Category: Colorado River

Southern Colorado Plateau has dried 17 percent since 1985

New study projects impacts for world’s drylands

Hikers enjoying the view at Colorado National Monument, near Grand Junction. Researchers say recreation economies in the world’s drier zones are likely to take a big hit from global warming in the next few decades. @bberwyn photo.

Staff Report

Global warming is bad enough on its own for the world’s drylands, but when you add in the impacts of population growth, development and the increasing demand for water, the future looks downright grim.

The end result will be conditions that are detrimental to the recreation economy, wildlife habitat, water availability and other resources in hyper-arid landscapes, according to a recent paper published in Ecosphere. Drylands are of concern because broad-scale changes in these systems have the potential to affect 36 percent of the world’s human population. Continue reading “Southern Colorado Plateau has dried 17 percent since 1985”

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How will global warming affect Colorado River flows?

Water woes ahead for the Southwest

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The Colorado River will be hit hard by climate change. @bberwyn photo.

Even if precipitation stays the same or increases slightly in the next few decades, Colorado River flows are likely to dwindle due to increasing temperatures in the West. The projected warming in the 21st century could reduce flows by half a million acre feet per year, according to a new study to be published in the AGU journal Water Resources Research. Continue reading “How will global warming affect Colorado River flows?”

Study says global warming ups odds of Southwest megadrought

Heat-trapping greenhouse gases may dessicate Colorado River Basin

The paradox of water in the desert, illustrated by a NASA satellite image of the Colorado River.
Megadroughts ahead? Satellite photo of the Colorado River Basin via NASA.

Staff Report

It’s very likely the southwestern U.S. will be hit by droughts unlike any seen since the region was settled by Europeans. Global warming has driven the odds of a 10-year drought to at least 50 percent, and the chances of a 35-year megadrought range from 20 to 50 percent during the next century, according to a new study led by researchers with Cornell, the University of Arizona and the U.S. Geological Survey.

Global warming is “weighting the dice” for megadroughts, said lead study author Toby Ault, explaining that the buildup of greenhouse gases is shifting the climate dramatically. The study is set to be published in an upcoming issue of the  American Meteorological Society’s Journal of Climate. Continue reading “Study says global warming ups odds of Southwest megadrought”

Will global warming boost groundwater supplies in the Upper Colorado River Basin?

Some climate models project more rainfall in the West

A bend in the Yampa River near Dinosaur National Monument in northwest Colorado.
Will global warming boost flows in Colorado River tributaries? @bberwyn photo.

Staff Report

While most recent research suggests that the Colorado River will be depleted well beyond current demands as global temperatures increase, there may be one small bright spot on the horizon. Even if runoff from snow declines, groundwater replenishment in the basin may hold stead under projected increases in  precipitation, the U.S. Geological Survey and U.S. Bureau of Reclamation found in a new study.

“You can’t manage what you don’t measure,” said Fred Tillman, lead author and USGS scientist. “These results are the first step in understanding the quantity of groundwater we can expect in the Upper Colorado River Basin; however, further studies are needed to help more accurately forecast future groundwater availability.”

The Colorado River is a critically important source of water for more than 35 million people in the United States and 3 million people in Mexico. As much as half the water flowing in the rivers and streams in the Upper Colorado River Basin originates as groundwater. Understanding how much groundwater is available and how it’s replenished is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future.

In the new study, USGS and Reclamation scientists estimated projected changes in groundwater recharge for the Upper Colorado River Basin from recent historical (1950–2015) through future (2016–2099) time periods using climate projections and a groundwater-recharge model.

Simulated future groundwater recharge through 2099 is generally expected to be somewhat greater than the historical average in most decades due to an anticipated wetter future climate in the basin under the most advanced climate modeling projections. Groundwater resources are replenished through increases in precipitation, which may offset reductions from increased temperatures. The full report is available online in the journal Geophysical Research Letters.

