At one time, the Colorado river discharged 20000 gigalitres into the ocean annually.
The thorough damming and diversion of the Colorado river in the USA during the second half of the 20th century all but destroyed the ecosystem of the Colorado delta in Mexico. The actual size of the delta decreased 90%. Once a habitat for deer, jaguars and many species of waterfowl, by the start of the 21st century it was completely dry. The cessation of flow also ended the supply of silt to maintain soil fertility. Since 1970 the Colorado river has not reached the sea, except in rare overflows events.
In 2012, officials signed Minute 319, a US-Mexico agreement to allocate some of the Colorado basin’s water to the delta. Over a two month period in 2014, a 129 gigalitre pulse flow was released, resembling the annual floods that used to feed the delta. The results were spectacular, resulting in the rapid growth of willow and cottonwood trees, and the return of migratory birds, coyotes, crustaceans, and amphibians.
NGOs are pushing for a regular allocation of water for the delta, and the agreement will be up for renegotiation next year.
http://www.nature.org/ourinitiatives/regions/northamerica/areas/coloradoriver/colorado-river-six-months-after-the-pulse-flow.xml
http://www.kpbs.org/news/2014/jun/12/colorado-river-delta-begins-come-back-dead/
Colorado River Delta Begins To Come Back From The Dead
http://www.ibwc.gov/Files/Minutes/Minute_319.pdf
IBWC Interim Internation Cooperation Measures in the Colorado River Basin through 2017
http://voices.nationalgeographic.com/tag/minute-319/
VIDEO: The Colorado River Reaches the Sea and Brings Life to Its Delta
http://www.nasa.gov/content/goddard/nasa-usgs-satellite-sees-green-up-along-colorado-rivers-delta-after-experimental-flow/
NASA/USGS Satellite Sees Green-up Along Colorado River’s Delta After Experimental Flow
http://www.outsideonline.com/1928261/day-we-set-colorado-river-free
The Day We Set the Colorado River Free