America's second largest reservoir -- Lake Powell -- is disappearing

As water levels plummet to 45% in America’s second-largest reservoir, new islands appear – and fears grow for a waterway that serves 40 million people

The Colorado river and its tributaries took a hundred million years or two to carve the Glen Canyon out of the pink and scarlet sandstone which marks out the American southwest.

Its myriad gorges, sheer cliffs and towering spires remain ed largely hidden. Prehistoric peoples farmed part of the canyon and Navajo Indian communities built camps close to the river, but few modern Americans ventured there besides explorers – until they disappeared under a man-made wonder, the vast Lake Powell, with the construction of Glen Canyon dam half a century ago.

Almost immediately, environmentalists and archaeologists mourned the loss. A final burst of exploration had turned up thousands of ancient ruins and drawn a belated focus on the canyon’s stunning natural architecture.

“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.

Hidden treasures

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.

Under those agreements, Lake Powell serves in part as a reservoir for the states clustered around the Colorado river’s upper basin – Colorado, Wyoming, Utah and New Mexico. It is also obliged to release specified amounts of water into its sister reservoir and the country’s largest, Lake Mead, 180 miles downriver. Lake Mead in turn provides water to seven out of 10 Nevada residents, to a vast construct of aqueducts serving Arizona plantations and cities, and to help slate the seemingly insatiable thirst of southern California.

But after 15 years of diminishing snow falls on the Rockies, the US government agency managing the Colorado river’s water, the Bureau of Reclamation, is now facing a difficult balancing act as levels in both lakes sink to record lows and rationing looms.

“We all are depending on the snow pack on the Rockies and Lake Powell is the first reservoir,” said Rose Davis of the Bureau of Reclamation’s Upper Colorado region. “It doesn’t look very good. We have 56% of normal snowpack is the last reading that I saw. It’s just terrible.”

The fall in water levels in Lake Mead are as dramatic as those in Lake Powell. It has dropped from over 90% of capacity in 2000 to less than 40%. In April, the water in Lake Mead fell to its lowest level since 1937 when it was still being filled after construction of the Hoover dam.

“We are at a record low and we expect to drop even lower in the summer months,” said Davis.

The immediate cause is the longest drought in a century.

“This 15-year drought that we’re in is the worst drought in the last 100 years,” said Davis. “But we also have tree-ring studies going back to the year 1075 and this is the fourth-worst drought since 1075. So the drought and weather cycles have a natural variability to them but we’ve got data on warmer temperatures and climate change making a difference.

“We could get a crazy amount of snow this winter. We just don’t know. We had a good year in 2011 and it’s not unusual to have one good year in the middle of a drought but this is the longest one in the last 100 years.”

Davis said the longest drought in the Colorado Basin of the past millennia lasted more than 60 years.

Water conservation as a way of life

The southern edge of Lake Powell marks out part of the border of the sprawling Navajo Indian reservation in Arizona. John Begay’s farm sits farm sits alone just off the road south out of Page. At 74, he has watched the transformation of the canyon to a lake, and the rise and fall of the water.

“There are people who talk about a drought but I don’t know if there’s a drought or not,” he said. “We don’t get rain like we used to in the 40s, 50s. The two best years were 1949 and 1967. After that it changed. I know it because of my animals. When there’s less rain we have to collect more water. There hasn’t been enough rain since I was a young man.

“We used to get a lot of snow. There’s not been much since 1980. Used to get eight or 10in. Not now.”

All the talk of a crisis looming leaves Begay baffled. Like many people living in the sprawling, parched reservation lands, he has spent years conserving water. Seated on the worn wooden porch of the house he has lived in his entire life, he draws from a well run by the Navajo government, filling two 12,000 gallon tanks for his 45 head of beef.

“I don’t know if there’s a drought or not,” he repeated. “People talk about drought. The Navajo council is having meetings about this. It doesn’t really change anything for us. We’ve always had to be careful with water here. Look, see how dry this place is.”

Much of the reservation is scrub, offering sparse grazing for livestock and making hard work of growing anything more than food for the family. But Begay can at least rely on the well. Others on the reservation are forced to haul every drop they use.

Although he lives with his family close to one of the US’s largest reservoirs, Dwight Denatsosie gets his water from a pump at the Shell petrol station in Page. He drops a handful of quarters into the machine to fill three 55-gallon drums on the back of his pickup truck.

“I live near Coppermine. It’s real hot over there,” he said. “I need about 15 barrels a week. It depends on the livestock.”

The water is cheap but there’s the cost of the fuel for the constant trips to collect it. His house, like those around it, is deemed too isolated to be on the mains. Denatsosie’s brother-in-law, Leraydo Gishie, helps him collect the water.

“I grew up in a house with no running water and no electricity,” he said.

