The Bosque of the Rio Grande, a Gem to Protect

The Rio Grande flows bank-full during September floods. Photo by Sandra Postel
After three years of drought, the Rio Grande flows bank-full during September floods, replenishing parts of its floodplain in New Mexico. Photo by Sandra Postel

September’s record-breaking rainfall and floods brought tragic loss of life and property to parts of Colorado and New Mexico.  The devastation has been hard to fathom.

But for a river like the Rio Grande, which has suffered through years of drought, the floods produced a welcome reunion in parts of New Mexico: the river once again connected with its floodplain forests, a vital component of its overall health.

The Rio Grande, the second largest river in the southwestern United States, boasts a remarkable bosque, or riverside cottonwood forest, which extends some 200 miles (320 kilometers) through New Mexico – from Santa Fe south to the Bosque del Apache National Wildlife Refuge, famed for its overwintering population of sandhill cranes.

By some accounts, the bosque of the Rio Grande is the largest continuous cottonwood gallery forest in the world.

Derived from the Spanish word for woodlands, the bosque is literally a ribbon of green in the desert landscape.

For many centuries, its tiered layers of trees and vegetation, all nourished by the river’s natural floods, provided habitats and homes for a rich diversity of birds and wildlife, including whooping cranes, wild turkeys, beaver and mink.  Some 24 native fish species lived in the river and the adjacent wetlands of the bosque.

But the construction of dams and levees over the last half-century has severed the river’s natural connection to its floodplain forest.  The annual spring flood, driven by melting snows in the headwaters, largely disappeared as dams captured and stored the floodwaters.  Without the nutrient-rich sediment brought in by the annual floods, the riverside ecosystem – and its diversity of life – declined.

And so it was with some excitement that I headed to the middle Rio Grande on Saturday, September 14, when the river was raging higher than it had in decades.  The floodwaters pouring out of the canyons upstream had dumped an enormous volume of water into its channel.

While Cochiti Dam upstream of Albuquerque and the levees along the floodplain did their jobs of preventing catastrophic flooding of property through the middle Rio Grande valley, the river flowed high enough in places to spread out into its adjacent forests, rejuvenating this aquatic ecosystem after years of drought.

The bosque, shown here 25 miles south of Albuquerque, gets a welcome flush of nutrient-rich floodwaters. Photo by Sandra Postel
The bosque, shown here 25 miles south of Albuquerque, gets a welcome flush of nutrient-rich floodwaters. Photo by Sandra Postel

I walked through the bosque outside the town of Los Lunas, some 25 miles south of Albuquerque.  There, stately cottonwoods stood in saturated soils, soaking up vital nutrients as they drank in the floodwaters.  The groundwater below, which sustains the trees through the dry spells, was getting replenished as the floodwaters seeped into the earth.

The scene was a timely reminder of the bosque’s ecological needs, because Albuquerque Mayor Richard Berry has proposed a new and much debated vision for the city’s stretch of the bosque that, in its attempts to make the river more accessible to residents, risks further damage to this unique ecosystem’s long-term health.

Chiming in on the debate is Estella Leopold, whose father, the great conservationist Aldo Leopold, was instrumental in developing a plan to conserve the bosque of the Rio Grande.  In 1918-1919, Leopold served as Secretary of the Albuquerque Chamber of Commerce and pushed for the creation of a bosque nature park that would protect this critical ecosystem – a vision realized in 1983 when the New Mexico legislature created a state park encompassing 4,300 acres (1,740 hectares) of the riverside woodland.

In a recent letter to the mayor, Dr. Leopold, an emeritus professor of biology at the University of Washington in Seattle, wrote:

“We at the Aldo Leopold Foundation are deeply alarmed by the new plan that would, if enacted, work against the goal of having an extensive area of wild nature and bird habitat along the river bordering the city.  We feel that the Rio Grande Vision discards the protective mechanisms for the existing park—the city’s Bosque action plan which established policies to ensure the conservation of the bosque in its natural state.”

Preservation of the Rio Grande’s cottonwood forests will require not only a more ecologically sound strategy for people’s use of them, but changes in river management as well.

But hopefully the city with the Rio Grande running through it will step back and develop a plan that preserves the legacy of Aldo Leopold and his land ethic – and protects the ecological richness of the bosque for generations to come.

Sandra Postel is director of the Global Water Policy Project, Freshwater Fellow of the National Geographic Society, and author of several books and numerous articles on global water issues. She is co-creator of Change the Course, the national freshwater conservation and restoration campaign being piloted in the Colorado River Basin.

Sandra Postel is director of the Global Water Policy Project and author of Replenish: The Virtuous Cycle of Water and Prosperity. From 2009-2015, she served as Freshwater Fellow of the National Geographic Society. Sandra is also co-creator of Change the Course, the national water stewardship initiative awarded the 2017 US Water Prize for restoring billions of gallons of water to depleted rivers and wetlands. The recipient of several honorary degrees, she works to bridge science, policy, and practice to promote innovative ways of securing water to meet both human and ecosystem needs.

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