The Great Lakes hold about one-fifth of the Earth's fresh water, but a new report indicates they're getting saltier - and says that's reason for concern.

Lake Michigan used to sit at a salinity level of one to two milligrams of chloride per liter of lake water. Now, that concentration has risen to nearly 15 milligrams per liter.

Hilary Dugan, an assistant professor in the Center for Limnology at University of Wisconsin-Madison, said it's still a relatively low level for a water body as large as Lake Michigan. But rising chloride levels could pose problems for plants and animals in the smaller lakes and tributaries that feed into it.

"If anything, we're just hurting those native freshwater species that are adapted to, you know, Wisconsin waters that basically have no salt in them," said Dugan. "And now, you know, we've increased the salt ten-, hundredfold, depending on what body of water we're looking at."

She said salt levels have to hit roughly 250 milligrams per liter to pose a serious risk to plants, animals and humans, and notes virtually all the chloride pollution is from road salt.

Dugan added that people can reduce pollution in lakes and streams this winter by limiting their use of salt on roads, driveways and sidewalks.

Unlike other chemical pollutants, Dugan said salt pollution isn't irreversible. She explained that over the course of their life cycle, lakes and streams will gradually flush it out of their system.

"Salt stays dissolved in water, and so lakes and rivers will naturally flush themselves out," said Dugan. "So what it takes to reduce the salinity is just to stop the amount of salt that's going into these bodies of water."

The report found about 70% of the salt flowing into Lake Michigan comes from just five of the body's 300 tributaries.

Dugan said if nothing's done to address the issue, salt concentration in the lake will rise by about one milligram per liter, every two to three years.

As Wyoming and other states grapple with shrinking Colorado River water levels - new research pinpoints how much water is being diverted to feed cattle, to sprawling desert cities, and the river's 40 million other stakeholders.

The stakes are high in a time of persistent and widespread drought.

Brian Richter - president of Sustainable Waters - said if Upper Basin states can't deliver the volume of water required under a century-old agreement, Lower Basin states could force the issue with what's known as a compact call.

"The likely result would be that the Upper Basin states, including Wyoming, would be forced to use less water," said Richter, "so that more water could be flowing into Lake Powell and downstream into the Lower Basin."

Researchers found that in Upper Basin states, cattle-feed crops soak up 90% of all irrigation water - which is three times the amount that goes to all cities, towns, commercial and industrial uses combined.

Just 19% of the Colorado River feeds the wetlands and riparian areas wildlife depend on.

Richter noted that cities in Utah and along Colorado's Front Range are at risk because they have very low priority for accessing water under the 1922 Colorado River Compact.

Despite calls for closing off spigots used exclusively for cattle feed, Richter said blaming any single user is counter-productive.

"Farmers and ranchers are growing the things that people want, and are willing to pay a necessary price for," said Richter. "So they are just responding to consumer demands."

He said he believes the new data could be an important tool for Colorado River stakeholders as they work to build a long term plan to bring the total use of water back in balance with what nature provides.

Richter said right now, water use is at least 10% to 15% over that limit.

"We need a long range plan that says how much water do we want to use in the cities? How much water do we want to use on the irrigated farms? How much are the industries going to need?" said Richter. "And until we do that long range plan, we are just going to be reacting to these water shortages on a year-by-year basis."




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Colorado lawmakers are considering legislation to restore protections to key waters and wetlands struck down by the U.S. Supreme Court last year in a decision leaving more than half of the nation's water supply at risk of industrial pollution.

Margaret Kran-Annexstein, director of the Colorado chapter of the Sierra Club, said House Bill 1379 is in sync with Colorado voters, pointing to a recent survey which found nearly nine in 10 voters want to limit damage and pollution from development, industry and mining on wetlands and streams.

"Recent polling has found that massive majorities of Coloradans, whether they are Democrat, Republican or Independent, really support common sense water protections that would happen under this bill," Kran-Annexstein reported. "I think we can all agree that clean water is a necessity."

A coalition of conservation groups support the measure to create a permitting program for responsible development through the Colorado Department of Health and Environment.

Last month, Sen. Barb Kirkmeyer, R-Brighton, introduced an alternative proposal supported by the homebuilding industry, which would require a new division and staffing in the Department of Natural Resources.

Kran-Annexstein stressed clean, reliable water resources drive the economy and are vital for the health of communities. She believes the high court's ruling, claiming some waterways do not have significant connections to watersheds, was a win for corporate polluters who want to avoid permitting.

"In Colorado we know that there are a lot of streams and rivers and wetlands that run dry for certain parts of the year," Kran-Annexstein pointed out. "This ruling said that those waterways don't deserve protections and they don't count, just because they are seasonal."

Mountain states like Colorado are the source of drinking water for some 40 million Americans living in downslope states and Kran-Annexstein said the House bill is an opportunity to pass important and necessary protections after last year's Supreme Court decision.

"This decision left half of the waters across the United States unprotected by the Clean Water Act," Kran-Annexstein emphasized. "And really left it to states to make their own laws to protect state waters. And now it is the responsibility of states to step up and close that gap."

Today is World Water Day, a global observance to raise awareness about the importance of access to clean, fresh and safe water.

This year, advocates in the U.S. are urging Congress to restore protections under the Clean Water Act for smaller streams and wetlands, which were overturned in a U.S. Supreme Court ruling last year.

Jim Murphy, senior director of legal advocacy for the National Wildlife Federation, said rivers and streams in Mississippi used for swimming and fishing flow into larger bodies of water, so it is essential for the waterways to be safeguarded.

"It's really important for people to ensure that, with the rollbacks from the Supreme Court, that they're ensuring that their state and local leaders are doing what they can to protect the waters that people rely on," Murphy asserted.

A bill in Congress, the Clean Water Act of 2023, would reinstate the rule the Supreme Court struck down, and broaden the definition of which streams and waterways are subject to federal protection. It has more than 120 co-sponsors, but remains stalled in the U.S. House.

Murphy pointed to a poll, which found more than 90% of Americans think protecting the safety of drinking water, and the water in lakes, streams and rivers should be a priority. He added the most effective and cost-efficient approach to safeguarding water is to protect it before it gets to your home faucet.

"Protecting water at its source is the most important and one of the cheapest things we can do to ensure that people who are facing a crisis of dirty water are protected," Murphy explained. "In other cases, we also have to invest in the right type of infrastructure, to make sure that water is clean."

A boil water alert was issued for Jackson this week, as the result of repair work performed on the water system. In 2022, Jackson's water system crisis affected more than 150,000 residents, who were without clean or running water for weeks at a time.