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A Vision for Restoring Yosemite’s Hetch Hetchy Valley

It’s time to undo a great American mistake

Paintings by Laura Cunningham

Excerpted from Hetch Hetchy: Undoing a Great American Mistake (Heyday Press). Buy a copy of the book today.

Editor’s Note: A hundred years ago today, President Woodrow Wilson signed the Raker Act, allowing for the construction of a hydroelectric dam and reservoir in the United States’ oldest national park, Yosemite. The fight over the impoundment of the Tuolumne River and the flooding of the Hetch Hetchy Valley was a crucible for the American environmental movement. Many of today’s environmental debates – how, for example, do we balance human needs against the desire to preserve the world we inherited? – echo of the battle over Hetch Hetchy.

Today, some visionaries keep alive the hope of one day removing the dam and restoring Hetch Hetchy to a place that John Muir described as “one of Nature’s rarest and most precious mountain temples.”  In his latest book, Hetch Hetchy: Undoing a Great American Mistake, journalist (and Earth Island Institute board member) Kenneth Brower imagines what restored valley would look like. It’s an inspiring idea, a vision of how we could repair some of the damage we’ve done.

After the Deluge

The Western yellow or ponderosa pine, Pinus ponderosa – the tall tree for which, if you believe Chief Tenaya, Hetch Hetchy was named – grows best on flat or rolling land. In the Sierra Nevada it flourishes on the floors of U-shaped, glacier-carved valleys, just the sort of landscape that was flooded by O’Shaughnessy Dam. If Hetch Hetchy is drained, and if its reclamation proceeds more or less naturally, then the ponderosa-pine restoration will be led by chipmunks. Ponderosa-pine seedlings that spring up densely from forgotten chipmunk caches survive better, for some reason, than do solitary seeds sown by the wind. The Sierra Nevada is fortunate in having the greatest diversity of chipmunks on Earth.

painting of the recently drained Hetch Hetchy valleyLaura Cunningham

For the seedling, whether dispersed by chipmunk or breeze, the first year is brutal. Frost heave, summer heat, and the browsing of mule deer thin the ranks mercilessly. The first mission of any newborn yellow pine, then, is to get purchase. The seedling sends down from seven to twelve inches of taproot its first year, while sending up just two or three inches of tree. At eight years old, the mighty ponderosa pine towers up about sixteen inches. Into its early teens, it continues to grow slowly. In the reborn landscape of the Hetch Hetchy floor, at this early stage of the return of the yellow pine, the tree will call little attention to itself. Then, in its midteens, the tree shoots up, and for the next seventy-five to one hundred years grows fast, sometimes as much as two feet a year. When the ponderosa pine is fiftyish, it begins to bear cones profusely, offering up its winged seeds to chipmunks and the wind. It may never make the 220 feet that John Muir measured in one Sierra specimen, but it is headed that way.

“Of all Pines,” wrote Muir, “this one gives forth the finest music to the winds.” And of all pines, this one is also the most refulgent, its long reflective needles scintillant in sunshine, like upraised sabers, so that on a bright and windy day each tree makes a kind of cavalry charge. A century after the demise of the dam, the music and shimmer of big yellow pines will have returned to Hetch Hetchy.

The incense cedar, its sprays of foliage fashioned into a pillow by Muir, put him to sleep with its “spicy breath” on the eve of his first descent into Hetch Hetchy. It, too, will reseed itself, perhaps from Muir’s very tree, and surely from other incense cedars growing now on the shores of the reservoir. The gray pine will do the same. For the Miwoks and Paiutes who hunted and foraged this valley, the seeds of the gray pine were nearly as important as Hetch Hetchy’s acorns. The Natives ate the inner bark and young buds in springtime, cut out and consumed the soft cores of the cones when these were small and green, and ate the pine’s resinous exudations like candy. The gray pine has fallen out of favor with humans as food, an unfortunate narrowing of the diet of our species, but a good thing for restoration, as there will be diminished competition for the ten-inch, sharp-spined cones that squirrels disassemble and plant across Hetch Hetchy.

painting of a fisher

The giant cones of the sugar pine, sometimes more than two feet long, will ripen in late summer and fall. The scales will open to send brown-winged seeds sailing out across the valley floor. The Douglas fir will return, as will the white fir, the cottonwood, the willow, the bigleaf maple, the Western azalea, the interior live oak, and the buckeye. At least a few black oaks – Kellogg’s oak, as Muir called the tree – will come back, and with moderate restoration management, many black oaks. This big, black-trunked oak will leaf out pink for several weeks in spring, and in fall it will turn yellow-gold, providing most of what Hetch Hetchy offers in the way of hot color. The dogwood in springtime will open its four to six big, showy, petal-shaped bracts, green at first, then turning white. These pale, six-inch “flowers” will glow ghostly in the dimness of the conifers, like some sort of invasive orchid from the tropics.

