Map of Colorado River pulse moving toward Sea of Cortez

 

Photo credit: Francisco Zamora, Sonoran Institute.

Update May 16: The Colorado River has now reached the delta for the first time since the 1990s. Conservationists will study environmental effects of the pulse for years to come.

Update May 13 from Karl Flessa: "Image taken Monday May 12.  Tidal waters in foreground, Colorado River in background. Connection will likely take place on or slightly before Thursday's high tide."

Update May 1 from Karl Flessa at the University of Arizona: "The river has resumed advancing, likely in response to the removal of an earthen dam downstream of the CILA restoration site and new, scheduled pulse flow deliveries from the Km 27 wasteway.  We don't know how far this mini-pulse will go."

On March 23 at about 8:15 a.m., a 2012 agreement between the U.S. and Mexico that was years in the making finally got real. Morelos Dam at the international border began releasing water in an experiment meant to restore a parched Colorado River Delta. The pulse of water may even allow the river to reach the Gulf of California for the first time since the late 1990s (and even so, reaching the ocean hasn't been a regular occurrence since the 1960s). The agreement, known as Minute 319, amends the 1944 U.S.-Mexico Water Treaty to guide bi-national management of Colorado River water until 2017. Over the course of eight weeks, the current flow, which is mostly through the Morelos dam, will release about 105,000 acre-feet of water (an acre-foot is about 326,000 gallons); the final release is planned for May 18. 

Karl Flessa, co-chief scientist of the Minute 319 Monitoring Program, is coordinating multi-agency efforts to understand hydrologic and biological effects of the pulses. Among other things, they're monitoring how much the water table is rising, how many cottonwood and willow seedlings will spring up near the river as a result, and how many more birds show up next year. As far as whether the experiment will reconnect the river with the Gulf in any definitive way, Flessa isn't very optimistic:

"I wasn’t encouraged when I saw the flow at the last crossing on Saturday (April 13). The river’s mouth is blocked by a low sand bar that causes the river’s flow to pond up before the Gulf. Connecting that ponded-up water with the Gulf may depend as much on the effect of the tide as the level of the water. The upper Gulf has a tidal range of 8 meters or so during new and full moons, so there’s a better chance of connection during those times of the month than at other times. And there’s no one geographic spot that’s easy to get to on the ground, where one can definitively state ‘the river has reached the sea.’ We may need to depend on satellite images and observations from small planes. And finally, to be even more downbeat over what is a really upbeat event, the amount of water that may reach the Gulf will be pretty small, and not likely to have much ecological impact. We’d all love to see it reach the gulf, but it’s not one of the stated objectives (of Minute 319). It will have great symbolic value, that’s for sure.”

This map from the Bureau of Reclamation shows the rate at which the water from the dam has moved down the Colorado, beginning in March. Flessa said Wednesday that the next stretch of river will be fairly difficult to monitor. "It's now in a zone that's really hard to get access to -- no more crossings, lots of shallow water and branching channels." Check back for updates we get on the river's progress. Tay Wiles is the online editor of High Country News. She tweets @taywiles.

High Country News Classifieds
  • SOCIAL MEDIA AND DIGITAL ADVERTISING SPECIALIST
    The Southern Utah Wilderness Alliance (SUWA), Utah's largest conservation organization, has an immediate opening for a full-time Social Media and Digital Advertising Specialist. This position...
  • SPRING-FED PARCELS ON THE UPPER SAC RIVER
    Adjacent parcels above the Upper Sacramento river, near Dunsmuir. The smaller is just under 3 acres, with the larger at just under 15 acres. Multiple...
  • DEVELOPMENT COORDINATOR
    Greater Yellowstone Coalition seeks a development professional to coordinate the organization's individual giving program. The position description is available at http://greateryellowstone.org/careers Please email a letter...
  • IDAHO STATE DIRECTOR
    The Wilderness Society is seeking a full time Idaho State Director who will preferably be based in Boise, Idaho. At least 8-10 years of experience...
  • COMMUNICATIONS MANAGER AND BEARS EARS EDUCATION CENTER MANAGER
    Conservation nonprofit Friends of Cedar Mesa in Bluff, Utah is hiring for two positions. We seek a Communications Manager to execute inspiring and impactful communications...
  • EXECUTIVE DIRECTOR
    Wilderness Volunteers Wilderness Volunteers (WV), a 24-year leader in preserving our nation's wildlands, is seeking a motivated person with deep outdoor interests to guide our...
  • HECHO POLICY AND ADVOCACY MANAGER
    Hispanics Enjoying Camping, Hunting, and the Outdoors (HECHO) was created in 2013 to help fulfill our duty to conserve and protect our public lands for...
  • FISHERIES BIOLOGIST
    Under the direct supervision of the Director of Shoshone-Paiute Tribe's Fish, Wildlife & Parks, in coordination with the Tribal Programs Administrator and the Tribal Chairman,...
  • REGIONAL EXECUTIVE DIRECTOR NORTHERN ROCKIES, PRAIRIES & PACIFIC REGION
    Founded in 1936, the National Wildlife Federation has grown into America's largest and most trusted grassroots conservation organization with 53 state/territorial affiliates and more than...
  • STEWARDSHIP MANAGER
    STEWARDSHIP MANAGER Job Vacancy and Description Posted June 2, 2021: Open until filled The New Mexico Land Conservancy (NMLC) is a non-profit, regional land trust...
  • KSJD - MORNING EDITION HOST/REPORTER
    KSJD is seeking a host/reporter. Please see for www.ksjd.org for more information. EEO compliant.
  • ON THE EDGE OF CEDAR MESA/BEARS EARS
    Quiet, comfy house for rent in Bluff, Utah. Walk to San Juan River. Bike or hike to many nearby ruins and rock art sites. Beautiful...
  • CARPENTER AND LABORER WANTED.
    Come to Ketchikan and check out the Rain forest on the coast, Hike the shorelines, hug the big trees, watch deer in the muskeg meadows,...
  • PROJECT MANAGER
    Title: Project Manager Reports To: Program Director Salary Range: Negotiable; starting at $60,000 Location: Bend, OR The Deschutes River Conservancy seeks a Project Manager to...
  • PROGRAM DIRECTOR
    The Deschutes River Conservancy seeks a Program Director to join our dynamic team in restoring streamflow and improving water quality in the Deschutes Basin. WHO...
  • EXECUTIVE DIRECTOR - TWISPWORKS
    Established healthy nonprofit in the Methow Valley of Washington state, TwispWorks is hiring the next Executive Director. Terrific opportunity to strive for our mission to...
  • BOARD DIRECTOR
    Help us achieve our mission of promoting excellence in the professional practice of wilderness stewardship, science and education to ensure the life-sustaining benefits of wilderness....
  • TEMPORARY FULL-TIME RANCH OPERATIONS ASSISTANT
    Twin Willows Ranch in Ocate, NM is seeking to immediately fill a Temporary Full-Time employment position as Ranch Operations Assistant for Facilities, Equipment, Land, and...
  • RANCH OPERATIONS ASSISTANT
    Twin Willows Ranch in Ocate, NM is seeking an individual to fill the Regular Full-Time position of Resident Operations Assistant for Technology, Hospitality, Gardening, and...
  • POEM+ NEWSLETTER
    Start each month with a poem in your inbox by signing up for Taylor S. Winchell's monthly Poem+ Newsletter. No frills. No news. No politics....