Mountain Town News: Why is climate change frying the Colorado Plateau?

Map of the greater Colorado River Basin which encompasses the Colorado Plateau. Credit:

From (Allen Best):

Colorado Plateau stands out on global warming map

Graphic credit: The Washington Post (Note: NOAA does not provide data for Alaska or Hawaii for this time period.)

Climbers gather each January in the canyon shadows of the San Juan Mountains to test their skills on giant columns of ice. The towers in the Ouray Ice Park are created by feeding water to the canyon walls, but the cold is natural.

It’s not as cold in Ouray County as it used to be, though. A data set assembled by The Washington Post shows Ouray as one of the places with the most rapid rise in temperatures in the lower 48 states since the late 19th century. Average temperatures have increased 2.3 degrees Celsius, or 4.4 degrees Fahrenheit.

Other counties in western Colorado and eastern Utah have warmed significantly. Utah’s Grand County, where Moab is located, increased 2.5 degrees C. Colorado’s San Miguel County, home to Telluride — a short distance from Ouray — had a 2.2-degree C rise.

The Washington Post drew on statistics from the National Oceanic and Atmospheric Administration’s Climate Division Database between the years 1895 and 1918. It found uneven warming across the United States, with some areas of the South actually cooling a bit. Rhode Island and New Jersey stand out for their heating, as did Los Angeles.

The biggest blob of red and burgundy on the Washington Post’s map was in the mountains and deserts of the Colorado Plateau. The newspaper noted that the area altogether has exceeded the 2-degree C threshold that policymakers, based on the advice of scientists, have identified as critical threshold for global warming.

The newspaper’s work echoes that of a 2014 report, “Climate Change in Colorado,” which also called out spiking warming in western Colorado through 2012. Every year since then with the exception of 2013 has been much warmer than the 20th century average.

Russ Schumacher, Colorado’s state climatologist, says he’s not sure why that portion of Colorado has been warming disproportionately. “We could definitely quibble about some of the details on their maps, but the overall picture is nicely represented,” he says.

The cause of rising temperatures globally has long been understood: the sharp increase in greenhouse gases, which traps heat near the Earth’s surface. The regional variations sometimes remain puzzling…

Directly linking greenhouse gases and changes in a mountain valley remains complicated. “Certainly a substantial fraction is connected to global warming, but in complex terrain areas, and with changes in land use over the last century, those factors can also be important,” he told Mountain Town News.

Broadly speaking, the higher latitudes will warm (and are warming) more than the tropics. Alaska has had outsized warming streak, but Costa Rica, not so much.

“But elevation effects are still an area of active research, in part because we don’t have a lot of reliable data at high elevations (say, above 10,000 feet) nor do models represent the terrain of Colorado particularly well.”

Several teams of scientists in recent years have issued studies that identified rising temperatures as playing a large role in declining flows of the Colorado River. About 92% of the river’s flows originate upstream of the Grand Canyon, much of it in western Colorado. Flows since 2000 have declined 19% from the 20th-century average.

Brad Udall, a scientist with the Colorado Water Institute, told a U.S. House of Representatives subcommittee in February that 2018 was the hottest and driest year in the Four Corners region since records were first kept in 1895.

Udall said that a study that he and two other researchers published in 2018 found 50% of flow reductions in the first 14 years of the century were due to higher temperatures. The other half were due to shifting precipitation patterns.

“It is clear the Colorado River, and the entire Southwest, has shifted to a new hotter and drier climate, and, equally important, will continue to shift to a hotter and drier climate for several decades after we stop emitting greenhouse gases,” he said.

@ASU water policy expert addresses new #drought plan: State will take less water from the #ColoradoRiver under a new contingency plan #DCP #COriver #aridification

Lake Mead, behind Hoover Dam, shows the effects of nearly two decades of drought. (Image: Bureau of Reclamation)

Here’s the release from Arizona State University (Marshall Terrill):

The Southwest’s long-standing drought has left the state staring down a historic and first-ever Colorado River water cutback in 2020.

Starting Jan. 1, Arizona will see a 6.9% reduction of Colorado River water under the Lower Basin Drought Contingency Plan, which was finalized in May with California, Nevada and the federal government. Mexico will give up 3% of its allotment under a separate agreement.

The cuts are part of a plan to keep Lake Mead, a reservoir at the Arizona-Nevada boundary, functional. Water levels for both Lake Mead and Lake Powell have precipitously dropped as a result of historic over-allocation and a drought that started in 2000.

ASU Now spoke to Sarah Porter, director of the Kyl Center for Water Policy at ASU’s Morrison Institute for Public Policy, about the cutbacks and what they will mean for Arizona’s agriculture and the state’s roughly 7 million residents.

Sarah Porter, director of the Kyl Center for Water Policy at ASU’s Morrison Institute for Public Policy. Photo credit: Arizona State University

Question: Are these cuts a move that has been anticipated for some time, and should Arizona residents be worried?

