The Colorado River Delta Pulse Flow: 1 year later

Director, Environmental Flows Program, The Nature Conservancy

Director, Environmental Flows Program, The Nature Conservancy

  By: Eloise Kendy

Water creeping, then pouring, then flowing into bone-dry sand until the desiccated channel transformed into a bona-fide river once again. Children splashing and kayakers paddling in a river they had never seen before—a celebration of a river reborn. These are the images I recall from a year ago, when I travelled along this road, just south of the U.S. / Mexico border.

These amazing memories came rushing back recently as I traveled once again to the path of the historic March 23, 2014, pulse flow. The pulse flow was an experimental release of water designed to mimic spring runoffs and rejuvenate the dry Colorado River Delta. Of course, I was anxious to see the changes the “pulse of life” had brought forth.

The release of Colorado River water back into its parched Delta was a shining star of cooperation for the environment. Discover Magazine and the US Department of Interior are among those hailing the event as a top achievement of 2014.

By all accounts, the pulse flow’s most important outcome is that it actually happened. For so long, the forces against it seemed overwhelming. In fact, the Raise the River Coalition – The Nature Conservancy, Environmental Defense Fund, Sonoran Institute, Redford Center, Pronatura Noereste, and the National Fish and Wildlife Foundation – negotiated on behalf of nature with the U.S. and Mexican governments for more than a decade before an agreement was reached to release water to restore the Delta!

With western water such a scarce commodity and so many entities drawing water from the Colorado River, any change to status quo water management was met with fear and suspicion. It took an earthquake, which destroyed canals bringing the water to Mexican farms, to get both nations to agree to retain enough of Mexico’s foregone water allotment in Lake Mead to enable the pulse flow to happen.

By temporarily storing water at Lake Mead, more than 105,000 acre-feet of water (equal to 34 billion gallons) was released in one large pulse between March 23 and May 18, 2014. Even though that’s less than 0.1% of the annual water allocated to the seven U.S. states and Republic of Mexico for consumptive uses, it is a lot of water – and represents the first-ever international flow restoration agreement. Since it came as such a big surge over such a short time, the river channel was inundated. Cottonwood and willow seeds floated in the air, perfectly timed for this opportunistic watering. To everyone’s surprise and delight, the pulse flow temporarily connected the river with the Gulf of California – something that hadn’t happened in decades.

I’ve been part of a bi-national science team monitoring the effects the water had on the river environment. Science, photos and anecdotes are painting a clear picture – one year later.

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In terms of restoration, everything we expected to happen, happened. We expected native willows and cottonwoods to germinate wherever the pulse flow inundated bare soil, and that happened. A natural flood would have scoured out old vegetation, leaving fresh surfaces for new seedlings to germinate. We knew the pulse flow was too small to do that critical scouring work. As a result, native plants germinated primarily on surfaces that were recently cleared, mostly in restoration areas along the river’s path.

We also expected the new seedlings to survive where they received supplemental water through the summer. That happened too. The supplemental water, officially called “base flow,” is water that’s purchased from willing Mexican farmers by the Colorado Delta Water Trust, in partnership with the Raise the River coalition.

We also discovered new seedlings did not survive where they didn’t get water through the summer. We expected that, but secretly hoped we would be wrong.

Base flow water is limited, so it is strategically delivered only to places where the groundwater table is high enough for new growth eventually to become self-sustaining. In one area, willows that germinated during the pulse flow were already well over our heads just six months later! (See photo, below.) This confirmed our theory that a pulse flow is only one of several critical ingredients – scouring, seeds, and sustained access to water — for establishing new streamside habitat.

willows

Gooding’s willows in Laguna Grande restoration area. Photo: Karen Schlatter, Sonoran Institute.

We also observed how the pulse flow benefitted existing vegetation in the Delta, well beyond designated restoration sites. In fact, there was a 43-percent increase in green vegetation in places the pulse flow inundated, and a 23-percent increase in the broader riparian area.

