colorado river

California Storms And The Megadrought | Earth Wise

February 22, 2023 By EarthWise Leave a Comment

California experienced its wettest 10-day period in 25 years as a result of a series of storms driven by atmospheric rivers in January. The Rocky Mountains got buried in snow from the same weather pattern. For the drought-stricken West, the storms were good news. But they are not the cure for what’s been ailing the region.

In California, the snowpack in the Sierra Nevada mountains has been greatly enhanced, containing twice as much snow as is considered average for this time of year. Without a doubt, it will reduce the impact of the drought that has plagued the state for 23 years. But one big storm or even a series of them is not enough to undo years of minimal precipitation and rising temperatures. Many of the states’ largest reservoirs remain well below historical averages despite the record-breaking rain. It would take several wet years to really allow the state to recover from the drought.

The snowfall in the Rockies is crucial because it is the source of more than two-thirds of the water in the Colorado River. The Colorado River is the water lifeline for 40 million people from Wyoming to Mexico.

The ongoing shrinking of the Colorado River is a crisis that has created massive problems for the multibillion-dollar agriculture industry and for many large cities, including Denver, Phoenix, Salt Lake City, Las Vegas, and Los Angeles. Two of the nation’s largest reservoirs – Lake Mead and Lake Powell – are filled by the Colorado River. The historic low levels of these reservoirs have threatened the functioning of hydropower facilities that provide electricity to millions of people.

The January storms were good news for the West, but its problems are not over.

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This Winter’s Rain and Snow Won’t be Enough to Pull the West Out of Drought

Photo, posted September 18, 2022, courtesy of Sarah Stierch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Atmosphere Is Thirstier | Earth Wise

May 9, 2022 By EarthWise Leave a Comment

The American West is in the throes of a two-decade-long drought. The climate there is getting warmer and drier, which has led to increasing demand for water resources from both humans and ecosystems. According to a new study by the Desert Research Institute and collaborators, the atmosphere across much of the U.S. is also demanding a greater share of water than it used to.

Evaporative demand, which is also called atmospheric thirst, is a measure of the potential loss of water from the earth’s surface up to the atmosphere. It is a function of temperature, humidity, wind speed, and solar radiation. The study, published in the Journal of Hydrometeorology, assessed trends in evaporative demand during a 40-year period from 1980-2020.

The study’s findings showed substantial increases in atmospheric thirst across much of the Western U.S. over that period, with the largest increases centered around the Rio Grande and Lower Colorado rivers. This is important because atmospheric thirst is a persistent force in pushing Western landscapes and water supplies toward drought.

The study found that, on average, increases in temperature were responsible for 57% of the changes observed in atmospheric thirst, humidity 26%, and the other factors playing lesser roles.

For farmers and other water users, increases in atmospheric thirst mean that, in the future, more water will be required to meet existing water needs. Crops already require more water than they did in the past and can be expected to require more water in the future. Over time, for every drop of precipitation that falls, less and less water is likely to drain into streams, wetlands, aquifers, or other water bodies.

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New study shows robust increases in atmospheric thirst across much of U.S. during past 40 years

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Drought And Desalination | Earth Wise

October 11, 2021 By EarthWise Leave a Comment

The Western US is currently experiencing what might be the worst drought in over 1,000 years. The region has seen many droughts in the past, but the changing climate is making dry years drier and wet years wetter. Diminishing snow-packs mean that rivers, streams, reservoirs, and soil are not replenished enough in the spring and summer.

Meanwhile, the Southwest has seen a growth rate over the past 60 years that is twice that of the rest of the country. More and more people are moving to areas expected to get even drier in the years to come. There have been unprecedented water allocation cuts from the Colorado River – which provides water to seven states – and there have been shutdowns of hydroelectric power plants.

Only three percent of the planet’s water is fresh water and much of that is not available for our use. Over 120 countries have turned to desalination for at least some of their drinking water. In the US, the largest plant is in Carlsbad, California and a huge new plant is likely to be built in Huntington Beach, California.

Desalination has its drawbacks. It is expensive, consumes large amounts of energy, and has detrimental environmental impacts. Most of the world’s desal plants now use membrane filtration technology but there are still many that use the thermal distillation method.

There are efforts around the world aimed at improving desalination. A giant project in Saudi Arabia is based on solar heating of sea water. The U.S. Army and the University of Rochester are working on a different solar-based system. European companies are developing a floating seawater desalination plant powered by wind energy.

Droughts seem to be here to stay. Finding better ways to get fresh water is essential.

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A 1,000 Year Drought is Hitting the West. Could Desalination Be a Solution?

Photo, posted May 31, 2021, courtesy of Frank Schulenburg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rivers Changing Color | Earth Wise

February 10, 2021 By EarthWise Leave a Comment

A recent study, published in Geophysical Research Letters, found that one-third of large American rivers have had significant changes of color over the past 30 years. Rivers can appear to be shades of blue, green, and yellow and we tend to expect healthy rivers to have colors in shades of blue. According to the new study, only 6% of American rivers are dominantly blue.

The study looked at 235,000 Landsat images taken from 1984 to 2018. The results are that 56% of rivers studied were dominantly yellow, 38% dominantly green, and 6% blue. Over the 34 years studied, 33% of the rivers had significant changes in color. About 21% became greener and 12% more yellow.

