Beneath the roads and sidewalks we pass every day are underground reservoirs that provide a substantial portion of the country’s overall water needs. These underground aquifers once supported American cities and farmlands. Now, according to a New York Times investigationthey could dry up for good.
Aquifers – geological formations of layered rock or sediment that filter and retain groundwater – power much of the country’s industry and agriculture. But the growth of cities and industrial agriculture is rapidly depleting the country’s groundwater, faster than the rate of recharge. Additionally, public attention to the problem is lacking, experts say.
More than a century ago, the movement of groundwater seemed to those responsible: “so secret and occult» to the point of seeming ungovernable. The fact that the problem is not easily visible has made it difficult for scientists to collect data, according to James Dennedy-Frankassistant professor of marine and environmental sciences, as well as civil and environmental engineering, at Northeastern.
Dennedy-Frank spoke to Northeastern Global News about his ongoing research on the issue, which harnesses the power of computing to create models simulating rates of groundwater depletion, while exploring environmental factors linked to recharge .
The conversation has been edited for brevity and clarity.
Why don’t you start by explaining the problem. What is happening to our groundwater and what prompted this major Times investigation?
The problem is that we know that reliable water resources are a critical need, and we see many places where water resources are becoming less reliable. The Times’ first big story concerns falling water levels across the country.
It’s certainly something we’ve known about for a long time — particularly on the West Coast. But the Times has put together a whole new database on falling water levels nationwide. As we experience more severe droughts in many places, including here on the East Coast — in places like Cape Cod, for example, which relies heavily on groundwater — we’re seeing groundwater levels dropping everywhere.
And that has all sorts of effects. This has effects on water availability. Many rivers and streams are fed by groundwater, particularly during dry seasons. Thus, these rivers and streams diminish and flow less.
As a result, they also warm up because less cold groundwater flows into them. This also has potential effects on aquatic life. There’s a whole range of effects here – and it’s not just happening in the “dry” West, where you tend to hear a lot about it.
Phoenix recently made the decision to restrict home construction in certain areas because there was no reliable water source. It’s obviously a very big problem when cities say they can’t build new houses.
The second place the Times looked at was Minnesota, which is not a place you think of when you think of drylands. They had a drought in 2021 and a lot of the big agricultural companies were pumping a lot of groundwater – in fact, much more than their nominal permits would allow.
(One thing I will say about groundwater is that where there are permits, they are generally not well enforced, and in many places there aren’t even permits, so there are has very flexible regulations.)
Even in Minnesota – we think of Minnesota as the “Land of 10,000 Lakes,” where there is plenty of water – many wells were drying up due to drought, and these agricultural uses were pumping out millions of gallons of water . This is a rough sketch of the problem.
Do we know how much of this is specifically a product of climate change?
I don’t think anyone has hard numbers on that at the moment. There are certainly people who strive to understand this as a question of climate attribution: how much of this is due to climate, how much of this is due to humans, etc. There have been many places where groundwater and other water resources have been put under severe strain by humans. use in the absence of climate change, but climate change puts more stress on systems and puts strain on systems that we didn’t worry about as much before.
I think what seems true is that better human management can significantly reduce these effects if we were just more thoughtful about our management and more thoughtful about how many resources we use and where they are used . The largest crop in the United States is turf; it covers the largest area. Lawns in the middle of Phoenix are real water guzzlers. Many places in the West have started to tackle this problem. But this is not the case in many other places.
What are cities and municipalities doing to help solve the problem?
There are various approaches. Decades ago, the town of Thornton, Colorado, purchased land with water rights associated with it to transport to suburban Denver.
Recently (the city) has been legal battles to move this waterbecause very complex water laws are at play. Last summer on Cape Cod, many watering restrictions were put in place.
Cape Cod, as I pointed out, relies heavily on groundwater, so these groundwater issues are a classic story there. Even in East Coast systems that we consider to be quite wet, people are being told to limit watering lawns.
Tell me about your research and how it contributes to the search for solutions.
I am a hydrologist and I mainly do watershed simulations. I use computers to represent these watersheds, with the aim of trying to better understand how we can manage them more sustainably.
More recently, a lot of the work we’ve been doing is looking at how groundwater recharges and how rain and snow relate to stream flow and evapotranspiration, it’s i.e. water that flows through rivers and water used by vegetation.
What we found is that in at least one mountainous watershed in Colorado, more of the water that falls as snow ends up as streamflow, while more of water that falls as rain ends up as evapotranspiration. This has important implications in a world where we have more rain and less snow in the future.
We’re working to try to determine how fundamental this is to the behavior of rain and snow in these systems, both in the western United States and here in the east. As for groundwater, we published a paper earlier this year that I co-authored that looked at these large atmospheric river storms that are coming into California and tracked the water in these atmospheric rivers relative to other smaller storms.
We found that what recharged groundwater the most in our model of this California watershed was actually snow from less severe storms. So these very large, violent storms recharge groundwater much less. This has important implications as the climate changes and we see more of these atmospheric rivers.
Where do you think we will be in a decade on this issue?
For a very long time, around water, we have been managing in confusion. When things get really bad, we find a temporary solution to fix it.
In the future, our abilities to simulate and better understand these systems improve, and I think the hope is that officials and governments use these tools and work with academics to better plan and manage water resources of these hard-hit areas. , and thus move towards a more sustainable future.
But there will always be stressors – and we don’t know exactly what those stressors will be as the climate changes.