In the vast Colorado River delta, where the river once met the sea, the land is mostly dry, brown and lifeless. The area, in northern Mexico, has been shaped by upstream demand for water, where cities and farms on both sides of the international border have stretched its supplies thin.
But amid all of that brown, there are a few thriving dots of green. A relatively small amount of water was allocated to grow plants in select ecosystems, and they are now teeming with life. A new study captures the extent of that work, highlighting the success of restoration projects and calling for the work — and water deliveries — to continue.
“It's really quite remarkable how a little bit of water can go a long way in the Colorado River Delta,” said Karl Flessa, an emeritus professor of geosciences at the University of Arizona who co-authored the report.
Flessa and his colleagues, who are based in Colorado and Mexico, monitored water deliveries to the delta beginning in 2014. Efforts by the U.S. and Mexican governments, as well as a group of environmental nonprofits, have resulted in 1,381 acres of restored riparian habitat, which the study calls a success.
Crews have planted and nurtured more than 250,000 trees, creating a network of green oases for wildlife. Birds migrating between North and South America rely heavily on the Colorado River Delta, which provides a crucial stopover during their long flights. In the spring, the area can receive up to 17 million wetland birds. The new study found that birds were more abundant and diverse in restoration sites than the surrounding areas.
Beavers, bobcats and coyotes were also seen in the restoration sites, as well as ten species of birds and animals listed as endangered in the U.S. and Mexico.
Flessa said the restoration took a lot of hard work, and wasn’t as simple as dumping water on the landscape and letting nature take its course.
“Nature can't take its course,” he said. “Nature needs a lot of help in this particular habitat, so it's really careful, shall I say, farming of nature, and it's very successful in that sense.”
The river is overtaxed, as shrinking supplies are insufficient to supply the nearly 40 million people and massive agriculture industry that depend on it. Water users from Wyoming to Mexico are under pressure to cut back on their take from the river.
Flessa said restoration work in the delta, which has been carried out with a relatively miniscule amount of water, could serve as a lesson for other regions that use the Colorado River.
“Some of the techniques that we're learning here to restore these habitats can be applied anywhere along the river to use water most efficiently,” he said, “And I think as a society that's what we need to learn to do for the Colorado River, use the water as efficiently as possible.”
Flessa and his co-authors called for continued water deliveries to the Colorado River delta, as well as financial support for the maintenance of restoration sites.
