Nitrogen fertilizers are critical for growing crops to feed the world, yet when applied in excess can pollute our water for decades. A new study provides six steps to address nitrogen pollution and improve water quality.
Since nitrogen persists for so long, management efforts may seem futile and unattractive because it can take a long time to see results. The study from the University of Waterloo appearing in Nature Geoscience provides a roadmap for scientists, policymakers, and the public to overcome the challenges associated with this legacy nitrogen for faster improvements to our water quality.
“We have to think about the legacy we leave for the future in a strategic way from both the scientific and socio-economic angles,” said Nandita Basu, a professor of Earth and Environmental Sciences and Civil and Environmental Engineering at Waterloo and the study’s lead author. “This is a call to action for us to accept that these legacies exist and figure out how to use them to our advantage.”
The study recommends the following six steps:
Focus research to quantify the length of time the nitrogen stays in our ecosystems to adjust our expectations for conservation timelines.
Find ways to use the legacy nitrogen as a resource for growing crops instead of adding new nitrogen fertilizers to our ecosystems with already high levels of nitrogen.
Target conservation strategies to get the maximum water quality improvement instead of a widespread blanket approach.
Combine conservation methods that reduce the amount of nitrogen that has already left the farm fields, such as in wetlands, with methods that harvest nitrogen from past legacies accumulated in the soil.
Monitor water quality at both large and small scales so that short-term results can be seen at scales like a farm field and long-term results downstream at river basins can also be tracked.
When assessing the economic impacts of conservation strategies, incorporate both short- and long-term cost-benefit analyses.
Nitrogen legacies are different around the world depending on the climate and historical land use, and land management patterns. While theoretical knowledge of these legacies has existed for decades, measurements and monitoring have not yet been widespread enough to understand these differences and support water quality policies, where there is still an expectation of short-term water quality improvement.
“It’s time we stop treating nitrogen legacies as the elephant in the room and design watershed management strategies that can address these past legacies,” said Basu. “We need to ask ourselves how we can do better for the future.”
“Increasing incidences of eutrophication and groundwater quality impairment from agricultural nitrogen pollution are threatening humans and ecosystem health. Minimal improvements in water quality have been achieved despite billions of dollars invested in conservation measures worldwide. Such apparent failures can be attributed in part to legacy nitrogen that has accumulated over decades of agricultural intensification and that can lead to time lags in water quality improvement. Here, we identify the key knowledge gaps related to landscape nitrogen legacies and propose approaches to manage and improve water quality, given the presence of these legacies.”
Ranking and time evolution of summer (June–August) drought severity as indicated by negative 0–200 cm soil moisture anomalies. Maps show how gridded summer drought severity in each year from 2000–2021 ranked among all years 1901–2021, where low (brown) means low soil moisture and therefore high drought severity. Yellow boxes bound the southwestern North America (SWNA) study region. Time series shows standardized anomalies (σ) of the SWNA regionally averaged soil moisture record relative to a 1950–1999 baseline. Black time series shows annual values and the red time series shows the 22-year running mean, with values displayed on the final year of each 22-year window. Geographic boundaries in maps were accessed through Matlab 2020a.
Amid a rapid worsening of Western conditions in 2020 and 2021, the dry spell that has gripped the Colorado River Basin for the last 22 years is now the region’s worst drought since at least 800 A.D., researchers concluded in a study published Monday.
The research, conducted by scientists from the University of California Los Angeles and Columbia University and published in the journal Nature Climate Change, also found that human-caused climate change accounts for approximately 42% of the severity of the “megadrought” that the southwestern U.S., including western Colorado, has experienced since 2000.
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“Had the sequence of wet-dry years occurred as observed but without the human-caused drying trend, we estimate that the 2000s would have still been dry, but not on the same level as the worst (of the) last millennium’s megadroughts,” the study’s lead author, UCLA climatologist Park Williams, wrote on Twitter.
The study was conducted using both observed soil-moisture data since 1901 and reconstructed data based on tree-ring records covering the last 1,200 years. No 22-year period during that span was found to have been as dry as the West’s current megadrought.
The study builds on previous research published in 2020, which found that the drought was, at the time, the worst since a prolonged dry spell recorded in the late 16th century. But the severely dry conditions experienced across the Colorado River Basin in the last two years mean that the post-2000 drought has now become the driest period in the available historical record.