But researchers urged caution interpreting the results because a few of the models suggested  decreased future recharge relative to the historical climate period.

Continue reading “Will global warming boost groundwater supplies in the Upper Colorado River Basin?”

Colorado River pulse flow released surge of greenhouse gases

New growth in delta could offset CO2 released from riverbed

Colorado River delta
The Colorado River Delta captured in a 2004 image from the International Space Station. Via NASA Earth Observatory.
Our special series on the Upper Colorado River is made possible with support from the Colorado River Water Conservation District. Contact Summit Voice for other sponsorship opportunities and click on the banner to visit the river district online.
Supported by the Colorado River District.

Staff Report

Human management of natural ecosystems always has unintended consequences, and the Colorado River is no exception. After decades of intense dam building and diversions, the mighty river is a mere shadow of it former self, reduced to a trickle in some places and polluted by return flows in others. Along its entire length, ecosystems, including riparian zones and native fish, have suffered, with some of the biggest impacts in the Colorado River delta.

In an effort to restore at least some key reaches of the river, scientists and water managers have teamed up to try mimic some of the Colorado’s natural functions, with controlled releases of water to build up beaches. Those efforts culminated in early 2014 during an eight-week experiment that unleashed a mighty torrent of water from Morelos dam (on the border with Mexico and the USA).

The huge surge (130 million cubic metres) of water raised river levels down to the delta, which has been starved of water for decades. Scientists closely monitored how the release — and potential future releases — affect agricultural crops and natural plant and animal life of the lower delta.

But the pulse flow had another side effect. As the water washed over earth and rocks that had been dried out for many years, it dissolved carbon and sent a surge of greenhouse gases into the atmosphere. Continue reading “Colorado River pulse flow released surge of greenhouse gases”

Colorado Parks and Wildlife targets illegally stocked pike in Green Mountain Reservoir with a bounty for anglers

Northern pike
Colorado Parks and Wildlife is offering a $20 bounty for northern pike caught in Green Mountain Reservoir. Photo courtesy CPW.

Non-native predators could threaten endangered species in Colorado River

Staff Report

Colorado wildlife managers will try to curb expansion of non-native northern pike in Summit County’s Green Mountain Reservoir by paying anglers a $20 bounty for each fish they deliver to the Heeney Marina.

The illegally introduced fish are taking a toll on trout in the reservoir north of Silverthorne and could escape to the Blue River and make their way to the Colorado River. That could add to the challenges of trying to recover four endangered native Colorado River fish species, according to Colorado Parks and Wildlife.

“The (pike) were dumped in there several years ago by someone who selfishly didn’t consider the serious consequences we are now dealing with,” said CPW aquatic biologist Jon Ewert. “People should know that illicit stocking is a problem not only for ethical reasons but legal reasons as well. Anyone caught doing it faces severe penalties.” Continue reading “Colorado Parks and Wildlife targets illegally stocked pike in Green Mountain Reservoir with a bounty for anglers”

Groundwater a huge factor in sustaining Colorado River flows

New study helps resource managers plan for climate change

Evening clouds along the Yampa River in northwestern Colorado.
Groundwater is a huge factor in assessing climate change impacts on the Colorado River. @bberwyn photo.
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Resource managers need as much information as possible about Colorado River flows to make sustainable management decisions.

Staff Report

Resource managers grappling with the vexing question of how to allocate Colorado River water to the thirsty cities, ranches and farms of the Southwest have some new food for thought. A new U.S. Geological Survey study published this week in the journal Water Resources Research shows that more than half the streamflow in Upper Colorado River Basin originates as groundwater.

The information is especially important in the context of how climate change — through increased temperatures and evaporation, as well as changing precipitation patterns — will affect the river. One recent study, for example, showed that warmer spring temperatures are reducing flows independently of winter precipitation. In 2014, another study found that groundwater depletion threatens the sustainability of the Colorado River. Continue reading “Groundwater a huge factor in sustaining Colorado River flows”