Report: State of the #climate in 2020 — NOAA #ActOnClimate

Click here to read the report. Here’s the abstract:

In 2020, the dominant greenhouse gases stored in Earth’s atmosphere continued to increase. The annual global average carbon dioxide (CO2) concentration at Earth’s surface was 412.5 ± 0.1 ppm, an increase of 2.5 ± 0.1 ppm over 2019, and the highest in the modern instrumental record and in ice core records dating back 800,000 years. While anthropogenic CO2 emissions were estimated to decrease around 6%–7% globally during the year due to reduced human activities during the COVID-19 pandemic, the reduction did not materially affect atmospheric CO2 accumulation as it is a relatively small change, less even than interannual variability driven by the terrestrial biosphere. The net global uptake of ~3.0 petagrams of anthropogenic carbon by oceans in 2020 was the highest in the 39-year record and almost 30% higher than the 1999–2019 average.

Weak El Niño-like conditions in the eastern equatorial Pacific Ocean in early 2020 cooled and transitioned to a moderate La Niña later in the year. Even so, the annual global surface temperature across land and oceans was among the three highest in records dating to the mid- to late 1800s. In Europe, 17 countries reported record high annual mean temperatures, contributing to the warmest year on record for the European continent. Elsewhere, Japan, Mexico, and Seychelles also experienced record high annual mean temperatures. In the Caribbean, Aruba, Martinique, and St. Lucia reported their all-time monthly maximum temperatures. In the United States, Furnace Creek in Death Valley, California, reached 54.4°C on 16 August—the hottest temperature measured on Earth since 1931, pending confirmation. North of 60°N, the annual mean temperature over Arctic land areas was 2.1°C above the 1981–2010 average, the highest in the 121-year record. On 20 June, a temperature of 38°C was observed at Verkhoyansk, Russia (67.6°N), provisionally the highest temperature ever measured within the Arctic Circle.

Near the opposite pole, an atmospheric river—a long, narrow region in the atmosphere that transports heat and moisture from sub-tropical and midlatitudes—brought extreme warmth from sub-tropical and midlatitudes to parts of Antarctica during austral summer. On 6 February, Esperanza Station recorded a temperature of 18.3°C, the highest temperature recorded on the continent, surpassing the previous record set in 2015 by 1.1°C. The warmth also led to the largest late-summer surface melt event in the 43-year record, affecting more than 50% of the Antarctic Peninsula. In August, daily sea ice extent in the waters surrounding Antarctica shifted from below to above average, marking the end of persistent below-average sea ice extent since austral spring 2016.

In the Arctic, when sea ice reached its annual maximum extent in March, thin, first-year ice comprised ~70% of the ice; the thickest ice, which is usually more than four years old, had declined by more than 86% since 1985 to make up just 2% of total ice in 2020. When the minimum sea ice extent was reached in September, it was the second smallest except for 2012 in the 42-year satellite record. The Northern Sea Route along the Siberian coast was open for about 2.5 months, from late July through mid-October, compared to less than a month typically.

Glaciers across the global cryosphere lost mass for the 33rd consecutive year, and permafrost temperatures continued to reach record highs at many high latitude and mountain locations. In the Northern Hemisphere, lakes froze three days later and thawed 5.5 days earlier on average. In Finland, the average duration of lake ice was 42 days shorter. Record high spring temperatures in central Siberia drove rapid snow melt that contributed to the lowest June snow cover extent across Eurasia in the 54-year record.

As is typical, some areas around the world were notably dry in 2020 and some were notably wet. The Middle East experienced an extreme drought during autumn, with most places reporting no precipitation in October. In South America, the Bolivian lowlands suffered one of its most severe droughts on record during autumn. Drought also spanned the Chaco and Pantanal in Bolivia, Paraguay, and southern Brazil. The Paraguay River shrank to its lowest levels in half a century. A decadal “mega drought” in south-central Chile continued through its 11th year, with extreme conditions in the most populated areas. Argentina reported its driest year since 1995. In North America, drought continued to prevail in the West.