Answer: Yes, the cuts have been anticipated and were agreed to by the parties to the Drought Contingency Plan or DCP. In fact, until a few months ago, we expected deeper cuts, but good mountain snowpack last winter and aggressive conservation efforts shored Lake Mead up a bit. The cuts are part of a larger plan to safeguard the Colorado River system. The plan was negotiated for several years and finalized this spring.

The Lower Basin DCP incentivizes conserving water in Lake Mead while also imposing bigger and bigger cuts should lake levels fall to certain levels. Water users on the Central Arizona Project, which brings Colorado River water to central and southern Arizona, are in line to take largest cuts because they are the lowest priority users.

The 2020 cuts won’t really be felt by Arizona water users because the state has never built out demand for all of its Colorado River supplies. For years, Arizona water managers have used “extra” Colorado River water for aquifer recharge and other purposes. Annually starting in 2015, Arizona has voluntarily conserved in Lake Mead the equivalent amount of this year’s cut.

Rather than worry, Arizona residents should continue to find ways to permanently use water more efficiently. Statewide, Arizona uses the same amount of water today as it did in the mid-1950s, though we now have seven or eight times the population and a much larger economy. There are still lots of opportunities to stretch our water supplies through conservation and efficiency measures.

Q: Who will be the first group of people to feel the sting of cuts in Colorado River supplies?

A: If Lake Mead falls below 1,075-feet elevation, Arizona will take additional cuts and farmers in Pinal County will be the first to feel the impacts. They plan to turn to groundwater (that is, water pumped from wells) to make up for some of those cuts.

Cities are in a different situation. Municipal providers that use CAP supplies tend to have high priority rights, so they would be among the last CAP users to experience cuts. Many cities in the Phoenix and Tucson areas have diverse water portfolios, including groundwater, reclaimed water and other surface water, which gives them a measure of resilience against cuts in Colorado River supplies. And since passage of the 1980 Groundwater Management Act, growth has been tied to long-term water supplies in the state’s most populous areas, so water providers must plan well in advance for foreseeable supply reductions.

Q: So if agricultural is the first to take a hit, will this mean the cost of fruits and vegetables will likely go up — and by how much?

A: That’s a question for an economist, but I will note that Arizona’s agriculture industry is not monolithic when it comes to water supplies. Right now, only Pinal County farmers are facing cuts — other Arizona farmers have higher priority Colorado River rights or get their water from other sources. Two-thirds of Pinal County’s agricultural revenues come from cattle and dairy. That production will not be directly affected by cuts in CAP deliveries. The county’s main irrigated crops are cotton and hay.

Q: What’s the effect going to be on individual households and what should consumers be mindful of, or start practicing?

A: For some households, water rates may increase as their water providers take additional steps to ensure water deliveries in the event of decreased Colorado River supplies. In addition, some households in newer developments in Maricopa, Pinal and Pima Counties depend on groundwater and are required to pay into a fund to purchase water supplies to replenish the groundwater withdrawn for their use. This amount shows up as an assessment on county property-tax bills. As fewer supplies become available, the costs of water to meet the replenishment obligation may also increase.

We should always treat water as the precious resource it is here in Arizona. The single best way for an individual household to help is to permanently reduce the amount of water used for outside landscaping.

Q: Is this going to be the new normal or a sign of things to come?

A: We should think of this as the new normal. Lake Mead is over-allocated. The prolonged drought has exacerbated the problem because it results in less extra water in the system. There are signs that the region is aridifying, meaning that average flows in the Colorado River may decrease.

We shouldn’t overlook the conservation efforts that are critical to keeping the Colorado River system functional. The Drought Contingency Plan includes important ground rules for conserving water in Lake Mead, and Arizona’s Colorado River Indian Tribes and the Gila River Indian Community, along with CAP, will be conserving and storing significant quantities of water in the lake.

Changing nature of Colorado River droughts, Udall/Overpeck 2017.

Colorado River: The West’s precious, but limited resource — Brenda Burman

From “Exploration of the Colorado River of the West and Its Tributaries” By J. W . Powell, 1875

Here’s a guest column from USBR Commissioner Brenda Burman that’s running in The Hill:

One hundred fifty years ago, John Wesley Powell and his small band of courageous explorers captured the nation’s imagination as they completed their first expedition down the Colorado River. Powell and his team faced the unknown, and they came through the river’s canyons with a hard-earned appreciation for the Colorado River as a precious, but limited resource. His vision of diverting water for agriculture contributed to the Reclamation Act of 1902 and the birth of the Bureau of Reclamation.

Powell’s descriptions of Western water scarcity helped inspire American investment in water storage and conveyance infrastructure up and down the Colorado River — forward-thinking investment that built facilities like Glen Canyon Dam with his namesake reservoir, Lake Powell; Hoover Dam with Lake Mead; and other important reservoirs.

Today, that system of reservoirs can store four times the average annual inflow of the Colorado River Basin — absolutely critical storage for the life and livelihood of 40 million people across the West. In fact, without Lake Powell, Lake Mead and other key storage reservoirs along the Colorado River, the basin would have already faced an overwhelming water crisis many years ago.

