The salinity of the Salton Sea now is almost twice as high as that of the ocean. Photo © J. Carl Ganter / Circle of Blue

November 4, 2019

Eileen Wray-McCann: This is Eileen Wray-McCann for Circle of Blue and this is Speaking of Water, a look into vital water topics that often flow beneath the headlines.

26 years ago, a writer for the LA Times, called the Salton Sea, “A shallow body of water in deep trouble.” And said, “California’s largest Lake has become the ecological equivalent of the Broadway stage. Always dying but never quite dead.” The intervening decades have revitalized Broadway, but not so for the Salton Sea. It has watched many highly billed revivals close before opening night as studies and proposals and plans come and go. All the while, the water has been getting scarcer, saltier, sicker and stinkier. But the long suffering advocates of the Salton Sea are once again hoping they’ve got their lucky break. Reported one expert, “2019 brought a new state administration and new enthusiasm and even hope for the Salton Sea. The pieces are all in place for real action.” Those are the words of Michael Cohen, senior researcher at the Pacific Institute, a global water think tank providing thought leadership for sustainable water policy. 

For over 20 years, he’s been focused on water use in the Colorado River Basin and the saga of the Salton Sea, and his experience and expertise were an important part in the recent Salton Sea Summit co-hosted by the Pacific Institute and the University of California Riverside. Glad to have you here, Mike.

Michael Cohen: Thanks very much for having me.

Eileen Wray-McCann: You were just at the Salton Sea for this summit, could you start this conversation by painting us a picture of what it’s like to be there these days?

Michael Cohen:  So the Salton Sea continues to be a very incongruous body of water. It’s huge, it’s really hard to even comprehend how big the body of water is without getting up in the air. So it’s 35 miles long, some 15 miles wide, in the middle of one of the driest deserts in Southern California. So here’s this vast, very shallow, body of water providing and continuing to provide refuge for many birds that are passing along on the Pacific Flyway. And yet in one of the driest parts of the State of California. In a state currently under siege by, not just wildfires, but continuing water shortages.

The sea varies because it’s so large, some 100 miles of shorelines. So it depends where you are. So there’s three major rivers that empty into the Salton Sea. Those deltas are your, I guess, typical silty deltas. There’s a lot of vegetation encroaching as the Salton Sea continues to recede. And then in some areas there’s a lot of barnacles or fish bones and sandy areas of the shoreline as well. So there’s a variety of different areas. And it’s this variety, this heterogeneity, that helps provide the variety of habitats that birds seem to flock to.

So looking across, it depends on the time of day and how warm it is out there. So in the middle of the summer it can get to over a 110 degrees and can be pretty rich in smells, much like if you’re by the ocean, sometimes the ocean can be pretty strong smelling as well.

Eileen Wray-McCann: Well, the sea has transmogrified in the last 20 years that you’ve been studying it. Could you describe how it formed in the first place, and what has happened along the way?

Michael Cohen: So the sea, not just in the past 20 years or even the past 114 years since the current incarnation form, but essentially over millennia, the Salton Sea has been part of the Colorado River Delta. So the Colorado River meanders, sometimes discharging into the Upper Gulf of California and sometimes discharging it to the Salton Sea Basin. And in fact, the whole area, that whole part of the Salton Sea Basin, stretching down now to the Upper Gulf of California, is in many ways the antithesis of the Grand Canyon and Glen Canyon and the other major canyons that the Colorado River has carved, because those sediments had to go somewhere, where they were deposited as the river meandered throughout its delta is essentially now the Upper Gulf of California now filled in with the sediments of these major canyons on the river.

So over time, as the river meandered, it sometimes discharged into what used to be called Lake Cahuilla, currently is now known as the Salton Sea, and continues to flow there now through agricultural fields. But the river has moved and in many ways has always been a dynamic body of water. And some of the challenge now is that we’re trying to impose some idea of stasis to what used to be a very, or continues to be, a very dynamic system.

Eileen Wray-McCann:  And could you explain some of the challenges that have grabbed our attention because of this?

