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Pulse flow feeds more than the dry Colorado River delta 

If Boulder Creek dried up, and the bridge on Broadway spanned nothing but an empty stretch of sand, and it stayed that way for decades, eventually people would forget what it had meant to see a stream running there. To have place to put feet in the water, a green bank on which to sit, a surge to seed the cottonwoods and willows downstream, an exhale from the mountains when the snow unpacks itself into melt water each spring.

That’s the way it has been in San Luis Rio Colorado — a city in Mexico of about 160,000 people named for the Colorado River that hasn’t seen a consistently wet riverbed since the 1960s. In March, the Morelos Dam near the U.S.-Mexico border made a unique and deliberate release of water. The so-called pulse flow was .7 percent of the annual flow of the Colorado River — a fractional imitation of the spring runoff floods the river saw for eons — but for a few weeks, it brought water back to a river city without a river.

The people threw a party. 

“People really turned out for it, I think because they knew it was being sent there deliberately to see the good that it could do, and also because it hadn’t flowed like that for a long time,” says Jennifer Pitt, with the Environmental Defense Fund, one of the parties instrumental in orchestrating the bi-national agreement between Mexico and the U.S. to allow for this flow of water.

“We’re talking about a bed of the river about 200 feet from bank to bank, the bed of the river is virtually just sand, and it has been like that since 1960, with some exceptions of water coming down maybe four times. But from 1960 to now … the Colorado river has been 16 inches wide and 6 inches deep, and you have three generations of people, that’s what they’ve had since 1960, a river that’s 16 inches wide and 6 inches deep, then suddenly you have a river that’s 200 feet wide and 16 feet deep,” says Jorge Figueroa of Western Resource Advocates, who went down to document the pulse flow. Before the water came, people went to the riverbed to use drugs and drink alcohol, run motorcross bikes and jeeps.

“The river literally flushed that out, and brought this wholesome, healthy experience,” Figueroa says.

Pitt was there for two weeks to watch as children who had never seen the Colorado River running through their town were brought out to see it, and elders who remembered the river before it began to shrivel up and dry out in the 1960s were brought to see it and remember that past. A month later, photos showed that there were taco stands, live music and a ferris wheel alongside the river, and boats floating in it. They were still celebrating its return.

“When I was down there for that pulse flow, the song that kept going through my head was, ‘You don’t know what you got ’til it’s gone,’ but in some ways, when something’s gone for a really long time, and you get decades into it, people kind of get used to the absence. Like, the kids had no memory of a river,” Pitt says. “But then, if it reappears for a moment, you get this glimpse of what could be. I think a lot of people got a little glimmer of what a restored river could look like, and so I think it’s in that that we have a real hope for long-term progress in this area.”

Western Resource Advocates has worked on Colorado River issues for the last 15 years, beginning with dam operations and endangered species, but also now working on the water use programs designed to help cities live within their means when it comes to water. They’re often looking at the issue from the “30,000-foot level,” talking in acre feet and wrangling with policy. For this trip to Mexico, Figueroa wanted to focus on a different story — the people.

He also wanted to bring this story home to the upper Colorado River, and helped to convene a panel at the Americas Latino Eco- Festival to discuss the pulse flow and what it meant for the ecosystems and the people far down river. Speakers include himself, Pitt, the Sonoran Institute’s Colorado River Delta Program Project Manager Karen Schlatter and San Luis Rio Colorado resident Nancy Saldaña, who led a campaign to clean up the river bed before the water arrived, clearing four tons of garbage that included needles, glass and cars.

“Most people, at least in the United States, don’t see it as a river that actually goes to Mexico and reaches the Sea of Cortez, or that should reach the Sea of Cortez, so this experience for me really crystallized the fact that all Colorado River water users are an integral part of the Colorado River — from the headwaters to the Sea of Cortez, it’s our river. Our river does not stop at Morelos Dam,” Figueroa says. “This issue of grandmothers and their granddaughters enjoying their majestic river, or being deprived of such a majestic river for three generations, should resonate with all Colorado River water users, whether you’re a farmer or somebody who lives in Denver, or in Phoenix, or a federal policymaker. I think this resonates more than acre feet of water. … I would hope that the cat is out of the bag, that after this event, hopefully it’s going to be very, very hard to deprive these people of their majestic river.”

Right below the Morelos Dam at the U.S.-Mexico border, there was water most of the year from leaks in the dam, often only about three feed deep. Farther down river, more water dries up. In some areas, the river channel was completely dry all year round. In places in the middle, where groundwater and agricultural return flows are higher, standing water sits in the river bed, continuing to support habitat and wildlife in those areas. 

