The previous winter had been a season full of storms that dumped copious amounts of snow on the Sierra Nevada, and I heard that the waterfalls were roaring. So my 10-year-old son and I decided to make an impromptu June trip to the mountains to see the spectacle for ourselves. Our destination: Wapama Falls, a thousand-foot cascade that John Muir once described as "roaring and thundering, pounding its way with the weight and energy of an avalanche."

Muir's description was spot-on. A mile from Wapama Falls, we could hear its thunderous bass, as if the very rock overhead was being torn asunder. Before we'd started the 2.5-mile hike along the Hetch Hetchy Trail, a ranger had told us to be careful. "There's lots of water in the streams," she said, gesturing to a poster of a hiker who had been swept away while crossing the Wapama footbridge days earlier. "We're still looking for him."

An hour into the hike, we crested a ridge and were hit with a heavy mist from the falling water. We donned rain jackets and pressed on. When we reached the footbridge, we were confronted with churning pinwheels of foam. The Wapama was a white torrent, smashing against the wooden bridge, which was hitched to the cliff below, with deadly force. Several steel support cables had come unmoored and were snapping to and fro.

Water streamed from the brim of my son's ball cap as he surveyed the scene. "We're not going to try to cross that, are we?" he asked, smiling wildly, teeth chattering.

"Not today," I replied. "Next time."

I expect that next time will be soon, because I've come to believe that Hetch Hetchy Valley is among the underappreciated gems of Yosemite National Park. In more than a decade as an environmental writer, I've become a tourist of ecological carnage. I've wandered amid the hydrogen sulfide stench of oilfields and circumnavigated the calderas of pit mines. But until I visited Hetch Hetchy, I'd never seen a landscape desecration that elicited such feelings of ambivalence. On the one hand, Hetch Hetchy Reservoir is an incontrovertible stain on the map of American environmentalism. On the other, the drowned valley has become an oasis of solitude in a national park that, in many places, has come to resemble a shopping mall parking lot more than a nature reserve.

Those two words, Hetch Hetchy—which come from a Miwok word that translates roughly to "edible grasses"—have become a sort of shorthand for ecological destruction. San Francisco leaders used the 1906 earthquake and subsequent fire that destroyed the city as political leverage for a water-diversion project that they had been unsuccessfully trying to get built for years. The object of their desire was a valley teeming with waterfalls and rushing streams. In its depths grew tall pines and thigh-high grasses among which the Tuolumne River meandered. In the eyes of the dam builders, the valley was a massive water-storage basin, eight miles long and in some places as much as 2,000 feet deep.

In 1908, as surveyors staked out the valley, Sierra Club founder John Muir wrote, "Dam Hetch Hetchy! As well dam for water-tanks the people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man."

And yet, for all the force of his rhetoric, Muir could not stop the reservoir; in 1923, O'Shaughnessy Dam was completed.

There's no doubt that a bathtub of impounded water is not, in any true sense of the word, wild. Yet more than a century after the valley's damnation, Hetch Hetchy and its surroundings have become an unlikely sanctuary, an accidental wilderness that is free of the commercialization and overcrowding that today's visitors encounter throughout so many national parks.

Map by Steve Stankiewicz 

Walking in the calm of Hetch Hetchy, it's easy to see why early-20th-century conservationists wanted to protect it from the dam. Even drowned, the glacier-carved valley is stunning. Here, days pass slowly, measured by the clockwork wheeling of golden eagles overhead and the blooming of wildflowers from granite fissures underfoot. No car engine sounds reverberate from the canyon's fortresslike walls. Nor are boats allowed on the reservoir, leaving its surface unbroken by any wake. The mirrorlike reflection of the cone-shaped Kolana Rock—little brother to Yosemite Valley's Cathedral Rocks—gives an illusion of the canyon's former depth.

During the recent hike with my son, one of the few sounds we heard, apart from the roar of the falls, was the glissando call of a lone canyon wren echoing from the cliffs. This corner of the park is a welcome respite from the clamor and clatter of Yosemite Valley. While Hetch Hetchy suffered the fate of being submerged, the wildlands above the waterline have been spared being flooded by people.

It is, of course, possible to love a place without acceding to the forces that created it. O'Shaughnessy Dam should be torn down; Hetch Hetchy should be restored to the valley paradise it was for millennia. And in the course of that ecological restoration, we might also rethink our ideas about wildlands recreation, and strike a better balance between public access and private solitude. In the process, we might end up creating a wilderness by design.

This article appeared in the September/October 2019 edition with the headline "An Accidental Wilderness."