Michael Cohen: One of the big challenges currently facing the Salton Sea, is that back in 2003 San Diego County Water Authority and the major irrigation district in the region, the Imperial Irrigation District, signed a water transfer as part of a much broader set of agreements, reallocating water within the State of California. That agreement, known as the Quantification Settlement Agreement, really set the stage for the current efforts, because at the time there was concern and acknowledgement that this water transfer was going to dramatically reduce the amount of water flowing into the Salton Sea and increasing the rate of which salinity increases and also shrinking the Salton Sea. But the two water agencies didn’t want to bear the mitigation costs, the responsibility for alleviating those impacts. It was up to the State of California to step in and say that they were going to backstop that deal. And that’s what’s driving the current efforts by the State of California to really address the problems at the Salton Sea.

Eileen Wray-McCann: So there was a water agreement that diverted more water from the Colorado River, so less flowed into the Salton Sea?

Michael Cohen: It diverted some of the existing use within the Imperial Irrigation District, the Imperial Valley, which is the largest user of Colorado River water in the Colorado River Basin. At some point as much as 20% of the total flows of the Colorado River were used in the Imperial Valley.

So the San Diego County Water Authority invested in irrigation efficiencies and system efficiencies, infrastructure efficiencies, so that the idea was that Imperial Valley would continue to irrigate the same amount of land using less water. And the water that was conserved by that, would then move to San Diego. So it was not a net additional consumption of the Colorado River. And in fact, the opposite is true. Over time, both Imperial Irrigation District and the State of California as a whole have reduced their total take of Colorado River water. But the impacts of that have been felt by reducing the amount of water flowing into the Salton Sea. So essentially what it does, what it shows, is that increasing conservation, increasing efficiency, has these negative impacts on the environment. And that’s what we’re really grappling with now.

Eileen Wray-McCann: Yeah, I had never really thought about it that way. Because the Salton Sea gets water from runoff or water that was previously wasted before? Is that kind of what’s happening here?

Michael Cohen: Right, so it’s essentially irrigation runoff provides some 85 to 90% of the water flowing into the Salton Sea. There’s a little bit of water from urban runoff or from, at least, from some of the cities in Imperial and Coachella Valley and then a little bit from Mexico as well. There’s also some local precipitation, although in the desert that’s not very much. But again, some 85 to 90% of the water flowing into the Salton Sea flows through and over the fields, primarily the Imperial Valley.

And without that water flowing through those fields, you couldn’t irrigate those fields, because one of the reasons there’s so much water use there is that A, the soils are fertile, so there’s a lot of land to irrigate, but also a lot of the salts from the Colorado River Basin, from upstream, concentrate in the Imperial Valley. So they have to apply additional water to wash those salts out, otherwise that land would not be productive. So the Salton Sea essentially is an agricultural sump and receives both some of the fertilizers, pesticides, but particularly the salts contained within the Colorado River and then concentrated as that land is irrigated, some of that water evaporates and those salts continue down into the Salton Sea.

Eileen Wray-McCann: So, that water is a mixed blessing. It does have nitrates and fertilizer and various runoff?

Michael Cohen: Exactly.

Eileen Wray-McCann: So less of it gets into the Salton Sea, it has less to dilute those things, and so the salinity is incredibly high, right?

Michael Cohen: Correct. So the salinity of the Salton Sea now is almost twice as high as that of the ocean. So when I started working on this problem a little over 20 years ago, it was just a little bit saltier than the ocean, 10, 15% saltier. So just in the past 20 years salinity at the Salton Sea has increased by more than 50%

Eileen Wray-McCann: That and various chemicals and things like that have had devastating effects on the ecosystem there, right, with the fish and so forth?

Michael Cohen: Right, exactly. So there’s a couple of major problems facing the ecosystem at the Salton Sea. One is rising salinity. So salinity at the Salton Sea now exceeds the tolerance of almost every fish in the sea. So in another curious development, the main species of fish in the Salton Sea 20 years ago was tilapia, which is traditionally a freshwater species, but the tilapia in the Salton Sea adapted remarkably quickly to rising salinity, such that they were able to out-compete other fish species in the Salton Sea.

And again, some 20 years ago, fish production in the Salton Sea was essentially off the charts. There were some estimates that there were more than 100 000 000 tilapia in the Salton Sea. So anecdotally, people would report that as they were boating through the Salton Sea you could see fish coming up in the wake. So this incredibly productive ecosystem in turn supported tremendous numbers of birds. And some of that productivity, in fact, most of that productivity came because these fertilizers that were flowing into the Salton Sea because of fertilizer practices in the Imperial Valley, essentially the fertilizers that grow crops on the ground also help produce a lot of biological activity in the waters of the Salton Sea. In turn, leading to these huge fish numbers.

