2026-06-18 アリゾナ大学
The El Chausseé restoration site, seen here in June 2025, is a 180-acre habitat revival project near San Luis Río Colorado in Baja California, Mexico. The site is managed by Restauremos el Colorado, one of several organizations working to revitalize parts of the Colorado River Delta. Martha Gomez-Sapiens
＜関連情報＞
- https://news.arizona.edu/news/revitalizing-colorado-river-delta-little-goes-long-way
- https://qanr.usu.edu/coloradoriver/files/research/deliveries-flessa-june-15.pdf
コロラド川デルタの現状：環境用水供給の影響（2014年～2025年） The State of the Colorado River Delta: Effects of Environmental Water Deliveries, 2014-2025
Karl W. Flessa1, Martha Gómez-Sapiens1, Eduardo González-Sargas2 and Roberto Real Rangel
Center for Colorado River Studies Published:June 15, 2026
Abstract
Ever since the pulse flow of 2014, a binational team of scientists have been monitoring the hydrological, biological and social effects of environmental water deliveries to the Colorado River Delta mandated by Minutes 319 and 323 of the U.S.-Mexico Water Treaty of 1944.
The pulse flow demonstrated the political, logistical, and hydrological feasibility of delivering environmental water. The river briefly reached the sea, groundwater levels rose, the river corridor became greener, and local communities celebrated the return of the river. These effects, however, were short-term.
Four smaller flows delivered from 2021 to 2025 directly to the main channel downstream of the dry reaches resulted in a flowing portion of the river, higher groundwater levels, revitalization of marshlands and invasive vegetation, and provided local recreation opportunities. These effects were also short-lived. Native vegetation was planted and thrived when flows irrigated three prepared restoration sites. Bird abundance and diversity increased in these restored areas. To date, 559 hectares (1,381 acres) of riparian habitat have been restored. These sites require regular irrigation and maintenance. Visitor programs connect the sites to the local communities.
Restoration sites are not self-sustaining. They require continuing irrigation, maintenance and monitoring. We estimate that annual irrigation deliveries of 8.5 million cubic meters (6,890 acre-feet) are needed to preserve existing sites. Additional water for the environment should be directed first to new or expanded restoration sites, then to additional in-channel flows.
