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Rocky Mountain Riverway
BEGINNING AT PALISADES DAM
The equinox was long past on May 1, but for me, it was the first day of spring—a rebirth of life and the start of my first voyage on the Snake River. The blustery rigors of the early spring had proven to be excessive for outdoor living in Jackson Hole, Wyoming, where I had started my explorations near the headwaters of the Snake, so I skipped over the highest 154 miles of waterway and drove down to Palisades Dam, just across the state boundary in Idaho.
I unloaded my canoe from the roof of my van, and guarding against an upset, I lashed waterproof bags into the boat. My first Snake River voyage will take me 106 miles from Palisades to Idaho Falls. All but the final 10 miles run without dams—the third longest free-flowing reach of the river.
Palisades Dam stills the water upstream for 29 miles. The second dam down from the headwaters, it forms the third largest reservoir on the Snake (almost the size of Brownlee Reservoir, above Hells Canyon). Palisades was built by the Bureau of Reclamation in 1958 for supplemental irrigation water on 670,000 acres—lands that had already been irrigated but were now assured deliveries in dry years.
I had arrived thirty years too late to see Grand Valley, which is now beneath the reservoir. Bernard DeVoto, the great western historian, wrote about this reach in 1947: "The Snake is a noble and various river, nowhere lovelier than in the stretch from the lower end of its first great canyon till it comes entirely out of the mountains." On my way to the river, at a local cafe, I met Jerry Hansen, who grew up in Grand Valley.
It was wide, with farms, cottonwoods, and willows, a lot like Swan Valley today. There were about thirty farms, and the hot springs at Indian Creek were flooded too. The local people didn't want the dam but felt powerless. The government was going to take it; you just tried to get a good price for your farm. It was good fishing, but fishermen didn't fight it much. There was a feeling that you could always go someplace else. Me, I have no bitterness about the dam. I have a new way of life. I have a motorboat now. It's part of the change that goes on. I didn't like farming anyway.
A superb river flows for 69 miles from the dam to the Henry's Fork of the Snake, which most Idahoans used to call the North Fork. To many it was the dominant river of eastern Idaho. Even though the Snake River carries three times the volume of the North Fork, Idahoans call the main stem the "South Fork." Above Palisades Dam, however, everyone simply calls it the Snake River. Thus, the main stem perversely empties into a "fork" of much greater size, like a river dumping into a creek. Unaffected by the Idaho tradition, the U.S. Geological Survey—the official carrier of geographic names—calls this the Snake River from source to mouth.
The 50 miles from Palisades to Heise are a nationally known trout fishery where thousands of people embark on float trips each year, though in May I stood alone in the brittle wind, looking upriver at the dam's rock pile and downriver at the alluring landscape of mountain and valley. In a boat, two fishermen arrived and eyed my gear. "How far you going?" one asked.
"No. Five or six days."
"A long trip."
To me, it didn't seem far on a river that, if straightened, would reach from its source to Mexico. Six free-flowing sections are long enough for overnight trips by canoe or raft, yet people rarely speak of multiday outings except in Hells Canyon.
Downriver—an eagle? Yes. Light glinted from white head, white tail. From Yellowstone to the Henry's Fork, the Snake River is prime eagle habitat. This endangered species has survived until now along the upper river because of clean water, plentiful fish, and sparse development. A great blue heron stalked through the shallows, a winter wren fluttered among willows, sandpipers bobbed on beaches, mergansers dove into pools, and swallows darted from insect to insect. In sheer numbers, the swallow is the bird of the Snake River.
Swan Valley, amid snowy peaks of the Snake River Range to the northeast and the Caribou Range to the southwest, is a graben or sink created by faults lowering the valley on both sides. I entered a complex of sloughs that split and resplit to form wetlands, sandbars, and swampy cottonwood coves.
The Bureau of Land Management (BLM) is responsible for 15,000 acres on this section of the river. The BLM manages as much land in the West as the Forest Service and Park Service combined, most of it drylands unclaimed by homesteaders. The agency manages three major reaches of the Snake, plus several major tributaries. On this reach, thirty-nine islands are eligible for wilderness status. A hundred pages of BLM paperwork fail to explain why the islands are not recommended for protection, though the environmental statement repeatedly mentions Lynn Crandall Dam, a dusty old proposal of the Bureau of Reclamation—a dominant bureau within the Department of the Interior. Banning the dam is the only major effect that wilderness status would have.