Michael Cohen: But as salinity continues to rise in the Salton Sea, and as the sea has become so productive, the amount of oxygen in the waters of the Salton Sea is very low, which in turn puts additional stress on the fish and the invertebrates in the Salton Sea as well. So that’s part of the reason why we’ve seen those populations crash.

Eileen Wray-McCann:  And there’s also the problem that as the sea recedes, it exposes lake bed, which has layers and layers of the sediment that has been running off the land for a long time. What’s the story about that?

Michael Cohen: Right. So exactly. So the Salton Sea, and again, in the past 15 or so years has dropped more than nine feet. So the elevation has gone down. But because the sea is such a shallow body of water, the decline and the elevation is translated into more than 20 000 acres of former lake bed being exposed to the blowing winds of the region. So one of the challenges there is that air quality in the region is already very bad. So this additional dust source exacerbates an already bad situation. And the challenge is not just the amount of dust coming off this land, but the constituents in this dust.

So there’s, again, some of these fertilizers, there’s a variety of other heavy metals in some of this dust. So there’s concern that it’s not just the size, the physical characteristics of the dust being blown off the Salton Sea lake bed, but also some of the chemical properties may further endanger public health.

Eileen Wray-McCann: These issues are not new to people. Obviously this has been a concern for quite some time and as I alluded to earlier, there have been many proposals and policy initiatives and studies that seem to raise hope, and then for one reason or another, fail to materialize. The Pacific Institute joined the University of California Riverside and co-hosted the Salton Sea Summit. That was October 17th and 18th. And the institute described it as, “A multidisciplinary conference, including panels on hydrology, ecology, dust control, projects and policy, all intended to attract a broad range of interests and promote an exchange of ideas, as well as developing new opportunities and partnerships.” Can you give us an idea of what came out of that?

Michael Cohen: Part of the idea for the conference was really to bring these different disciplines together to get people talking to each other. And it had been many years since there had been a conference of this scale, with the Salton Sea as a topic. So we thought the time was right to bring people together for this. And in fact, there was even more interest in this than we expected. The final count with some 270 people registered for the conference, which is a great number. So the good news is that the conference proceedings are posted online. There’s a conference website, So the various presentations and video from the conference are all available for people to review, but there’s also a few posters posted online as well.

So several things came out of the conference. One, is that we’re continuing to see bird populations decline. In better news, some of the shorebird populations seem to be holding steady or even increasing slightly. One of the presenters mentioned that he’s been seeing some passive re-vegetation as the Salton Sea’s receding. Some of the drain water, as that continues to flow to the shrinking Salton Sea, has prompted the growth of new vegetation, so that provides some additional habitat. It’s certainly not keeping up with the amount of playa or lake bed that’s been exposed to date, but there is some good news there.

We learned a little bit about some additional dust control projects that are being constructed, to date, exclusively by the Imperial Irrigation District, and then some of the plans from the state to start to catch up to their requirements to build both habitat and dust control projects.

Eileen Wray-McCann: Is there anything that is in the works in terms of funded initiatives to help restore the Salton Sea?

Michael Cohen: So, the encouraging news is that to date, the voters of California have approved bonds and there’s various other funding sources that total more than $350 000 000 in available funding for Salton Sea efforts. So there’s a pretty sized pot of money available to start building these projects. That’s certainly not going to be sufficient to build at the scale required to address the challenges posed by the Salton Sea. But there’s a good chunk of money to get those projects started.

There’s several projects in the works. There’s general consensus on what those projects should look like, and there’s been greater cooperation between the State of California and the local irrigation districts. So those are all good signs. And perhaps the most encouraging thing recently, is that the new administration in the State of California and the new resources secretary for the State of California have shown considerable political will, the enthusiasm needed to actually build these projects, and that has been sorely lacking to date. So, been optimistic before, but perhaps I’m most optimistic now, that we’re finally going to start seeing some projects built at the Salton Sea.

Eileen Wray-McCann: There is also something that I saw, I think it was locally, requests or demands for declaring an environmental state of emergency to mobilize some of these efforts. Could you talk about that?

