Transcript

This is Eileen Wray-McCann for Circle of Blue. And this is What’s Up with Water, your “need-to-know news” of the world’s water, made possible by support from people like you.

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In Southeast Asia, a new study connects Chinese dams to diminished flows in the lower Mekong River. The study claims that last year, the Mekong’s reduced levels were partly due to more water being held back by China’s dams upstream. The study was funded by the U.S. State Department.

Chinese authorities disputed the findings, according to Reuters news service. They blamed low river flows on below-average rainfall in their country’s section of the watershed. Less rainfall, they said, meant less water that its dams could release downstream.

The study contradicts China’s argument. The U.S.-based research firm Eyes on Earth, using satellite data, found a slight increase in precipitation in China’s section of the basin. Although the rest of the watershed suffered from a historic drought, Yunnan province, through which the upper Mekong flows, saw a slight uptick in moisture.

China and the four countries in the lower Mekong have long been at odds over management of a river system that sustains the livelihoods of 60 million people who live within the basin in Cambodia, Laos, Thailand, and Vietnam.
China has completed six dams on the trunk of the Mekong and is building several more in order to maximize the river’s hydropower potential. The dams retain not only water but also the sediments that build land in the Mekong delta. Without those sediments, the land is sinking and the rising sea is encroaching.

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In the United States, a new study led by researchers at Columbia University finds that the ongoing drought in the American Southwest is among the worst regional dry spells in over a thousand years, and it’s worse because of a warming climate.

The study was published in the journal Science. It used tree-ring data to model drought conditions each year back to 800 A.D. Scientists found four periods of “megadrought” where soil moisture content appeared to be far below average for over two decades. Only one of those dry spells, in the 1500s, had lower soil moisture than the current drought, which began in 2000.

Park Williams is the lead author of the study. He said that the study is less about prediction than it is a glimpse of where the region is now. He said “We now have enough observations of current drought and tree-ring records of past drought to say that we’re on the same trajectory as the worst prehistoric droughts.”

The researchers say the dry spell is undoubtedly tied to global warming. Scientists believe that the region is undergoing a shift towards a hotter, drier climate. They say that it’s inaccurate to call the process a drought. Drought suggests a temporary phase. Instead, they prefer the term aridification.

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In Chile, the government has filed a complaint against an international mining company for alleged damage to an aquifer in the dry northern Andean region.
The State Defense Council brought the complaint against the mining company BHP for excessive pumping of groundwater beneath the Punta Negra salt flat. That’s according to Reuters new service. The region is rich in copper deposits, but also one of the driest areas in the world. The complaint charged that in addition to excessive water use, BHP’s operations also jeopardized wetlands, vegetation, and wildlife in the area. An environmental court says it will investigate the claims.

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This week, Circle of Blue reports on the risks of water contamination that lurk in buildings closed by the coronavirus pandemic.

During the global health crisis, countless buildings across the U.S. have experienced extended idle periods and unexpected transformations. Hotels, offices, restaurants, churches, and college campuses are vacant or operating at drastically reduced capacity. Like the Angel of the Winds Arena in Washington State, some buildings have been repurposed as field hospitals, emergency medical wards, or sites for self-isolation. Retired buildings, meanwhile, are being pressed into service. Hospitals in Chicago, Los Angeles, and Phoenix that closed months or years ago have opened their doors to victims of Covid-19, the disease caused by the new coronavirus.

Building closures have obvious repercussions for local economies and social connections. Politicians want to lift stay-at-home orders and reopen public and private spaces as soon as the health risks from Covid-19 are manageable.
But plumbing experts say that before the all-clear sounds, one hidden risk should not be overlooked. Prolonged closures can degrade water quality within buildings. Water sitting in pipes over time can lead to harmful pathogens like Legionella bacteria and chemical contaminants such as lead. Experts say that clearing a building’s plumbing system is an important part of making it fit for reopening.

Christoph Lohr is a director and plumbing engineering specialist at the water management firm LiquiTech. He warned that closing buildings can have unintended consequences on water quality. He told Circle of Blue “We don’t want to see a second crisis of waterborne disease.”

Andrew Whelton, a Purdue University environmental engineer, agrees. He said that this is an unprecedented plumbing system situation: to have entire city districts filled with buildings that are largely empty for weeks and months. Whelton and eight plumbing experts from across North America published a rapid review of existing literature on water stagnation in plumbing. Their goal is to inform the safe reopening of buildings, outline the challenges and information gaps, and serve as a foundation for individual building strategies.

There is some precedent for restarting plumbing systems. For example, there are established guidelines for reopening after seasonal closures that hotels in resort towns would experience, and for new construction. But Whelton said for widespread shutdowns of this magnitude and extent, building owners, regulators, and utilities, are essentially flying blind. He told Circle of Blue “Ultimately you want to know if the plumbing is safe. And the only way to know is to test.”

But test for what? And where? And in what parts of the plumbing system? The review concluded that there is still much to learn about the extent to which old water will pose a health risk and what needs to be done to address it.

One obvious indicator is chlorine or other chemicals used as drinking water disinfectants. Chlorine kills most but not all bacteria. And chlorine can degrade in a matter of days. Any bacteria that were not initially killed could recolonize inside pipes, nozzles, joints, and other parts of plumbing and faucet fixtures.

Another challenge is purging the system of the old water. Whelton said that plumbing design will dictate flushing times: pipes that are farther away from the city distribution main will take longer to clear, potentially an hour in some buildings. Pipe material, the chemical composition of the water, and the current condition of the pipes are also factors.

Caitlin Proctor is a postdoctoral fellow at Purdue who contributed to the study. She said that repurposing buildings for medical facilities or quarantine sites requires additional information.

“What are patients using water for?” Proctor said. If it is only for washing floors, then less caution is needed. “If the water is used for showering,” she said, “the quality needs to be high because of the risk of Legionella.”

Legionella bacteria thrive in warm, stagnant water. The bacteria cause Legionnaires’ disease, an illness that spreads through contaminated droplets and resembles pneumonia. Legionnaire’s disease kills more U.S. residents than any other waterborne pathogen.

Lohr and others said that the next few months are a crucial window for planning how to recommission water systems in buildings. That is because of heightened disease risk. Legionnaires’ disease shifts with the seasons and geographic patterns. Cases spike in the late summer and early fall, and are most prevalent in the Great Lakes states and the mid-Atlantic region. Those are two areas that have been hit hard by Covid-19.

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And that’s What’s Up With Water from Circle of Blue, which relies on your support for independent water news and analysis. Please visit circleofblue.org and make a difference through your tax-deductible donation.