At the mouth of Fall Creek, I paddled to the base of the tributary's waterfall, which drops directly into the river; the crash and spray were loud and soaking. Below the Swan Valley bridge, the road sliced away from the valley, and I entered the river's third canyon (the uppermost is in Yellowstone; the second is below Jackson Hole). The Big Hole Range rose to my right, the Caribou foothills to my left. With tiny hooves but effective, long legs, a deer swam across the river as fast as I could paddle. Pools alternated with riffles that had formed where bedrock crossed the channel and where rocks had washed down from tributaries. Additional shoals resulted from the physics of the current; hydrologists have found that a pool and riffle sequence occurs at intervals equal to five to seven widths of river. Flood flows erode pools deeper and deposit gravel at the riffles, accentuating each. At low flows, riffles gradually erode and pools are filled, subduing each. The cycles maintain a balance to which life of the river is well adapted. Without occasional floods, the river becomes a "glide" of nearly uniform gradient without the pools needed for fish cover, without the riffles needed for spawning. Ducks, otters, eagles, and other creatures suffer.
I camped at a sandy beach where the music of riffles lightened the air. The yellow-green grass of springtime had broken through moist soil, and the robins sang a mating song. Cottonwoods had released constellations of newborn leaves. The cottonwood—the tree of the Snake River—is the maker of fruitful forest edges and the keeper of many lives. The shells of its buds lay pungent on the ground and stuck to my shoes like honey. Volcanic cliffs jutted up to dark slopes. Grouse drummed in the woods, muskrats surfaced in the eddy. Moose and coyote tracks decorated the ground. Here, I thought, is the Snake River as it always was.
A RIPARIAN KINGDOM
While frost still slicked the morning grass, I paddled on my second day to Dry Canyon and its rich tangle of vegetation in the river-dependent zone called riparian. I picture the river in halves of blue and green equipoise: first, the water, then the green river of plant life on either side. For wildlife, this zone is the most important part of the earth. Three-quarters of all endangered species need riparian habitat. Biologists in the Blue Mountains, bordering the Snake River in Oregon, found that 285 of 378 terrestrial species depend on riparian zones.
Through much of the Snake River's course, the average precipitation is 15 inches or less, the sun shines a lot, humidity is low, and the wind blows hard. All of this means aridity, and along the desert river, only the riparian zone supports more than sagebrush, bitterbrush, hardy grasses and forbs, and noxious weeds, many of them introduced from Eurasia. On searing days, the riparian plantlife becomes nature's air conditioner, a shaded refuge. During floods, the riparian areas dissipate high flows and reduce the overflow downstream. Riverfront wetlands improve water quality by filtering sediment, wastes, and nutrients and buffer pollution coming from cropland, excavated soil, and overgrazed range.
Though lowland areas are undisputedly the richest for wildlife and provide winter range that is scarce habitat for many species, few bottomlands of large streams are protected. Many national park and wilderness areas, for example, are in higher country and were set aside only after proven to have no economic value. "Rock and ice" conservation was often the main concern of early conservationists lobbying for preservation of spectacular high country. The wilderness system represents only eighty-one of 233 ecosystem types in America; fifty are not even found on federal lands.
William Platts, a Boise-based national authority on riparian habitat, believes that interest in this area is growing. "The name 'riparian' just came into use in the seventies," he noted. A veteran of the Forest Service, Platts recalled, "For awhile you couldn't use the word 'riparian' in the Forest Service or the BLM. There was anxiety over what would happen to grazing and logging. In the Southwest the government clearcut cottonwoods and willows because they were 'water users.' Those streams fell apart, and then the agencies recognized that the vegetation had been a water retainer. Now the pendulum has swung back, and we've done plans and plans for riparian protection, but action is still hard to come by."
Eighty percent of the riverfront habitat along the Snake River has been lost, according to the U.S. Fish and Wildlife Service. Rich sections such as in Grand Teton National Park and here above the Henry's Fork are not only rare but unrepeated in Wyoming and Idaho. Most riparian habitat has been leveled, cleared, farmed, developed, riprapped, leveed, dammed, or ditched.
The story of the Snake River is also the story of the West and the United States. In California, where land use in the Central Valley is far more similar to the Snake River plain than Idahoans want to admit, 90 percent of the riparian habitat has been lost. Along the Missouri River, dams flooded most riparian acreage, and on the little that remains, reduced floods led to a 67 percent reduction of wetlands. Along the Colorado River, 90 percent of the riparian values are gone. The Ohio River is comparable in length to the Snake, but every inch is dammed, flooded, and lined with railroad tracks, highways, industries, or towns. The Mississippi River flows through a constant chain of dams from Minneapolis to St. Louis and then a levee straitjacket to the Gulf of Mexico. The Army Corps of Engineers dammed the one remaining section of the Savannah River in South Carolina, with deadly impacts on wildlife and water quality. The corps channelized the Tennessee and Tombigbee rivers for 232 miles, burying a biological utopia at a cost of $4 billion, all to duplicate an existing barge route.
Dependent on wetlands that include riverfronts, North American duck populations plummeted from 46 million in 1971 to 30 million in 1985. Mallards, a duck of the Snake River, declined from 14 million on the continent in 1957 to 8 million in 1987. Nationwide, we lose 450,000 acres of wetlands each year; farming and logging cause 80 percent of the losses. Urban and agricultural uses preempt 70 percent of the floodplains along rivers. Once covering 6 percent of North America, riparian ecosystems remain intact on 1.5 percent.
