I wake up and every night when I go to bed. I have to be optimistic. If this place isn't worthy of saving, then what in the world is?

SEVIGNY: The U.S. Bureau of Reclamation declined to give an interview for this story but says they're considering whether to do a fall flood this year. For NPR News, I'm Melissa Sevigny.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.

Melissa grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert. She has a B.S. in Environmental Science from the University of Arizona and an M.FA. in Creative Writing and Environment from Iowa State University. Her first book, Mythical River, forthcoming from the University of Iowa Press, is about water issues in the Southwest. She has worked as a science communicator for NASA’s Phoenix Mars Scout Mission, the Water Resources Research Center, and the Leopold Center for Sustainable Agriculture. Melissa relocated to Flagstaff in 2015 to join KNAU’s team. She enjoys hiking, fishing and reading fantasy novels.