Bureau of Reclamation Banner, Upper Colorado Region

Navajo Reservoir from the air

 

Navajo Reservoir –Reclamation is currently releasing 350 cfs. Releases are made for the authorized purposes of the Navajo Unit, and to attempt to maintain a target base flow through the endangered fish critical habitat reach of the San Juan River (Farmington to Lake Powell). The San Juan River Basin Recovery Implementation Program recommends a target base flow of between 500 cfs and 1,000 cfs through the critical habitat area.  The target base flow is calculated as the weekly average of gaged flows throughout the critical habitat area.

Navajo was at 6045.2 ft of pool elevation and 1,170,470 acre-ft of storage by the end of April, which was 86% of average for the end of the month. Modified unregulated inflow into Navajo was 80,166 af, which was 47% of average for the month. Calculated evaporation for the month was 2,199 acre-ft.  NIIP diverted a total of 19,793 acre-ft. The release averaged close to 350 cfs throughout the month.  Precipitation at the dam totaled 0.65 inches (61% of average).

As of May 7th, the release at Navajo (as measured at the USGS at Archuleta gage) was 350 cfs, and the observed inflow is 2,288 cfs. The reservoir elevation is 6045.95 ft and the content is 1,178,742 acre-ft, or 69% full (50% of Active).  The San Juan River at Four Corners USGS gage is at 1,130 cfs, and the Animas River at Farmington USGS gage is at 1,230 cfs.  Snotel sites above Navajo are showing 3.3 inches of SWE (22% of median on this date).

To view the most current reservoir elevation, content, inflow and release, click on: Navajo Reservoir Data. For up-to-date release information and notices, click on Navajo webpage Notices.

The most probable modified-unregulated inflow forecast for May at Navajo is 100,000 acre-ft (36% of average), for June is 40,000 acre-ft (18% of average), and for July is 10,000 acre-ft (15% of average).  The April-July modified unregulated inflow forecasts are as follows:

Min Probable: 170,000 acre-ft (23% of average, a decrease of 3,000 af from mid-April)
Most Probable: 230,000 acre-ft (31% of average, a decrease of 50,000 af from mid-April)
Max Probable: 300,000 acre-ft (41% of average, a decrease of 95,000 af from mid-April)

Under all three forecast probabilities, no spring peak release is expected in 2015.  The most probable forecast shows the reservoir will peak in early June at an elevation just under 6047 ft (1,190,000 af), and reach a minimum overwinter storage level near 6035 ft (1,060,000 af) in winter of 2016.  

The last public operations meeting was held April 28th at the Farmington Civic Center. The next operations meeting is scheduled for Tuesday, August 11th 2015. To view minutes from the last Navajo Operations Meeting, click on: Meeting Notes.

Updated May 20th, 2015
Susan Behery

Email comments/inquires to: ResourceMgr@usbr.gov