Valuable riparian areas survive along the Snake River at Jackson Hole, Wyoming; from Palisades to Idaho Falls; from the town of Blackfoot to American Falls Reservoir; and at shorter reaches downriver. Riparian forests in Idaho total 327,347 acres or 0.6 percent of the land, down from a million acres, and within the remaining forests, the quality of habitat is reduced. "The frustrating thing about habitat is that there's only one direction you can go," said Al Van Vooren, head of resident fisheries (fishes that do not migrate to the ocean) for the Idaho Department of Fish and Game. "At our best we only decrease the rate of decline."
On the flood plain at Dry Canyon, red osier dogwood grew in a barrier impenetrable by me but prized by evening grosbeaks, purple finches, robins, hermit thrushes, mule deer, and elk. Though the flowering dogwood is better known, red osier is the most widespread dogwood on the continent. Water birch, box elder, and white alder also rank high in importance along the river. Alders fix 350 pounds of nitrogen in the soil per acre each year—comparable to an alfalfa field. The Pacific and other willows flourish as a favorite food of spruce grouse, moose, elk, deer, beaver, and snowshoe hares.
The cottonwood crowns the riparian ecosystem. I found the narrowleaf species, Populus angustifolia, along the upper river and the black cottonwood, Populus trichocarpus, mostly below American Falls and especially along tributary streams. The narrowleaf grows to a 1.5-foot diameter and a 60-foot height; the black cottonwood—king of the deciduous forest—can grow to 4 feet in diameter, 125 feet high. Both species and hybrids of the two are used by a host of birds and animals for shelter, nesting, and food. Also called poplars, the cottonwood family includes aspens and about fifteen species in the United States. Half of a beaver's diet comes from this family. Grouse eat the buds and catkins. Elk, deer, and rabbits savor the bark, twigs, and leaves. A moose's diet may be one-fourth cottonwood and aspen. The endangered bald eagle nests in cottonwoods.
The Fish and Wildlife Service called the riparian zone "extremely important" and credited this section of the Snake River as "one of the largest such ecosystems in the western intermountain region," "the most important fish and wildlife habitat site in Idaho," and "one of the most important areas for wildlife in the northwest." This reach of the Snake is to the Rockies what the Everglades are to the Southeast.
Like everything else in the riparian zone, the cottonwoods depend on the river. Roots probe sandy soils for water. Some cottonwoods, including the black, can reproduce from root sprouts, though sprouted trees frequently lack vigor. Others germinate from seeds, dependent on precise conditions. They require deposits of river-borne silt delivered by large floods. When the timing is right, the receding floodwaters carry the seeds to the fertile new silt. In this and other ways, riparian life depends on seasonal variations in flow, the erosion and deposition of silt, and other factors, all of them upset when dams arrest floods and trap silt in reservoirs.
Because of upstream dams, researchers found little new germination of the plains cottonwood on Montana's Milk River. Cheryl Bradley, a research botanist, wrote that without revised management there will be a "slow elimination of cottonwood forests. With most of the North American prairie rivers regulated by dams, we predict that most of the floodplain cottonwood forests will be eliminated by the end of the next century." Botanists found similar effects on the Missouri River, the South Platte in Colorado, the Salt in Arizona, the Bighorn in Wyoming, and the St. Mary and Waterton in Alberta. There are no studies of cottonwood regeneration on the Snake River, though the Fish and Wildlife Service is initiating a "trend analysis" for the corridor above Heise, Idaho. Biologist Platts said, "Any species dependent on fluctuating water levels is going to be drastically reduced unless the Bureau [of Reclamation] emulates natural floods when releasing water from the dams."
For now, I walked as if released from all cares through one splendid cottonwood grove after another. They lay in slender bands parallel to the shore—a river of cottonwoods above the river of water. The trees within each grove appeared to be the same age, probably germinating after the same receding flood. The river had deposited silt on the inside of the bend because the current was slower there, and while the trees grew, the bank increased in height around them. Unlike other trees, cottonwoods are not "suffocated" by the silt; in fact, silt protects the trunks from high water, from bombardment by rocks, and from claws of driftwood. The river is a life-support system for the trees. Inevitably the current changes course and begins cutting into the banks it had formed a century before. It undermines mature cottonwoods, which only live about a hundred years anyway, and they plunge into the river and form cover for fish or wash down to shoals where they cause the formation of islands. They may drift to established islands and act as further traps for driftwood. Eventually those piles of trunks and branches become soil-covered, but underneath are hollow places, homes for beaver, muskrat, and otter.
Excerpted from The Snake River by Tim Palmer. Copyright © 1991 Tim Palmer. Excerpted by permission of ISLAND PRESS.
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