Colorado River pulse flow at the Laguna CILA environmental restoration site. Picture by Tomás Rivas of the Sonoran Institute, used with permission

Folks on the Colorado River delta “pulse flow” science monitoring team sent around a few pictures yesterday taken by the Sonoran Institute’s  Tomás Rivas of the water arriving at the Laguna CILA environmental restoration site. The beauty of this picture for me, beyond the obvious sight of water in a formerly dry delta river channel, is that despite taking a site tour two weeks ago, I don’t recognize the spot where the picture was taken. Water changes everything. Here’s one of my pictures from our tour.

Scientists and journalists tour Laguna Cori restoration site in the Mexican Colorado River Delta, which awaits its first flows. March 27, 2014, by John Fleck

Imagine that now filled with water!

As I’ve written previously, Laguna CILA is one of the restoration sites that takes advantage of the high water table in stretches of the levee-pinned delta river channel to bring back native riparian vegetation. The idea here is that a pulse of “nature” in the form of water flows like this can help regenerate willows, cottonwoods and the like, which can then get their roots down into the water table and sustain themselves. Here’s how Jennifer Pitt of the Environmental Defense Fund and a group of colleagues explained it in back in 2000 (pdf), in one of the early academic papers explaining how it might work:

Annual flood events are not necessary for survival of these native tree species: they are capable of surviving at least a three-to-four-year interval between major flow events in the flood plain. Pulse flows of 260,000 acre-feet, released at a rate of 3,500-7,000 cubic-feet per second, are sufficient to inundate the Delta’s floodplain within the levees, sustain riparian corridor vegetation, and stimulate seed germination.

Much has changed since that was written. In 2000, the Colorado River’s reservoirs were mostly full, which made carving out a modest chunk of water to serve society’s environmental values seem more possible. The reservoirs are now half empty, which makes the political and policy challenge far greater. The flows in the current pulse are substantially less, but the water is now hitting sites that have been engineered to take better advantage of it.

This is fundamentally new territory. You drive across the farm fields of Mexicali and San Luis and see an agricultural technology that’s been optimized over a century to grow the most food and fiber with the least inputs. This thing that we’re seeing, in essence farming nature, is a new gig. Much study yet to come….

Ultimately, what’s going on down in the Colorado River right now turns on a complicated mix of politics and science. The politics involves how much support advocates can gain for environmental restoration of the troubled system, on both sides of the border. The science supports those decisions After the rush of excitement about the historic release of a small environmental “pulse flow” into the Colorado River delta, most of the reporters (including, sadly, me) are gone, and the scientists are getting down to their work.

As of yesterday, the water had reached past a major dry stretch, and was approaching the crucial Laguna restoration sites, according to an email last night from one of the project scientists.

Sandra Postel, who thankfully has remained has a nice look at the scientists getting down to the science:

On Wednesday this past week, when the advancing Colorado River met up with the higher water table of Reach 4, delta scientists breathed a sigh of relief.

“It was very exciting to see the leading edge get connected to Reach 4,” said Osvel Hinojosa Huerta, a wetlands ecologist and bird specialist with the Mexican conservation organization Pronatura Noroeste. Hinojosa has been working in the delta since 1998.

The swallows and cinnamon teals were not here this morning, Hinojosa said, standing near the location where the flowing river met the channel filled with groundwater. “They came after the water arrived.”

“We’ll be tracking birds very carefully,” Hinojosa added. “They are good indicators of system health.”

Hinojosa and his colleagues were doing this work from the moment the release started. In the first days of the release, as the water was making its way past the groundwater “hole” near the San Luis Bridge, I caught up with him after the group had just completed a bird survey: wigeons, cinamon teal, blue-winged teal, ruddy ducks, lesser scaup along with coopers and sharp-shinned hawks following the water (and their lunch) downstream). They even say coots, which had lost their happy shallow home in the pool immediately behind Morelos Dam, riding the pulse flow down on cattail rafts. And carp “this big”, he said, his hands held apart fisherman-style to indicate a very large fish floating through a previously uninhabitable desert.

Osvel Hinojosa (second from right, in broad-brimmed hat) and crew as the pulse flow approaches San Luis, March 25, 2014, photo by John Fleck

Colorado Basin groundwater declines, courtesy Chris Austin

New data from NASA’s GRACE satellite, which scientists use to track changes in groundwater storage, shows some remarkable declines in the Colorado River Basin, according to a recent presentation by Jay Famiglietti of UC Irvine to a California legislative committee (huge thanks to Chris Austin for catching this and bringing it to my attention):

“Unfortunately, looking beyond our borders isn’t going to help – just like in California, the Colorado River basin is in long term decline,” Mr. Famiglietti said, presenting a slide showing the total water storage for the Colorado River basin. “When we separate the surface water storage in Lake Powell and Lake Mead and the groundwater storage, we get the graph on the bottom, which is showing us what’s happening. With Lake Powell and Lake Mead’s storage, not much of a trend albeit there’s a recent decline, but the important thing to recognize here is that the groundwater losses from the Colorado River Basin in this time period completely swamped the losses and dominated the total water storage change. They are far bigger than the surface water changes. The message is that we pay all this attention to surface water management, and while no one’s watching, the groundwater is being depleted at a rapid clip.”

The Havasu News-Herald, which serves Lake Havasu City along the Colorado River, assured its readers today that the environmental pulse flow, which is passing through on its way from Hoover Dam to the Colorado River delta, shouldn’t have an impact on Lake Havasu recreational boating:

Lake Havasu will remain at normal water levels during the next six and a half weeks as the Minute 3:19 Pulse Flow brings water to the once-parched Colorado River Delta in Mexico, according to Bureau of Reclamation Water Resources Specialist Aaron Marshall.

Marshall said normal water levels at Lake Havasu approximately range between 445 feet and 449 feet above sea level. As of Thursday, the lake’s water level was at about 447.5 feet, which is about a foot less than a week ago.

“Fluctuations of a few feet are normal for our operations in Lake Havasu,” Marshall said. “The pulse flow will not have any effect on the lake’s elevation changes.”

 

The U.S. Bureau of Reclamation sent around this updated map this afternoon on the progress of the Colorado River delta pulse flow (apologies for large file size, trying to offer up the highest resolution I can):

Updated Pulse Flow map as of 4/3/2013, courtesy USBR