Navajo Unit Operations

April 23rd, 2019

Coordination Meeting

Navajo Current Conditions

(as of 4/22/19)

Elevation = 6034.07 ft

Storage = 1,050,120 af (62% Full, 37% Active)

Inflow* = 3,400 cfs

Release* = 340 cfs

NIIP* = 380 cfs

San Juan-Chama Diversion* = 415 cfs

*Flows averaged over the past 7 days
Greg Smith

Sr. Hydrologist

Colorado Basin River Forecast Center

National Weather Service / NOAA

Water Supply Forecasts:

Navajo & San Juan / Animas Basins

Conditions impacting the forecast

Animas peak flow outlook

Limitations / Accuracy of the forecast

Future weather impacts

Navajo Reservoir / San Juan Basin – Water Supply Outlook 2019

2019 Navajo Operations Meeting

April 23 2019

Farmington, New Mexico

1000’s Acre-Feet (KAF)

Navajo April-July Inflow Forecast

875 KAF (119% of Average)

974 in 

2008

875

2019 April-July Navajo Inflow Forecast (Comparison to historical record)

Historical Average = 735 

This would be the largest inflow dating back to 2008

2019 Forecast

1184 in 

2005

154

2018

1022 in 

1997
Upper Boundary: 

Future weather wet Solid Blue Line

Future weather average

(Primary Forecast)

Lower Boundary: 

Future weather dry

Historical 

Average

April-July Navajo Inflow Volume

Model Guidance Over Time 

Evolution of the Forecast: Significant increase early February to mid March

Model indicates 90% chance of April-July volume above 750 KAF (102% average)

What is driving the forecast: February & early March storms contained significant moisture

March 2nd 2019

March 12th 2019

NOAA / SFSU Meteorology
What is driving the forecast

A record wet February through March

Over 20 inches of water in high elevations

(historical record 33-38 years)

What is driving the forecast

This year

Last year

Normal

Last year

Normal

This year

Above Navajo 

Snowpack peak was 

near 145% of normal

Animas Basin

Snowpack peak was near 

155% of normal
Percent of normal 

soil moisture

What is driving the forecast: Soil Moisture Conditions in the Hydrologic Model

San Juan River Basin

Soil moisture 

situation entering 

the winter season

Generally knocks 

5% to 15% of 

average off the 

seasonal runoff 

volume

2008: 974 KAF

1997: 1022 KAF

2019: 875 KAF

1997 – Conditions were very wet through the spring and summer (3rd-4th wettest Apr-Jun)

2008 – Dry April, near to above average precipitation May & July, below average June

Soil Moisture conditions were better heading into winter in both years compared to this year

April-July runoff in similar snow years – Above Navajo Reservoir

Normal
2008: 232 KAF

1997: 281 KAF

2019: 235 KAF

1997 – Conditions were very wet through the spring and summer (3rd-4th wettest Apr-Jun)

2001 – Near to above average April-May, July precipitation, below average in June

2008 – Dry April, near to above average precipitation May & July, below average June

April-July runoff in similar snow years – Above Vallecito Reservoir

2001: 230 KAF

In all years soil 

moisture was 

better than this 

year

Upper Colorado: San Juan Basin

San JuanFarmington

1370 / 125%

Lemon Res

65 / 118%

Animas-Durango

515 / 124% Vallecito Res

235 / 120%

Navajo Res

875 / 119%

San JuanBluff

1380 / 125%

MancosMancos

36 / 116%

San JuanCarracas

450 / 118%

Most Recent April-July Runoff Volume Forecasts

Volume in 1000’s acre-feet / Percent of 1981-2010 average
2019 Animas Durango Peak Flow: Current Forecast 5000 mean daily CFS (top 35% of record)

(most probable forecast range 4500-5600 mean daily CFS)

2008 April-July: 

514 KAF Peak 5800

1997 April-July:

599 KAF Peak 6700

• Future Weather (temperatures) will determine the pattern and magnitude of peak flows

• 1997 and 2008 had much above average snow and were similar to this year’s snowpack.