“It’s kind of a no-brainer for restoration as far as ecosystems go, because it is so resilient and we’re at a point right now where we can do a lot by doing a little bit. We can add water and do these very no-brainer restoration efforts and get really great ecosystem response, so we get habitat established, wildlife coming back,” says Schlatter, with the Sonoran Institute, which has led an effort to plant thousands of cottonwood and willow tree seedlings in the area and removed nonnative salt cedar to make space for native vegetation to take root.

From the city of San Luis Rio Colorado, the pulse flow of water continued on down toward the delta at the Sea of Cortez, once 2 million acres of wetlands and riparian habitat. The delta has since gone so dry and dead that it’s threatening to the endangered species, including the Yuma clapper rails, Virginia rails and California black rails, and migratory birds such as warblers and flycatchers, that rely on that vanishing thread of green.

“There were still some flows going down there, but really, over the drought over the last 10, 15 years, it got extremely dry and even the remnant habitat that was down there was beginning to disappear,” Pitt says.

This spring, for less than 24 hours, while the tide was up and that pulse of river water was reaching for its ancient home, the Colorado River touched the sea.

In 1944, the U.S. and Mexico signed a treaty on how the waters of the Colorado and Tijuana rivers were to be utilized. The treaty failed to provide a share of water for ecological protection, however.

“As with every other piece of legislation, interstate compact, treaty, et cetera, from the early 20th century, we just weren’t putting environmental management on the table in a straightforward way,” Pitt says. “And largely, my view is that that had to do with the fact that our population wasn’t as large as it is today, so we didn’t really see the limits on our resources. So it wasn’t until the late ’60s and early ’70s that you started to see environmental legislation both in the United States and in Mexico and really nothing that predates that era takes managing for the environment into account in an explicit way.”

Getting the river to run again took a lot of people working through a lot of issues, says Pitt. The push to get a river for the sake of a river hadn’t gone anywhere.

“It kind of became clear to us that just talking about the environment and just having the two countries and getting the attention of the level of policy and decision maker we needed to have to get an agreement could never only be about the environment. It just doesn’t rise to the priority level of them expending the effort to get there,” Pitt says.

Flexibility for future clarifications or adjustments to the 1944 treaty was built in with an ability for the International Boundary and Water Commission, the enforcement authority created by the treaty, to craft new rules, added to the treaty as minutes. The agreement for the pulse flow, written up in Minute 319 of the treaty, included clarifications on how the U.S. and Mexico would define shortages and surpluses and a provision to allow Mexico to store water in U.S. reservoirs — increased clarity to help water managers plan for the future, and a commitment to binationally share in water conservation and perhaps even water generation projects, including a possible de-salination plant off the Pacific coast of Mexico.

The water for the pulse itself came from a project the U.S. funded with $22 million to line an irrigation ditch in Mexico, decreasing water loss there.

Essentially, Pitt says, the science team was “handed a bucket of water” and told to pour it out how they thought best. The team included scientists from both countries, and one who had worked on the experimental flow program in the Grand Canyon. The advice from that scientist was clear: Whatever you design, it isn’t going to be right. His suggestion was to deliver the water in a way that the signal of what the water was doing would be clear.

“Ecosystems, rivers, are a real landscape, it’s not like a lab experiment where you can tightly control all the variables,” Pitt says. “We believe this pulse flow will have done some good at the end of the day and we also believe we’re going to learn a ton from it and the conservation community is definitely going to be working hard to make sure we get an opportunity to do another pulse flow in the future, to make sure there is more water committed to the area and hopefully we’ll do it next time with the hindsight of this pulse flow and do it better.”

There’s precedent to suggest that the results will be positive. In the 1980s and ’90s, flood events brought water to areas of the delta that had been dry for decades.

“Everyone had kind of given up the delta for dead, like a dead ecosystem that had been desecrated and degraded, but after these flows, a lot of the vegetation was able to come back, so that demonstrated to the conservation community and scientists that this is a pretty resilient ecosystem that can withstand long periods of no flows, little flows, and then boom, you have water and the vegetation can make a comeback,” Schlatter says. “That’s what sparked the idea to dedicate environmental flows to the region with the notion that even a little bit of water in this area can really make a difference and bring back a lot of habitat.”

Figueroa visited a restoration site the size of 15 football fields where trees have grown to 10 or 15 feet in height three years after they were planted.

“The people working on the restoration sites have shown that if you have the capacity, the knowledge and the resources and especially the water to do restoration, you can have a huge, significant impact and you can do it fast,” Figueroa says. “The beauty of the pulse flow was that you had this extraordinary response from the ecosystem with just a little bit of water.”