Michael Cohen: Right. So at the conference, the chair of the Imperial County Board of Supervisors noted that last week, on October 22nd, that his board was going to review, and then ultimately they approved, a public health emergency declaration, because of the additional dust blowing off the Salton Sea, seeking additional state support and expedited state activities, and ultimately looking towards the federal government to help build some of these projects necessary to mitigate or prevent the additional dust from being emitted into the local air shed. So it remains to be seen how this is going to play out. But there is increasing attention, I think, to the threats, not just to the environment or to the ecology of the Salton Sea, but to public health as well.

Eileen Wray-McCann: The LA Times writer comparing the Salton Sea to Broadway, always dying but never quite dead, made me think of the lyric from the musical, The Producers, “We can do it and I know it’s going to work.” And as someone who has watched a lot of policies flop, how do you feel about the latest big buildup for the Salton Sea?

Michael Cohen: So we’ve seen, as you’ve mentioned, many, many efforts over the decades, and it’s been four more decades now, that there’ve been plans proposed to address some of the challenges of the Salton Sea and those plans have never actually seen projects in the ground. So we’re continuing to wait for those projects to get in the ground. The hope is that with this new administration, this new commitment to building these projects, we’re finally going to see some activity. Like I said, I’ve been, I don’t know if I should say fooled in the past, but overly optimistic and again, I’m feeling more optimistic, although I’ve been disappointed to see that that hasn’t, those projects have not materialized, but I’m hoping this time will be different.

Eileen Wray-McCann: Perhaps it’s a matter of context. Why is what happens to the Salton Sea, important in the big picture?

Michael Cohen: There are several key reasons why this is such an important issue. One of which is that the local irrigation district has made their participation in additional Colorado River planning efforts contingent on state activity and federal activity and investment in Salton Sea activities. Increasingly, what we’ve seen in the past 15 and 20 years, is a recognition and acknowledgement by other parties, including agencies outside of the State of California that the Salton Sea is a problem for the Colorado River Basin as a whole. So that’s been, to my mind, an important change over time, is this recognition that the Salton Sea is part of the basin and solutions at the Salton Sea are critical to addressing some of the broader challenges in the Colorado River as a whole. Including, essentially, over-allocation and over-use of Colorado River water.

So the Imperial Irrigation District continues to be the largest single user of Colorado River water and has additional conservation potential. So they could continue to contribute more than they already have, to addressing some of the challenges in the river, including the draw down of Lake Mead and the threat of ever deepening shortages and declarations of shortage and reductions in use, in particularly, in Arizona. So IID’s, could be a very helpful participant in addressing those problems, but has made their participation in those efforts contingent, again, on activities at the Salton Sea, so that’s one key reason.

I think a broader reason, and very related to the first, is that the area is really shifted from developing new supplies of water to reallocating water that’s already being used. But one of the challenges that we’re seeing, in particular at the Salton Sea, is as systems become more efficient, ecosystems that relied on Inefficiencies in the system, such as the Salton Sea relying on essentially additional water or water flowing from those fields, as those fields become more and more efficient, less and less water flows to the Salton Sea.

So the big question then is, as we implement additional efficiency throughout the system, how do we address these third-party impacts, these impacts not just to the ecosystem, but as we’re learning now, to public health, as these water bodies shrink and more dust as emitted, who’s going to be responsible and how are they going to take action and how can we ensure that those actions occur on a timely basis?

Eileen Wray-McCann: That’s a really interesting thing to think about. When you’re describing what’s happening with the Salton Sea, I think of, for example, the Murray Darling River Basin, where you have a situation of starvation of the ecosystem, because it’s essentially been living off scraps, right? Nobody has designated a certain amount of water as necessary to sustain the system. It’s been invisible, maybe unmeasured, unmeasurable without a lot of effort. Are there any thoughts to reconfiguring the allocation to supply the ecosystem?

Michael Cohen: The broader questions of water rights for ecosystems or public trust benefits, tends to be a pretty sticky conversation. I think one of the real benefits at the Salton Sea is that even with the dramatic less water flowing into it, even if IID were to become considerably more efficient or use much less water to grow the same amount of crops or keep the same amount of land irrigated, you could still spread out the water that flows into the Salton Sea and generate or try to match the amount of habitat that we saw 15 and 20 years ago. So there’s a way to really optimize the runoff that flows into the Salton Sea and maximize habitat benefits and minimize public health impacts. So there is an opportunity there to use less water to become more efficient and still provide those ecosystem and public health protections.