The century and a half since Powell’s expedition brought many challenges and innovative solutions for the Colorado River. A year ago, the basin was suffering its fifth driest year in over a century; another abysmal datapoint in one of the driest 20-year periods of the last 1,200 years. In contrast, as recently as 2000, both Lake Powell and Lake Mead were nearly full. The water stored in those massive reservoirs blunted the effects of prolonged drought and protected cities, farms and families across the basin from devastating water shortage impacts.

In fact, Colorado River reservoirs helped ensure water deliveries each year during the current 20-year drought — enabling certainty and predictability for water users while avoiding the need for shortage declarations. That’s the value of water storage reservoirs and the lasting legacy of past water leaders like John Wesley Powell.

Unfortunately, not all Western river basins are positioned to withstand the effects of prolonged drought. For example, water storage infrastructure in California’s Sacramento River Basin stores less than one year’s average flow — that’s not enough to sustain ever-increasing demand. As water scarcity in the West becomes more challenging, stretching existing supplies while expanding and improving water storage infrastructure is even more important. We must strengthen our ability to capture, store and deliver limited water supplies while maximizing efficiency to enhance conservation.

While our Colorado River reservoirs have performed very well through prolonged severe drought, we cannot simply maintain the status quo. In January 2019, the combined storage of Lakes Powell and Mead fell to just 38 percent of capacity. That’s what brought the seven Colorado River basin states, the Republic of Mexico, the U.S. government, Native American Tribes, conservation interests and other non-governmental organizations together earlier this year to complete historic drought contingency plans.

Water users in the Colorado River Basin have survived the drought through a combination of water storage infrastructure and voluntary actions to protect reservoir storage and water supply. Adoption of drought contingency plans this summer, developed over years of collaborative negotiation, takes the next step by implementing mandatory action to reduce risk and protect limited water supplies.

I agree with others who believe John Wesley Powell would be happy with the level and success of collaboration in the Colorado River Basin; collaboration that helps focus governance on community and local needs along the river.

On Aug.15 the Bureau of Reclamation released its 2020 operational plans for Lake Mead and Lake Powell. Looking ahead, we are pleased that the basin will avoid deep water delivery reductions or face rapidly-declining reservoirs next year. That’s welcome news and reflects the impact of 2019’s excellent snowpack and runoff into Lake Powell and Lake Mead. That above-average runoff pushed today’s total system storage to 55 percent of capacity. But, one good year can’t undo nearly two decades of drought. We must remain focused on infrastructure improvement, conservation and other efforts to protect the Colorado River’s precious limited water.

John Wesley Powell’s courage and vision introduced America to the treasure that is the Colorado River. Our courage and vision must equal his as we confront challenges like ongoing drought and growing demand throughout the basin. Like we’ve done for the 150 years since Powell first explored those awe-inspiring canyons, we must continue to collaborate and cooperate to find innovative water management solutions for today and future generations. That’s our mandate and, if recent drought contingency plans are an indication, we are up to the task.

Brenda Burman is the commissioner of the U.S. Bureau of Reclamation. The Bureau of Reclamation is a contemporary water management agency and the largest wholesale provider of water in the country. It brings water to more than 31 million people and provides one out of five Western farmers with irrigation water for farmland that produces much of the nation’s produce. It is also the second largest producer of hydroelectric power in the country.

Colorado’s drought-free streak is over: Here’s where it’s the driest —

West Drought Monitor August 27, 2019.

From (Ryan Osborne):

A sliver of Montezuma and La Plata counties in the far southwestern corner of the state were under “moderate” drought conditions, or “D1,” according to the U.S. Drought Monitor . About 36,000 people live in the drought area.

D1 is the lowest drought level, followed by severe, extreme and exceptional conditions. A larger area of southwest Colorado is what the drought monitor considers “abnormally dry” but not quite to the level of drought conditions. Areas of central Colorado and corners in the southeast and northwest part of the state are also abnormally dry. (See the map on the tweet below).

The state became 100% drought-free in late May, marking first time in nearly 20 years of monitoring that no drought conditions were in Colorado…

The drought here in Colorado is part of a larger area of dry conditions across New Mexico, Arizona and parts of Utah, as some areas have experience one of their driest monsoon seasons on record…

In Colorado, many areas are above normal precipitation levels for the year but have been below normal over the last two months, according to the Colorado Climate Center.

Denver, for example, is at 12.58 inches of rain for the year, about 1.25 inches above normal, according to the National Weather Service. In the short term, only a little more than a half-inch has fallen this month, down by more than an inch of normal.

In Cortez, the closest precipitation station to the drought area, rain levels this year are at 9.78 inches, about 1.40 inches above normal. But since June 1, only 1.30 inches have fallen, nearly two inches below normal.

The Climate Center highlighted one of these variations this week, pointing out the rain levels in Walsh, in southeast Colorado. After a good rain on July 2, the area was more than 10.3 inches above normal for the year. Since then, Walsh has been more than four inches drier than normal.

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