Navajo Reservoir –As a result of increasing flows in the San Juan River Basin, Reclamation decreased the release from Navajo Reservoir from 350 cfs (cubic feet per second) to 250 cfs on Tuesday, September 24th at 10:00 am. 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). To see up-to-date project notices for Navajo Reservoir, click on: Project Notices.
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 6022.08 ft of pool elevation and 933,199 acre-ft of storage by the end of September, which was 68% of average for the end of the month. Modified unregulated inflow for the month of September was 151,458 acre-ft, which was 358% of average (for comparison, the peak snowmelt month this year for Navajo, May, saw 154,495 af of modified unregulated inflow into Navajo). Calculated evaporation for the month was 1,986 acre-ft. The reservoir gained an an average of 2,270 acre-ft per day throughout September, including NIIP diversions and evaporation. The outlet works release ranged from 650 cfs down to 250 cfs. NIIP diverted a total of 14,781 acre-ft in the month of September. Monsoon patterns continued throughout September, and 2.6 inches of precipitation were recorded at Navajo Reservoir (179% of average).
As of October 21st, the release at Navajo is 250 cfs, and the observed inflow is 567 cfs. The pool elevation is 6023.76 ft and the content is 947,298 acre-ft, or 56% full (27% of Active). NIIP has ceased diverting for the season as of October 21st. The San Juan River at Four Corners USGS gage is at 649 cfs and the Animas River at Farmington USGS gage is at 572 cfs. The reservoir began storing water as of September 9th and continues to gain storage at present.
The most probable modified-unregulated inflow forecast for October at Navajo is 65,000 acre-ft (138% of average), for November is 38,000 acre-ft (114% of average), and for December is 25,000 acre-ft (100% of average). Modified unregulated inflow is defined as the predicted hydrologic inflow volume into Navajo plus the change in storage at Vallecito Reservoir and the San-Juan Chama diversion volume.
The Fall Operations Meeting was held on August 27th at the Farmington Civic Center. These meetings are open forum discussions on the operation of Navajo Reservoir with many interested groups participating. Anyone interested in the general operation of the reservoir is encouraged to attend. Please contact Ryan Christianson in Reclamation's Durango, Colorado Office at (970) 385-6590 for information about these meetings or the daily operation of Navajo Reservoir.
To view minutes from the last Navajo Operations Meeting, click on: Meeting Notes.
Updated October 22, 2013
Email comments/inquires to: ResourceMgr@usbr.gov