FLOOD AND DROUGHT: Upper regions of the Colorado River face floods while the lower endure drought, which could presage unstable water supplies for the western U.S.
Image: Wolfpack306/Wikimedia Commons
The Colorado River has a long journey. It flows from mountains, runs by cities, winds through remote, rust-colored canyons and touches seven states before entering Mexico. It's a natural wonder, but also a life source of the more than 30 million people who rely on it.
But in recent years, the Colorado River has become less reliable. Since 1999, abnormally low precipitation totals and hot and dry conditions have brought reservoir water levels close to record lows. The multiyear drought, the most severe since documentation began more than 100 years ago, has put the water supply in the thirsty Southwest in jeopardy.
This year, heavy snowpack and spring precipitation have brought the region some relief by partially refilling the reservoirs. But while National Oceanic and Atmospheric Administration research shows that snowmelt runoff into the upper basin hasn't been this high since 1986, the southern end of the Colorado River continues to stop shy of the Sea of Cortez, where it used to run until the late 1990s.
The paradox is that this season stands in such stark contrast to the past 11 years of drought, highlighting the types of variability that climate change can wreak on the hydrological cycle.
"It's not at all uncommon for the basin to have high runoff years in a longer period of drought," said Pamela Adams, outreach coordinator with the Bureau of Reclamation, the body that manages the Colorado River Basin. "We can see that in both the past 100 years of data, plus you can see it in the tree-ring data."
The Bureau of Reclamation released the first of three interim reports last month as part of its broader Colorado River Basin Water Supply and Demand Study. The report is designed to provide an outlook on the next "highly uncertain" 50 years (until 2060) of the river's life. Authors wrote that in the nearly quarter-million-square-mile Colorado River Basin, "climate change, record drought, population increases and environmental needs" are likely to make water supplies ever scarcer.
One scenario already found that the mean natural flow at Lees Ferry, Ariz., is projected to decrease by 9 percent over the next 50 years and experience an increased frequency and duration of drought.
Understanding the supplies, demands and risks
The Colorado River is vital to all of the seven states touching the basin -- Arizona, California, Colorado, New Mexico, Nevada, Utah and Wyoming. Apart from providing water for municipal use, the river irrigates 4 million acres of land and sustains 15 Native American tribes, seven National Wildlife Refuges and 11 National Parks, according to the basin study. Hydropower stations along the Colorado River supply more than 4,200 megawatts of generating capacity.
It is also a significant resource for Mexico, because the United States is legally required to ensure its southern neighbor receives 1.5 million acre-feet -- the unit used to measure water resources -- of water annually.
"What this is trying to do is help us think about the possible ways the future will evolve along the Colorado River," said Adams of the Colorado Basin report. "We're looking at scenarios and get a range of possible futures and understand a range of supply and demand so we get a range of what the balances may be."
Previous environmental impact statements have been focused on managing supply, said Adams. This new report, scheduled for completion by July 2012, will for the first time focus on understanding demand because of the effects of climate change. The study is based on data from historically observed and paleo-reconstructed water flow records, as well as projections from global climate models.
"Concerns regarding the reliability of the Colorado River system to meet the future needs of Basin resources in the 21st-century are heightened, given the likelihood of increasing demand for water throughout the Basin, coupled with projections of reduced supply due to climate change," wrote the authors of the report.
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10 Comments
Add CommentYes, there is a serious problem. It is caused by blame. Global warming takes the blame for the problems caused by water rights, over grazing, and general land mismanagement leading to desertification. Make the people of Denver stop watering their lawns. End water rights. Hold back on some of the water upstream as nature and beavers used to do before white man came. Then the land will recover.
Reply | Report Abuse | Link to thisAll of those are problems. Climate change needs to be factored in as well as all other impact factors so that loss of water is less than the river's natural recovery rate.
Reply | Report Abuse | Link to thisIf you choose to live in a desert, why would you expect to have a green lawn anyway? That never made sense to me.