But there is this broader question, as you’re mentioning, about minimum flows, or to flip that around a little bit, some of the unintended or the third-party impacts of water relocation. So, oftentimes we hear that the solution to problems in the West is simply to look towards the water markets. But the challenge has been, and I think most clearly demonstrated at the Salton Sea, is that there are a lot of unintended consequences and a lot of externalities, these third-party costs, which aren’t directly captured by the agreements, the contracts, between the different water parties. So how do those costs get captured and who pays for that? Whether directly by the water agencies themselves or the taxpayers of California, or in the case of the Salton Sea to date, the people living in the region who are dealing with additional public health impacts? Asthma, missing work days, caring for sick family members. Those kinds of costs have not been captured and in fact are being felt most directly by the people in the region.

Eileen Wray-McCann: This is very, very complex, and in a world that is increasingly made more uncertain by things like climate change. We know that there are a number of policies and plans that have been proposed. Could you talk a little bit about the State of California’s approach to what might work for the Salton Sea?

Michael Cohen:  Sure. So, the State of California about two years ago came out with what they’re calling the 10 year plan, and that involves the construction of some 15 000 acres of habitat and an equivalent amount of dust control projects at the Salton Sea within the next 10 years, by 2028. The dust control projects we know work because the Imperial Irrigation District has been building them for the past several years as a separate but related effort. And those essentially involve, in many ways, stopping the sand that the wind blows across the playa, across the Salton Sea lake bed, from kicking up dust. So by capturing those sand particles, you help reduce the amount of dust produced by this lake bed. And essentially that’s just plowing ground with very deep furrows, which captures those sand particles, so that’s pretty straightforward.

The habitat, it turns out, is actually pretty straightforward as well. And the idea there is to capture the drainage flowing into the Salton Sea and spreading that water out before it actually mixes with the remnant body of water, with what’s increasingly becoming a brine pool. So by capturing that water and spreading it out higher or above the elevation of the remnant Salton Sea, you can create a lot of really good habitat for birds. And we know that’s the case because from 2006 to 2010 the US Bureau of Reclamation and the US Geological Survey built a 100 acre pilot project that saw more than 200 different species of birds, including white and brown pelicans, cormorants and a variety of other birds, in very large numbers, using those ponds. And as well, when they drained the ponds in 2010, there were 1,000, 000 desert pupfish, a listed species, in those ponds, even though they were trying to keep the fish out.

So that’s the general idea, is essentially you push up some of the dirt, you create these berms or dikes, which is what people see at South San Diego Bay or South San Francisco Bay, a series of these habitat cells, which capture the water, spread it out. Which also provides the additional benefit of completely eliminating any dust that would otherwise flow off that now flooded habitat, so that’s pretty straightforward.

And then there’s an idea to build a deeper body of water at the north end of the Salton Sea, supported by the whitewater river, which has better water quality. And then you could have more fish habitat as well as a recreational area. So the idea is to build some habitat cells, primarily down in the south end and then this larger north lake up in the Coachella Valley.

Eileen Wray-McCann: Well that sounds promising. What’s the outlook for continuing that sort of thing? Or in some cases initiating that sort of thing?

Michael Cohen: So the State of California, in the next couple of weeks or so, is supposed to have a design build contract, request for proposals out to various design firms that should be awarded by early next year. And then the idea is that construction on some 3 700 acres of habitat cells will begin towards the late-summer, early-fall of next year. And then at the north end they’re continuing to develop plans for that larger deeper lake project.

So there’s some funding to get those projects started. Additional funding will be needed from the voters or the general fund in California, but certainly enough money to get started on those projects.

Eileen Wray-McCann: Mike, I really do appreciate the insights from your many years of work on the Salton Sea, and we, many of us, will be watching to see how the latest strategies play out and what lessons they offer us for the bigger picture. So thank you so much for being here.

Michael Cohen:  Thanks very much for highlighting the Salton Sea, appreciate it.

Eileen Wray-McCann: That was Michael Cohen, senior researcher at the Pacific Institute, whose work you’ll find at And this is Eileen Wray-McCann for Speaking of Water, from Circle of Blue, where water speaks. You can share this interview and find more water news and analysis Thanks for listening.