They too are wary of the idea that the present water crisis is all down to a 15-year drought. Years ago, Denatsosie’s family ran a herd of livestock but the water holes they relied on dried up. One of them was filled by a pump run by a windmill. Looking into the 7ft-high holding tank next to it, there is little more than a few inches of water in the bottom.

“A decade ago that was full. It’s not just the rain. The water isn’t coming out of the ground any more,” said Denatsosie. “We had to get rid of our goats and cows. It’s not just the water. Without the rain, there’s nothing for them to eat because nothing grows properly. Now we only have two horses.”

Deeper cuts

Last year, for the first time, the amount of water transferred from Lake Powell to Lake Mead was reduced, by enough to supply about 1.5m homes. If the snowpack on the Rockies is as bad as Davis fears, then there is likely to be a deeper cut in the coming months under a series of agreements which allocate water rights.

The original agreement, the Colorado River Compact , carved out nearly a century ago, divides the river’s water between the states that rely on it. With hindsight, it sowed the seeds of some of today’s problems. It failed to foresee the rapid rise in population in the desert states of Nevada and Arizona, and the demands of their cities and farms. Nevada, for instance, was allocated only 2% of total of the water distribution.

The compact was also premised on predictions of snow packs on the Rockies which some environmentalists have concluded were based on a period of abnormally high rains in the west during the first quarter of the 20th century.

The agreement gives some states greater claim than others when the water runs short. Arizona loses out, except for a county next to the Mexican border which has what are known as “senior rights” because it produces much of the US vegetable crop in winter. Nevada also does badly. The big winner is California, which gets to keep its much larger allocation, for a while, at least.

That state of affairs can be traced back nearly half a century to construction of the largest aqueduct system in the US to deliver the Colorado’s water to central and southern Arizona. The canals of the Central Arizona Project (CAP) provide water to cities such as Tucson and Phoenix, and irrigate close to 400,000 hectares (1m acres) of farmland. Without it, Arizona would be less fertile and, probably, less inhabited.

But the CAP required the support of California’s members of Congress to win funding and they exacted a price – if the water is rationed, Arizona’s allocation is cut by half before California takes any hit at all.

In 2007, seven years into the present drought, new allocations were signed by the US secretary of the interior in case the water shortages grew. The cutbacks to the states kicks in if Lake Mead falls below 1,075ft.

In April of this year it was just 4ft short of that benchmark as it fell to its lowest level since 1937, when the lake was still being filled. If the water levels continue to drop, Arizona and Nevada will face immediate cuts, escalating as the lake falls further.

That would threaten cities such as Las Vegas and the very existence farms fed by the Arizona aqueduct. If the lake sinks below 1,000ft, the water intake pipes would start sucking air. The Hoover Dam power turbines would also stop spinning, interrupting an important source of electricity to the region.

Davis said it’s a prospect that kicked state governments into gear.

“We signed these guidelines in 2007, so all of the states have been very proactive in storing groundwater, implementing conservation measures, using recycling technologies. They have seen this coming,” she said.

Nevada is recycling most of the water used by residents and tourists in Las Vegas. The Southern Nevada Water Authority put in place a conservation plan that includes limiting the size of lawns, restrictions on watering gardens and campaigns to shorten the time spent in showers or running dishwashers. The authority says it has reduced demand from about 314 gallons per person per day in 2002 to about 205 gallons per day last year, and saved 32bn gallons of water despite the region’s population rising by more than 500,000 people.

California has been implementing a raft of measures, with new laws to come, to deal with a water crisis across the state beyond areas dependent on the Colorado river.

Arizona has cut back water usage to levels last seen in the 1950s. If it comes to it, the state has had to set its own priorities. The cities will get first call over the farmers of central Arizona.

Arizona also stashed surplus water in the years of plenty in underground water banks which should provide it with about two years of reserves, although it is a major operation to extract it.

But all of that looks a relative sticking plaster next to the predictions made by some environmental studies that the Colorado river’s flow is permanently diminished. Some predict the volume of water coming off the Rocky mountains will fall by a further third by 2050.

It’s not just what is on the surface that’s of concern.

With less water coming off the mountains, farmers and local municipalities began drilling down to tap into the Colorado Basin’s aquifers. A study by the University of California, Irvine using Nasa satellites found that over the decade to the end of 2013, the Colorado basin lost 65 cubic kilometres, or 17 trillion gallons, of water – more than double the capacity of Lake Mead. The study describes water from the Colorado River Basin as the “most over allocated in the world”.

“Quite honestly, we are alarmed and concerned about the implications of our findings,” wrote one of the study’s authors , Jay Famiglietti. “From a group that studies groundwater depletion in the hottest of the hot spots of water stress around the world – in India, the Middle East, and in California’s Central Valley – that says something.”

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