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New Colorado River basin projections show dire conditions for reservoirs as drought persists

NOAA predicts La Niña conditions for Southwest this winter as administration prepares for Glasgow
lake mead colorado river
Posted at 2:51 PM, Oct 21, 2021
and last updated 2021-10-22 14:12:30-04

DENVER – New projections of Colorado River system inflows into Lake Powell and Lake Mead released this week by the U.S. Bureau of Reclamation show both reservoirs could reach critical, and lower, levels in the next two years with another drier La Niña weather pattern setting up for the basin this winter.

The latest iteration of the Bureau of Reclamation’s two-year study and two- and five-year projections for levels at the two major western reservoirs within the Colorado River system incorporates the new U.S. Climate Normals released earlier this year, which includes data from 1991-2020 and eliminates the wetter conditions seen in the basin during the 1980s, data that was used for projections for the past 10 years.

It also puts more weight on the 22-year drought that has been ongoing since 2000, and the bureau said the updated data gives forecasters a better look at what could happen to the river basin in the next few years as climate change continues to alter the climatological and weather patterns in the West.

“Incorporating the updated climate normal into the [Colorado Basin River Forecast Center] forecasts, and, in turn, into our modeling projections, provides us with a better understanding of what is happening now and will give us a more informed assessment of potential future conditions,” said Upper Colorado Basin Regional Director Wayne Pullan.

The updated data resulted in the bureau downgrading inflow projections from September’s forecast for Lake Powell’s 2022 inflows, and the latest puts the reservoir eight feet lower at the end of September 2022 that what was forecast last month.

If the projections hold true and the basin does not get increasing precipitation, Lake Powell would fall below its minimum power pool level of 3,490 feet as soon as next July, according to the bureau.

Lake Mead is projected to be less than one foot above the Tier 2 shortage elevation by the end of next year, according to the bureau, which would lead to more water cuts for states that get their water from the reservoir.

The reservoir dropped to its lowest levels since the 1930s earlier this year, and federal officials declared the first-ever water shortage for the Colorado River, leading to cuts across the Southwest after runoff into Lake Powell from April to July amounted to just 26% of its average. Though the median snowpack was close to 90% for the basin, persistent drought and above-average temperatures did not lead to the runoff that was expected into the reservoirs.

The two- and five-year projections from the Bureau of Reclamation show better possibilities for Lake Powell than Lake Mead – the latter of whom is seeing the minimum, maximum and most probable scenarios all leading to lower pool elevations than they currently sit over the next two years. However, the bureau warns the models are subject to degrees of uncertainty based on demand, policymaking, physical changes and more.

“We have had to make difficult choices this year, and we will all have to make more difficult decisions if it continues to remain dry next year to protect Lake Mead and Lake Powell,” said Jacklynn Gould, the Lower Colorado Basin Regional Director for the bureau.

The projections come as the National Oceanic and Atmospheric Administration released its winter outlook for the U.S., which shows above-normal temperatures and average-to-below-normal precipitation for Colorado and the Southwest from December through February.

“Consistent with typical La Nina conditions during winter months, we anticipate below-normal temperatures along portions of the northern tier of the U.S. while much of the South experiences above-normal temperatures,” said Jon Gottschalck, the chief of the NOAA Climate Prediction Center’s Operational Prediction Branch. “The Southwest will certainly remain a region of concern as we anticipate below-normal precipitation where drought conditions continue in most areas.”

The outlook also shows continuing or worsening drought conditions in Colorado and across the Colorado River basin for the winter.

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Colorado’s drought conditions were mostly unchanged week-over-week, with just 5% of the state drought-free and nearly one-third of Colorado experiencing severe-to-exceptional drought, according to the U.S. Drought Monitor.

In the West region, which includes New Mexico, Arizona, Utah, Nevada, California, Oregon, Washington, Idaho and Montana, conditions have not changed much over the year. Just 2% of the region is drought-free, and 58% is experiencing extreme or exceptional drought. Twenty percent of the region is in the worst drought category, exceptional drought – only a slight improvement from where conditions sat at the start of the calendar year.

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The Biden administration also released a series of national security and foreign policy reports Thursday that say climate change will continue to increase risks to both – including geopolitical tension over responsibility to fight climate change and physical changes to the climate that could increase tension between nations and regions, among other things.

“The scientific community is clear: Human activities are directly contributing to climate change. We are already experiencing the devastating impacts that climate has wrecked on almost every aspect of our lives – from food and water insecurity to infrastructure and public health,” a senior administration official said in a briefing about the reports, according to a transcript. “And this crisis is exacerbating inequalities that intersect with gender, race, ethnicity and economic security.”

360 in-depth: While climate spending is in jeopardy, new data, modeling paint dire picture

The Biden administration is expected to send more than one dozen cabinet members and senior officials to the UN climate summit next month in Glasgow and is expected to attend himself, CNN reported, as the House and Senate still battle over what climate change policies and plans to include in the infrastructure bill that is seeing cuts made to it to appease certain lawmakers.