Denver is on the other side of the Continental Divide. Look at a map. My so-called "over-grazing" is what provides your food. Also, most of the Colorado Basin's lands have been deserts for thousands of years. The ONLY part that isn't desert is the Rocky Mountains. And what don't you understand about the "RIGHTS" associated with water rights? Basic water rights are an area of the law that hasn't been altered in centuries. My water rights were created over a century ago. Beavers create dams to provide a safe place to raise their families. Have you ever seen Lakes Powell and Mead? They are probably larger than the county that you live in.
Reply | Report Abuse | Link to thisAs a rancher in western Colorado, I despise you people that spew blame without knowing ANY facts about the situation. EVERY SINGLE THING THAT YOU SAY IS ABSOLUTELY WRONG! Local weather, and the climate in general, are changing. We need to adapt.
Now we know why the Anasazi civilization ended, and they didn't have 30 million people living off the limited water supply. The Southwest has always had droughts and likely always will. We may not be able to limit population growth, but mother nature surely will.
Reply | Report Abuse | Link to thisWell nostalic since you are a Colorado rancher, I guess you know more than I do. I therefore assume that Denver does not have water rights to the Colorado river and does not get municipal water through the Colorado-Big Thompson project which sends water over the continental divide. I guess that the area has always been desert and John Wesley Powell was wrong when he described what would happen if the area did not hold back its water and reuse it but instead shipped it out of the area. Thus, there would no point in restoring the land to what once existed. Xeriscape and drip irrigation make no sense to you.
Reply | Report Abuse | Link to thishubert says: "Make the people of Denver stop watering their lawns."
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Hmmmm......while hubert likes to point fingers and assign "blame" in this instance, he really needs to understand that Denver is on the eastern side of the Continental Divide, and that the Colorado River Basin is on the western side, flowing AWAY from Denver!
notslic says: "Local weather, and the climate in general, are changing. We need to adapt."
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This is very true, and climate change is already giving us more El Nino and La Nina winters, and it was the La Nina pattern this past winter that deposited more snow in the north-central mountains of Colorado, while generally sparing the southwestern part of the state and the San Juan Mtns. All the lakes including Blue Mesa, Powell and Mead are still rising, but probably not for much longer:
http://snowpack.water-data.com/uppercolorado/index.php
Lake Mead hit a historical low level at the end of Nov. and has rebounded quite nicely, but even after all the record snowpack has melted, it will only be at 56%.
Lake Powell has risen 50 feet since its low in April.
I'd much rather see that Colorado snow being used as irrigation in western Colorado, than watering golf courses in the desert of Nevada!
BTW, where's that Olathe sweet corn we usually see by mid-July?
Thanks for the info about the C-BT Project, which was built between 1938 and 1957, providing supplemental water to 30 cities and towns. The water is used to help irrigate approximately 693,000 acres of northeastern Colorado farmland, and not sure if Denver is one of the cities that gets supplemental water from it or not. I do hear from time to time that Denver does indeed invoke water restrictions on its residents, but probably not this year with a good snowpack and good monsoonal flow.
Reply | Report Abuse | Link to thisHi Lakota. Sweet corn is armpit high. You'll see it soon. Almost an inch and a half of rain so far in July!!! This is the latest that I can remember my irrigation ditch being so full and dirty. That IS good news about Mead and Powell. But, as it says in the article, they need a few more years like this one to make a real difference.
Reply | Report Abuse | Link to thisSince Hubert knew about the Big Thompson, and put down Denver, he probably lives in the Fort Collins area. I understand why he is so upset. It used to be a nice mellow farming community back in the 70's when I went to CSU. Now it is solid city from the Springs to Wyoming. Definitely the wrong side of the Rockies. As far as I know, Denver gets its water from the Platte drainage.
Cheers
Re: "The study is based on data from historically observed and paleo-reconstructed water flow records, as well as projections from global climate models."
Reply | Report Abuse | Link to thisHistorical observation is empirical; climate models would seem to indicate inherently-biased computer simulations (i.e., output from the computer is only as good as the data entered). What is the procedure to paleo-reconstruct water flow records?