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San Juan River Flow, Navajo Dam, NM

The San Juan Flow Graph data above are provided Aspire Computer Solutions, LLC as information to fishermen/women and other interested parties.  The data are drawn from the USGS (United States Geological Survey) and BOR (Bureau of Reclamation) public records, some of the data are provisional and may be subject to change.  In some cases CFS values were missing and estimated CFS Average values were substituted based on available Gauge readings.  

The flows in the San Juan river below Navajo Dam are controlled by the Bureau of Reclamation (BOR) in compliance with existing law for authorized purposes.  As is the case with many other western waters, some flows are influenced by system wide efforts to protect endangered species.  Water is naturally limited and always in high demand  in the Southwest, many competing entities are present staking claims to San Juan water and by complying with previous agreements/laws,  the BOR has limited flexibility in how flows are maintained.  

The reservoir at Navajo Dam was constructed from 1958 to 1962 as part of the Colorado River Storage Project.  There were two important provisions to the congressional authorization to build the dam, one included a substantial diversion of water from the San Juan Basin through the Continental Divide to the Chama river in northern New Mexico to supply additional waters to New Mexico cities along the Rio Grande.  These flows are not shown on the graph as the San Juan Chama Project water is drawn from the system before it enters Navajo Reservoir.  The second provision set aside a substantial amount of San Juan water to provide for the Navajo Indian Irrigation Project (NIIP).  The NIIP project is intended to irrigate approximately 110,600 acres of Navajo farmland south of the San Juan River.  The water for the NIIP project is drawn from the reservoir through a diversion headworks near the south side of the dam and moves water to the NIIP Project through approximately 60 miles of tunnels and canals south of the river,  bypassing the San Juan fishery.  As a result of the San Juan Chama Project and the NIIP Project waters no longer being present in the main river channel,  the San Juan fishery has been a smaller river with lower flows since the dam and Chama River diversion projects were constructed. 

In recent years flows on the San Juan have been significantly influenced by the San Juan River Basin Recovery Implementation Program (SJRIP) which recommends minimum flows (500 - 1000 cfs) in a targeted critical habitat downstream for two endangered species,  the Colorado Pikeminnow and the Razorback Sucker.  The critical habitat area is between Farmington and Lake Powell.  When sufficient water is available a short period of high water (5,000 CFS) is delivered to the river in spring to mimic historical flows in the interest of improving downstream habitat for the Endangered Species.  The main contributors to flow in the Endangered Species Habitat area are the San Juan and the Animas rivers.  As the Animas is a free flowing river, flows from the San Juan are adjusted up and down to try to meet the recommended flows in the Critical Habitat Area. 

The SJRIP recommends a target base flow of between 500 cfs and 1,000 cfs through the critical habitat area from Farmington to Lake Powell.  Most of this flow comes from the San Juan River and the Animas River.  As the Animas River is a free flowing river, increases in the Animas due to precipitation and runoff can result in decreases in flow on the San Juan and the converse is true also.  When the Animas is running low the flow on the San Juan may be increased to make up the necessary difference.  In spring it is desireable to increase flows from the San Juan to mimic natural flows in the interest of maintaining habitat for endangered species.  This can result in flows of up to 5000 cfs on the San Juan for 1 or more weeks.

 Data for the San Juan Flow graph is updated several times each week, especially during flow changes.

Additional information on the San Juan River Basin Recovery Implementation Program is available at the following link:

Additional information on the Colorado Pikeminnow and Razorback Sucker is available on the links below: