...

Upstream damage dooms river system Watershed management replaces cycles of nature after humans alter water's flow Aug. 8, 2006 12:00 AM CAMERON - Water hadn't flowed through this stretch of the Little Colorado River in weeks, months maybe. The dry winter produced little runoff, and almost none made it this far downstream, barely 40 miles from the river's end.

But the empty riverbed wasn't the troubling part of the view from the old suspension bridge. What stuck out sorely were the deep green stands of tamarisk that lined the banks and pushed into the channel, creating an artificial path almost as rigid as concrete.

"The Little Colorado River is at the epicenter of the tamarisk invasion," said Sharon Masek-Lopez, a biologist who advises the Hopi Tribe on water issues. "With all the tamarisk in there, the river can't function as it normally would. It needs to spread out and meander, but it can't." Invasion is not too strong of a word to describe what is happening to the Little Colorado and other Arizona rivers, whose riparian areas are choking on invasive plants that take advantage of weakened ecosystems.

Once established, the strongest plants - and tamarisk heads the list - reshape habitats and force out wildlife that can't adapt. Thick stands of tamarisk, or salt cedar, reroute a river's flow, destroying its ability to control floods and move sediment. The dense growth leaves rivers without the natural backwaters needed by many wildlife species.

A river's riparian system, the plants and habitat closest to the channel, is an often unappreciated value, one that cleans air and water, provides home for birds and wildlife and creates the cool, green places people seem to crave.

Arizona's riparian environment is vanishing at an alarming rate, leaving behind a harsher landscape that takes more than it gives.

Riparian areas break down fastest along unhealthy systems, rivers that have been deprived of water by dams, groundwater pumping or prolonged drought. Some of the clearest examples occur along the Little Colorado as it runs through Holbrook, Winslow and the Navajo Reservation, but broken systems are also evident on the Santa Cruz, San Pedro, Gila and Salt rivers.

An unhealthy watershed, a river's wider environment from its headwaters to all the streams and creeks that flow into it, can help speed the decline of a riparian corridor and of the river itself. Development, overgrazing and uneven forest-management practices have robbed Arizona rivers of water and pushed some closer to their demise.

Human activity to blame Drought gnaws away at river systems, especially a prolonged dry period like the one that has gripped Arizona for more than a decade. But droughts fit into the natural rhythm, and rivers recover when the rains return. Human activities, on the other hand, threaten riparian systems with permanent harm.

On the Little Colorado, the flow retreats to dust earlier in the year and for longer distances between the headwaters in the White Mountains and Blue Springs about 10 miles above the river's confluence with the big Colorado. The river was probably never full year-round, but water stored in its banks and underground sustained the riparian areas.

When reservoirs halted the flow for longer periods and altered the way the river ran, the system began to break down.

Cottonwoods and willows, native plants that are the backbone of a healthy riparian area, started to die, and tamarisk, Russian olive and camel thorn, all invasive plants hostile to native vegetation, replaced them, chewing up riverbank along more than half of the Little Colorado's length.

Some of the communities along the middle river have undertaken projects to remove tamarisk, often as a flood- control measure, but scientists have learned over the years that rivers are much too complex for such a basic solution.

"You can't just remove an invasive like salt cedar," said Tom Moody, a Flagstaff-based engineer who oversees river- advertisement channel projects. "You have to put something else in its place." Experiments have found that it's possible to replant cottonwood trees and willows where tamarisk was growing, but it requires the right conditions in the river. The native plants rely on high flows early in the year, while tamarisk prospers with summer floods. This year, the Little Colorado never flowed high enough to support seedlings.

But without giving a river back its natural flow, spot restoration is the only way to bring back a damaged riparian area.

The Hopi Tribe has begun a series of those projects on washes that flow into the Little Colorado. Although the washes usually run only after heavy storms, they had lost their ability to control flows and move sediment.

In a wide wash at the foot of a chalky bluff on the edge of Tuba City, a dozen young Hopis grabbed shovels, soil augurs and cottonwood saplings one recent afternoon and waited for their turn with a water-powered hole driller.

Their saplings would join others already planted in an area known as Pasture Canyon.

