It's taken around two months, but National Geographic reports the Colorado River has reached the sea once more.
After coursing through its delta for nearly eight weeks, the fresh waters of the Colorado River have touched the high tides of the salty sea.
It is the first time in sixteen years that the Colorado River, which flows 1,450 miles (2,334 kilometers) from its headwaters in the Rocky Mountains of Colorado to the Sea of Cortez (Gulf of California) in northwestern Mexico, will have reached its final, natural destination.
This reunion between river and sea is due to an agreement between Mexico and the United States, known as Minute 319, to advance the restoration of the Colorado Delta by releasing a pulse flow and sustaining base flows in a five-year experiment.
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.
I had posted about this back in March, when the water release was just starting. This is just a trickle compared to the historic flow rate of the Colorado, before it was dammed and diverted to exhaustion. It's the result of years of negotiations between Mexico and the United States, a five year experiment to see to what extent a once flourishing biome can recover. The river is being heavily monitored, and efforts have been made to restore appropriate vegetation. It was doubted that enough water would be released to make it all the way to the Sea of Cortez, but it has. As New Scientist notes:
"We know that it has raised the water table, we know that it reached the prime restoration areas, we know that native vegetation has germinated in those areas," says Karl Flessa of the University of Arizona, Tucson, one of the lead scientists monitoring the pulse flow. "We have learned a lot."
The river once brought nutrients to the Sea of Cortez that sustained a rich marine ecosystem and a vibrant fishery. The diversion of the river to other uses caused that system to collapse. The
river itself supported a number of plant and animal species, not to mention the humans that live along its banks.
One of the planet’s great desert aquatic ecosystems, the delta once boasted some 2 million acres of lush wetlands teeming with birds and wildlife.
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.
While this is only a fraction of the water that once reached the sea, it's still a landmark event in the growing recognition of the need to mitigate human impact on the planet. It's going to provide valuable experience in coping with the effects of Climate Change, because a lot of habitats are already in trouble, are suffering from disruption, and need all the help we can give them - the better to help ourselves.