“Exceptionally dry soil in 2021 was critical for the current drought to escalate and overtake the 1500s megadrought as the period with the highest 22-year mean severity,” the study’s authors wrote. “Both 2002 and 2021 were probably drier than any other year in nearly three centuries.”
Due to rising atmospheric concentrations of greenhouse gases, parts of Colorado — especially areas on the Western Slope — have warmed by an annual average of 4 degrees Fahrenheit above pre-1900 levels, temperature data from the National Oceanic and Atmospheric Administration show.
Amid record dry conditions, the three largest wildfires in Colorado history burned in 2020, and all of its 20 largest fires on record have occurred during the current megadrought.
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People fishing along the banks of the White River as it winds through Indianapolis sometimes pass by ominous signs warning about eating the fish they catch.
Mercury is a neurotoxic metal that can cause irreparable harm to human health – especially the brain development of young children. It is tied to lower IQ and results in decreased earning potential, as well as higher health costs. Lost productivity from mercury alone was calculated in 2005 to reach almost $9 billion per year.
One way mercury gets into river fish is with the gases that rise up the smokestacks of coal-burning power plants.
The Environmental Protection Agency has had a rule since 2012 limiting mercury emissions from coal-fired power plants. But the Trump administration stopped enforcing it, arguing that the costs to industry outweighed the health benefit.
I study mercury and its sources as a biogeochemist at Indiana University-Purdue University Indianapolis. Before the EPA’s original mercury rule went into effect, my students and I launched a project to track how Indianapolis-area power plants were increasing mercury in the rivers and soil.
Mercury bioaccumulates in the food chain
The risks from eating a fish from a river downwind from a coal-burning power plant depends on both the type of fish caught and the age and condition of the person consuming it.
Mercury is a bioaccumulative toxin, meaning that it increasingly concentrates in the flesh of organisms as it makes its way up the food chain.
The mercury emitted from coal-burning power plants falls onto soils and washes into waterways. There, the moderately benign mercury is transformed by bacteria into a toxic organic form called methylmercury.
Each bacterium might contain only one unit of toxic methylmercury, but a worm chewing through sediment and eating 1,000 of those bacteria now contains 1,000 doses of mercury. The catfish that eats the worm then get more doses, and so on up the food chain to humans.
In this way, top-level predator fishes, such as smallmouth bass, walleye, largemouth bass, lake trout and Northern pike, typically contain the highest amounts of mercury in aquatic ecosystems. On average, one of these fish contains enough to make eating only one serving of them per month dangerous for the developing fetuses of pregnant women and for children.
How coal plant mercury rains down
In our study, we wanted to answer a simple question: Did the local coal-burning power plants, known to be major emitters of toxic mercury, have an impact on the local environment?
The obvious answer seems to be yes, they do. But in fact, quite a bit of research – and coal industry advertising – noted that mercury is a “global pollutant” and could not necessarily be traced to a local source. A recurring argument is that mercury deposited on the landscape came from coal-burning power plants in China, so why regulate local emissions if others were still burning coal?
That justification was based on the unique chemistry of this element. It is the only metal that is liquid at room temperature, and when heated just to a moderate level, will evaporate into mercury vapor. Thus, when coal is burned in a power plant, the mercury that is present in it is released through the smokestacks as a gas and dilutes as it travels. Low levels of mercury also occur naturally.
Although this argument was technically true, we found it obscured the bigger picture.
People sometimes fish along the White River where it flows through Indianapolis. alexeys via Getty Images
We found the overwhelming source of mercury was within sight of the White River fishermen – a large coal-burning power plant on the edge of the city.
When we surveyed hundreds of surface soils ranging from about 1 to 31 miles (2 to 50 km) from the coal-fired power plant, then the single largest emitter of mercury in central Indiana, we were shocked. We found a clear “plume” of elevated mercury in Indianapolis, with much higher values near the power plant tailing off to almost background values 31 miles downwind.
The White River flows from the northeast to the southwest through Indianapolis, opposite the wind patterns. When we sampled sediments from most of its course through central Indiana, we found that mercury levels started low well upstream of Indianapolis, but increased substantially as the river flowed through downtown, apparently accumulating deposited mercury along its flow path.
We also found high levels well downstream of the city. Thus a fisherman out in the countryside, far away from the city, was still at significant risk of catching, and eating, high-mercury fish.
The region’s fish advisories still recommend sharply limiting the amount of fish eaten from the White River. In Indianapolis, for example, pregnant women are advised to avoid eating some fish from the river altogether.