The lack of moisture in drought-stricken regions often provide ideal conditions for fire. Total fire emissions in the western United States in 2020 were almost three times higher than the 2003–10 mean. The Arctic experienced its highest fire year in terms of carbon emitted into the atmosphere, surpassing the record set in 2019 by 34%, with most of the fires occurring in Arctic Asia. In the tropics, the Amazon saw its highest fire activity since 2012, while fire activity in tropical Asia—including Indonesia—was one of the lowest on record, related to wet conditions as La Niña evolved during the fire season.

The 2020 Southwest Asian Monsoon season (June–September) was the wettest since 1981, also coincident with the emergence of La Niña. The Meiyu rainy season, which usually occurs between July and August over the Yangtze and Huaihe River Valleys of China, was extended by two months in 2020. The May–October total rainfall averaged over the area was the most since the start of the record in 1961. Associated severe flooding affected about 45.5 million people.

A widespread desert locust infestation during 2019–20 impacted equatorial and northern East Africa, as heavy rains and prevailing winds were favorable for breeding and movement of swarms across Kenya, Ethiopia, northeastern Somalia, Uganda, South Sudan, and northern Tanzania. The massive infestation destroyed thousands of square kilometers of cropland and pasture lands, resulting in one million people in need of food aid in Ethiopia alone. Extremely heavy rains in April also triggered widespread flooding and landslides in Ethiopia, Somalia, Rwanda, and Burundi. The Lake Victoria region was the wettest in its 40-year record.

Across the global oceans, the average ocean heat content reached a record high in 2020 and the sea surface temperature was the third highest on record, surpassed only by 2016 and 2019. Approximately 84% of the ocean surface experienced at least one marine heatwave (MHW) in 2020. For the second time in the past decade, a major MHW developed in the northeast Pacific, covering an area roughly six times the size of Alaska in September. Global mean sea level was record high for the ninth consecutive year, reaching 91.3 mm above the 1993 average when satellite measurements began, an increase of 3.5 mm over 2019. Melting of the Greenland Ice Sheet accounted for about 0.8 mm of the sea level rise, with an overall loss of 293 ± 66 gigatons of ice.

A total of 102 named tropical storms were observed during the Northern and Southern Hemisphere storm seasons, well above the 1981–2010 average of 85. In the North Atlantic, a record 30 tropical cyclones formed, surpassing the previous record of 28 in 2005. Major Hurricanes Eta and Iota made landfall along the eastern coast of Nicaragua in nearly the same location within a two-week period, impacting over seven million people across Central America. In the western North Pacific, Super Typhoon Goni was the strongest tropical cyclone to make landfall in the historical record and led to the evacuation of almost 1 million people in the Philippines. Very Severe Cyclonic Storm Gati was the strongest recorded cyclone to make landfall over Somalia. Bosaso, in northeast Somalia, received 128 mm of rainfall in a 24-hour period, exceeding the city’s average annual total of 100 mm.

Above Earth’s surface, the annual lower troposphere temperature equaled 2016 as the highest on record, while stratospheric temperatures continued to decline. In 2020, the stratospheric winter polar vortices in both hemispheres were unusually strong and stable. Between December 2019 and March 2020, the Arctic polar vortex was the strongest since the beginning of the satellite era, contributing to record low stratospheric ozone levels in the region that lasted into spring. The anomalously strong and persistent Antarctic polar vortex was linked to the longest-lived, and 12th-largest, ozone hole over the region, which lasted to the end of December.

Emissions from fossil fuel use in 2020 dropped by around 6% to 7% over 2019 due to decreased activity during the pandemic (section 2g1); however atmospheric concentration of carbon dioxide (CO2), still reached the highest levels in the modern climate record.

@ColoradoParksWildlife begins to stock pure #RioGrande Cutthroat Trout into Sand Creek Lakes

Here’s the release from Colorado Parks & Wildlife (John Livingston):

Colorado Parks and Wildlife successfully stocked a small number of pure Rio Grande Cutthroat Trout into Upper and Lower Sand Creek Lakes via helicopter on Aug. 24.

