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Replenishing a Broken Water Cycle

For centuries, we have built big dams, reservoirs, and levees. Humans have steered and shaped the flow of water to irrigate deserts, prevent floods and access groundwater. But through big engineering, we’ve also created breaks in the natural flow of freshwater from source to sea. The good news is: we can look to nature for solutions to fix it.

In this episode we speak with Sandra Postel, one of the world’s leading freshwater experts, about how solutions rooted in nature – like cover cropping and river restoration – are key to mending the broken water cycle. We also speak with Lisa Hollingsworth-Segedy, a Director of River Restoration for American Rivers, about dam removal as a critical first step to river restoration.

Guest Bios

Sandra PostelSandra Postel

Sandra Postel is an American conservationist, a leading expert on international water issues, and Director of the Global Water Policy Project. During her years at the Worldwatch Institute in Washington, DC, she was early in adopting a multi-disciplinary approach to water, after having studied geology, political science, and environmental management.

In 1994 Postel founded the Global Water Policy Project. She is also the co-creator of the water stewardship initiative Change the Course, as well as a prolific writer and a sought-after communicator. Between 2009 and 2015, Postel served as Freshwater Fellow of the National Geographic Society.

Lisa Hollingsworth-SegedyLisa Hollingsworth-Segedy

Lisa joined American Rivers in 2008 to work with communities, individuals, government, and other non-profit organizations to facilitate the removal of dams that have outlived their useful life. She has been involved in the removal of more than 75 obsolete dams in Pennsylvania.

Lisa is a member of the American Institute of Certified Planners and brings more than three decades of experience in community and regional planning, environmental and resource protection planning, water resource management, project management, community economic revitalization, geology, and hydrogeology to her position.

Lisa was an associate producer for American Rivers’ documentary “Restoring America’s Rivers,” and has completed several demonstration projects using Large Wood Debris for river restoration and aquatic habitat in Pennsylvania.

Further Reading

2021 Water Prize Laureate Press Release – Stockholm International Water Institute

Replenish: The Virtuous Cycle of Water and Prosperity – Book by Sandra Postel

American Rivers



@siwi_water – Stockholm International Water Institute

@AmericanRivers – American Rivers

@InsideNatGeo – National Geographic Society


@AmericanRivers – American Rivers

@InsideNatGeo – National Geographic Society

Photo Credit

Sandra Postel Cheryl Zook, National Geographic
Lisa Hollingsworth-Segedy Lisa Hollingsworth-Segedy

Full Transcript


Sandra Postel:
Big diversions that move water to farms and cities, tremendous amounts of engineering. And it’s hard in some ways, I think, to imagine our world without this engineering, and yet this kind of command and control approach to water and water management has kind of entailed a bit of a Faustian bargain.

Jay Famiglietti:
For centuries, humans built big dams, reservoirs, levees. We’ve steered and shaped the flow of water. We irrigate deserts. We prevent floods. But what happens,when our control and command of freshwater pushes it beyond its limits?

I’m Jay Famiglietti, Executive Director of the Global Institute for Water Security at the University of Saskatchewan. On this episode of “What About Water?” we speak with Sandra Postel about how to mend our broken water cycle, how to work in tandem with nature, not against it. How to build a resilient and secure water future.

Sandra Postel is the Director of the Global Water Policy Project. Sandra wrote the book Replenish:. The virtuous cycle of water and prosperity. She’s a former freshwater fellow of the National Geographic Society. Sandra joins me now from her home office in Corrales, New Mexico.

Sandra, welcome to “What About Water?”

Sandra Postel:
Thanks, Jay. It’s great to be here.

Jay Famiglietti:
Let me start off by congratulating you on winning the 2021 Stockholm water prize. This is a huge deal. It’s like the Nobel prize for water. What does this mean to you?

Sandra Postel:
Oh my goodness. Um, I was so surprised, first of all, to get the award this year. You know, and I think you probably understand this very well.

