From The Guardian (Chris McGreal):
“Glen Canyon died in 1963,” wrote the renowned conservationist David Brower, who founded Friends of the Earth. “Neither you, nor I, nor anyone else knew it well enough to insist that at all costs it should endure. When we began to find out, it was too late.”
But Lake Powell, the US’s second largest reservoir, proved its own marvel. It draws about three million tourists a year to boat, swim and take days on the water, exploring the crevices and side canyons of a lake that stretches nearly 190 miles across the border between Utah and Arizona. The otherworldly landscape of monumental rock piles and soaring sandstone cliffs has provided the backdrop for scenes in Planet of the Apes and Gravity, and for episodes of Doctor Who.
After the dam was constructed at the southern tip of the canyon, the lake took more than a decade to fill with melting snow from the Rocky mountains flowing down the 1,450-mile Colorado river. That brought its own natural phenomenon.
What locals nickname the “bathtub ring” runs for most of Lake Powell’s 1,900-mile shoreline, which is half as long again as the US west coast. The ring of white calcium carbonate absorbed into the rock from the water contrasts sharply with the deep colours of the sandstone.
These days, it also provides a dramatically visible marker of the crisis facing the Colorado river after years of diminishing snowfalls on the Rockies.
Month by month, as water levels fall, more of the bathtub ring is exposed. Today, it towers 100ft or more above the boaters as what federal officials are describing as the worst drought in the Colorado Basin in a century diminishes a river that provides water to 40 million people in seven states. Lake Powell – a crucial cog in the machinery of water delivery – is at only 45% of capacity.
The falling water level has delivered up hidden treasures, the natural arches and narrow side canyons not seen in years. Perhaps the most spectacular is the Cathedral in the Desert, a multi-coloured sandstone arch forming a huge natural amphitheatre, with a waterfall lit by narrow beams of sunlight.
In parts of the lake, new islands have emerged and old ones have become towering sandstone pillars. Shores once underwater are now lined with new beaches while old ones, left high above the waterline, are bristling with plants.
As the water levels dropped, some of the boating arteries linking different parts of the lake could only be kept open by cutting through the rock.
Erin Janicki, an aquatic biologist, has watched the change from the water’s edge. The town of Page, Arizona was built to house workers constructing the dam that flooded Glen Canyon. Janicki lives in one of the original houses, a stone’s throw from the lake. For nine years, she has seen the water rise and fall, but says the overall trend is down.
“The water’s 110ft below the top of bathtub ring,” she said. “There are parts of the lake that have pretty much become mud flats. The inlets get silted up. It takes longer to jet around the lake because some of the waterways aren’t open and you have to go around obstacles.
“There’s still a lot of water out there, but there’s been a big change. People hit rock islands all the time.”
For Janicki, this has raised questions about the nature of development in arid regions.
“I don’t like seeing big developments in the desert,” she said. “These cities growing all the time. More people and less water. It doesn’t seem sustainable to me. Page has a golf course. Here, in the desert.”
The Colorado river serves Wyoming ranches, Arizona agricultural plantations and Nevada’s gambling mecca, Las Vegas. It is crucial to the California food industry and growing desert cities across the southwest.
What goes into Lake Powell is largely decided by how much snow falls on the Rockies in winter. But what comes out is governed by complex agreements made nearly a century ago, and adjusted over the years, which divvy up the river’s water between seven states.