Water is flowing again in the Mexican dry delta of the Colorado River

Water is flowing again in the Mexican dry delta of the Colorado River

Next to the canal, which runs through farmland, flowing water roared through the irrigation gate and trickled through a concrete culvert to a wetland lined with poplars and willows.

For decades, so much water was drained to supply farms and cities that the Colorado River rarely encountered the sea, and much of its delta in Mexico was reduced to a dry riverbed, of which only small remnants of once vast wetlands survived.

Over the past eight weeks, water in parts of the delta has flowed again, restoring a stretch of river in Mexico where there were miles of desert sand before.

Water is discharged from an irrigation canal to help the arid delta environment under an agreement between the Mexican and American governments and with the support of environmental groups. Those involved are saying that while severe droughts and global warming are affecting the Colorado River, the initiative shows how small amounts of water can be used to benefit ecosystems that are struggling.

Water is released from the irrigation canal into a section of the Colorado River Delta in Baja California, Mexico. The streams, which began in May, have reached parts of the delta that are normally dry.

(Luis Sinco / Los Angeles Times)

“The river has been almost dead for so many years. And right now is a historic moment. We connect the river, “said Gaby González Olimón, coordinator of environmental education for the Sonoran Institute, one of six groups in the coalition called Raise the River.

She stood and watched the swirling wild water cascade down the culvert toward the wetland.

This site, a habitat restoration area called El Chausse, is located in the southern part of the delta, downstream from long stretches of arid riverbed, and has been selected as a place where limited water leakage would strengthen the ecosystem by nourishing vegetation and expanding habitats. wild animals. It is one of the few places in Mexico where conservationists are restoring wetlands and forests along the way the river once flowed.

Six years ago, on-site workers removed the invading tamarisks and planted a forest of native poplars, willows and mesquites. These trees grew rapidly and now cover the wetland in the shade and attract various birds such as yellow warblers, blue-gray mosquitoes and vermilion flycatchers.

Eduardo Blancas, restoration coordinator for Restauremos El Colorado, kayaked and paddled in a pond by the forest.

Colorado River Restoration

“The ecosystem has deteriorated due to water shortages. So this whole process is going on and at the same time it brings benefits for the environment, “said Blancas. “These ecosystems will provide habitat for wildlife.”

This is the second consecutive year of water discharges in Mexico. As water flowed through parts of the delta last year, the plants released seeds that settled along the banks.

Blancas and his colleagues saw vegetation flourish along the river canal. About 120 species of birds have been recorded in the area.

“It’s an oasis in the middle of the desert,” Blancas said.

The discharges, which began on May 1 and will continue until September, are timed to mimic the much larger seasonal floods that once filled the desert valley than the delta in the 20th century was dried up by the construction of dams in the United States.

More than a century ago, the Colorado River Delta covered an area of ​​about 2 million acres of wetlands, forests and swamps. When ecologist Aldo Leopold paced the delta in 1922, he described it as a “hundred green lagoons,” with emerald waters and huge flocks of cormorants and herons towering overhead.

Tide tentacles create a pattern in the mud of the Colorado River Delta in Mexico

Tide tentacles create a pattern in the mud of the Colorado River Delta in Baja California.

(Brian van der Brug / Los Angeles Times)

The delta Leopold had seen had long since dried up and disappeared. Instead, fields of cotton, wheat, hay and vegetables fill the Mexicali Valley and embrace the meandering sections of the dusty riverbed.

While paddling in the wetland, Blancas pointed to trees that had grown more than 30 feet in five years. He said the forest was a nature-based solution that could help address the climate crisis.

“These places are big carbon sinks,” Blancas said. And by devoting a small amount of water to them, he said, the effort “contributes our grains of sand in these places to reduce the effects of climate change.”

In April, a wildlife camera captured a video of a beaver gnawing a tree until it collapsed in the El Chausse habitat restoration area of ​​the Colorado River Delta in Mexico. (El Colorado Restaurants)

Recently, Blancas and his team saw beavers eroding tree trunks and building dikes. The motion-activated wildlife cameras captured night images of beavers swimming and climbing. One bit into the poplar until it overturned.

Over the past decade, Mexican and American conservationists have made progress in providing water for three regenerated areas in the upper, middle and lower deltas, where they irrigate trees and maintain wetlands and form green islands in the desert.

These efforts represent a dramatic change since decades ago, when the river was completely depleted and there was almost no water left in the delta for nature.

The river was divided among seven U.S. states starting in the 1922 Colorado River Compact. Mexico secured its share of the water, 1.5 million acres-feet per year, under a 1944 contract.

When the last part of the river reaches the American-Mexican border, it pushes against the Morelos Dam and almost all the water is drained to the Reforma Canal, which brings water to farms and towns from the Mexicali Valley to the Pacific coast.

To the south of the dam, the remains of the river in the desert disappear.

The Mexican and American governments, encouraged by conservation groups, have begun allocating some water to the environment.

In the largest such experiment in 2014, a rush of water was released through the gates of the Morelos dam. The “pulse flow” was 105,000 acres and brought back the flowing river for eight weeks, with the water flowing into the Gulf of California.