You know, you work for so long to try to make a difference and you wonder if you are, and somehow this validation coming right now meant a lot to me, that all this hard work over decades maybe has made a difference in the world. So that, I think that was the greatest thing for me about it. And plus recognizing that, of course I don’t stand alone on this. I’ve worked with so many great colleagues and just, just a lot of appreciation and gratitude for it.

Jay Famiglietti:
When we last met, we were at the National Academy of Science at Washington DC for the rollout of this issue of Trend Magazine from the Pew Trusts in which we both have articles. And even in that article, you talk about how the water cycle is broken. What do you mean by that?

Sandra Postel:
Well, you know, if we think about water on the planet, this movement of water from source to sea, you know, from watersheds across the landscape, through the land, toward the sea, it’s the water cycle that keeps everything going all of life on terrestrial earth depends on this water cycle.

And yet, if you look at how we’ve managed water and land, which of course are very connected, we can see all kinds of ways in which we’ve broken that cycle. We have now 60,000 large dams around the world that are blocking rivers from flowing the way they naturally should flow.

That means that many rivers, because of dams and diversions, are not reaching the sea. So they’re not bringing nutrients and sediment and fresh water to our coastal environments. That’s part of what rivers do is reach the sea and many are no longer doing it. We have these huge levies to guard against flood.

Rivers are meant to flood. And so they’re no longer connecting to their flood. Plain. That’s a break in the water cycle. We’re over pumping groundwater, which means that that part of the water cycle is also broken. Groundwater is the base flow for rivers. And so those are just a few ways in which we’ve broken the water cycle.

And of course with climate change, the heating of the atmosphere is fundamentally changing the water cycle. The warmer atmosphere is holding more and more moisture, which means that droughts and floods are intensifying and that’s changing water cycles everywhere locally, globally, regionally, and so on.

These are fundamental changes, um, that have very dramatic impacts for us. For food security, water security. The health of people. And in nature in general.

Jay Famiglietti:
We don’t often think of ourselves, humans, as part of the water cycle, but, but we really are, aren’t we?.

Sandra Postel:
Yeah, we, we very much are a part of the water cycle. Not just because we’re made of water.

60% of us is water, but how we live, how we manage the land is, is very much influencing how water flows and how water is stored and how we’re going to be resilient in these coming years.

Jay Famiglietti:
So just a little side fact, when you were talking about the 60,000 dams and reservoirs and how they’re holding back and withholding stream flow, a couple of things: That really has an impact on sea level rise and actually slowing the rate of sea level rise because that water’s on land and not in the ocean.

Um, but another thing that’s kind of cool is that water is so heavy that when you distribute water around the world like that in these reservoirs It actually changes the rotation of the earth. And so it makes the earth spin a little bit faster and it changes the axis of rotation a little bit.

So we’ve played a big role so far, but what do you think our role should be going forward? Can we fix it?

Sandra Postel:
Well, the good news is I think we can, and I think it it’s going to require kind of a shift in mindset in our relationship with water and how we use and manage water. You know, we have this tremendous water engineering that’s incredibly impressive. You know, the 60,000 large dams, many tens of thousands of hundreds, of thousands of smaller dams, big diversions that move water to farms and cities, tremendous amounts of engineering. And it’s hard in some ways, I think to imagine our world without this engineering, the ability to store water for when and where we need it and so on.

And yet, this kind of command and control approach to water and water management has kind of entailed a bit of a Faustian bargain, if you will. You know, it is breaking that water cycle. And I come back to something, something Einstein said, that we can’t solve problems using the same kind of thinking we used when we created the problems.

So thinking we can engineer our way out by doing more and bigger of the same kinds of things is really not going to work. And so what I feel is our best hope for building a more secure, resilient water future is to really begin working with nature as more of a partner, less command and control approach and more looking at natural services, ecosystem services, looking at nature and working with nature as much as we can.

Jay Famiglietti:
So let’s talk about what you see as some of these solutions and working with nature. Can you give us some examples?