The fish used to stock the lakes came from the nearby Medano Creek drainage, which is located in the Great Sand Dunes National Preserve in the San Luis Valley. That drainage was previously restored with Rio Grande cutthroat trout in the 1980s.

By pulling trout from Medano Creek, CPW aims to accelerate the restoration project in the Sand Creek drainage by stocking a small number of adult trout capable of producing a spawn as early as 2022.

After capturing Rio Grande cutthroat trout from Medano Creek, CPW coordinated with the Colorado Division of Fire Prevention and Control to stock Upper and Lower Sand Creek Lakes from a helicopter, using the same bucket a firefighting helicopter would use to dump water onto a fire.

CPW will stock another 500 fingerling Rio Grande cutthroat trout spawned at the Monte Vista Hatchery later this year. That stocking will be completed via airplane.

“This is a challenging project, but it will provide ideal and protected habitat for these fish,” said CPW Senior Aquatic Biologist John Alves. “We are on our way to rebuilding a conservation population of the Rio Grande cutthroat trout.”

Last year, CPW treated the Upper Sand Creek drainage to successfully remove non-native fish.

CPW, the New Mexico Department of Game and Fish, the National Park Service, U.S. Forest Service, Bureau of Land Management and Native American tribes have been working to re-establish Rio Grande cutthroats across their native range for more than 20 years. Currently, Rio Grande cutthroat can only be found in about 12% of its historic habitat. Mining, water development, intensive land-use, stocking of non-native fish and over-fishing have caused the trout’s populations to decline significantly during the last 150 years.

The Rio Grande cutthroat is one of three native trout indigenous to Colorado. The Colorado River cutthroat is found on Colorado’s Western Slope, and the Greenback cutthroat is found in the South Platte drainage. CPW is also working on a variety of projects to restore those populations.

For more information on Rio Grande cutthroat trout, go to

Water-starved #ColoradoRiver Delta gets another shot of life from the river’s flows — @WaterEdFdn #COriver #aridification #conservation

Water from the Colorado River environmental release flows into the El Chausse restoration site in Baja California, Mexico. (Source: Jesus Salazar, Raise the River)

From the Water Education Foundation (Gary Pitzer):

Western Water Notebook: Despite water shortages along the drought-stressed river, experimental flows resume in Mexico to revive trees and provide habitat for birds and wildlife

Water is flowing once again to the Colorado River’s delta in Mexico, a vast region that was once a natural splendor before the iconic Western river was dammed and diverted at the turn of the last century, essentially turning the delta into a desert.

In 2012, the idea emerged that water could be intentionally sent down the river to inundate the delta floodplain and regenerate native cottonwood and willow trees, even in an overallocated river system. Ultimately, dedicated flows of river water were brokered under cooperative efforts by the U.S. and Mexican governments.

The first intentional flows happened for about eight weeks in 2014. This year, the flows will be much longer despite an ongoing drought that sparked first-ever declared shortage on the river earlier this month. The flows started May 1 and will continue through October. They are supported by myriad groups, including the International Boundary and Water Commission (IBWC), created by the two countries 132 years ago.

“The United States is committed to meeting its environmental commitments to Mexico,” Daniel Avila, the IBWC’s acting U.S. commissioner, said in a statement. “I’m pleased to see the environmental water deliveries this year as part of our effort to improve wildlife habitat in the region.”

Avila’s counterpart in Mexico, Humberto Marengo, said in a statement that environmental cooperation on the Colorado River in Mexico is very important for both countries, as reflected by the agreed-upon use of water to help replenish parts of the riparian corridor leading to the Gulf of California.

It’s an audacious experiment, part of a multifaceted agreement that helps the two countries share the river. But it comes this time despite shortages elsewhere on the drought-stressed Colorado River, which supplies water to millions of people in the Southwest and large swaths of farmland in the U.S. and Mexico.

Amy Witherall, binational program manager with the U.S. Bureau of Reclamation, said the current flow for the delta has a lower peak volume and is spread across a longer time period than the 2014 experimental flow. And by using Mexico’s irrigation canals, water is moving more effectively to restoration sites.

“As a result of the binational coordination and collaboration that has developed, we were able to design a creative solution to maximizing the benefits of the environmental water available,” she said.