Normal period of peak

San Juan at Pagosa Springs

Limitations of The Forecast – Future Weather (temperatures)

As the temperature forecasts change, the streamflow forecast will change

Model is sensitive to as little as a 3-4 degree change in temperatures

Forecast into the future

Forecasts from previous days

Notice the changes due to temperature forecasts
Basin Zone Elevation Ranges (ft)

Upper Zone: 11,000 – 13,278

65 mi2

Middle Zone: 9,500 – 11,000

91 mi2

Lower Zone: 7,060 – 9,500

125 mi2

Limitations of The Forecast – Does the model have a good handle on current conditions?

Our model represents snow as an area value (by elevation zone)

Upper San 

Juan

Wolf Creek 

Summit

Middle Creek

Lily Pond

Relationships are needed between SNOTEL data and area snow representation. 

This relationship is created in the model calibration period (1981-2015).

San Juan Basin above 

Pagosa Springs

Upper Zone: 11,000 – 13,278

65 mi2

Middle Zone: 9,500 – 11,000

91 mi2

Lower Zone: 7,060 – 9,500

125 mi2

Limitations of The Forecast – Does the model have a good handle on current conditions?

The area snow representation in the model for 2019
Verification of The April-July Navajo Inflow Forecast: 

Historical May 1st model forecast error is 15%

May 1st Forecast 1991-2018

Years with above 

average observed 

volumes (shaded area)

We over 

forecast

under forecast

• In years with above average observed volumes:

• There were a greater number of forecasts that were too high on May 1st

• There were also a few years under-forecast (where observations were closer to average)

Verification of The April-July Vallecito Inflow Forecast: 

Historical May 1st model forecast error is 13%

May 1st Forecast 1991-2018

Years with above 

average observed 

volumes (shaded area)

We over 

forecast

under forecast

• In years with above average observed volumes:

• Generally near or two low with forecasts on May 1st. 
Going Forward – Parting Thoughts

• We’re going from such a low year to such a high year. While not out of the realm of possibilities (1972 

to 1973, 1974 to 1975, 1996 to 1997) the 2018 inflow to Navajo was the 3rd lowest on record. It’s 

challenging to know just how much impact such a dry year will have on this years runoff.

• Timing and rate of snowmelt will impact peak flow levels and volumes. Heavier snowpack will typically 

melt out later and rapid melt may overcome some soil moisture deficiencies.

• From this point forward forecasters are very actively interacting with the model on a daily basis to adjust 

simulated flow to match observed flows. Many things will impact snowmelt but usually we begin to get 

a handle on how well the area snow representation was handled in the model. So far so good, models 

have been tracking fairly well.

• Communication between the RFC, Reclamation, and others is frequent throughout the spring. A good 

relationship exists in order to communicate forecast uncertainties and changing hydrologic conditions.
Weather Outlook

April 2019

Aldis Strautins

National Weather Service

Grand Junction, CO

http://www.weather.gov/gjt

The Past

April 2019

Water Year 2019

Temperature

Departure from normal

Precipitation

% of normal
The Past

April 2019

From January 1, 2019

Temperature

Departure from normal

Precipitation

% of normal

The Past

April 2019

April 1‐22, 2019

Temperature

Departure from normal

Precipitation

% of normal
Snotel

April 22, 2019

SNOTEL ‐ Percent of Normal

Water Year 2019

SWE Precipitation

Snow

April 22, 2019

SNOTEL Snow Water Equivalent – NRCS

Southwestern Colorado
Snow

April 22, 2019

SNOTEL Snow Water Equivalent – NRCS

Southwestern Colorado

As of 

April 22: 

159% of 

normal 

and  

154% of 

peak 

median

Drought

April 2019

April 16, 2019 January 1, 2019

Drought – Monitor
Season La Niña Neutral El Niño

MAM 2019 0% 6% 94%

AMJ 2019 0% 15% 85%

MJJ 2019 1% 25% 74%

JJA 2019 2% 32% 66%

JAS 2019 5% 35% 60%

ASO 2019 6% 39% 55%

SON 2019 8% 39% 53%

OND 2019 10% 39% 51%

NDJ 2019 11% 38% 51%

ENSO

April 2019

CPC/IRI Early‐Month Consensus ENSO Forecast 

Probabilities

(using NWS CPC classification system)

