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Sunday, July 16, 2000
Overdrawn at the Riverbank
By Tania Soussan
Journal Staff Writer
The Rio Grande weaves a thread of life through the high desert of New Mexico. The great river offers habitat to hundreds of animal and plant species. It also lies at the heart of the lives and cultures of the people who live along its 470-mile journey through the state.
"It is so fundamental that it is easy for us to take it for granted," said conservationist and author William deBuys of Santa Fe.
"The Rio Grande is like the floor joists of the building in which we live," deBuys said. "We are not aware of it all the time, but we depend on it all the time."
Today, those joists are under increasing stresses as human population swells along the river and drought robs it of precious water.
The population of the counties that flank the Rio Grande is expected to increase 61 percent to almost 1.1 million by 2030.
And this year, the entire state of New Mexico is drought-stricken. Runoff from the snowpack that nourishes the river is less than 40 percent of normal, and river flows also are low.
Because of those challenges, and major demands by agriculture, the Rio Grande recently was named the seventh-most-endangered river in the United States by the conservation group American Rivers.
Water uses along the Rio Grande are diverse.
The river maintains habitat for everything from dragonflies to deer. It provides farmers with irrigation water. It offers recreation for urban refugees.
The river indirectly supports urban populations by recharging aquifers, offsetting the effects of municipal ground water pumping.
But humans might have to change or scale back some of those uses.
"We can't do everything that everybody expects this river to do," said Norman Gaume, Interstate Stream Commission engineer. "There just isn't enough water to do it all."
For centuries, the Rio Grande has lured people to settle along its banks: first the Pueblo Indians, then Spanish and Mexican colonists in the late 1500s.
Author Tony Hillerman researched and traveled the river for his 1975 book "Rio Grande."
"It's absolutely the backbone and lifeblood of New Mexico, that river, and always has been," he said in a recent interview.
The Rio Grande is the setting for some of writer Rudolfo Anaya's stories, just as the Mississippi figures prominently in Mark Twain's writings.
"A great deal of the early history of New Mexico and the Southwest took place along this river," Anaya wrote in the preface to his children's book, "My Land Sings, Stories from the Rio Grande."
Beautiful, useful
The river begins as a trickle from melting snow high in the San Juan Mountains of southern Colorado. Fed by that snowmelt and by tributaries, the Rio Grande grows as it flows south into New Mexico.
Around Taos, the rugged beauty of the river is awe-inspiring, snaking through an 800-foot-deep gorge carved into volcanic rock.
As the river flows southward, anglers fish along its banks, boaters brave its rapids and small farmers use it to irrigate their crops.
"Without that river, we would not do any of this," New Mexico native Margaret Campos said as she looked across her Embudo farm in Rio Arriba County.
"If that river goes away, I can't farm," she said. "The only reason this area is lush and so beautiful is because the river is there."
In the Pojoaque Valley, the river passes an important checkpoint — the Otowi Gauge. It is here that flows are carefully measured to determine how much water will be available for downstream users, according to an interstate treaty called the Rio Grande Compact. The 62-year-old agreement divides the river's water among Colorado, New Mexico and Texas.
In an average year, New Mexico is allowed to consume 393,000 acre-feet of water between Otowi and Elephant Butte Dam in south central New Mexico. Streamside vegetation and evaporation take most of that.
Near Cochiti Pueblo about 70 miles south of Taos, everything changes: Cochiti Dam is the first of a series of dams that check the river's progress.
From Cochiti Dam south, the Rio Grande is an engineered river.
Where it once meandered across a broad flood plain, it is now confined to a narrow channel by a straitjacket of levees and jetty jacks — large, crossed steel structures that trap sediment to stabilize the river's banks. Diversion dams and irrigation canals drain water for farms.
Human intervention has made the Rio Grande more efficient at delivering water downstream, but at a price.
Many native species have been lost, and others are barely hanging on.
The tiny Rio Grande silvery minnow has become the poster fish for the beleaguered river. The endangered minnow now lives in a small fraction of its original habitat.
The altered river — its flow accelerated by the straightened channel and the dams that trap silt — runs too fast and deep to give the minnow a sheltered place to spawn.
Changes to the river's natural flow also have altered the bosque, giving exotic species like salt cedar the upper hand and crippling what is the largest remaining cottonwood forest in the Southwest.
Like a row of dominoes, the harmful effects cascade. The unhealthy bosque has been bad for many animals, most notably the endangered Southwest willow flycatcher.
But controlling the river also has had benefits. Residents up and down the valley are protected from flooding, formerly waterlogged lands have been reclaimed, and farming on thousands of acres is possible.
Throughout the middle valley, from Cochiti to Bosque del Apache, the Middle Rio Grande Conservancy District draws water for irrigation, sends it to farms and then returns unused water and water collected by drains back to the river. Then the district diverts water again, replaying the cycle over and over.
The city of Albuquerque is gearing up to take large amounts of water from the river as well. Albuquerque has rights to 48,200 acre-feet a year of San Juan-Chama Project water from the Colorado River Basin — reaching the Rio Grande via the San Juan and Chama rivers.
About 150 miles downstream from Albuquerque sits Elephant Butte Reservoir, the point at which New Mexico delivers Rio Grande water to Texas under the compact.
Below the massive dam lie the chile, cotton and onion farms of the Elephant Butte Irrigation District and a river whose main purpose is to move water as efficiently as possible. Little vegetation is seen along the banks as the river passes Las Cruces and flows on to the Texas border.
Habitats endure change
The Rio Grande has been dramatically changed over time. Centuries ago, the river meandered across a wide flood plain, providing the water necessary to nurture young cottonwood forests and establishing wetlands.
As sediment built up and the river bed aggraded, the river chose a new channel. Old bosque areas became disconnected from the river or wiped out completely by heavy flood flows. But in the process, new forests were born.
"When it was all said and done, you wound up with a mosaic of different habitats," said biologist John Taylor of Bosque del Apache National Wildlife Refuge.
The river remains a critical flyway and winter habitat for migrating birds, supporting more than 240 species. But experts worry that such habitat might further erode.
"We're allowing their habitat to diminish and disappear, and birds will follow very quickly," said David Henderson, executive director of the Audubon Society in New Mexico. "I'm worried."
Human intervention has caused many problems. Now, nature has added a drought that Steve Harris, director of Rio Grande Restoration, hopes will be a wake-up call.
Harris questioned the way water managers are handling this first year of drought — essentially relying on healthy reservoir supplies to meet demand without saving water for the future.
If the drought stretches into a second or third year, the situation could be "desperate," he said.
The drought, he said, "should start to illustrate how dependent everything is on the river."