Under the minimalist management strategy of Alternative 1, according to the predictions of the Yosemite Park team of Riegelhuth, Botti, and Keay, within two years of the draining of Hetch Hetchy Reservoir, extensive areas of the valley floor will be covered by grasses, sedges, and rushes, most of them non-native, growing most thickly on the sloping sides of the valley, as those slopes are drier and closer to seed sources. Dense nurseries of conifer and broadleaf seedlings will have sprung up in moister places at the edges of the valley.

Within ten years, some of the conifers established in the early succession will have grown to twenty feet tall. Stumps from the clear-cutting by the dam-builders will still be visible, but the general pattern of the vegetative communities to come will be evident. Areas that once were meadows will be reappearing as meadows again. Native plants – grasses, sedges, and rushes – will predominate in the meadows, excluding almost all non-native plants in the wettest areas. Non-natives will predominate elsewhere.

In fifty years, forest cover will be even more extensive than before the inundation. Some of the conifers established early will now be ninety feet tall. Pines and incense cedars more recently established will be rising in dense and expanding thickets, some of which will be invading the meadows.

In one hundred years, some of the ponderosa pines and incense cedars will stand 125 feet high and five feet in diameter at the base. Native plants will have reoccupied all their old favorable habitats, and all those species present in the old days will be here again. Non-native plants will have decreased in abundance.

Mammals will return, all the usual suspects mentioned in the resurrection scenarios for the valley – black bear, coyote, mule deer, mountain lion, squirrels – but also that large fauna of less familiar Sierra creatures that do not immediately come to mind. 

The ringtail inhabits this zone and it will come in unseen. A small, nocturnal member of the family of the raccoons and coatis, the ringtail weighs two pounds or so, and has a bushy, banded tail longer than its body and huge eyes. It looks like a creature from somewhere else, Madagascar most likely, as if some Dr. Moreau of that island managed to cross a raccoon with a lemur. In gold rush days, in the foothills below Hetch Hetchy, ringtails were called “civet cats” by the miners, who domesticated them to rid their cabins of mice. Ringtails are cryptic creatures and belong to the night. In my own lifetime I have seen only one, an early-morning Sierra Nevada roadkill.

painting of a pine marten

The Mustelidae, the family of the weasels, will come to Hetch Hetchy. Curious, always testing the world around them, the mustelids are sure to investigate the valley floor as it emerges, all of them fierce and indomitable, most of them built sinuous and close to the ground, with hindquarters slightly elevated. A few family members slightly divergent from the basic weasel body plan – the striped skunk, spotted skunk, and badger – will find their way here. All the more weasel-like weasels will arrive, too, in their smoothly graduated succession of sizes: The short-tailed weasel, or ermine, a dwarf predator smaller than some of the larger chipmunks, at just two ounces. The long-tailed weasel, sometimes called the mountain weasel, the males weighing ten ounces, the females five. (In the cold months, both these small weasels, short-tailed and long, will bound across Hetch Hetchy snow in their white winter coats, invisible except for the black tips of their tails.) Then the two-pound pine marten, which will pursue and overtake squirrels in spiral, skittery, scratchy chases around the trunks of trees and out the branches. Then the ten-pound fisher, a scaled-up pine marten, heavy but acrobatic, fast both on the ground and in the trees, capable of overtaking and killing both squirrels and pine martens high above the earth. And finally, with any luck, the wolverine, the superweasel, king of the family Mustelidae.

As soon as the Tuolumne quickens and starts to flow freely through Hetch Hetchy again, the valley’s aquatic ecosystem will begin reassembling itself. The current will recruit organisms upstream and transport them down, even as determined downstream volunteers work their way up against the flow.

painting of the Hetch Hetchy valley, gradually revegetatingLaura Cunningham

The large water boatman and the small water boatman will swim in along the bottom, right side up, hind legs modified into oars and rowing a kind of breaststroke. Kirby’s backswimmer and the small backswimmer will swim in at the surface, upside down, rowing a sort of backstroke. (At first glance, the boatmen and backswimmers will be hard to distinguish, except for this inversion.) The common water strider and the small water strider will glide in four-oared, either species built like a two-man racing shell. Standing spidery and weightless above the water, the striders will be visible less in themselves than by the dimples they make on the surface.