Sandra Postel:
Yeah. And, and, and for me, an important backdrop to this is that we’ve got three big crises happening. At the same time. We have the climate crisis, we have the water crisis. We have a crisis in biodiversity and we simply do not have time to solve these major crises in a piecemeal fashion, we have got to find holistic solutions that solve them simultaneously.

A couple examples. So one that I think is really important is how we go about controlling floods. We have tended to build big dams, big levees, alongside rivers as a way of keeping floodwaters at bay. But if we think about a different approach, letting rivers move laterally during floods, reactivate floodplains, reconnect rivers to their natural floodplain, we get these multiple co-benefits where we’re controlling and mitigating floods. We’re storing more carbon in the soil, we’re recharging groundwater, we’re holding and purifying water before it heads downstream.

And we’re rebuilding fish, wildlife, and bird habitat along the Riverside. Those are multiple benefits that are solving simultaneously for those three big challenges.

Jay Famiglietti:
So I think that sounds fantastic, of course. But you’re preaching to the choir. So let me play devil’s advocate a little bit. I mean, do you think this is really feasible at a large scale in the United States?

Sandra Postel:
You know, I think it is. It turns out that the science suggests that we don’t need to reconstruct, you know, a huge area of wetlands. For example, in the upper upper basin of the Mississippi. Again, taking the Mississippi river basin as an example, the Mississippi river basin covers 41% of the continental United States.

And if we could rebuild a relatively small percentage of the wetlands and the upper part of the basin, it could help control a significant amount of flooding and as floods intensify, we’re going to need more of that. And so I think very much we could scale something like this. I think it would take bringing all the stakeholders together, including farmers and compensating. But I think there’s a tremendous amount of opportunity to repair that part of the water cycle and control floods differently. And we’re beginning to see this happen.

Jay Famiglietti:
I wanted to underscore something you just said, that we really don’t have to change that much, and we can make small changes and have a huge impact.

And I’ve seen some literature on this with respect to biodiversity and wetland drainage up here in Canada that even small changes have a huge impact on water retention and soils on biodiversity at the farm scale. And so I think that’s important for people to recognize that we can make small changes and have a huge impact.

Sandra Postel:
Yeah, and you bring up farming again. And I think this is another really important example, you know, I’ve been studying water issues for nearly four decades now. And I readily admit that I have paid far too little attention to the health of soil as a water reservoir. Right? I mean, we kind of go right from rivers to groundwater and we forget about that layer of earth we call soil in between. And yet when you look globally soils hold eight times as much water as all the world’s rivers combined, but we rarely manage that soil reservoir for a water reservoir. So if we can improve soil health, again, we’re getting multiple benefits, better yields, the need to apply less chemical fertilizer, more carbon in the soil, and the ability to hold more water.

One simple solution here is to incentivize the planting of cover crops. You know, during the off season, when you finished growing your commercial crop many farmers just leave the soil and their land sort of barren. And instead if you plant a cover of crops so that you have a living root in the soil at all times, you’re going to improve the health of that soil. And you’re going to reduce wind and water erosion, which takes away that healthy topsoil. I think in the United States, maybe 6% of all of our farmland gets cover cropped. A state like Maryland, I believe has more like 29% because it has incentivized this, to incentivize what’s working and encourage more of those kinds of solutions.

Jay Famiglietti:
We’ve been talking a little bit about the Mississippi river basin. Why don’t we switch to talking about the Colorado river basin, which I know is a basin that you’ve spent a lot of time in and have done a lot of work on. What do you see in terms of this over-engineering in the basin and how that’s playing out in the Colorado River?

Sandra Postel:
Well, you know, next year will actually be the hundredth anniversary of the Colorado River Compact that was signed in 1922. And you know, one of the things that I think is important to note is, well, a couple of things: One is of course, more water was promised to the seven states than the river naturally carries now, so the river is completely over allocated. But secondly, there were important parties missing around that table in 1922. One, of course, was Mexico. And we rectified that a few decades later with an agreement with Mexico. But the river wasn’t represented around that table, the Native Americans weren’t represented around that table.

