Paradox Valley Unit

Paradox Valley Unit
Aerial view of the Paradox Valley Unit


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.

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. The PVU extracts naturally-occurring brine groundwater in the Paradox Valley, thereby preventing it from entering the Dolores River. Saline concentrations of this natural brine groundwater have been measured in excess of 250,000 milligrams per liter, which, prior to the PVU, added more than 205,000 tons of salt to the Dolores River annually. The Dolores River is a major tributary to the Colorado River. The PVU is designed to prevent the natural salt load from degrading the water quality of the main stem of the Colorado River.

Paradox Valley Location Map
Paradox Valley Location Map

The PVU consists of facilities to intercept shallow brine and inject it into the Leadville geologic formation via a Class V deep injection well. The PVU has been injecting brine since 1996. Approximately 100,000 tons of salt are injected annually; this correlates to about ten percent of the total salinity control in the Colorado River, making the PVU one of the most effective salinity control projects in the Colorado River Basin.

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Environmental Impact Statement

The existing brine injection well is nearing the end of its useful life, so the Bureau of Reclamation is investigating alternatives for disposing ofthe brine in order to enhance and protect the quality of water available in the Colorado River for use in the United States and the Republic of Mexico.

Reclamation is preparing an Environmental Impact Statement and has released a draft for public review and comment to evaluate brine disposal alternatives to replace the existing brine injection well. Alternatives analyzed in the EIS include:

  • Alternative A – No Action (no salinity control in the Paradox Valley)
  • Alternative B – New Injection Well
  • Alternative C – Evaporation Ponds
  • Alternative D – Zero Liquid Discharge Technology

A preferred alternative will be identified in the final EIS in the summer of 2020. The ROD, anticipated in fall 2020, will officially present the Bureau of Reclamation’s decision on brine disposal at the PVU.

Questions and comments can be submitted to:

Public meeting materials:

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Environmental Impact Statement Documents

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Environmental Impact Statement Technical Documents

Alternative B – New Injection Well

Alternative C – Evaporation Ponds

Alternative D – Zero Liquid Discharge Technology

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Other Paradox Valley Unit Documents

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:

for questions concerning the EIS contact:
Lesley McWhirter, Chief
Environmental and Planning Group
Bureau of Reclamation
Western Colorado Area Office
445 West Gunnison Avenue, Suite 221
Grand Junction, CO 81501-5711
(970) 248-0608

for questions concerning PVU operations 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: 11/3/20