The water scorpion will drift in, its head downward, its mantis-like raptorial forelimbs dangling. Connected to the surface by its snorkel – a long tube appended where the stinging tail would be in a genuine, arachnid sort of scorpion – it will scan the bottom for the small worms, isopods, and nymphs that are its prey. Nymph,theGreek for stream sprite or spirit, is applied by science to the water-dwelling larvae of dragonflies, damselflies, stoneflies, and mayflies. This recycled Greek is apt when it comes to habitat, but all wrong when it comes to appearance. The dragonfly larva in particular – gigantic compound eyes, wicked biting mouthparts, spiky forked tail, gills in the anus – is more ogre than nymph. When it finally crawls up on its stem, splits its old skin, and emerges as a dragonfly – as fast as Tinker Bell, more maneuverable than any aircraft, its sides flashing iridescent red or blue or green in the mountain sunlight – then it might pass for a sprite, but not in its previous incarnation under the surface.

The larva of the giant caddisfly, upon arriving, will quarry the stream for the large sand grains with which it builds its protective case, and it will drag that little house over river-rounded stones exposed again by the flushing away of reservoir sediment.

The smaller larva of the caddisfly Desmona will build its case of smaller sand grains. On warm summer nights, when it reaches its fifth instar, Desmona will drag its house up on land – a concretion of stream-bottom materials come ashore – and it will graze on semiaquatic plants until the cold Sierra night drives it back into the water again.

The filter-feeding larva of log-cabin caddisfly, Brachycentrus, will scavenge chips of Hetch Hetchy driftwood, square these off neatly with its jaws, and silk-cement them into the square, laminated case of its log cabin.

The predaceous larva of the caddisfly Yphria, perhaps the most primitive genus among these casemakers, will build its case of mica chips, slipshod and disorderly, like the log cabin of its cousin Brachycentrus after an earthquake.

The larva of the northern snail-shell caddisfly, Helicopsyche (“Spiral-soul”), will coil its case of tiny sand grains into an uncanny facsimile of a snail shell – convergent evolution with the mollusks.

The larva of the long-horned casemaker caddisfly, Heteroplectron, will take up residence in a hollow stick and graze on Tuolumne leaf litter.

The various larvae of the many caddisfly species in the genus Limnephilus (“Lake-lover”) will build their cases in a wide assortment of styles, and from a multitude of materials: grass, or reeds, or moss, or woodchips, or sand, or the delicate and translucent shells of freshwater snails, or even the cast-off cases of smaller caddisfly larvae.

The free-living larva of the caddisfly Rhycacophila will hunt the bottom nude, with no protective case at all.

The Tuolumne, in finding its old channel again, will rediscover all those meanders where formerly it ran slowly, “often with a lingering expression, as if half inclined to become a lake,” as Muir described it. In this peaceful water the predatory larva of the funnel-web caddisfly will weave its wide-mouthed, five-inch-long sack and wait inside for victims. The larva of the fingernet caddisfly will set out its tubular nets of fine silk on the undersides of rocks and feed on the small organic particles trapped in the mesh. In the slowest water, the larva of the soldier fly, armored in calcium carbonate, will scavenge and eat almost anything it can find.

As the reservoir subsides, the bar of glacier-polished granite that once divided the meadow of lower Hetch Hetchy from the forest of upper Hetch Hetchy will rise again, and the rapids that once ran over the bar will pick up speed and dash once more. The larva of the web-spinning caddisfly will cast its web into the fast water. The larva of the riffle beetle will forage on wood debris carried down by the riffles. The predaceous larvae of the alderfly, stonefly, and mayfly will hunt along the bottom, holding on against the current with the hooks on their feet. The larva of the black fly will filter-feed from river-rounded stones, belayed against the current by a silken safety line – convergent evolution with the human rock climber. In the fastest water, the tiny larvae of Comstock’s net-winged midge will stick to the rock by its six suction cups, one each on the undersides of all six segments.

painting of the Hetch Hetchy valley with substantial forest cover, wolf in the foregroundLaura Cunningham

As the Tuolumne retraces its old course down the middle of the newly risen valley floor, and as Falls Creek, Tiltil Creek, Rancheria Creek, and the other tributaries cross that floor to join the river, riparian vegetation will reseed itself along the stream courses: willows, alders, dogwood. As this stream-loving flora takes hold, the Sierra’s streamside fauna will follow. Yellow, yellow-rumped, orange-crowned, and black-throated warblers will linger in the riparian forests on their migration through the range. Black-headed grosbeaks and Bullock’s orioles are likely to breed there. The mink should appear, and maybe the river otter, the two members of the weasel family most dependent on water. Amphibians will come: the California toad, the gregarious slender salamander, the California slender salamander, the Sierra newt, the arboreal salamander. The Pacific tree frog will surely show up, a tiny frog with a big voice, its choruses filling the Hetch Hetchy night. The mink should appear, and maybe the river otter, the two members of the weasel family most dependent on water.

