Lack of rain in the Ohio River Valley and along the Upper Mississippi has the Mississippi River ... [+]
The entire Mississippi River basin is experiencing drought conditions that are being compared to the Dust Bowl days of the 1930s. The scenes — from exposed shipwrecks to sand dunes cropping up where the river used to flow — are surreal, and people from New Orleans to the Upper Midwest are getting nervous. I’m increasingly being asked: Is this the future of the Mississippi? And what would that mean for the world's food supply — 92% of all U.S. agricultural exports are produced in the Mississippi River basin?
Underpinning these questions is the same fear: Will the Mississippi turn into a new Colorado River—which is so oversubscribed it never reaches its historic delta anymore? While the Colorado has an irrefutable impact on our economy, way of life and wildlife populations, the Mississippi is on a different order of magnitude. It drains 32 states and two Canadian provinces. Low water levels are already impeding navigation, and with winter on the way, locking up precipitation in snowpack, there’s little hope of a short-term reversal.
I don’t have a crystal ball, but I know what the science tells us. For decades we have been living through what statisticians would call the “first moment” of climate changethe long, inexorable rise of global mean temperature and decline (in some places) of annual precipitation. But the extreme conditions we are witnessing today indicate that we are now entering what those statisticians would call the “second moment” of climate change – wild-swinging variability from year to year, from drought to flooding and back again.
So: No one knows if the Mississippi is going to recover next year. What I am certain of is that what we need to be talking about and preparing for this second moment – an ever-increasing oscillation of extremes within the basin.
The Extremes are Wilder and the Balance is Changing
The Mississippi River basin covers two-thirds of the landmass of the United States. Its sheer size means there should be enough places where it's raining that offset those places where it's dry, keeping overall river flows reasonably stable on the whole.
But that balance is changing. 2022 experienced opposing superlatives: a five-hundred-year flood in the Yellowstone River, which is part of the Mississippi basin, and record-low water levels in some reaches of the mainstem Mississippi. Flows did not average out.
Some of the consequences of this “not normal new normal” drought in the Mississippi River basin include:
- Threats to commerce: The Mississippi is ordinarily a thoroughfare for exporting the food staples and commodities from the U.S. to global markets. But in recent weeks, barge traffic has been hampered by low flows, with empty container ships waiting in the Gulf for goods to come down the river. Everyone is talking about inflation, and the inability to move these goods down is absolutely connected to it: The rising cost of food, for example, is related to dwindling water supply to irrigate crops in California. The Army Corps is dredging to deepen the channel of the river, which we absolutely have to do to try to keep things moving, but we can’t indefinitely rely on quick fixes.
- Impacts of fluctuating salinity on plants and animals—and communities and the economy: Because of extreme drought, less fresh water is going into the Mississippi’s Gulf of Mexico delta. As a result, we're going to see increased encroachment of the saltwater wedge. This is a layer of deeper saline water that is pushed out to see by incoming freshwater, when it is abundant. Coastal fisheries, from oysters to fin-fish, will be affected, and in-shore fisheries will as well. The impacts will show up this year, but even if the river recovers next year the possibility of a reduction in recruitment remains, affecting the long-term viability of those resources. Coastal plants will also struggle with changes in salinity, potentially reducing their ability to buffer communities and habitats from hurricanes. And all of those things add up to dollar signs.
- Water supply challenges: New Orleans gets its water from the Mississippi River pretty close to salt water. If the saltwater wedge edges close enough to municipal water systems, their efficacy to treat freshwater and the longterm durability of that infrastructure could be affected. The costs of treating water could go up and there could be implications for human health.
But its not all bad. For a real-world example of a positive outcome of drought, I don’t need to look any further than out my window here in New Orleans. Because of the extreme drought, less fresh water made its way down to Louisiana. And that’s where things get really interesting. Because of lower flows, the pernicious Gulf of Mexico “dead zone” is smaller this year. This environmental nightmare, caused by an overabundance of nitrogen from fertilizer used on agricultural fields across the Mississippi River basin, allows algae to flourish.
When algae die they are eaten by bacteria that, because of the algal bonanza, burn all available oxygen and choke aquatic species higher on the food chain, like fish. A smaller dead zone means healthier deep water marine fish stocks, possibly offsetting some losses from fishes that require more freshwater. In nature’s ironic fashion, the reduction in freshwater inflows means that less nutrients arrive to the Gulf at historic median strength, and this effect will be as fleeting as the oscillations between drought and rain in the basin.
A water tank intended for drought-affected livestock from a community rancher's well on the Navajo ... [+]
How Can We Prepare Better for the Mississippi in Extreme Drought and Flooding?
It isn’t going to be easy, but to have a chance of maintaining the Mississippi River basin—and the Colorado, and really, any major freshwater system — in some semblance of health and productivity into the future, we must stop thinking about floods and droughts in extreme terms that leave the impression that these are infrequent outliers. That makes them easy to push aside as anomalies that only require band-aids sturdy enough to weather the storm. The extremes are becoming more extreme. They are happening more often. They are less predictable. They are not balancing out at the system level. And the combination of those factors becomes a cycle that feeds on itself, ever gaining momentum.
As hard as it is to stomach, it’s time to push ourselves here in the second moment of the climate era to find new solutions. We can’t keep applying existing strategies to an entirely new problem. They are not up to the task. We have to prepare for the wild swings, because they are coming for us. The potential for drought in the Mississippi River basin is one more reason why we shouldn’t build a pipeline from this river to the drought-beleaguered Colorado River basin. However, to take a page out of the Western Water playbook, perhaps the Mississippi River water users could learn from long term drought strategies that have long been used in parts of the Colorado like Arizona–banking water underground.
Arizona has banked more than 10 million acre feet of Colorado River underground–it has stored its historical share of compact water during years of abundance to use in years of scarcity. This is abundance thinking. Several parts of the Mississippi River basin suffer from groundwater overdraft. These include posterchildren like the basins overlying the Ogallala Aquifer–the dustbowl. These also include unusual suspects like the states that straddle the 100th Meridian where we see a transition from rainfed (east) and irrigated (west) agriculture and where groundwater stores are used (and being depleted) when rainfall isn't sufficient to grow and deliver commodities to the global market. Distributed groundwater banking and more generally, conjunctive management of surface water (when it rains) and groundwater (when it doesn’t rain) in states as widespread as Indiana, Missouri and Arkansas seems like a play that would score.