ENSO – Outlook

ENSO‐ Neutral moving to El Nino

Weather Outlook

April 2019

Forecast ‐ Wednesday
Weather Outlook

April 2019

WPC 7‐Day Precipitation

Weather Outlook

April 2019

6‐10 Day Outlook

Apr 28 ‐ May 02

Temperature Precipitation
Weather Outlook

April 2019

8‐14 Day Outlook

Apr 30 ‐ May 06

Temperature Precipitation

Weather Outlook

April 2019

Temperature Precipitation

May – Outlook
Weather Outlook

April 2019

Temperature Precipitation

May/Jun/Jul – Outlook

Weather Outlook

April 2019

Temperature Precipitation

Jun/Jul/Aug – Outlook
Weather Outlook

April 2019

Temperature Precipitation

Jul/Aug/Sep – Outlook

Weather Outlook

April 2019

Seasonal

Drought– Outlook
Latest Forecast

WATER YEAR 2019 

PROPOSED OPERATIONS 

SUMMARY

Based on mid-April CBRFC forecast

• Reservoir recovery with releases made to 

target minimum baseflows in the critical 

habitat reach

• Short duration maintenance release to be 

timed with the peak of the Animas River 
Ramp-up 

4-7 days

Peak at or 

near 5,000 

cfs for 5 days

Ramp-down 

3 days

Peak will be measured at the USGS Archuleta gage and will 

be coordinated with SJOEM 

Total Volume of around 70kaf

WHY?

• As part of a strategy to improve and 

maintain existing channel capacity with the 

goal of reaching 5,000 cfs release

• Remove and disturb sediment and debris 

before it has a chance to establish 

vegetation

• Push back channel bank encroachment on 

a consistent basis
WHY?

“...the magnitude of the peak river flow is 

more important than the duration. The 

release of high flows for even one or two 

weeks will help maintain the flow 

conveyance capacity of the downstream 

channel.” 

-San Juan River Channel Processes and Flow Conveyance below 

Navajo Dam, NM. U.S. Department of Interior Technical Report No. 

SRH-2016-33 September 2016

WHEN?

• For maximum benefit, the release will be 

timed to coincide with the peak on the 

Animas River. 

• Daily communication with weather and 

flow forecasters throughout spring will help 

determine the peak timing. 

• Call or email any time for latest updates.
WHEN?

WHEN?

Based on history, the Animas peaked as early as 

May 21st, as late as June 18th with an average 

date of June 1st.

Years: 2008,2005,1997,1995,1993,1987 

But 1995 was an odd year, 

and had a lot of very late 

season snow. Unless we see 

that coming, I’m going to 

take it out.
WHEN?

Based on history, the Animas peaked as early as 

May 21st, as late as June 7th with an average 

date of May 28th.

Years: 2008,2005,1997,1993,1987 

WHEN?

Based on history, we can guess that the peak will 

occur around May 28-ish. This puts our ramp up 

beginning the previous week around May 22-ish. 

THIS IS A GUESS AND IS 

LIKELY TO CHANGE

It could be earlier! Look for a notice!

Call or email any time for an update 

sbehery@usbr.gov or 970-385-6560
Monitoring

Sediment monitoring in the channel is being 

conducted before and after the release.
Major San Juan River Basin Reservoirs

(4/22/2019)
Summary

• Peak snow water equivalent over Navajo was 29.9 inches (148% 

of median peak) on April 5th.

• Current Most Probable forecast into Navajo is 875kaf

• A short maintenance release is proposed for spring 2019.

• End of water year reservoir elevation is forecast to be around

6055 ft

• Releases will likely range between 300 and 800 cfs for the 

remainder of the water year, that necessary to maintain target 

baseflow in the critical habitat reach

• Next meeting Tuesday, August 20th, 2019
How You Can 

Access Information

Bureau of Reclamation

www.usbr.gov/uc

USGS

http://water.usgs.gov/nwis

Colorado Basin River Forecast Center

www.cbrfc.noaa.gov

For Operations Updates

• EMAIL UPDATES

• to be added, email rswickard@usbr.gov

• WEBSITE

• Navajo Reservoir:

http://www.usbr.gov/uc/wcao/water/rsvrs/notice/nav_rel.html

• All UC Operations

https://www.usbr.gov/uc/water/index.html

• PHONE

• Susan Behery 970-385-6560 

• WCAO Main Office 970-385-6500
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