Reviving the MATS rule
The EPA announced the Mercury and Air Toxic Standards rule in 2011 to deal with the exact health risk Indianapolis was facing.
The rule stipulated that mercury sources had to be sharply reduced. For coal-fired power plants, this meant either installing costly mercury-capturing filters in the smokestacks or converting to another energy source. Many converted to natural gas, which reduces the mercury risk but still contributes to health problems and global warming.
The MATS rule helped tilt the national energy playing field away from coal, until the Trump Administration attempted to weaken the rule in 2020 to try to bolster the declining U.S. coal industry. The administration rescinded a “supplemental finding” that determined it is “appropriate and necessary” to regulate mercury from power plants.
More than a quarter of U.S. coal-fired power plants currently operating were scheduled as of 2021 to be retired by 2035. EIA
Some economists have calculated the net cost of the MATS rule to the U.S. electricity sector to be about $9.6 billion per year. This is roughly equal to the earlier estimates of productivity loss from the harm mercury emissions cause.
To a public health expert, this math problem is a no-brainer, and I am pleased to see the rule back in place, protecting the health of generations of future Americans.
Gabriel Filippelli, Chancellor’s Professor of Earth Sciences and Executive Director, Indiana University Environmental Resilience Institute, IUPUI
As the need to address the climate crisis grows ever more urgent, land conservationists are taking meaningful action to reduce carbon in the atmosphere and protect natural systems from the unavoidable impacts of a warming planet.
Our new Policy Focus Report documents how land trusts and conservancies are developing and implementing creative, nature-based strategies to address climate change around the globe, from the Great Plains of the United States to the high-altitude wetlands of Ecuador.
In this report, we document a dozen case examples that demonstrate how conservation organizations can help to mitigate and adapt to a changing climate.
Paul Bruchez speaking from his ranch in Grand County to the Colorado River Water Users Association Annual Convention December 16, 2021. Governor Polis has nominated Bruchez to the Colorado Water Conservation Board as the mainstem Colorado River representative.
Click on the link to read the article at Aspen Journalism (Heather Sackett):
Gov. Jared Polis has appointed a Kremmling rancher to replace former state Sen. Gail Schwartz on the state’s top water board.
Paul Bruchez will now represent the main stem of the Colorado River on the Colorado Water Conservation Board. Bruchez, 40, currently serves as the agriculture representative and vice chair of the Colorado Basin Roundtable.
Rancher and fly fishing guide Paul Bruchez’s daughter and nephew sit in a hay field at the family ranch near Kremmling. Bruchez is helping spearhead a study among local ranchers, which could inform a potential statewide demand management program. Photo credit: Paul Bruchez via Aspen Journalism
Along with his family, Bruchez runs Reeder Creek Ranch, a 6,000-acre cattle and hay operation, about five miles east of Kremmling, which is irrigated with water from the headwaters of the Colorado River. Bruchez is also a fly-fishing guide and has been active since about 2012 in state-level water management discussions. He is a governor appointee to the Inter-Basin Compact Committee and is on the board of the Colorado Water Trust.
“For the last 23 years, everything Colorado River and water has touched and impacted my life substantially, as well as my entire family,” he said. “We all live and breathe Colorado River issues.”
This mowed hay field is part of Reeder Creek Ranch, owned by the Bruchez family near Kremmling. Little data exists on the impacts of reducing irrigation water on higher elevation pastures like this one, but Paul Bruchez and a group of local ranchers have volunteered their fields for a study that will help scientists learn more about what happens to pastures that receive less irrigation water. Photo credit: Paul Bruchez via Aspen Journalism
Bruchez is also spearheading a project with other neighboring irrigators to see what happens when water is temporarily removed from high-elevation hay meadows. The results of the state grant-funded study could have implications for demand management, a program state officials are exploring, designed to save water by paying irrigators to temporarily fallow fields.
Tri-State Generation and Transmission has a power-purchase agreement for 104 megawatts of generating capacity from the Crossing Trails Wind Farm, a wind farm between Seibert and Kit Carson, in eastern Colorado, on October 3, 2021. Photo: Allen Best/Big Pivots
Click on the link to read the article on Big Pivots (Allen Best):
Transmission that will be critical to delivering wind energy from farms and ranches in eastern Colorado to electrical consumers along the Front Range was tentatively approved by the Public Utilities Commission on Feb. 11.
Click the image to go to Xcel’s project page and the interactive map.