Habitat restoration work (the projects are named in yellow) extends along the main channel of the Colorado River from the US-Mexico border to the upper estuary of the Gulf of California. (Source: Sonoran Institute)

Learning from the Flows

The dedicated environmental flows delight conservation advocates who see ample opportunity to bring back some of the ecosystem benefits for birds, plants and wildlife.

“One really interesting thing to report is that it’s working,” said Jennifer Pitt, Colorado River program director with the National Audubon Society. “There’s definitely been reports and visual confirmation of the connection of those flows to the sea.”

Raise the River, a partnership of six U.S. and Mexican nongovernmental organizations (NGOs), is leading the work to reimagine parts of the Colorado River Delta to establish pockets of wildlife-friendly habitat and recreational opportunities for local communities. It’s an iterative process that reveals how the landscape responds when it gets water from the Colorado River.

It’s likely the lessons learned from the coming months will influence how water is applied during a future flow release – sometimes through the dry reaches and sometimes around them. “We are going to collect data and have lots of conversations about the tradeoffs,” Pitt said.

The flow that began this year will be one in a series of rewatering efforts on the delta’s riparian corridor through 2026. The U.S. and Mexican governments provide the water in tandem with coalition of conservation groups. From the time the first flows began in 2014, those living near the river have been profoundly affected.

“I have grown up watching a river die and today I see a river revived,” Antonia Torres Gonzalez, a member of the Cucapá tribe indigenous to the lower Colorado River, said in a video produced by the Sonoran Institute of Mexico, one of the NGOs involved with the river. “We have been taught that the river is like a person that we have to love and respect.”

Jennifer Pitt, the National Audubon Society’s Colorado River program director, paddles a kayak through a restoration site. (Source: Jesus Salazar, Raise the River)

Even with a drought-stressed Colorado River on the brink of severe use restrictions that limit water for all purposes, water is flowing to restoration sites and will continue to do so under addendums to an international treaty. Still, those restoration flows are expected to be pared back – though not halted – next year as a result of the Bureau of Reclamation’s Aug. 16 declaration of a shortage in 2022 that will reduce water supplies for Arizona and Nevada.

“You can’t just sort of take one part of it and say, oh we’re going to do this part, not this other part,” said Karl Flessa, professor of geosciences at the University of Arizona who closely monitors the delta flows. With Reclamation’s shortage declaration, “Mexico is going to share that shortage and there’s going to be a comparable shortage or sharing of the water that goes towards the restoration projects.”

Bringing Back the Delta

Across the Colorado River Basin, climate change is upending the expected patterns of hydrology. Reduced Rocky Mountain snowpack and rising temperatures are stressing the system, leaving less runoff flowing downstream to reservoirs, farms and cities. Those working to restore delta habitat using river flows hope that their efforts will help.

Tree nurseries at Raise the River restoration sites provide the seedlings to expand native vegetation along the Colorado River corridor in Mexico. (Source: Jesus Salazar, Raise the River)

“We are trying to mitigate [climate change] in the areas with restoration, as we help to lower the temperature with the trees planted,” said Gabriela Caloca Michel, restoration project coordinator with Pronatura Noroeste, the oldest and largest conservation nonprofit in Mexico that manages several restoration sites.

The Colorado River once traveled all the way to the Gulf of California – an estuary of about 2 million acres. Dams and aqueducts moved water to irrigate farms, including those in Mexico and seven western U.S. states, and provide drinking water. As a result, the river made it all the way to the mouth of the estuary only during high flow years.

But people have come to realize that it’s possible to bring back a portion of the Colorado River Delta with relatively small contributions of river water. The first experimental pulse flow of Colorado River water – 105,000 acre-feet of water in total – into the delta was delivered to mimic the flood flows that used to naturally reach the delta with spring snowmelt. Some water was routed to established restoration sites along the river corridor to nurture newly planted native trees, such as cottonwoods and willows.

Much was learned from that 2014 flow. Even though the river would sometimes flood the delta, the 2014 release helped foster knowledge about water movement (including infiltration) that is aiding the current effort.