Bi-national negotiations for another agreement will be beginning soon. Our goal is to restore more river reaches until, over time, we fulfill our long-term vision of well-connected, self-sustaining streamside habitat that supports diverse local and migratory birds in the Delta. To that end, the bi-national science team will continue to monitor hydrology, vegetation, and wildlife through 2017 to inform the design of future pulse flows.

As a scientist who cares deeply about the environment, it’s hard to put into words what it means to be part of this successful and historic experiment.

Eloise Kendy is a member of the bi-national science team that designed the Delta Pulse Flow and monitoring program, and is the Director of the Environmental Flows Program, The Nature Conservancy.

Upcoming WATERSHED Screenings

Join us at one of the upcoming screenings of the film WATERSHED, which tells the story of the threats to the Colorado River and offers solutions and hope for the future of the American West.

Since Watershed’s release in 2012, it has aired on PIVOT tv, screened in 12 countries, and in over 500 community settings, and has been selected for 52 film festivals, winning numerous awards. It provided the inspiration for launching the Raise the River campaign and continues to play a significant role in engaging support to restore the Colorado River’s delta corridor.

Upcoming

Stay up to date with screening at the WATERSHED website.

Part 4: Farmers Benefit from the Return of the River

This is the fourth blog in a 5-part series on the Colorado River pulse flow, written by Cesar Angulo, an environmental journalist in Mexico, and commissioned by Environmental Defense Fund. Read Parts 1, 2 and 3.

In the last stretch before reaching the Gulf of California, the Colorado River divides two of the most productive agricultural valleys of Northwestern Mexico: the San Luis Valley on the left bank and the Mexicali Valley on the right bank.

These valleys have nutrient rich soil resulting from the transportation of sediments to the low lands that were formerly flooded by the Colorado River, which together with the diverted river water for irrigation has led to a rich agricultural region that is central to the local economy.

Farmers and water managers in this region understand that the pulse flow will bring direct and positive benefits to the agricultural sector.

José Fidencio Gonzalez Arroyo is the chairman of Irrigation Module No. 22 in the San Luis Valley, an extensive agricultural area that has served the region since the early part of the last century, producing wheat, cotton and vegetables. It also has thousands of acres of date palm plantations.

Arroyo Gonzalez is a native farmer in this valley and remembers the last major flood of the Colorado River decades ago. Since then, the volume of water running freely in the delta has been reduced to nothing.

Due to the lack of water in the lower Colorado River, Arroyo Gonzalez says, the vegetation and riparian ecosystem has suffered.

But in recent years, a new partnership has been developed among farmers, water managers, and conservation groups to restore the the delta ecosystem.

Arroyo Gonzalez explains that his irrigation module is responsible for providing water for restoration projects that have irrigation rights, such as the Laguna Grande project and the CILA site, where thousands of trees have been planted with the purpose of ecological restoration.

According to Arroyo Gonzalez, these reforestation projects have a very positive effect on agricultural areas by helping to reduce high temperatures, as well as recharging aquifers used by the agricultural sector. However, he recognizes that there is still a lack of information among farmers about the restoration projects and their extended benefits on the farming community.

There is even some doubt among farmers about where the water for the pulse flow comes from, and if it is the best use of water, especially since the demand for water in the region is so high. Some believe that the first priority should be to irrigate land to produce food, and deliveries for ecological purposes should be secondary.

Alfonso Rubio Russel is another irrigation chariman in the San Luis agricultural valley. He said that one of the main purposes of the pulse flow and accompanying base flow is to help recharge aquifers which in turn will promote the extraction of water in deep wells for agricultural use.

The pulse flow, he stressed, will help to create microclimates in areas near the river and will benefit the vegetation, even if only temporarily.

“The pulse flow is a good idea, but it will hardly restore a river that has suffered a lack of water for years,” he said.

Chairman Russel said that it is precisely because of the ever-increasing demand for water that we must take care of it.

“We would like to see the Colorado River as it was before,” he said. But to do that, “we must be in harmony with nature.”

“When it comes to water, there is rarely consensus among agencies, municipalities and environmentalists. Agreement among multiple states and nations? That’s just not something that happens.

Until it does.”

Read more about Minute 319’s major successs in the Las Vegas Review-Journal.

