Wednesday, May 22, 2019
‘These are parks’: Signs of life returning to the depleted Colorado River Delta
LAGUNA GRANDE, Mexico – It’s midmorning in the Sonoran Desert, and already the heat is on.
Karen Schlatter suggests we find shade, a relatively easy task at Laguna Grande, a restoration site along the Colorado River’s historic channel in northern Mexico. It’s managed by the Sonoran Institute, where Schlatter is associate director of the binational environmental group’s Colorado River Delta program.
We head to a stand of 30-foot cottonwoods within the intensely managed site. Beneath the canopy, away from the direct sun, the temperature drops quickly.
“This forest here is probably five years old,” Schlatter said. “Trees and habitat can establish really quickly in the Colorado River Delta when you give it the adequate conditions: water, sunlight and not very high soil salinity.”
Zig-zagging around us, among the trees, is a sprawling network of irrigation ditches. The site is almost laid out like a farm, but instead of the food crops that are grown in fields all around Laguna Grande, Schlatter’s team grows cottonwoods and willows, prime habitat for birds, coyotes, frogs and other wildlife. The whole site receives water only a couple of times a year.
Midway through our walk, we come across a dusty trail leading from the trees down to a pool in the Colorado’s channel.
“This is a beaver trail,” Schlatter said. “We had beavers arrive to the site, I think, five years ago. Two years ago, we had an entire beaver family, and there were little baby beavers running everywhere and everyone was freaking out.”
This place is an attempt to give a glimpse at what the Colorado River Delta was when the river emptied into the Gulf of California – a healthy mix of cottonwood forests, vast lagoons and thriving estuaries.
But over the past 50 years, the delta has become a shadow of its former self.
Since the mid-20th century, growing cities and farms in the Southwest have claimed more and more water promised to them under the 1922 Colorado River Compact, leaving the delta in northern Mexico dry. The problem isn’t one caused by drought and aridity. It’s the byproduct of a river promised to too many people, collateral damage in the effort to make the desert Southwest capable of supporting millions of acres of crops and burgeoning cities.
Within the past 15 years, though, the U.S. and Mexico have committed both funding and water to restore portions of the dried-out delta and return some life to the river’s final hundred miles.
‘A scarce resource’
The water arrives at Laguna Grande the same way it arrives at farms in Mexico’s Mexicali Valley: through a crisscrossing network of concrete-lined irrigation canals, one of which passes right by the restoration site.
The water either is purchased from farmers within the valley by a trust, or is water dedicated to restoration by the U.S. and Mexico. Under an agreement called Minute 323, 210,000 acre-feet of water will flow to sites like Laguna Grande until 2026. A portion of that water is made available by irrigation upgrades within the Mexicali Valley, which the U.S. committed $31.5 million to fund.
“Both countries have an interest in restoring the Colorado River Delta,” Schlatter said. “Particularly Mexico is interested in restoring the habitat and some of that economic value that was lost. And the U.S., because this is a binational river, also has an interest in helping Mexico do that.”
A previous agreement, called Minute 319, allowed for a so-called pulse flow through some of the restoration sites as well as some water for so-called base flows, which is water that would be delivered more deliberately to the restoration areas.
Under Minute 323, $9 million is set aside for restoration work, split equally among the U.S., Mexico and a set of environmental organizations that work in both countries. Another $9 million is committed to an ecological monitoring program. Karl Flessa at the University of Arizona is part of that team of scientists gathering data and observations from the delta.
“These are parks,” Flessa said. “Think of them as little green parks scattered along the course of the river.”
So far, Flessa’s group of scientists has found a dramatic increase in the number and species of birds coming here, and other wildlife are making a comeback, too. Flessa called the early results promising.
A report published in December 2018 by the International Boundary and Water Commission found the “abundance and diversity of birds in the riparian corridor increased 20% and 42% after the 2014 pulse flow.” That burst of bird activity diminished after 2014 but remained higher in the managed restoration areas.
“The river is dried up below Morelos Dam (at the U.S.-Mexico border),” Flessa said. “And restoring some of that flow below the dam even to small parklike restoration areas, that’s restoring a little bit of environmental justice.”
‘It is for wildlife and for people’
A few miles upstream of Laguna Grande, whitewater gushes from an irrigation canal into another restoration site, El Chausse.
Adrian Salcedo manages the flow of water for Restauremos El Colorado, a Mexican environmental group. It receives funding from the Walton Family Foundation, which also funds KUNC’s Colorado River coverage.
“This site is very complex, maybe more than other sites because of the water management,” Salcedo said through a translator.
Chausse is meant to replicate a bend in the Colorado River. Teams here ripped out invasive species like tamarisk and planted native vegetation. Instead of Laguna Grande’s bare, dry furrows, the site looks more natural, with water flowing through multiple channels. Achieving that look and feel, with grassy marshes, takes a lot more resources.
“We have the water rights to make this place possible now,” Salcedo said. “But thinking about the future, it could be complicated to restore this kind of habitat at this level because water could be more scarce.”
The restoration sites also employ local workers needed to manage the flow of water, plant native trees and host visitors. The sites have become regular stops for groups of schoolchildren.
“It is for wildlife and for people,” Salcedo said. “In the beginning, the plan was to just restore the river, the riparian vegetation, and then when you get that back, the wildlife will start to come: birds, mammals, polecats, coyotes. Then when the people see that, they want to come to the area and help.”
Like the entire Colorado River Basin, climate change will put these restoration sites to the test, turning up the heat, increasing evaporation and further diminishing water supplies.
“People are always asking, ‘Are you taking climate change into account?’” said Jennifer Pitt of the National Audubon Society. “And we are, in that we know that water will continue to be scarce and scarcer. And so we’re trying to use it to greatest effect.”
(The National Audubon Society receives funding from the Walton Family Foundation, which also funds KUNC’s Colorado River coverage.)
For example, Pitt said, in the latest U.S.-Mexico Colorado River agreements, both countries spelled out how to handle shortages and ensured restoration efforts wouldn’t be sidelined if supplies became more scarce.
Before leaving the site, we head down to a marsh, where tall reeds have taken root in a shallow pool. A secretive marsh bird called the sora has captured the attention of some of the site’s staff members.
Alejandra Calvo, of environmental group Pronatura Noroeste, pulls out her phone to mimic the bird’s call. (The group receives funding from the Walton Family Foundation, which also funds KUNC’s Colorado River coverage.)
The tiny, spindly-legged sora weaves through the stalks and calls back, making a “kerwee” sound from its corn colored beak. It walks like it’s late for a midday appointment. Disappointed to find only a group of gawking humans and not a mate, the bird eventually heads back into the reeds.
“Nobody intentionally dried out the Colorado River Delta, but it happened,” Pitt said. “When we had our eyes open to look at it and say, ‘Oh that’s terrible, what have we done?’ it took a kind of high-level sovereign-to-sovereign agreement to start doing something about it.”
This story is part of a series on the Colorado River delta, and part of an ongoing project covering the Colorado River watershed, produced by KUNC and supported through a Walton Family Foundation grant. KUNC is solely responsible for its editorial content.
Special thanks for help in making this series possible to Alejandra Calvo-Fonseca, Will Worthington, Jim Afinowich, Esther Duke, Christine Steele and Esther Honig.