Send Mississippi River water to southwestern reservoirs? New analysis casts doubts.

Frederick Melo, Pioneer Press
·7 min read
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As an environmental scientist, Roger Viadero had to scratch his head over news reports last summer of the thirsty demand in Palm Springs and Las Vegas, among other western cities, for water from the Mississippi River and the Great Lakes.

The letters pages of the Palm Springs Desert Sun newspaper broke their own records for online traffic last June with readers’ proposals to siphon some 22 billion gallons of water per day from the Midwest. To solve the Southwest’s water crisis, the desert denizens wrote, a series of canals and reservoirs could pipe water from the flood-prone Mississippi River to the Colorado River, a supposed win-win for everyone.

Aqueducts, pipelines and open channels pumping water from Minnesota and thereabouts to drier climates could easily do the trick, according to the letter writers. “We could fill Lake Powell in less than a year with an aqueduct from (the) Mississippi River,” wrote a reader. “It’s about will,” wrote another.

The proposals provoked Viadero, a skeptic and board-certified environmental engineer, to take up their feasibility with his students at Western Illinois University, where he chairs the environmental science doctorate program from the school’s Moline campus, located along the Mississippi River near the state’s Iowa border.

“The idea we have this abundance of water, it’s just a fantasy,” said Viadero, director of the university’s Institute for Environmental Studies, pointing to severe drought and low Midwestern water levels in an interview Monday.

“We sent astronauts to the moon,” he added. “We didn’t send the moon to us. People say all kinds of things about what they heard on Facebook. … We’re trying to give them some tools to help people make decisions.”

‘PHYSICAL, ECONOMIC AND ENVIRONMENTAL MAGNITUDE’

On Oct. 17, he and two doctoral students — E. Dave Thomas and Samuel Babatunde — released a 21-page technical analysis of the “physical, economic and environmental magnitude” of potentially diverting trillions of gallons of water from the Mississippi River to the lower Colorado River.

They presented their white paper two days later at the Upper Mississippi River Conference, which was held in Moline, and hope to have it peer-reviewed and published in an academic journal.

“We noticed a lack of information that can be used by the public to weigh the practical aspects of these proposals,” wrote the scientists. “This has created a void that’s being filled by proposals that lack realistic goals, violate a number of physical laws, and convey a poor understanding of scale, among other issues.”

Their findings, in a nutshell?

“Time, space, ecology, finances, and politics aren’t on the side” of water diverters, they wrote.

20 YEARS OF DROUGHT

The researchers noted there’s nothing hypothetical about the 20-plus years of drought that have plagued the Colorado River, which travels through seven U.S. states, provides drinking water for roughly 1-in-10 Americans and irrigates the vast majority of the nation’s winter vegetables.

Below Lake Powell in northern Arizona, the lower Colorado winds through Nevada, Arizona and California into Mexico, watering Las Vegas, Phoenix, Tucson, Los Angeles and San Diego on its way.

In 2012, the U.S. Bureau of Reclamation gave the possibility of diverting Mississippi River water westward serious consideration, calling it at the time a potential 30-year project. The Arizona state legislature petitioned Congress in 2021 to revisit the idea, and on June 26, a letter in the Desert Sun went viral for suggesting using the river water to replenish Lake Powell, a reservoir in Utah and Arizona, as well as Lake Mead, another drought-stricken reservoir in Nevada and Arizona.

Together, the two reservoirs are about 27 percent full, or some 13 trillion gallons short of capacity, and sinking fast.

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Still, the 2012 drought that hit both the upper and lower Mississippi River basins was even more severe — though less long-lasting — than the ongoing drought along the Colorado River basins, according to the scientists.

Drought conditions have continued to impact river communities from Minnesota on down through Tennessee and Mississippi. In the past few weeks alone, low water levels have clogged Mississippi River barge traffic, impacting both recreation and national commerce, including corn supplies.

“The severity of dry conditions has become worse over time,” the scientists wrote. “Given the length and geographic extent of these dry conditions, it is unlikely that this will abate under natural circumstances.”

21.6 BILLION GALLONS DAILY

Refilling Lake Mead and Lake Powell in less than two years, as Desert Sun readers suggested, would require moving 21.6 billion gallons of water per day — enough water to fill the Washington Monument 2,600 times daily.

Examining discharge rates by Vicksburg, Miss., the scientists found that diverting some 250,000 gallons of Mississippi River water per second would reduce the average downstream flow by roughly 8 percent, or by 5.6 percent during flooding conditions and by 17 percent compared to periods of low water discharge.

The scientists scoffed at suggestions that would save taxpayers money by reducing the need to build and maintain flood levees and other infrastructure along the Mississippi River and its major tributaries. They noted that in 2019, the impact of flooding in the Midwest and southern plains was estimated at $20 billion in flood response, reconstruction and recovery, among other losses.

Even if the diverted river water was valued at just a penny per gallon, the cost to fill both lakes would total at least $134.8 billion, or 6.7 times the cost of the response to the basin-wide Mississippi River flooding three years ago.

And those totals do not include the added costs to acquire land, design and construct a conveyance system, treat the water and provide for annual operation and maintenance.

A LONG CHANNEL OR A BIG PIPE UPHILL

What kind of system could transport that much water? An open channel would have to be 100 feet wide and 61 feet deep, or 1,000 feet wide and 6 feet deep, stretching across a massive swathe of the U.S., according to the scientists.

That channel would span the width of an interstate highway, if not 10, and require heavy political buy-in from the cities and states along some 1,200 to 1,600 miles of future river highway. Construction would require some 1.9 billion yards of excavated material for the channel alone, not including its foundation.

Using a closed pipe instead of an open channel would result in a structure 88 feet in diameter — about the length across of 1 1/2 semi-trailers.

Then there’s the question of crossing the mountainous continental divide. The elevation difference between Lake Powell and the Old River Control Structure, the Mississippi River floodgate system in central Louisiana, is about 4,600 feet. The maximum elevation is 11,000 feet some 12 miles east of Santa Fe, New Mexico. While the U.S. Army Corps of Engineers commands powerful pumps, “their lift capabilities are relatively low,” wrote the scientists.

ADVERSE EFFECTS

The report also touched briefly upon questions beyond engineering, including the likelihood that invasive species such as silver and bighead carp could travel westward from the Midwest and its tributaries.

On average, the concentration of nitrogen in Mississippi River water is 6.8 times greater than the concentration in Lake Mead. At a rate of 250,000 gallons per second, some 69 million lbs. of nitrogen would be sent westward over the course of one and a half years, likely requiring costly added treatment.

While the scientists did not dwell on political considerations, they noted that a Colorado River Compact dating to 1922 divides water allocation by basin, not by state, further complicating political questions around water access.

Both the state of Minnesota and individual communities such as Dakota County have crafted laws against removing massive loads of groundwater for non-emergency, commercial and out-of-state use.

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