Pronatura’s Caloca Michel, who has worked on the delta since 2015, said the aim with the 2021 water release is to carefully map out the design of restoration sites, factoring irrigation infrastructure, plant selection and local nursery production, soil type and water table and water rights to be able to irrigate.

Getting To the Green-Up

Under the terms of a 2017 agreement, the United States, Mexico and the coalition of NGOs each agreed to provide one-third of the 210,000 acre-feet of water for environmental purposes in the delta through 2026. The NGOs have provided 26,369 acre-feet of water between 2018 and 2020.

Native cottonwood trees are back in large numbers in some sections of the Colorado River Delta. (Source: Jesus Salazar, Raise the River)

The plan is to move water to different locations at different rates and times to realize the most ecosystem advantages. It’s a give and take between providing open water habitat for birds and moving releases to specific restoration sites that have been cultivated with native vegetation. Some flows are carried via established irrigation canals to limit the amount that seeps into the ground.

Infiltration of the flows into the ground isn’t a loss, Flessa said.

“If you’re pumping groundwater or a Mexican farmer, that’s a good thing. Groundwater does sustain a lot of vegetation along the way,” he said. “But if you want to deliver water to some of the more downstream restoration sites you really need to find a way to make sure that you maximize the efficiency of the water delivery so you don’t lose as much of the delivery as you would by putting water in the main channel.”

Teams constantly measure how the flows affect the groundwater table, the established vegetation and the new acreage plots established by the conservation groups.

Having water available through summer helps, given the harsh desert heat.

“It is a pretty stressful time for everybody,” Flessa said. “For the plants, if there is lack of irrigation or lack of support, those trees don’t like it.”

A common refrain is the surprise about how quickly vegetation such as cottonwoods and willows respond to what Pitt called “a drink of water.” But it’s not just water. The foundation established by conservation groups provides jobs for the community and re-establishes a connection to the riparian environment.

“I see a very big impact that the ecosystem is working well and the work we do has paid off,” said Celedonia Alvarado Camacho, who supervises tree preparation and planting for the Sonoran Institute.

Long-term, the question remains how to reimagine the delta with relatively small amounts of water. The flows were included as part of a pair of recent amendments to the 1944 Water Treaty with Mexico. Conservationists expect that a commitment for environmental flows will be included in future treaty agreements.

“I have every reason to believe an environmental program will be part of [a new agreement], in part because we had it in the last two … and because both countries have made enormous investments in restoring habitat,” Pitt said.

Still, a sense of perspective is needed for the ancient delta. “We are not going to bring the whole river delta back, that’s for sure,” Flessa said. “But I do think we could sort of get a green ribbon from the border to the Gulf of California.”

The invasive emerald ash borer has destroyed millions of trees – scientists aim to control it with tiny parasitic wasps — The Conversation

Emerald ash borer larva cut these feeding galleries on the trunk of a dead ash tree in Michigan.
corfoto via Getty Images

Kristine Grayson, University of Richmond

The emerald ash borer (Agrilus planipennis) is a deceptively attractive metallic-green adult beetle with a red abdomen. But few people ever actually see the insect itself – just the trail of destruction it leaves behind under the bark of ash trees.

These insects, which are native to Asia and Russia, were first discovered in Michigan in 2002. Since then they have spread to 35 states and become the most destructive and costly invasive wood-boring insect in U.S. history. They have also been detected in the Canadian provinces of Ontario, Quebec, Manitoba, New Brunswick and Nova Scotia.

In 2021 the U.S. Department of Agriculture stopped regulating the movement of ash trees and wood products in infested areas because the beetles spread rapidly despite quarantine efforts. Now federal regulators and researchers are pursuing a different strategy: biological control. Scientists think that tiny parasitic wasps, which prey on emerald ash borers in their native range, hold the key to curbing this invasive species and returning ash trees to North American forests.

Metallic green beetle.
Adult emerald ash borer beetles are about 0.5 inches long (photo not to scale).