The shrews will arrive. Trowbridge’s shrew or the Yosemite shrew, Sorex trowbridgii, inhabits moist ground, meadows, and streamside vegetation at these elevations. The vagrant or wandering shrew, Sorex vagrans, is even more closely associated with water, and it lives in this zone as well. The water shrew, Sorex palustris navigator (“marsh navigator shrew”) is the most aquatic of all, regularly diving from Sierra streamside vegetation to hunt the stream itself.

The shrews are the smallest of mammals, yet the most ferocious. They are not rodents, like mice, which generally dwarf them, but belong with moles in the primitive order Insectivora. More than anything they resemble small moles that have abandoned their burrows: the same velvety pelts, the same long, flexible snouts, the same tiny weak eyes, the same semiscrotal testes, the same frantic metabolism. As a general rule, a shrew consumes its own weight each day. Shrews in captivity have proved capable of eating their own weight every three hours. Shrews tear apart and gobble insects, spiders, centipedes, small reptiles and amphibians, snails, slugs, carrion, mice, and other shrews, feeding on all these things with a crazy insatiable desperation. Shrews are red in tooth and nail. The shrews of North America, indeed, belong in the group called red-toothed shrews – not red from blood, though that would make sense, but reddish from iron deposits reinforcing the enamel at the tips of the teeth, where the shrew’s life of ceaseless predation causes the heaviest wear. Deprived of food for a few hours, shrews die of starvation. Some species dig tunnels, but many are too busy eating for that; instead they travel the burrows and underground galleries of moles, mice, and gophers, and they dash along the runways that mice and voles make in the grass. In these tunnels and runways, on encountering the rightful owners, shrews attack without hesitation rodents several times their own size. The saliva of some North American shrews is venomous. Enough neurotoxin can be extracted from the poison gland of a single shrew to kill two hundred mice. Shrews hunt nearly blind, depending almost entirely on their acute senses of feel, smell, and hearing. Some species of shrew echolocate, like dolphins and bats, emitting high-pitched squeaks and reading the rebounding signals to find their way and their prey.

Everything is fast with shrews, including reproduction. Copulation lasts ten seconds, gestation three weeks, childhood another three weeks or so, and then the young disperse to begin it all again. Females, sexually mature at six weeks, can bear as many as ten litters a year, becoming pregnant again within a day or two of giving birth and weaning one litter as the next is born. In the tropics shrews breed all year. In the temperate Sierra Nevada they allow themselves a winter break. Shrews do not hibernate. Evolution has discovered no way to turn down the thermostat of shrew metabolism, no means of reducing the average shrew’s heart rate of 750 beats per minute at rest to the five heartbeats per minute of the hibernating chipmunk or the ten beats of the hibernating bear. Many shrew species respond to winter by shrinking. Under Sierra snows, they lose as much as half their body weight – a reduction not just of fat and muscle, but also of skull, bones, and internal organs. These abbreviated winter shrews, at half their summer size, must eat half again as much food to survive the cold season. For all their boldness and ferocity, shrews can be fatally jumpy and jittery. In their perpetual tachycardia – as many as 1200 heartbeats a minute, under stress – they are vulnerable to sudden loud noises, and even the rumble of Sierra thunder can kill them. Life is measured in heartbeats and a shrew’s life is never long. A two-year-old shrew is an ancient, its iron-tipped teeth worn down to nubs.

It is wearying just to think about it, the frantic pace of shrews.

The resurrection of Hetch Hetchy Valley will be a succession of many small yet momentous events. The arrival of Sorex palustris navigator, the water shrew, will be one such occasion, a great day in the reanimation of the Tuolumne River through this stretch of its canyon.

painting of a shrew

The water shrew is the largest of Sierra shrews, about the size of a house mouse. The feet of the water shrew are fringed with stiff hairs, a webbing especially noticeable on the hind feet, which are unusually large – swim paws, in effect. With each dive into the stream, tiny air bubbles trapped in the fur turn the shrew into an effervescent little silvery torpedo. It is as fast and agile underwater as a miniature otter, turning sharply and accelerating in pursuit of aquatic insects, small fish, and tadpoles. Often it leaves off swimming to scramble along the bottom, fighting its own buoyancy, poking its long snout under stones and sunken logs for whatever it can find there. Outside, its thick pelt keeps it warm in the icy, fast-running, snowmelt-fed Sierra streams. Inside it is warmed by the feverish shrew metabolism, its heart beating three hundred times per minute. When startled, it dives into the rapids, or, in stretches where the stream is smooth and glassy, it sprints away Jesus-like over the water, its webbed feet supporting it high and dry.