Part 3: Water Restores Ecosystems and Benefits Communities

This is the third blog in a 5-part series on the Colorado River pulse flow, written by Cesar Angulo, an environmental journalist in Mexico, and commissioned by Environmental Defense Fund. Read Parts 1 and 2.

The pulse flow that has brought water to a thirsty Colorado River Delta will allow the regeneration and restoration of the spacious riparian areas along the banks of the river, where communities and organizations have come together to restore vegetation and wildlife habitat that once existed.

Two of the most important restoration sites are Laguna Grande, located near the end of the agricultural areas of the San Luis and Mexicali valleys, and Miguel Aleman – the limitrophe on the right bank of the river in the North Valley of Mexicali.

Both sites are the product of the union and effort of civil societies, academia and the governments of the United States and Mexico, who have obtained federal land grants and water rights that will allow the creation and regeneration of native forests and species.

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Guadalupe Fonseca Molina shows trees that have matured at Laguna Grande

Guadalupe Fonseca Molina is the site coordinator for Laguna Grande, a project lead by Sonoran Institute since 2006 that works to reestablish new poplar and willow forests in the floodplains of the lower Colorado River.

The pulse flow has directly impacted this site, as water entered into Laguna Grande through channels built to connect with the Colorado River. In recent weeks, seeds have been spread in the hope that they will germinate and grow by the river channel as a result of the new flowing water.

image [Dredged channels bring water from the pulse flow to the restoration sites]

Fonseca commented that a lot of work as been put into this project to counter the advance of salt cedar (Tamarix aphylla), an invasive tree species that has imposed on the native vegetation and has become a pest throughout the lower basin.

The biologist responsible for the scientific monitoring of the Laguna Grande site, Tomás Rivas, said that poplar and willow forests used to grow naturally in wide areas along the Colorado River Delta, generating a riparian corridor with abundant wildlife. Through restoration, Tomás seeks to help restore some of these areas and connect some green patches of forest along delta.

The Miguel Aleman project, coordinated by Pronatura Noroeste, was born six years ago. It aims to restore woodlands that were destroyed by the lack of water in delta.

Salvador Chavez Alacaráz, restoration project coordinator for Pronatura Noroeste, said that the first years were focused on the production of test trees such as poplars, willows and mesquites.Subsequently, the focus shifted to the creation of nurseries for mass production of these trees.

image [Salvador Chavez Alacaráz oversees tree nurseries at Miguel Aleman]

This year, Pronatura Noroeste staff are ready to reforest 35 hectares (90 acres) and ensure good growth with an irrigation system that brings water from a canal intended for agricultural use. In the next three years, the objective is to reforest 90 hectares with mesquite, poplar and willow tress, which used to cover the areas bordering the Colorado River.

“Now, we expect the pulse flow to recharge the aquifer and provide moisture to the subsoil where the trees have been planted,” said Chavez Alacaráz.

He mentioned that Pronatura Noroeste managed to get a grant of 450 acres of federal land surrounding the bed of the Colorado River, in which it intends to implement ecological restoration projects. These projects will have direct benefits to the environment, and thanks to water brought by the pulse flow, the ecosystem will naturally be restored.

Meanwhile, Hector Patiño Garduño, restoration technician for Pronatura Noroeste and resident of Ejido Janitzio, recalls when he came to live in Ejido Janitzio about three decades ago. He remembers the Colorado River regularly bringing water to the area and settlers from Mexicali Valley would fish in the river.

“We have been waiting for the pulse flow for over a year now. We are hoping for positive impacts – the recharge of the aquifer and the restoration of wildlife that used to exist in the river,” he said.

Patiño Garduño thinks that the water in the river will help bring back the balance, since “lately, coyotes have been coming to our houses and trying to hunt our chickens. With the water, they will hopefully have more food to hunt by the river.”

He added that these restoration projects, besides helping families living in the surrounding towns of the Colorado River, will also generate jobs and keep people employed and living in Mexico, rather than moving elsewhere.

“As a community, we don’t want the pulse flow to end. The river is a necessity of the environment and communities,” he concluded.