In the Sonoran Institute’s restoration efforts in riparian habitat, removing nonnative species like salt cedar and replanting native ones, the saplings are irrigated for two or three years, and then have root systems deep enough to tap into the groundwater. The area has a level of groundwater favorable to restoration efforts that’s fed by agricultural return flows, and Minute 319 also allows for base flows into the Colorado River in Mexico to support those efforts.

“It is resilient, but it does need water, so without any intervention at all, there’s resilience up to a certain point, and if we keep taking water from the system, the river system never sees water again, it will eventually collapse and the invasive species that have already established there will become too dominant for native species to reestablish if there were ever flows in the future,” Schlatter says. “So I think the pulse flow came at a really critical time in this ecosystem’s trajectory where going too much longer with these flood flows is kind of a dangerous thing because you’re never sure how long is too long and when having a flood flow actually won’t be enough to restore the system because it’s lost its resiliency, so it does require intervention at some point.”

The pulse this year was intended to stimulate the germination of native vegetation — cottonwoods and willows require flood conditions to germinate, and the pulse, on a very small scale, simulated the kind of floods that used to hit that region each year.

“When some of the scientists who really brought up the idea that a pulse flow could do some real good for the delta’s ecosystem, the original speculation was that having that kind of a pulse flow every few years would probably be enough, because it’s the creation of cottonwood and willow habitat that’s critical, when you get the water up over the river’s banks, you create that disturbance that can cause those seedlings to grow. You don’t need to have that happen every year, but you do need a little bit of water provided year round, all the time, so that seedlings can continue to grow,” Pitt says. “Historically certainly it happened every year, but given that we’re fighting the uphill battle for getting just a little bit of water into this ecosystem, the thought is that every few years would work, every four or so, on average. So there is a need for some year round water to keep the roots wet, and in some places there’s adequate groundwater to do that already.”

Work to secure that year-round water has been done by the Colorado River Delta Trust, a private trust established by the Mexico-based conservation group Pronatura Noroeste, which, in addition to the Environmental Defense Fund and the Sonoran Institute, has been buying up water rights to make sure there’s a little bit of water in the river to sustain what the intermittent pulse flows, assuming they’re approved again, create.

The delta now has just a small remnant of a river left, but the big drink of water it just had is producing green up and down the river. An intensive monitoring effort undertaken by federal agencies from both countries as well as academics and nonprofits is scrutinizing details down to counting seedlings and wildlife, and should start producing numbers to quantify the effort in the coming years. It’s tough to know now, Pitt says, where things like the groundwater saw a recharge while the effects of this one-time pulse flow are still being studied.

When the five-year agreement that Mexico and the U.S. have settled on runs out at the end of 2017, they’ll be back to the drawing board and making a decision on whether to allocate water for this kind of water event again.

Signs point toward a momentum and support building for it, Pitt says, and the agreement has drawn some attention from the international community as an example of the kind of collaborative work countries can undertake to help preserve endangered transboundary rivers around the world.

“It gives me hope that we can manage our way through this and end up with the West that we want with limited water resources,” Pitt says. “That idea that the community responded and that there’s a path forward for them to take a role in stewardship of the Colorado River is a really exciting premise, and really shows a lot of promise, but clearly is dependent on this whole broader suite of governance issues. … I’d say the other community response has come from water managers, I mean, they kind of created the story, they created the pulse flow, but that sense that while the Colorado River basin in many ways is in a pretty urgent situation right now in terms of extended drought and allocation and use that exceeds our long-term supply, a sense that with our sleeves rolled up and good collaborative effort and instinct, that we can see our way to careful management that supports all the values that we want from the river, including the environment, and I’ll project a lot of stuff onto this, but including viable rural economies and thriving cities, all of which use water from the Colorado.”

The Raise the River campaign is organizing an ongoing effort to help ensure a future for the river. That campaign needs to raise $10 million by 2017 to fulfill their portion of the commitment for Minute 319 and pur chase water rights to support river restoration through the Colorado River Delta Trust. The still-in-development Colorado Water Plan also has fingers that reach to that delta, and adopting a plan that advocates for conservation is going to be key to keeping water in that delta despite a growing gap between supply and demand on the Front Range of Colorado.

“I don’t think it’s ever going to be that the full flow of the Colorado River is down there, which is what it was in the early 20th century. There’s 40 million people depending on that river, 4 million acres of farm land, 15 percent of U.S. ag produce — it’s just too big,” Pitt says. “But I do think there’s hope that the basic connectivity could be reestablished between the river that flows in the U.S. and the upper gulf, at least on a periodic basis. Not necessarily on a regular basis. But connectivity, a corridor, a ribbon of green that’s so important for the birds and for the people to see that there’s a natural area in their midst, not just a sandy desert.”

Respond: letters@boulderweekly.com

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