"For us, restoring this is important," said Micah Loma'omvaya, natural resources planner for the tribe. "We want the native vegetation to come back. When you walk around other wetland areas, you hear the birds. You don't hear them in the tamarisk areas. It's a world of difference." The native plants are needed for ceremonies, as are feathers from birds attracted to those plants.

"It hurts you in the heart knowing you need certain kinds of birds for ceremonies and you're not getting them because there are no more cottonwoods," Loma'omvaya said.

A similar project is under way upstream on a stretch of the Little Colorado considered sacred by the New Mexico Zuni Pueblos. The Zunis believe a lake that once occupied the area was a window to heaven, and they are replanting native vegetation and recreating a desert wetland.

In some areas, people are restoring vegetation lost not to a slow demise but to shovels or bulldozers. As people settled along rivers in Arizona, they began to rechannel them to allow more development and control floods. They were left with barren washes that still flooded, sometimes with greater intensity than before.

"That wide, unrestricted floodplain with the vegetation that's in it actually slows the water flow and reduces the velocity of the water coming through the system," said Tice Supplee, a wildlife biologist who now works for Audubon Arizona. "Then, when it's all done, the soils have been recharged with all sorts of good nutrients. These are highly dynamic systems. We introduced the static component." Changing with times The solutions are not so obvious away from the narrow riparian corridors, on the watershed that collects runoff and feeds it to the rivers.

For years, the goal of managing watersheds was increasing water production, finding ways to squeeze more water from the environment into the rivers, where growing towns and cities could use it. At one point in the 1960s, forest managers decided to remove cottonwoods and other vegetation from the Verde River system.

"Logically, it might sound like a reasonable alternative," said Larry Stevens, a Flagstaff scientist who consults on river issues. "But the role of vegetation is critical. It captures sediment. It increases bird species diversity. The environmental values the trees bring are enormous. In a purely pragmatic world, you could probably get more yield if you removed all the vegetation, but who wants to live in a world like that?" Wink Crigler may seem like someone who lives in a pragmatic world. She owns a ranch near Eager on the Little Colorado headwaters. She has fought drought and falling cattle prices and survives in a business that many others abandoned. She also has become quite the ecologist, bringing science into play as she figures where her cattle will graze.

On the way up to her U.S. Forest Service grazing allotment, she pointed to the pine trees filling in what was once a wide, high meadow.

"We have seen so much of this land turn from grassland into piñon and juniper thickets," she said. "When you lost grasslands, you lose watershed. We've gone from 20 to 40 trees per acre to 80 an acre. Multiply that out to 600 acres and the watershed's gone." Up top, she spotted cattle that don't belong in her pasture. "We probably ought to come up here early tomorrow and take care of that," Crigler said, slowing the truck to confirm her suspicions. The cattle ate lazily on a pasture atop a hilly ridge, flanked on either side by creeks that gather lower in the canyons to form the Little Colorado.

In earlier years, not even Crigler's animals would feed here so early in the summer, not at 9,400 feet. This is late- season forage, at least it was before the ranchers and the Forest Service decided to apply range science and start the cattle up top for a change, leaving more time for the lower pastures to recover.

"It's adaptive management," Crigler said. "You've got to look and see if the feed's there, if the water's there, what the soil moisture is like, then decide whether to use that pasture. Look at the ground and make the plan, don't make a plan and force it on the ground." Adaptive management may hold the key to preserving what is left of Arizona's watersheds and riparian areas. Not every river can remain isolated and protected. People have become part of the natural equation.

Jim Crosswhite runs a ranch on Nutrioso Creek, a tributary to the Little Colorado in the White Mountains. He has revegetated stream banks and teamed with the U.S. Fish and Wildlife Service to preserve habitat, but he hasn't closed off his land to ranching.

"I'm a conservationist," Crosswhite said. "I don't believe in what the environmentalists say, that all the land would be better if there were no people using them. There's nothing else natural anymore, you have to manage it. You can't ignore it." Ruined Rivers was produced by reporter Shaun McKinnon, who covers water and the environment, and photographer Mark Henle. They spent more than a month on the road, logging 5,000 miles in Arizona and Mexico as they reported along each of the six rivers. Henle shot thousands of photos, and McKinnon talked to more than a hundred people, including preservation experts and people who live and work along the rivers.