Navajo Unit Operations

Coordination Spring 

Meeting Slides

August 18, 2020

Reclamation 

Western Colorado Area Office
MEETING NOTICE

In response to the recommendations from the CDC, local authorities, and 

Department of Interior guidance, the spring coordination meeting for the operation 

of the Navajo Unit, scheduled for Tuesday, April 21st, at 1:00 pm, was canceled. 

These slides are being provided in lieu of the meeting, along with an operational 

summary document. Please contact Susan Behery (sbehery@usbr.gov, 970-385-

6560) for any questions or comments you might have.

The next coordination meeting for the Navajo Unit is being scheduled for January 

2021. A notice will be sent out when the date is finalized.
• Despite near-average snowpack, runoff throughout the basin was well belowaverage.

• Navajo Reservoir peaked at elevation 6062.7 ft on June 9th. There was no spring 

peak release.

• After runoff, flows decreased dramatically in the basin. High releases have been 

required to maintain the target baseflow in the critical habitat reach. The release 

has varied from 500 cfs to 1,000 cfs over the summer. Monsoonal moisture so far 

has been limited to an event in the last week of July.

• The long-term forecast is hot and dry, with a below-average winter expected in

WY 2021.

Summary
WY 2020 Snowpack


Current Reservoir Status
Final April – July 

Runoff

Navajo: 347 kaf (47% avg)

Vallecito: 131 kaf (68% avg)

Lemon: 32 kaf (58% avg)

Animas: 265 kaf (64% avg)

McPhee: 94 kaf (32% avg)

Powell: 3,759 kaf (53% avg) 
San Juan River Basin 2020 Water Supply

Preliminary April-July 2020 observations

Volume in 1000’s acre-feet / % of 1981-2010 average

San Juan-Farmington

500 / 45%

Lemon Res

32/ 57%

Animas-Durango

265 / 64% Vallecito Res

132/ 68%

Navajo Res

348 / 47%

San Juan-Bluff

472 / 43%

San Juan-Carracas

188 / 49%

San Juan-Pagosa

121/ 56%
Seasonal Forecast Progression for Navajo Reservoir Inflow

(Range of forecast probabilities throughout the season. Official forecast shown in red)

A record dry April 

resulted in a large 

decrease from the 

April-May forecasts

Observed Apr-Jul volume fell 

near the 90-70% exceedance 

forecasts. 

The largest forecast errors were 

in the early season forecasts 

(Jan-Apr) due to a dry spring.
2020 Observed Streamflow: San Juan River Basin 

Spring and Summer Highlights:

• Early, rapid and efficient snowmelt.

• Rain in late May and early June kept flows elevated longer than expected.

• Flow decreased rapidly after mid June to much below normal conditions.

• Minimal monsoon impacts; only one precipitation event in late July.

• Hot and dry conditions have prevailed since snowmelt runoff ended.
Where is the Monsoon? 

• So far it has been an underwhelming Monsoon season.

• High pressure has been in a favorable position over the region for limiting 

moisture.

• However, the single event in July resulted in average to above average monthly 

precipitation in some areas of the basin.

• Monsoon surges still possible into September

Upcoming Weather

• Continued hot and dry conditions through the end of the month

Precipitation Outlook:

August 20-26

Temperature Outlook:

August 20-26
Latest ENSO discussion from the Climate Prediction Center has 

most models indicating La Niña conditions developing by fall 

with a 55-60% chance of La Niña conditions during the winter 

of 2020-2021.

November-December-January

December-January-February

Any insight into Winter 2021?
Typical La Niña impacts

Persistent and active northern Jet stream. Typically favors drier conditions over the southern tier of the U.S.

For the San Juan Basin

Impacts have been mixed looking at historical runoff results. 

Some tendency towards below average runoff volumes during La Nina years.
Navajo Inflow during the Apr-Jul period following winters with moderate, strong, or very strong La Niña signatures

0

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20021977201819721974201319961971200320122000202020061981201419891988197620041990201620112007201519982010200919781991199419992017199220011982198420081997198319931995197520191986200519871980197319851979

April -July Inflow Volume (KAF)

Navajo Inflow April-July

La Nina Years (in blue)

Average: 735 KAF



• Despite near-average snowpack, runoff throughout the basin was well belowaverage.

• Navajo Reservoir peaked at elevation 6062.7 ft on June 9th. There was no spring 

peak release.

• After runoff, flows decreased dramatically in the basin. High releases have been 

required to maintain the target baseflow in the critical habitat reach. The release 

has varied from 500 cfs to 1,000 cfs over the summer. Monsoonal moisture so far 

has been limited to an event in the last week of July.

• The long-term forecast is hot and dry, with a below-average winter expected in

WY 2021.

Summary
Reclamation Contacts:

Marc Miller

970-385-6541 mbmiller@usbr.gov

Susan Novak Behery

970-385-6560 sbehery@usbr.gov 

Ruth Swickard

970-385-6523 rswickard@usbr.gov

Useful Links

Reclamation: www.usbr.gov/uc

USGS: water.usgs.gov/nwis

CBRFC: cbrfc.noaa.gov