I study invasive forest insects and work with the USDA to develop easier ways of raising emerald ash borers and other invasive insects in research laboratories. This work is critical for discovering and testing ways to better manage forest recovery and prevent future outbreaks. But while the emerald ash borer has spread uncontrollably in nature, producing a consistent laboratory supply of these insects is surprisingly challenging – and developing an effective biological control program requires a lot of target insects.

The value of ash trees

Researchers believe the emerald ash borer likely arrived in the U.S. on imported wood packaging material from Asia sometime in the 1990s. The insects lay eggs in the bark crevices of ash trees; when larva hatch, they tunnel through the bark and feed on the inner layer of the tree. Their impact becomes apparent when the bark is peeled back, revealing dramatic feeding tracks. These channels damage the trees’ vascular tissue – internal networks that transport water and nutrients – and ultimately kill the tree.

Before this invasive pest appeared on the scene, ash trees were particularly popular for residential developments, representing 20-40% of planted trees in some Midwestern communities. Emerald ash borers have killed tens of millions of U.S. trees with an estimated replacement cost of US$10-25 billion.

Ash wood is also popular for lumber used in furniture, sports equipment and paper, among many other products. The ash timber industry produces over 100 million board feet annually, valued at over $25 billion.

Why quarantines have failed

State and federal agencies have used quarantines to combat the spread of several invasive forest insects, including Asian longhorned beetles and Lymantria dispar, previously known as gypsy moth. This approach seeks to reduce the movement of eggs and young insects hidden in lumber, nursery plants and other wood products. In counties where an invasive species is detected, regulations typically require wood products to be heat-treated, stripped of bark, fumigated or chipped before they can be moved.

The federal emerald ash borer quarantine started with 13 counties in Michigan in 2003 and increased exponentially over time to cover than a quarter of the continental U.S. Quarantines can be effective when forest insect pests mainly spread through movement of their eggs, hitchhiking long distances when humans transport wood.

However, female emerald ash borers can fly up to 12 miles per day for as long as six weeks after mating. The beetles also are difficult to trap, and typically are not detected until they have been present for three to five years – too late for quarantines to work.

Map showing range of ash trees and counties where emerald ash borer has been detected.
The emerald ash borer has been detected throughout much of the range of ash trees in the U.S.

Next option: Wasps

Any biocontrol plan poses concerns about unintended consequences. One notorious example is the introduction of cane toads in Australia in the 1930s to reduce beetles on sugarcane farms. The toads didn’t eat the beetles, but they spread rapidly and ate lots of other species. And their toxins killed predators.

Introducing species for biocontrol is strictly regulated in the U.S. It can take two to 10 years to demonstrate the effectiveness of potential biocontrol agents, and obtaining a permit for field testing can take two more years. Scientists must demonstrate that the released species specializes on the target pest and has minimal impacts on other species.

Four wasp species from China and Russia that are natural enemies of the emerald ash borer have gone through the approval process for field release. These wasps are parasitoids: They deposit their eggs or larva into or on another insect, which becomes an unsuspecting food source for the growing parasite. Parasitoids are great candidates for biocontrol because they typically exploit a single host species.

The selected wasps are tiny and don’t sting, but their egg-laying organs can penetrate ash tree bark. And they have specialized sensory abilities to find emerald ash borer larva or eggs to serve as their hosts.

Ash borer larva and a wasp species that preys on it.
An emerald ash borer larva in wood (left); Tetrastichus planipennisi, a parasitic wasp that preys on ash borers; and wasp larva that have grown and eaten the ash borer.

The USDA is working to rear massive numbers of parasitoid wasps in lab facilities by providing lab-grown emerald ash borers as hosts for their eggs. Despite COVID-19 disruptions, the agency produced over 550,000 parasitoids in 2020 and released them at over 240 sites.

The goal is to create self-sustaining field populations of parasitoids that reduce emerald ash borer populations in nature enough to allow replanted ash trees to grow and thrive. Several studies have shown encouraging early results, but securing a future for ash trees will require more time and research.

One hurdle is that emerald ash borers grown in the lab need fresh ash logs and leaves to complete their life cycle. I’m part of a team working to develop an alternative to the time- and cost-intensive process of collecting logs: an artificial diet that the beetle larva can eat in the lab.