The chief causes of color changes in rivers are farm fertilizer runoff, dams, efforts to fight soil erosion, and climate change. Climate change increases water temperature and rain-related runoff.

Color changes are not necessarily a sign of poor river health, but dramatic changes could point to issues that need attention. A river can change color based on the amount of sediment, algae, or dissolved organic carbon in the water. If a river becomes greener, it can often mean large algae blooms are present that cause oxygen loss and can produce toxins. On the other hand, rivers that are getting less yellow demonstrate the success of regulations to prevent soil erosion.

The study of river colors can pinpoint which rivers are undergoing rapid environmental change. What the study does not provide is information on water quality. Water quality measurements will be important to determine the health of many of the rapidly changing rivers.

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One Third of U.S. Rivers Changed Their Color, Three Decades of Satellite Images Show

Photo, posted July 6, 2016, courtesy of Jeffrey Beall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conserving The Colorado River | Earth Wise

August 13, 2020 By EarthWise Leave a Comment

Last year, we talked about the troubles facing the Colorado River. Nearly two decades of drought conditions have reduced the water levels of the two largest reservoirs of Colorado River water and have threatened the water supply of millions of people in the region. Clear scientific evidence shows that climate change is constricting the iconic river and will do further damage as temperatures rise.

Faced with these facts, water resource managers have been implementing conservation policies in the region and the results so far are very encouraging.

The use of Colorado River water in the three states of the river’s lower basin – Arizona, California, and Nevada – fell to a 33-year low in 2019. The three states consumed just over 6.5 million acre-feet for the year, which is about 1 million acre-feet less than the three states are entitled to use under the legal agreement that allocates Colorado River water.

The last time water consumption from the river was that low was in 1986, which is the year that Arizona opened a large canal that extracts river water for its entitlement.

A key indicator of river health is the depth of Lake Mead, the largest reservoir of Colorado River water. It has been steadily dropping in recent years, but last year, with the reduced consumption, the water level actually increased by 12 feet.

According to water managers, the steady drop in water consumption in recent years is a sign that conservation efforts are working and that there are strategies that can deal with chronic shortages on the river in the future. It represents an important demonstration that it is possible to use less water in a region that irrigates 5 million acres of farmland and has 40 million people in 2 countries and 29 tribal nations.

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Remarkable Drop in Colorado River Water Use a Sign of Climate Adaptation

Photo, posted July 7, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Desalination On The Rise

July 23, 2019 By EarthWise Leave a Comment

Desalination has been regarded for decades as a solution for providing fresh water to places where it is scarce. With drought becoming more common around the world – sometimes even in places where water supplies were thought to be ample – there is increasing pressure to bring new desalination plants online.

San Diego gets only 12 inches of rain a year and has no groundwater. It gets half its water from the distant Colorado River, and that source is becoming increasingly unreliable. Thus, it is no surprise that America’s largest desalination plant is in Carlsbad, about 30 miles north of San Diego. That plant provides about 10% of the fresh water needs of the region’s 3.1 million people.

There are 11 desalination plants in California, and 10 more are proposed. Desalination is huge in Saudi Arabia, Australia and Israel. Globally, more than 300 million people get their water from desalination.

But there are problems. Desalination is expensive and energy-intensive. If the process is powered by fossil fuels, it contributes to global warming. There are ecological impacts as well since it takes two gallons of sea water to make a gallon of fresh water, and the gallon left behind is extremely briny and potentially harmful to dump back into the sea. The intake systems of desalination plants are also harmful to fish and other aquatic creatures.

The cost of desalination has dropped by more than half over the last 30 years but water from it still costs about twice as much as that from other main sources. The technology is getting better and cheaper, but the industry must confront and solve serious environmental and economic problems in order for desalination to be able to meet the needs of an increasingly thirsty world.

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As Water Scarcity Increases, Desalination Plants Are on the Rise

Photo, posted January 12, 2011, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Trouble On The Colorado

April 4, 2019 By EarthWise Leave a Comment

The 1450-mile-long Colorado River begins in the Rocky Mountains and wends its way to the Gulf of California, creating the Grand Canyon along the way, and providing water to some 40 million people. The amount of Colorado River water promised to users is far more than actually flows between its banks, and that amount is dropping.

An unrelenting drought since 2000 has resulted in the water levels of the two largest reservoirs of Colorado River water – Lake Mead and Lake Powell – being at all-time lows.

Lake Mead, just outside of Las Vegas, is the reservoir of Hoover Dam, which provides power for millions of people in Southern California, Nevada, and Arizona. The last time Lake Mead was full was in 1983. It has slowly declined and now is 40% full.

If the lake level drops another 7 feet to 1075 feet above sea level, it will trigger a Tier 1 declaration, mandating cuts to water allocations to Arizona and other states. If the level drops to 1050 feet, it would reach Tier 2 at which point Hoover Dam would have to stop generating electricity because water levels would be too low to flow through it. If the lake level drops all the way to 895 feet, it would be below the level at which water can be piped out of it. This is known as the “dead pool”.

These scenarios are no longer doomsday fantasies. Water managers in the Southwest see the writing on the wall and are busy making contingency plans and developing ways to use less water from the Colorado River. The booming city of Phoenix in particular is hard at work finding alternative ways to provide water for its millions of citizens. On the Colorado, drought in the new normal.

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