Later, under a 2017 pact called Minute 323, Mexico and the United States agreed to spread minor discharges over several years. Each government agreed to contribute a third of the water, while environmental NGOs pledged to secure the rest.

About 35,000 acres flowed through the delta last year, and a similar volume is discharged this year – representing less than 1% of Los Angeles’ total annual water consumption.

The US-Mexico agreement calls for more water discharges by 2026.

The rocks cast long shadows across a dry salt marsh at the southern end of the Colorado River Delta in Mexico.

The rocks cast long shadows across a dry salt marsh at the southern end of the Colorado River Delta in Mexico.

(Luis Sinco / Los Angeles Times)

At the same time, the Colorado River is in increasing demand. After more than two decades of extreme drought exacerbated by climate change, reservoirs have fallen to record lows, and U.S. officials have told seven states that are taking supplies from the river to draw up plans to drastically reduce water consumption.

Mexican farmers have already seen a reduction in water rations of almost 5% this year and more cuts are likely to be needed to cope with water shortages.

The collapse of the river has raised concerns among some of those leading the recovery effort. They fear that if the crisis is not managed effectively, it could jeopardize progress in the delta.

“Anything that is dependent on water and has no right to water is at risk,” said Jennifer Pitt, director of the Colorado River National Audubon Society.

Pitt said she understood the unprecedented water constraints would be difficult, but hoped the US and Mexico could continue to work together so that “an environment that uses so little water can continue to be part of the solution.”

This month, water flowed from the canal through three irrigation gates, filling the river canal and continuing toward the Gulf of California.

Downstream of the launch sites, González and her colleagues parked their pickup at the newly created pond.

The calm water reflected the sky like a mirror. Red-winged blackbirds sang, and pairs of scarlet dragonflies circled over the water.

Sonora scientists show fish caught during a survey at the mouth of the Colorado Delta in Mexico.

Sonora scientists show fish caught during a survey at the mouth of the Colorado Delta in Mexico.

(Luis Sinco / Los Angeles Times)

A dragonfly sticks to wild grass in the Colorado River Delta in Mexico.

A dragonfly sticks to wild grass in the Colorado River Delta in Mexico.

(Luis Sinco / Los Angeles Times)

“Water definitely changes the ecosystem a lot. This place was a very large sand bed a few weeks ago, “said González. “You can see the whole ecosystem coming to life.”

While a complete restoration would be impossible, places in the aquatic environment can bring great environmental benefits.

“We are building this green corridor,” she said, “connecting the river and the estuary.”

González said she was also happy to see families enjoying the place on the weekends, their children wading in the water and experiencing their first contact with the Colorado River.

The long-standing connection with the river is reflected in the local culture. The people of Mexicali proudly call themselves “cachanillas”, according to the hardy arrow plant that blooms by the water and which the first inhabitants of the area used to build shacks.

Drainage of the delta has changed the lives of people living along the river, including the natives of Cucapá (or Cocopah), who have traditionally depended on fishing.

Angela Melendez said her family came from southern Mexico and moved to a modest house by the river where her grandfather fished.

Angela Melendez and Gaby González Olimón will develop maps of habitat restoration areas in the Colorado Delta.

Conservationists Angela Melendez (left) and Gaby González Olimón look at maps showing coastal habitat restoration areas in the Colorado Delta in Mexico. The discharge of water from the canal into the riverbed has reached parts of the delta that are normally dry.

(Louis Sinco)

“They had fish, all the fish they could eat, all the lobsters and shrimp they could ever eat,” Melendez said.

Melendez said her mother had told her that she would swim in the river during her childhood at the turn of the 1960s and 1970s. Once, as she swam, she was caught in a stream and swept downstream into the Cucapá community.

“I’ll bring her here because she enjoyed these places,” Melendez, standing by the pond, said. “She’ll cry like me.”

Tears welled in her eyes. She said seeing the restored river would probably take her mother to the good times of her life before the environment in the area deteriorated and dried up.

Melendez, who works as a geographic information systems coordinator, flew a drone to take pictures of the river’s return in the southern part of the delta.

Near the former estuary, desert bushes grow beside the crunchy salt plains.

At the edge of the estuary, Israel Mateo Sánchez Leyva boarded a boat to collect fish for biological research. Technician Sánchez, who deals with ecological monitoring, pulled out a trap in which small fish fluttered.

Conservationist Israel Mateo Sanchez Leyva collects fish during a survey at the mouth of the Colorado River.

Conservationist Israel Mateo Sanchez Leyva collects fish during a survey at the mouth of the Colorado River.

(Luis Sinco / Los Angeles Times)

He released a thumb-sized fish into a bucket from a metal trap. It’s a muddy delta, he said, a species that bounced off.

“It’s a great success,” Sanchez said. “We give life to the last part of the Colorado River and return the ecosystem.”

He said he noticed new spots of tules growing at the mouth, suggesting that water leaks had reduced salinity.

A team from the Sonoran Institute watched the released water as it slowly crawled down the 40-mile canal toward the sea.

Last week, during high tide, this piece of the Colorado River finally returned to the sea.

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