And so there are more demands that are now coming forward that should have been represented at the beginning. And I think this is an important lesson to always make sure when you’re making big decisions, that all of the stakeholders are around the table. We’re of course now in a mega drought in the Southwest, that seems to be the second driest 20-year period in 1200 years.

So in June, Lake Mead, which is the largest US reservoir, dropped to its lowest level since Hoover Dam was built in the 1930s. And I think the science is quite clear that we’re just not going to see these reservoir levels come back up. And I think it’s very important that we begin talking less about drought and more about aridification – by which I mean, the drying out of the landscape. You know, there was…some numbers came out last year that the Colorado River Basin had a pretty normal snowpack in 2020, last year.

But the runoff from that snow melt was only about 52% of normal. The reason is that the atmosphere is thirstier, there’s more evaporation. The soil is desiccated. It’s absorbing more of that water. Plants are thirstier, they’re transpiring more water. So there’s less runoff. That’s what fills the rivers, the reservoirs, the groundwater. So if you have a relatively normal year of precipitation, but you’re only getting half the average runoff that you’re accustomed to…Wow. I mean that’s really something.

Jay Famiglietti:
That switch in perspective from thinking about a drought that has an end to aridification and chronic water scarcity, this is essential to adaptation. That change in mindset that it’s not going to go away, that we have to adapt. Do you agree with that?

Sandra Postel:
I do agree with that. We have to begin thinking of it as a long-term drying out in places like the desert Southwest, not a temporary drought phenomenon.

Jay Famiglietti:
We’ve been talking about the Colorado River Basin and I think that the river is so over allocated that it never makes it to the Delta. Can you talk to us about that a little bit?

Sandra Postel:
Yeah. So the Colorado River is over allocated. Mexico has rights to 10% of the river, the United States, 90% of the river, and all that water is spoken for. So when the water hits, you know, gets close to the border of the US and Mexico, the last dam is the Morelos dam near the border.

Pretty much every drop is siphoned into a canal that takes the water down to the Mexicali valley, the farmlands, and so on. And so there’s nothing for the Delta itself. And the last hundred miles of the Colorado river are through that Delta. And virtually it’s getting no water in most years anymore. And so what had been a 2 million acre wetland, beautiful wetland area, very lush, incredibly important for the migratory birds on the Pacific flyway, the Delta of course then feeds into the upper Gulf of California. Very important fisheries are not getting that delivery of fresh water and nutrients…So the Delta is now a desiccated landscape with a few exceptions of wetlands that remain about a 40,000 acre wetland that’s fed by agricultural drainage water from Arizona.

But for the most part it is very, very dried out. And so the US and Mexico, thanks to very, very hard work by scientists, conservation organizations, NGOs, passed an agreement called Minute 319 back in 2012, which said let’s do an experiment. Let’s give the Delta some water back.

And so this was an incredible opportunity for collaborative work to see if this community of people that has been working so hard on this could restore a small part of the Colorado River Delta. So Minute 319 was a five-year program with an experiment of a pulse flow of water mimicking the natural spring pulse of the Colorado. That water went through the Delta, took about eight weeks. Very little made it to the sea, but a little bit of it did reach the sea which made big news. And then scientists studied what had happened. And birds did begin to come back. There was some recharging of groundwater and so on. There were some benefits.

Okay. So fast forward five years later, that minute is running out. Another one was passed – Minute 323 in 2017. And this year from May 1st until about mid-October about 35,000 acre feet of water was delivered again through the Delta, but more strategically. So the scientists and NGOs had learned from that first experiment to maybe bypass the first part of the Delta, where a lot of the water seeps into the ground. Let’s go past there, deliver the water via irrigation canals, further down and release that water.

So more water reached the sea this time is my understanding. Both bird species variety and bird numbers came back in these restored areas. So there’s an active restoration area now of about 1100 acres where vegetation actively planted. So native vegetation – cottonwoods, willows, mesquite – are beginning to get enough irrigation water to restore some wetland areas.

