#ColoradoRiver: Where the river ran dry: A little water restores sliver of nature in Mexican delta — Arizona Central

Here’s a report about the conservation efforts in the Colorado River delta country from Brandon Loomis writing fo the Arizona Central. Click through for the whole article and the great photos. Here’s an excerpt:

The work of maintaining a little nature along a thoroughly re-plumbed Colorado River is, in fact, never-ending.

Little more than a year ago these cottonwoods, willows and cattails were absent. Non-profit groups from both sides of the border have worked or paid to plow, plant and irrigate some 650 acres so far, essentially farming nature where it once grew wild.

They’re using canals to put some of the river back into its channel in strategic places.

Both countries are working to reverse some of the ecological damage, even as the growing population causes officials to seek new water supplies through reuse and saltwater desalination before the Southwest’s thirst leaves even less of a river for nature.

These woodland strands — tiny replicas of the river’s creation — are emblematic of the realities facing a 246,000-square-mile watershed, upstream to its mountain origins in Wyoming and Colorado. Anything that requires more water from a climate-stressed source won’t come easily….

An earthquake creates an opening for change

Riverside restoration — both along a dry channel south of the border and a wet one north of it — is an ambitious undertaking given how little the river has left to give. Without intensified water conservation or supply augmentation, the U.S. government predicts the Southwest will be short 3.2 million acre-feet by 2060. That gap is larger than Arizona’s share of the river.

Beyond aesthetics, this restoration is a start on securing the futures of about two dozen creatures whose existence the dams and canals built throughout the Colorado River Basin threw into jeopardy.

Negotiations between the nations and states that use the river allowed Mexico to store water in Lake Mead for ecological flows after a 2010 earthquake destroyed canals supplying Mexican farms.

The U.S. released about 105,000 acre-feet over several weeks last year. That’s more than enough to supply Tucson for a year, but less than 2 percent of annual supplies out of Lake Mead. On a small scale, it mimicked the sort of springtime floods that poured across the delta before Hoover Dam’s construction in the 1930s.

U.S. interests including the Central Arizona Project will recover some of the water long-term because the deal trades American-funded canal repairs for Mexican water left in Lake Mead.

The flood soaked the roots of newly planted cottonwoods, which in this climate can grow 10 feet or more in a year. Some of the new trees sank roots deep enough to tap groundwater; others will need continuing irrigation.

When the river dried up again, conservation groups who bought both permanent water rights and short-term leases from Mexican farmers began moving water through Mexico’s canals to periodically wet their restoration sites. The international agreement allows them to use up to 50,000 acre-feet — each acre-foot equaling 325,851 gallons — over five years, ending in 2017.

New negotiations next year are expected to produce an agreement for what happens after 2017.

The 2014 flood, officially labeled a “pulse flow,” was effectively an experiment to see how much water the delta needs to rebuild some biologically meaningful patches of bird and fish habitat.

It turned out that such a big flood of water all at once may not be the most effective restoration tool.

Colorado River pulse flow (Minute 319) reaches the Sea of Cortez for the first time since 1998 on May 15, 2014 via the Sonoran Institute
Colorado River pulse flow (Minute 319) reaches the Sea of Cortez for the first time since 1998 on May 15, 2014 via the Sonoran Institute

Leave a Reply