The Middle Rio Grande: A Scholar’s Guide to the Law, Science, Literature, and Citizens of the River

Denise Fort and Theresa Strike, UNM School of Law

December 3, 2009

The Rio Grande is a symbol of New Mexico and closely tied to the state’s history and culture.  Only a stretch of the river’s range is in New Mexico; it begins in Colorado, descends from the north to the Texas border,  and forms a dividing line between the United States and Mexico.  This web site attempts to make available to the public, scholars, and students the published literature concerning the Middle Rio Grande, which we define as the reach from Cochiti Pueblo to Elephant Butte.   In addition to the information collected for this website, other websites with a collection of information on the Middle Rio Grande can be found at: and

History, anthropology, archeology

The Rio Grande plays a major role in the state’s history.  Pueblos and colonial settlements existed along the banks of the river. The early Spanish conquistadors, who first arrived in the 1500’s, left records of lush vegetation, wild fowl, and abundant fish.  Paul  Horgan’s Great River : The Rio Grande in North American History (1954) is one of the best known histories of the river, starting with the first settlements and continuing through to the early 1900s.Anthropologists and archeologists also study the communities that existed along the river and their relationship to the river.

The physical sciences

Scholars from geology, biology, restoration ecology, and other associated scientific disciplines also study the river. Its most significant transformations in recent history occurred with the construction of water diversion and storage facilities.  Reservoirs have transformed the river so that flows now are controlled by these facilities, and diversions have greatly reduced the flows in the rive.r Water quality has been affected by activities along the river, including runoff (called nonpoint pollution in federal law) and discharges from sewage treatment facilities. This stretch of the river has been classified by the New Mexico Water Quality Control Commission.The volume of water in the river also affects water quality.

Vectors of change

The Middle Rio Grande runs through four NM counties: Bernalillo, Sandoval, Socorro, and Valencia Counties.  Population growth ( ) within these four counties has increased significantly within the last 20 years.  At the time of the 1990 U.S. census, the population within the Middle Rio Grande counties was measured at 603,895 people.  These counties saw a 40% increase in the intervening 18 years, with the population in these same counties measured at 847,825 people in 2008.  It is also noteworthy that counties bordering the Middle Rio Grande include more than 43% of the total population of NM. This affects municipal demand for water, as well as the consumption of water from individual wells, and increases the pressure that human populations place on the resources of the Rio Grande. Projections indicate that population will continue to increase dramatically within this section of the Rio Grande.  One estimate is of an 80% increase in the four counties of the Middle Rio Grande between now and 2035.

Climate change is affecting change in river basins around the world. In the desert Southwest climate scholars believe the entire southern half of the continent will probably be drier and hotter with more of the year’s precipitation coming in the winter and spring and more in the form of rain than snow.  For much of the continental United States, parts of Canada, and all of Mexico, this will likely mean less runoff through the course of the year and much less runoff in late summer and fall.


The law provides one lens to view the Rio Grande. As long ago as the beginning of the 20th century there were conflicts over water deliveries among states, leading to the Treaty of 1906 between Mexico and the United States. A compact among Colorado, New Mexico, and Texas soon followed.

Deliveries of water to communities along the river were made through ditches, called acequias in Spanish. In the middle Rio Grande many of these acequias were absorbed in the Middle Rio Grande Conservation District, constructed by the federal government to address drainage, but now operated by an elected board. The Middle Rio Grande Conservancy District has water rights to an undetermined amount of water in the river, which it uses during the irrigation season. It also conducts activities in the water ditches and along the ditch banks.

The Middle Rio Grande is managed by a number of different agencies. The New Mexico Office of the State Engineer and the Interstate Stream Commission administer water rights and address compact compliance. The federal Bureau of Reclamation is responsible for water infrastructure on the river, including El Vado dam and the irrigation works of the Middle Rio Grande.  The federal Corps of Engineers also is involved in river management, including control of the Cochiti Dam.  The Albuquerque region is served by the Albuquerque Bernalillo County Water Utility Authority, which utilizes groundwater and water from the Colorado River basin, which is delivered down the Rio Grande and removed at a city operated diversion facility. In particular, the U.S. Geological Survey (USGS) has performed scientific research on the water resources of the region.

Indian pueblos have rights to the water in the Rio Grande. Indian pueblo water rights have not been adjudicated, nor is an adjudication underway. Some of these rights are met through delivery by the Conservancy District; pueblos also have developed deep wells and are using groundwater.  Under the Clean Water Act, pueblos can establish water quality standards for waters on the pueblo and several have done so on the Rio Grande, including Isleta Pueblo and Sandia Pueblo.

The passage of the Endangered Species Act and the identification of threatened and endangered species in the Rio Grande changed the legal relationships on the river. Environmentalists initiated litigation to protect the Rio Grande Silvery Minnow from the effect of water withdrawals. While the federal district court and the 10th Circuit Court of Appeals reached decisions favorable to the environmental perspective, a rider enacted by the Congress effectively overturned portions of the decision. The protection of the species now is controlled by a biological opinion of the U.S. Fish and Wildlife Service and by steps taken by the Collaborative Process to provide habitat for the species. Finally, two aquaria have been built to provide a location for fishes in low water years and to enable breeding in captivity.

The issues involved in the Rio Grande litigation are likely to be reignited by the issuance of a new biological opinion by the US Fish and Wildlife Service. With the City of Albuquerque taking water from the river, the stresses on the fish populations will be increased.

A number of nongovernmental organizations have been involved in some aspect of river protection and restoration in the Middle Rio Grande.   These include Defenders of Wildlife; WildEarth Guardians; Audubon New Mexico; Rio Grande Restoration; World Wildlife Fund; and Amigos Bravos. Also, a number of groups including nongovernmental agencies, researchers, and governmental agencies have commented on aspects of  biological and water use management plans for the Middle Rio Grande.

Agricultural water users have been active in river matters through the Conservancy District, but also as individuals. The Rio Grande Agricultural Land Trust has been established to protect this land use in the valley. Urban residents of the region make heavy use of the river’s bosque, which is used by walkers, bikers, horse back riders, birdwatchers, and picnickers. The riparian zone in the city is managed as the Rio Grande Nature Center State Park. The BioPark, Aquarium, Botanical Gardens and other recreational and educational institutions are linked to the river environment.

The Future of the Middle Rio Grande

Will the Rio Grande be a healthy river, with sufficient water to support fishes and other species, water for recreation and for the people of the valley to enjoy, water to maintain agriculture, and water that is free of pollutants? These questions are very much in doubt at this time. Climate change will decrease the flows in the river, especially in the summer months. The only legal mandate for protecting water in the river is the federal Endangered Species Act; should the silvery minnow become extinct that protection would be lost.  While many peoples’ lives are touched by the river, there is not a solid institutional base to bring about these many aspirations. The citizens of the region will have to determine whether the river will be as important in the future as it has been in the past.

Please send corrections, additions, and comments to Alexandra Siek