Fresh cut ash logs await processing to collect newly emerging emerald ash borer adults, which will lay eggs for the laboratory colony.
Anson Eaglin/USDA

The food must provide the right texture and nutrition. Other leaf-feeding insects readily eat artificial diets made from wheat germ, but species whose larva digest wood are pickier. In the wild, emerald ash borers only feed on species of ash tree.

In today’s global economy, with people and products moving rapidly around the world, it can be hard to find effective management options when invasive species become established over a large area. But lessons learned from the emerald ash borer will help researchers mobilize quickly when the next forest pest arrives.The Conversation

Kristine Grayson, Associate Professor of Biology, University of Richmond

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Lower #GunnisonRiver Project Helps Achieve [Water Quality] “Watershed Moment” — The #ColoradoRiver District #COriver

Lower Gunnison River Basin irrigated agriculture. Photo credit: The Colorado River District

From The Colorado River District (Marielle Cowdin and Lindsay DeFrates):

The Lower Gunnison River reached an important milestone this summer. During the June 2021 hearing, the Colorado Water Quality Control Commission deemed the Gunnison River in compliance with aquatic life standards for dissolved selenium – a naturally occurring element and micronutrient that can be unhealthy for aquatic ecosystems in high doses. As a result, the Commission delisted 66 miles of the Gunnison River downstream of Delta, Colorado from the impaired waters list. Decades of work in the Lower Gunnison Basin shepherded this achievement, which highlights a healthier environment for native and endangered species like the razorback sucker and the Colorado pikeminnow.

“This is a big victory and a reason to celebrate,” says Raquel Flinker, Senior Water Resources Engineer with the Colorado River District. “The Colorado River District has been a leader in this effort for over 20 years, working alongside multiple partners including the Bureau of Reclamation, the Colorado Water Conservation Board, the Natural Resources Conservation Service, the U.S. Geological Survey, non-governmental agencies, local conservancy districts, ditch companies, and even individual citizens to reach this point.”

Established and led by the Colorado River District as part of the cooperative Selenium Management Program, the Lower Gunnison Project (LGP) has proved instrumental in the final phases of the delisting. The decades of associated work began with the 1988 listing of the Gunnison River as an impaired water, with selenium levels as a focal point. Prevalence of the element results from the area’s marine-derived Mancos Shale, which contains vast amounts of selenium and releases it into ground and surface waters when saturated. Gunnison River Basin selenium levels had increased to such unhealthy levels that the reproductive abilities of egg-laying species – including native fish and birds – were impaired throughout the local ecosystems.

In response, the LGP was formed to address this and other natural resource issues in the Gunnison River Basin by investing in integrated water-use efficiency systems. Investments included enclosing canals and ditches into pressurized piping systems and upgrading irrigation equipment on farms with improved technology control. All together, these systems decreased water losses and minimized selenium-impacted runoff to the river resulting in better water quality and increased water availability. In 2020, the 5-year level of selenium measured at key stations in the river dropped below 4.6 ppb (parts per billion) for the first time, and the declining trend continues, as quantified by independent scientific agencies like the USGS.

“A lot of the credit goes to the local water users, especially the agricultural community,” said Ken Leib, Acting Director of the Colorado Water Science Center during the River District’s Gunnison State of the River event in June. “Often, lower flows in the river, as we are seeing today, result in higher concentrations of selenium. But despite drought conditions, we are not seeing that. So, we are really confident that the decreases we see have resulted from improvements in system efficiencies. It’s really quite impressive.”

Colorado River District Director of Science and Interstate Matters Dave “DK” Kanzer, creator of the Lower Gunnison Project, has been a long-time, integral leader in the Selenium Management. “We’re making a big difference for the environment by improving water quality and the aquatic habitat for sensitive and endangered species, while helping sustain productive agriculture in the Gunnison and Colorado River Basins,” he said. “Investments in strategic structural improvements and increased public education have moved us into full Clean Water Act compliance while helping take another step towards recovering key threatened and endangered fish species. This takes a lot of pressure off our hard-working agricultural producers; it is an important win-win for everyone.”