I think it’s an inspiring story that if we choose to return some water to the natural environment, life comes back.

Jay Famiglietti:
So that is inspiring Sandra and we face a similar situation. Of course, we don’t have the aridity that the Colorado River Basin and the Delta region have. But, um, at the end of the Saskatchewan River is the Saskatchewan River Delta. It’s the biggest freshwater Delta in North America. And it faces the same problems.

We’re getting more frequent drought. We’re expecting, you know, just like the Western US, we’re expecting the snowpack to decrease. We’re also talking about diverting more of that water to do irrigation to increase food production and you know, all of these impacts accumulate in the Delta.

So there’s a number of people that I work with and colleagues really around the world that are working with the Indigenous populations there to co-develop research projects to try to understand what the impacts are and how to avoid those impacts and how to mitigate those. So it’s great to see this kind of work going on in the United States and perhaps it can be a model for us up here in Canada.

I want to switch over to talking about groundwater, which you’ve called the “sleeping tiger” of water security risks, but just let me preface it by saying that some of our latest research shows that the rate of groundwater depletion that’s happening in the central valley is faster than ever before and faster than some of our previous satellite-based studies. So not good. When you call groundwater this, “the sleeping tiger” what do you mean by that?

Sandra Postel:
To me, it’s a sleeping tiger because it is literally out of sight, out of mind. The great satellite data that you and your colleagues have pulled together and brought to the world’s attention has really shown how important the depletion of groundwater is and how we’re not paying nearly enough attention to it.

And so that sleeping tiger is going to wake up and come and come get us if we’re not more attentive to it. What’s particularly of concern to me is that we know that groundwater is being depleted significantly in the major food-producing regions of the world. So Northwest India, the Western United States, China, Pakistan, you know, these are the four major irrigators and we have significant groundwater depletion in all of those major food producing areas. And that to me is a big red flag for food security going forward. You can think of it as a bubble in the food economy and it’s going to have to pop at some point. And we’re, you know, we see Wells going dry in parts of the Ogallala aquifer, wells going dry in India, and so this is a big concern. And yet we don’t pay nearly enough attention to it because it’s underground. We’re not seeing it.

Jay Famiglietti:
I spend a lot of time thinking about these issues, but in a global context, and it’s such a challenge to communicate what’s going on, to visit different regions around the world. You know, you mentioned India, Pakistan. I was recently out in Bangladesh, which is also in very rough shape with respect to groundwater. And it’s so difficult to get the message across to, you know, to try to share the science. What’s your experience been with that on the science communication side? Have you been able to penetrate with some of your messages?.

Sandra Postel:
Well, that’s a good question. I think the proof is in the pudding on that, you know, when you’re successful at communicating, you see change happening. You know, groundwater is a very, very hard thing to get across: the importance of monitoring it, managing it.

But I think we’re starting to see some progress here in India, for example, part of the issue has been the lack of any marginal cost in electricity. If there’s a flat rate for electricity, you can pump as much water as you need to or want to, and there’s no extra cost. And so I think they’re trying to come up with incentives for reducing that overpumping of groundwater.

You know, Texas has something called the rule of capture. Which essentially allows any farmer or rancher in Texas to pump as much water as they want from beneath their land. It’s considered a property right to do that. So you’ve got these state provincial national laws and regulations and water rights frameworks that just don’t encourage sustainable use of this common source of water.

Jay Famiglietti:
Yeah, I agree. And you know, one thing I always think about that Sandra is that when all these policies and laws and water rights were all granted and written up, nobody really understood the water cycle. No one understood the interconnectedness of the surface water and the groundwater.

No one was thinking about climate change and population growth. And none of that fits anymore. And I just see huge challenges, again, to amending any of that.

Sandra Postel:
I agree. I do agree. If you think about the way – getting back to the Colorado River for a minute, the way the compact was written. Yeah, there are explicit allocations rather than shares of available water.