The Greeks had a name, daimon, for the nature spirits that they believed to reside in and watch over every hill, forest, spring, and stream in Greece. The Greeks did not invent the concept. All peoples once saw the world in this way; it was simply human to sense these invisible guardian presences everywhere in the landscape. The water shrew, at home in every part of the stream – scampering the bottom, swimming the midwater, walking the surface – is one candidate for daimon of the reborn Tuolumne through Hetch Hetchy.

But there is another candidate, a feathered analogue to the water shrew, a bird with a loud, clear, flute-like voice and a similar relationship to Sierra Nevada streams. No creature in the Sierra is more beloved, or more symbolic of fast water, than the dipper or water ouzel. A stocky, slate-gray, short-tailed songbird related to the wrens and thrushes, the water ouzel has adapted to life in the torrents. Its chunky shape gives it a high volume-to-surface ratio for retaining warmth. Its plumage is much denser than in other wrens. The oil gland, which all birds possess at the base of the tail, and which all birds, in preening, strop with their bills to lubricate and waterproof their feathers, is ten times larger in the ouzel than in other wrens and thrushes. The ouzel has scaly moveable hatch covers that seal its nostrils while underwater. It has an inner eyelid – a nictitating or “winking” membrane – which flashes white across the eye when it emerges. It has large, strong feet for gripping the stream cobbles as it walks the bottom against the current, hunting nymphs, larvae, and minnows.

The water ouzel seldom leaves the vicinity of water. In flying patrols above its streams, it does not shortcut over land from one branch to the next. This might save time, but it would waste opportunity. Instead the ouzel flies down one fork to the confluence, then up the other fork, keeping white, turbulent water always underneath. Its favorite nesting spot is behind a waterfall, the sort of secret headquarters that a Jules Verne or Tom Sawyer would favor. Like all water birds, it spends an inordinate amount of time preening and waterproofing. It can’t seem to get enough of the stream. Often on finishing a dive it feels the need to water-bathe at the surface, shaking out its plumage, dunking its wings, scattering sunlit droplets of spray. On reaching water shallow enough to stand, or in flying to a streamside stone, the bird commences the odd, bobbing, genuflecting dance that earned it the name dipper. With each bob downward of the rounded breast, the tail flexes down, too, and often the nictitating membrane flashes white across the eye. When you first notice this white, sightless instant in the eye of a dipper, it is unsettling and creepy, as if for that instant the bird were possessed by a demon, but soon it seems normal. The dipping of the dipper is arrhythmic. The bird seems to be dancing to some syncopated beat it hears in the rush of the stream.

painting of a ouzel

“The water ouzel, in his rocky home amid foaming waters, seldom sees a gun, and of all the singers I like him the best,” John Muir wrote. “He is a plainly dressed little bird, about the size of a robin, with short, crisp, but rather broad wings, and a tail of moderate length, slanted up giving him, with his nodding, bobbing manners, a wrennish look. He is usually seen fluttering about in the spray of falls and the rapid cascading portions of the main branches of the rivers.…

“How romantic and beautiful is the life of this brave little singer on the wild mountain streams, building his round bossy nest of moss by the side of a rapid or fall, where it is sprinkled and kept fresh and green by the spray! No wonder he sings well, since all the air about him is music; every breath he draws is part of a song, and he gets his first music lessons before he is born; for the eggs vibrate in time with the tones of the waterfalls. Bird and stream are inseparable.”

Once the dam is gone, bird and stream will come together again. The first dipper will fly in over the Tuolumne as soon as the river rediscovers its gradient and begins to flow fast enough to please dippers. The bird will wade the shallow margins, sticking its head under and periscoping for nymphs. In deeper pools, it will wing through the water like a penguin. Bursting in full flight from the torrent, it will alight on a streamside stone and commence its bobbing, tail-flexing dance: a grace note, a seal of approval, a benediction.

Kenneth Brower
Ken Brower is the author of many books, including Hetch Hetchy: Undoing a Great American Mistake and Freeing Keiko: The Journey of a Killer Whale from Free Willy to the Wild. A regular contributor to National Geographic magazine, he is a member of the board of directors of Earth Island Institute.

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