Photo by Stina Sieg - KJZZ

An eight-week release of water from the Morelos Dam has filled parts of the Colorado River Delta that haven't seen water in nearly two decades, like this spot about 20 miles south of the dam.

It was a sunny day at Mexico’s Morelos Dam, just west of Yuma. It was also a momentous day. Like always, the Colorado River was being diverted, rushing into canals and toward thirsty crops and cities. But some of that water was quietly continuing through the dam and into a usually barren stretch of riverbed that meanders some 70 miles to the ocean. It was the height of the first-ever pulse flow, a temporary release of water meant to rehabilitate the Colorado’s long-barren delta.

The water was quiet and slow moving, but hundreds of people had come to cheer it on. They included Deputy U.S. Secretary of the Interior Michael Connor. He called the moment "exciting."

“It also gives a sense of urgency to trying to negotiate a long-term agreement and build on this success,” Connor said. “So, we’re relishing the moment, but we want to build upon it in building this partnership with Mexico.”

That partnership will last for at least the next three years. That’s according to Minute 319, an agreement signed by the U.S. and Mexico. For the first time ever, it allows the two countries share Colorado River water — in shortage and in surplus. It also lets Mexico store some of its water in Lake Mead, which helps keep the reservoir at needed levels. And a small portion of that is being released in one big, eight-week burst. You can still see its effects 20 miles downstream.

That’s where the Nature Conservancy’s Taylor Hawes was splashing her hand in the reawakened river. Her group is one six nonprofits in the Raise the River campaign, which has an ultimate goal of seeing the Colorado reach the ocean once more. Hawes doesn’t know if that will happen during this pulse flow. But she says this particular spot hasn’t seen water in 17 years.

“And you would never know that, because it looks like a river. It’s got tons of water in it,” she said. “People are hanging out on the beaches. This is not an area normally they would be hanging out, but they’re coming to see the river be a river again.”

It really was a party atmosphere, complete with music bumping from cars and a vendor selling ice cream to the crowd. Maria Sanchez is one of the dozens who came to see the flow with her family, which included two youngsters who had never seen water here. Nina Trasoff translated for Sanchez.

“She says they asked if they could take off their shoes and play, and she said no, no, no, but then they just let them go in and play,” Trasoff said. “And how wonderful that they can enjoy this water being down here.

Trasoff is with the Sonoran Institute, another big player with Raise the River. A few miles away, over bumpy roads, her group was busy digging trenches to help the river reconnect near a spot called Laguna Grande. Workers were also digging holes to plant cottonwood and willow trees, vital to reestablishing habitats for birds and other creatures.

It’s the front line of the Colorado River’s restoration. And the Sonoran Institute’s Edith Santiago explained that all kinds of people come to see it. This particular day, that included journalists and a few politicians. Not along ago, it was a troop of Boy Scouts. Santiago especially likes it when locals stop by.

“They reconnect with the river, and then, in that case, they will take care of the area,” she said.

And it’s an area benefited by the pulse flow, which ends May 18. Right now, the Sonoran Institute and the rest of Raise the River is trying generate funds to release a small about of water into the riverbed on a continual basis.