Paradox Valley Unit

The Paradox Valley Unit is currently undergoing an injection test to determine the operability of the injection well and injection zone at a reduced injection rate. Information gathered during the test will help guide future operational decisions.

Paradox Valley Unit
Paradox Valley Unit. Reclamation photo

During the test extracted brine groundwater is being injected into the 16,000-foot-deep well at a reduced rate of 115 gallons per minute (67% of past operations). Reclamation will continue to closely monitor seismicity; if unfavorable conditions are observed, the injection test will be suspended until it is deemed safe to continue. The test will continue while a risk analysis is being conducted which is expected to be completed in late 2024.


Illustration shows the Paradox Valley with the Dolores River running through the middle.  On the left side of the river there are collection wells along the river and farther to the left is a warehouse building representing the Paradox surface treatment facility and injection well. Underground you can see the layer of brine ground water and the natural salt dome that extends the length of the Paradox Valley
Click here to view full size diagram.

The Paradox Valley Unit was constructed to assist in meeting the objectives and standards of the Federal Water Pollution Control Act of 1948 (P.L. 80-845) and the Colorado River Basin Salinity Control Act of 1974, as amended and supplemented (P.L. 93-320). The Salinity Control Act authorizes the construction, operations, and maintenance of works in the Colorado River Basin to control the salinity of water delivered to users in the United States and the Republic of Mexico.

Paradox Valley Location Map
Click here to view full size map.

The PVU is located along the Dolores River in western Montrose County, approximately 50 miles southwest of Grand Junction, Colorado, and 10 miles east of the Colorado-Utah border. Its purpose is to extract naturally occurring brine groundwater in the Paradox Valley, thereby preventing it from entering the Dolores River, which is a major tributary of the Colorado River.

Saline concentrations of this natural brine groundwater have been measured in excess of 250,000 milligrams per liter—that's about eight times saltier than seawater—and have contributed up to 200,000 tons of salt per year to the Colorado River system. The PVU was designed to prevent the natural salt load from degrading the water quality of the main stem of the Colorado River.

From 1996 – 2019, the PVU prevented an average of 95,000 tons of salt each year from entering the Dolores and Colorado rivers, which provided substantial benefits—up to $23 million annually— such as improved water quality, increased life of municipal and industrial infrastructure, and increased crop yields for all downstream water users in the Colorado River Basin.

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Environmental Impact Statement

Because the existing brine injection well is nearing the end of its useful life, the Bureau of Reclamation investigated alternatives for disposing of the brine. Reclamation prepared and released a Final Environmental Impact Statement. Alternatives analyzed in the FEIS included a new injection well, evaporation ponds, zero liquid discharge technology, and no action.

After weighing the benefits and impacts of the alternatives analyzed in the FEIS, the Bureau of Reclamation has identified the no action alternative as the preferred alternative. The no action alternative achieves the best balance among the various goals and objectives outlined in the FEIS, including:

  • optimizing costs;
  • minimizing adverse effects on the affected environment;
  • minimizing the use of nonrenewable resources;
  • consistency with Bureau of Land Management Resource Management Plans;
  • and being in the best interest of the public, including considerations of health and safety.

The no action alternative would be implemented after the current injection well is decommissioned.

New technically, environmentally, and economically viable alternatives may be investigated in the future to continue salinity control at Paradox Valley.

Paradox Valley Unit of the Colorado River Basin Salinity Control Program – Final Environmental Impact Statement:

Supporting technical documents

Alternative B

Alternative C

Alternative D

Questions and comments can be submitted to:

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Other Paradox Valley Unit Documents

Paradox Valley Seismic Network Annual Reports

Published Papers

Geophysical Journal International - December 2014
Induced seismicity constraints on subsurface geological structure, Paradox Valley, Colorado

Geophysical Journal International - October 2014
Maximum magnitude estimations of induced earthquakes at Paradox Valley, Colorado, from cumulative injection volume and geometry of seismicity clusters

Journal of Geophysical Research: Solid Earth - June 2014
Geological structure of the Paradox Valley Region, Colorado, and relationship to seismicity induced by deep well injection

Seismological Research Letters - June 2014
The 24 January 2013 ML 4.4 Earthquake near Paradox, Colorado, and Its Relation to Deep Well Injection

Bulletin of the Seismological Society of America - April 2005
Deep-Injection and Closely Monitored Induced Seismicity at Paradox Valley, Colorado

Other Documents

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For more information please contact:

Andy Nicholas, Facility Operations Specialist
Paradox Valley Field Office
Bureau of Reclamation
P.O. Box 20
Bedrock, CO 81411
(970) 859-7214

Last Updated: 11/13/23