I think one lesson from, you know, from what’s happening in the Colorado River Basin is rather than come up with specific quantifications of water to give to each represented party share what’s actually there. And then everyone shares the pain in that way.

Jay Famiglietti:
That makes complete sense, but getting people to agree to rational issues is a challenge. And of course there are economies that are based around it, right? And so it’s really, really difficult. It’s going to cost someone a lot of money to give that, to give up those rights.

Sandra Postel:
Absolutely. Yeah.

Jay Famiglietti:
So let’s talk about the dollars and cents side of fixing the water cycle. This will take a huge investment, hundreds of millions of dollars. How do we get businesses, policy makers, are we gonna get them to buy in?

Sandra Postel:
One way is to make this connection between water and climate. You know, we’re about to hopefully encourage large investments in climate mitigation and adaptation. And to the extent we can begin to recognize that climate change is water change, and that changes in how we use and manage water can both help mitigate and adapt to climate, I think those investments can be forthcoming. We’ve done too little, really, to connect the water challenges to the climate challenges. You know, and I think that’s that that can really help a lot.

Jay Famiglietti:
Thank you so much for joining us today, Sandra.

Sandra Postel:
Thank you, Jay. It’s been great to be with you here today.

Jay Famiglietti:
Sandra Postel is the director of the Global Water Policy Project and the 2021 Stockholm Water Prize Laureate.

As Sandra Postel says, sometimes the best solution is to work with not against nature.. Lisa Hollingsworth-Segedy is doing that. She’s with American Rivers and she works as their Director of River Restoration in Pennsylvania and West Virginia.


Lisa Hollingsworth-Segedy:
In Pennsylvania we have long recognized the benefit of dam removal for ecological reasons. I have removed well over a hundred dams and those projects have resulted in the reconnection of well over a thousand miles of aquatic habitat connectivity.

One with the ones I’m most proud of is an upcoming dam removal on the Susquehanna River. It’s one that has been a long time coming. It’s an obsolete hydro-power dam that has been in total disuse for about 30 years. It’s got a large breach in the center that has a very dangerous hydraulic on it. And it’s also on a Pennsylvania water trail, so that makes it doubly dangerous because, you know, people are using that water trail every day. And a lot of people don’t understand the dangers of a dam. It’s kind of miraculous that nobody has gotten hurt there.

We’ll be removing that dam next year and it will reconnect 250 miles of aquatic habitat for the benefit of freshwater mussels and their fish host species as well as sport fish.

The benefit of removing dams is that it kick-starts river restoration. It’s one of the simplest things that starts a river on a journey to full restoration because it reconnects the habitat. It eliminates the thermal gain – the increase in temperature that is caused by water backing up and slowing down behind a dam. It returns the stream flow to normal conditions. It allows for seasonal variations that support the fish that depend on those natural cues to know when to go upstream and reproduce. It increases the oxygen in the water. It provides additional access for recreation and eliminates something that’s just totally unnatural in a river and allows it to return to natural form.

Jay Famiglietti:
That was Lisa Hollingsworth-Segedy. She’s with American Rivers. It’s a non-profit group. That’s been trying to restore wild and damaged rivers in America for nearly 50 years now.

Well, that’s it for this episode of “What About Water?”. We record and produce this podcast on Treaty Six territory. We live and work on this, the homeland of First Nations and Métis people. And we respect that relationship. “What About Water?” is produced by the Walrus Lab and the Global Institute for Water Security at the University of Saskatchewan. Check out as we continue to post water related stories and resources.

Our crew here at “What About Water?” is Mark Ferguson, Erin Stephens, Laura McFarlan, Fred Reibin, Jesse Witow, Shawn Ahmed, and Andrea Rowe. Thanks to Wayne Giesbrecht, our studio technician, and to Farha Akhtar and to Jen Quesnel at Cascade Communications, who put it all together.

“What About Water?”. Available on Spotify, Apple, or wherever you download your favorite podcasts. I’m Jay Famiglietti. Thanks for listening.