From the Arizona Daily Star (Tony Davis):
The gulf and river connected Thursday afternoon for the first time in 16 years, due to the artificial pulse flow released into the river over the past two months.
The sensor detected that the shallow river water in that vicinity wasn’t as saline as sea water or even local agricultural irrigation runoff, said Ed Glenn, a University of Arizona soil, water and environmental science professor who has been heavily involved in monitoring the pulse flow in the Colorado River Delta that led to Thursday’s historic event.
The sensor — a small meter tied to a pole that’s anchored to the river bottom — lies just south of an area where salty irrigation runoff from the Hardy River flows into the Colorado. It’s also near a huge sandbar that the gulf’s high tides had to clear to connect with the river. This event happened at a point 17 miles upstream from the river’s mouth.
On Friday, the International Boundary and Water Commission issued a news release heralding the river’s reconnection with the sea. The commission and the U.S. and Mexican governments jointly sponsored the delta pulse flow that is releasing a total of 105,000 acre-feet of water from Morelos Dam, south of Yuma, into the delta. The pulse flow releases end Sunday.
Because of the complexity of the Colorado River system, scientists didn’t know for sure if the pulse would contain enough water to reach the gulf, about 94 miles downstream of the dam, or if the water would all seep into the ground before reaching the sea, the commission said.
From National Geographic (Sandra Postel):
The pulse flow, which began on March 23, is now nearing its end. Scientists had not planned on the river reaching its estuary as part of this grand experiment. But that it has, is a wonderful bonus.
This confluence of the river and the high tides signals that “improving estuarine conditions in this upper part of the estuary is possible if restoration efforts continue in the future,” Francisco Zamora, director of the Colorado River Delta Legacy Program at the Sonoran Institute, wrote to me in an email. Zamora took the photos featured in this post on Thursday, May 15, from a low-flying plane operated by LightHawk.
If rivers are born with a destiny, it is to reach the sea. They carry sediment, nutrients and freshwater from the land to the coastal zones, helping sustain the productivity and abundance of marine environments.
Deltas and estuaries – where rivers and seas connect – are some of the most biologically rich ecosystems on the planet.
Before the big dams and diversions of the 20th century, the Colorado’s nutrient-rich freshwater mixed with the Upper Gulf’s salty tides to create the perfect water chemistry and nursery grounds for Gulf corvina, totoaba, brown and blue shrimp, and other fisheries of great commercial and cultural importance to the region and to the indigenous Cucapá.
But over recent decades, a combination of over-fishing and lack of freshwater in-flow has caused fish populations in the Upper Gulf to plummet.
Since the completion of Glen Canyon Dam in 1963, the Colorado has connected with the sea only a few times – mostly during El Niño weather events that brought unusually large amounts of snow and rain to the Colorado Rockies and the upper watershed. The last time the Colorado reached the sea was in 1998.
The estuary is now part of a protected biosphere reserve and no-fishing zone, an attempt to give fish – as well as the highly endangered vaquita, the world’s smallest porpoise – a chance to revive their numbers…
Over the past eight weeks, the pulse flow has brought needed water to active delta restoration sites, where conservation groups have planted hundreds of thousands of cottonwoods, willows and mesquite to begin re-establishing habitats for hundreds of species of birds and wildlife.
Timed to coincide with the germination of these native trees, the pulse is also helping new habitats emerge spontaneously along the river.
On the heels of the pulse flow, the Colorado River Delta Water Trust will provide sustaining base flows made possible by purchasing voluntary leases of water from delta farmers.
[Change the Course – a partnership of the National Geographic Society, Bonneville Environmental Foundation, and Participant Media – has partnered with the Delta Water Trust to help provide these crucial base flows.]
Compared with the natural, pre-dam flow of the river through its delta, the volume of water restored through Minute 319 is small – less than 1 percent of the river’s historic flow. But that flow is being strategically timed and directed to produce the highest ecological benefit possible. Teams of scientists are monitoring the effects on the hydrology, vegetation, birds and other ecological features of the delta, so that future flow releases can be even more effective.
Here’s a guest column about the Colorado River Delta from Kate Burchenal that’s running in the Vail Daily:
In the current climate, speaking about water can often be disheartening: Water gaps, profound drought, escalating contention. But while those themes are extremely pertinent, they don’t tell the whole story. One experiment in particular reaffirms the notion that water law need not be stagnant; real, exciting changes can happen and are happening right now.
Water law in the West revolves around the historic Colorado River Compact. Formed in 1922, the Compact governs water allocation and use among the seven states in the Colorado River watershed: Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona and California. A 1944 treaty expanded upon this agreement to include Mexico, in recognition of the fact that the Colorado River runs through Mexico on its final push to the sea.
At least it used to. Historically, the mighty Colorado has coursed over 1,400 miles from its headwaters in the mountains of Colorado to its confluence with the ocean and the Gulf of California. Since the 1960s, however, the Colorado River has not consistently reached its lush delta. In fact, it hasn’t reached the sea at all since the early ’90s.
Biodiverse Ecosystem
The Colorado River Delta was once an extremely biodiverse ecosystem, home to hundreds of resident and migratory species. It was an important connector along the Pacific Flyway, giving birds a welcome place to rest, feed and drink on their long journeys up and down the coast. Now, without water flowing through the delta, only 10 percent of the historical wetlands remain and much of the life is gone.
But all is not lost. As Sandra Postel wrote for National Geographic’s Freshwater Initiative, “the delta is not dead. It is merely dormant, waiting for water to return … the delta is resilient. With the addition of water, life comes bouncing back.” This is where the innovation and excitement comes in.
In November 2012, members of the International Boundary Water Commission from the US and Mexico agreed upon an amendment to the original 1944 treaty. This binational agreement, called Minute 319, solidifies subtle changes to the way the two countries share water from the Colorado River. With so much contention and disagreement surrounding water issues within our own borders, this international agreement is quite a milestone.
One of the major changes outlined by Minute 319 is that Mexico is now able to store its allocation of Colorado River water (or some portion thereof) in Lake Mead. For Mexico, a country with very little water storage capacity, this is very important.
A Natural Defibrillator
Since Minute 319 went into effect, Mexico has been utilizing this new storage arrangement in Lake Mead for one very important purpose: to restore the Colorado River Delta.
At the end of March, the amazing experiment began as this stored water was released, creating a pulse of water large enough to mimic historical spring runoff flows in the Colorado River. The water’s progress has been slow as much of the water is absorbed by the parched landscape, but the Colorado River is once again making its way toward the Gulf of California.
In preparation for the arrival of the pulse flow, local organizations have been planting native vegetation such as cottonwood and willows, along what used to be the banks of the river. The hope is that the water will inundate the floodplain, simulating spring flows and encouraging the growth and seed dispersal of these plants. The hope is that the pulse flow will act like a cardiac defibrillator, shocking the system back into its routine.
These experimental flows began nearly two months ago and, though there was no certainty that the river would reach the sea, it looks as though it will do just that. There is also no guarantee how the delta will respond to this experimental pulse. It is important to note that the amount of water meandering toward the delta as I write this is a far cry from the rushes of water typical of the spring runoff decades ago. Yet it is a grand and worthy experiment all the same.
Even beyond the ecological and experimental significance, Minute 319 represents a great compromise between nations — one that gives us reason for optimism when examining our own water struggles
Kate Burchenal is the education and outreach coordinator for the Eagle River Watershed Council. The council has a mission to advocate for the health and conservation of the Upper Colorado and Eagle River basins through research, education and projects. Call the Watershed Council at 970-827-5406 or visit http://www.erwc.org for more information.
More Colorado River Basin coverage here.