Navajo Reservoir – Reclamation has been releasing 350 cfs from Navajo Reservoir since June 23rd, 2014. A shift in the USGS gage at Archuleta, measured by the USGS on July 1st, shows the release to now be 400 cfs. The release was not decreased back to 350 cfs due to forecasted decreasing tributary inflows into the San Juan River. 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 6045.8 ft of pool elevation and 1,176,697 acre-ft of storage by the end of June, which was 81% of average for the end of the month. Observed inflow into Navajo was 97,789 af, (modified-unregulated inflow volume of 115,708 af) which was 53% of average for June. Calculated evaporation for the month was 3,745 acre-ft. Navajo released 300 cfs through the end of the month, and then increased to 350 cfs on June 23rd. The USGS made a physical measurement at the Archuleta gage, and updated the gage shift on June 30th, showing the flows to be closer to 400 cfs. Navajo Reservoir recorded 0.04 inches of liquid precipitation (6% of average).
The most probable modified-unregulated inflow forecast for July at Navajo is 10,000 acre-ft (15% of average), for August is 17,000 acre-ft (38% of average), and for September is 23,000 acre-ft (53% of average). The April-July total inflow forecasts are as follows: Min Probable: 420,000 acre-ft (57% of average),Most Probable: 425,000 acre-ft (58% of average), and Max Probable: 445,000 acre-ft (60% of average).
Reclamation and SJRIP agreed to forego a spring peak release for 2014 in the interests of recovering the reservoir and reducing the risk of a shortage. The release will continue to be that which is required to maintain the target base flows downstream.
To view minutes from the last Navajo Operations Meeting, click on: Meeting Notes.
Updated July 17, 2014
Email comments/inquires to: ResourceMgr@usbr.gov