The PUC commissioners will again take up the proposal by Xcel Energy on Feb. 23 to work through more details of what will likely produce $1.7 billion of transmission in a gigantic, 560-mile loop around eastern Colorado called the Pathway Project. Slightly less certain is approval of a 90-mile extension to wind-rich Baca County in the state’s southeastern corner. The cost tag of that extension is $250 million.
Some testimony had been filed with the PUC arguing that the massive investment as prposed was unneeded for Xcel to achieve its mandated carbon-reduction goals of 80% by 2030 as compared to 2005. PUC commissioners were not persuaded. They quickly concluded that Xcel had indeed delivered the evidence that the proposed 345-kV double-circuit transmission line will be needed—and soon.
“Time is of the essence. We don’t know what impediments might creep up as the project proceeds,” said John Gavan, one of the three commissioners.
“I also think it’s important to realize that this project will support generation beyond our planning with the current electric resource plan,” he added, referring to Xcel’s separate but concurrent proposal for new wind and solar projects, as well as natural gas plants and storage.
The PUC’s two other commissioners shared similar thoughts about urgency.
“They’ve met their burden (of proof) here,” said Megan Gilman. “I don’t want perfect to be the enemy of the good,” said Eric Blank, the commission chairman.
Xcel’s plans for transmission coupled with a concurrent proposal for new wind, solar, and other resources could deliver investments approaching $9 billion in coming years. This will allow Colorado’s largest electrical utility to close coal plants and likely will slow rate increases or possibly halt them altogether. Some utilities have actually been able to lower rates as they have pivoted to renewables.
“A really big moment in my career,” says Mark Detsky, an attorney who represents the Colorado Independent Energy Association, an organization of wind and other energy developers.
Many states have struggled to build the transmission necessary to more fully develop renewable resources. Texas and California have been exceptions, and Colorado will join them, says Detsky.
“There have been many, many studies that have shown that this is what the United States needs to do to meaningfully decarbonize,” he says.
“It has to have massive transmission infrastructure that maximizes the wind and solar resources across a wide geographic range.”
If Xcel’s plans get approved as proposed, the company’s renewable generation portfolio will double by 2030 as compared to the growth in renewables in the previous 17 years.
Transmission tower near Firestone. Photo credit: Allen Best/The Mountain Town News
To pull the trigger on that generation, though, the company needs transmission. In the past, both in Colorado and elsewhere, the two have gone forward on almost entirely separate paths. In this case, they’re separate but concurrent.
“It is one of the first times in Colorado, if not nationally, that this chicken-and-egg transmission problem has hopefully been addressed,” said Ellen Howard Kutzer, a senior staff attorney with Western Resource Advocates, an advocacy organization that participates in most utility cases before the PUC.
“We are being thoughtful about the needs of the next 5 to 10 years but also building transmission for future needs as well,” she said. “That’s something that I heard in the deliberations.”
The proposal for Colorado’s Pathway Project was submitted to the PUC in March 2021. Xcel was bolstered by a non-unanimous but comprehensive settlement agreement filed in November by a variety of environmental, labor, and state agencies, including the staff of the PUC. That agreement indicated broad support for Xcel’s plans.
Tri-State Generation and Transmission, Colorado’s second largest utility, which is also proposing a sharp pivot in its generation, filed testimony with the PUC that showed that in every case its own plans for more renewable generation will benefit from the new transmission in eastern Colorado.
Consumer groups had different advice: Go slower. The Colorado Office of the Utility Consumer Advocate and others argued that only one of the five segments proposed by Xcel, the 160-mile leg from near Brush-Fort Morgan to the Burlington area, could be justified at this time, as it would deliver nearly the same benefits but at a fraction of the costs.
The PUC commissioners agreed only to the extent that they want to see that segment and another shorter segment to a substation north of Lamar, a total of 225 miles, get done first. This will allow the wind projects to get federal tax credits that are scheduled to end, although such tax credits have been extended many times in the past. The three other segments closer to the Front Range have slightly less pressing need.
Uncertainty about the future of federal tax credits, both production and investment, also has the PUC commissioners fretting about what to do about the 90-mile extension to Baca County.
Studies by the National Renewable Energy Laboratory and others have shown southeastern Colorado to have the steadiest, strongest winds in all of Colorado. That should perhaps not be a surprise, as it was at the heart of the Dust Bowl during the 1930s. Xcel has proposed the $250 million extension from its Colorado’s Pathway Project loop. And consumer groups, if skeptical about other segments, are willing to see conditional approval.
The most resistant voice to approving the extension is perhaps the individual in the proceedings who knows most about the plentitude of wind in the Springfield area. As a wind developer in 2007, said Blank, he had investigated development opportunities in Baca County. He knows the potential, he said.
As an attorney, though, he worries about procedure if the PUC approves the May Valley-Longhorn extension into Baca County. Xcel, he said, had failed to document the benefits. “They didn’t even try,” he said. “There’s nothing in this record to quantify the benefit.”
Gavan pushed back. He said the extension from May Valley will be a “building block for the future.” He said he will support a conditional approval—and it needs to be understood as an approval that can save Xcel customers money in the long run. An earlier, rather than later, conditional approval helps open the door for development aided by the federal tax credits.
The federal tax credits are set to expire late this year. If Congress does not renew them, then the projects that are bid later will come in at a higher cost.
The three commissioners will be working this over hard with the aid of PUC staff members before their Feb. 23 meeting.
They’ll also be working over what are called performance-incentive mechanisms, or PIMs. Most people would call this the bag of carrots and sticks. The goal is to get the transmission built without unnecessary cost.
Transmission at a recent conference was described as difficult but doable. “Transmission is hard to build on one hand, and on the other hand it’s really not,’ said Mark Gabriel, the chief executive of Untied Power, Colorado’s second largest electrical cooperative. It costs a “ton of money,” he explained, and “permitting is a pain in the butt.” That said, it can get done.
In this case, the scale matters. PUC staff member Dan Greenberg told the commissioners that Xcel will have to work with 700 landowners as it puts together the transmission segments that go on-line, the first segments in 2025 and the remaining three segments by the end of 2027. There will be environmental issues, such as habitat of the lesser prairie chicken, uncertainty over price of materials—and more.
All three commissioners have backgrounds in business, with Blank and Gilman both having careers in renewable generation and Gavan in information technology prior to their appointments. They sometimes drew on personal experience in balancing bonuses and penalties so that Xcel gets the transmission built in time for Colorado to meet its decarbonization goals and without wasting money along the way. There is much talk about avoiding “cliffs.” Speed bumps and flying lights weren’t discussed, but you get the idea.
Another decision, but this one without footnotes, is about undergrounding. Lots of people would like to see transmission lines go underground, but Xcel had testified that the cost would increase 20-fold. That persuaded the PUC commissioners.
Undergrounding, however, might conceivably be involved some day in exporting electricity generated by solar panels in the San Luis Valley, Colorado’s richest area for solar. The commissioners are receptive to opening a miscellaneous proceeding late this year. That means nothing will necessarily happen, although it does represent a victory for the Colorado Solar and Storage Association.
A turbine whirls on a farm east of Burlington, Colo. Colorado’s eastern plains already have many wind farms—but it may look like a pin cushion during the next several years. Photo/Allen Best
The final major issue decided at least tentatively by the PUC commissioners was how much stock to put into the testimony of Larry Miloshevich, a Lafayette resident who has been conducting a deep investigation of evolving technology for electrical transmission. In the acronym-rich discussion, it was called ATT, or advanced transmission technologies.
Gavan gushed about the promise of such technologies, particularly one called carbon-core conduits that he said could eliminate upwards of 500 transmission towers. He pointed out that North Dakota-based Basin Electric used the technology on a 27-mile, 230-kV transmission line. If Basin, a distinctly conservative generation and transmission association, could embrace the technology, he argued, then certainly it should behoove Xcel Energy with its reputation for being one of the nation’s most progressive utilities, to do the same.
Blank, the chairman and an attorney, was resistant. He wanted stronger evidence for the record before he was willing to make it a conditional requirement of approval.
This most certainly will be discussed again. “I strongly support that it could really transform this world, but we just want to be careful about creating a (legal) mess,” said Blank.
Afterward, Miloshevich said he was pleased with the interest shown in his studies about advanced transmission technology, especially the use of advanced carbon-core conductors as a superior alternative to traditional aluminum-conducted steel-reinforced conductors.
“Carbon-core conductor (technology) in general has a 20-year history and a solid performance record” aside from fragility issues during installation, which have now been addressed, he wrote in an email.
Miloshevich said he believes a more careful combing of his testimony will demonstrate to the satisfaction of PUC commissioners that there is sufficient evidence to justify making it a requirement.
