Navajo Unit Operations

Coordination Meeting

August 22, 2023 

1:00 PM

Thank you for joining. The meeting will begin shortly.


Navajo Operations Meeting

August 22, 2023

Water Year 2023

Runoff Review

Ashley Nielson

Senior Hydrologist

Colorado Basin River Forecast Center

National Weather Service/NOAA
● Water Year 2023 Conditions Summary

○ Precipitation

○ Snow

● 2023 Water Supply Forecast Evolution 

● 2023 Water Supply Forecast Performance

● Late August conditions

Outline
March Precipitation

Animas River Basin: 225%

Above Navajo Reservoir: 230%

Observed precipitation is averaged by CBRFC defined basin elevation zones.

March 2023 Precipitation
April-June Precipitation/Temperature

Monthly Max 

Temperature 

Anomaly

Monthly 

Precipitation % 

Average
April 1

Snow Conditions: CBRFC Model Snow Water Equivalent

May 1 May 15 June 1

Animas below Silverton San Juan-Pagosa Springs

● Peak SWE

○ Above normal at all elevations

● Peak SWE Timing

○ Near Normal above 9500’

○ Late below 9500’

● Melt Out

○ Delayed at all elevations

○ ~3 weeks late below 9500’

% of Median

BLUE: >11000’

GREEN:<11000’

DASHED:91-20 Median

GREY: Red Mountain SNOTEL

BLUE: >11000’

RED: 9500’-11000’

GREEN:<9500’

DASHED:91-20 Median
April-July Unregulated Observed Volumes

Volume in 1000’s acre-feet / Percent of 1991-2020 average

April-July observed volumes ranged from 135-175% of average. 

San Juan River Basin: April-July Observed Volumes 

Vallecito

252 / 142%

Animas-Durango

532 / 138%

Navajo Reservoir

1030 / 163%

San Juan-Pagosa

311 / 160%

Piedra-Arboles

299 / 165%

Rio Blanco-Pagosa

79 / 161%
The forecast increased from March to April due to much above normal precipitation and below normal 

temperatures in March. An adjustment to the model snow was made in mid-April resulting in an another forecast 

increase between April-May. The forecast remained steady after May. 

Water Supply Forecast Evolution: Navajo Reservoir Inflow

Blue shading: Daily Raw Model Guidance 90% - 10% exceedance range

Blue line: Daily Raw Model Guidance 50% exceedance

Pink line: Official forecast 90%, 70%, 50%, 30%, 10% exceedance

Brown dotted: Average observed

Orange dashed: 2023 Observed Streamflow

Apr-Jul Observed Volume

1030 KAF / 163 %

Median/Average Wet March

Model Snow 

Update

735 KAF

117%

945 KAF

150%

1010 KAF

161%

1010 KAF

161%

Navajo Inflow Forecast Evolution Plot

985 KAF

157%
Forecast Performance: Navajo Reservoir Inflow Volume

2023 Forecast Error:

● Forecast errors fell into the normal range of errors 

for the April-June forecasts. 

● January-March forecast errors were higher than 

normal and fell outside of the min/max forecast 

range due to:

○ March precipitation being in the top10th

percentile. 

○ Model not capturing all of the March 

precipitation which resulted in a model snow 

update in mid-April.

■ Gages are less reliable in large snow 

years.

50% Forecast Mean Absolute Error

Over forecast

Under forecast

Over forecast

Under forecast
Forecasts Performance: Animas River Peak Flow 

Mid-April Peak Flow Forecast

4410 cfs on 5/26

100% of avg 

Unsettled spring weather with periods of above and below normal 

temperatures,cloud cover, and sporadic precipitation produced an 

extended period of high flows rather than a single well defined peak.This 

resulted in the early season peak flow forecasts that assume “normal” 

spring weather to over forecast the peak flow.
Late August Conditions

Streamflow Precipitation

August 1-11

July
• Water Supply Conditions:

• April -July observed unregulated runoff volumes ranged from 135-175% of average.

■ March was a game changer for water supply conditions.

● Above normal precipitation and below normal temperatures.

■ Above normal snow conditions and delayed melt, particularly at lower elevations.

■ Unsettled spring weather resulted a extended period of high flows.

● Near normal peak flows

● Less efficient runoff in the Animas

• Current conditions

■ Delayed start to the monsoon

● Dry July and August...so far

■ Streamflows are near average but declining rapidly to below normal conditions.

• Water Supply Forecasts

• Forecasts increase from Mar-May due March precipitation and snow model adjustment.

• Early season forecasts (Jan-Mar) had higher than normal errors. 

■ This in not unexpected given the March precipitation and model assumptions.

• Late season (Apr-Jun) forecasts performed well.

• Peak flow forecasts were over forecast.

Summary:
CBRFC Webpage

https://www.cbrfc.noaa.gov/

CBRFC Water Supply Presentations

https://www.cbrfc.noaa.gov/present/present.php

Contact Information

Ashley Nielson

Colorado Basin River Forecast Center

Hydrologist-San Juan River Forecaster

Email: ashley.nielson@noaa.gov

Phone: 801-524-5130 x333

Operational Hydrologist

Available 7 days as week: 6:30am-4pm

Email: cbrfc.operations@noaa.gov

Phone: 801-524-4004
Final 

Water Supply 

(April-July)

Navajo: 1,028 kaf (163% avg)

Vallecito: 252 kaf (142% avg)

Lemon: 67 kaf (140% avg)

Animas: 532 kaf (138% avg)

McPhee: 527 kaf (207% avg)

Powell: 10,619 kaf (166% avg) 
5990

6000

6010

6020

6030

6040

6050

6060

6070

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

Pool Eleva�on (�)

Flow (cfs)

Navajo Reservoir Opera�ons WY 2023

Pool Eleva�on (�) Inflow (cfs) Release To River (cfs) NIIP (cfs)
0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000

8,500

9,000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

Flow (cfs) 

San Juan River Flows WY 2023

San Juan at Shiprock (cfs) San Juan at 4C (cfs) San Juan at Bluff (cfs) San Juan at Farmington (cfs)

Animas at Farmington (cfs) Navajo Release (cfs) 7-Day Avg Target Base Flow (cfs)
Navajo Dam Record of Decision 2006
Spring Peak Release 

Determination

Reclamation operates to 

the ROD (2006).

The decision tree is used 

as a guide to aid in 

determining sufficient 

water available for a spring 

peak release. The final 

volume, shape, and timing 

is subject to conditions at 

the time of the release. From the SJRIP 2018 Flow Recommendations update
FLOW GOALS April 1 - July 31 2023

SAN JUAN AT FOUR CORNERS

Goal Flow Goal Days Days in 2023

2500 10 74 MET

5000 21 38 MET

8000 10 12 MET

10000 5 0
• SJRIP-Recommended Spring Peak Release: 

• May 13 – June 13 ramp-up and peak, June 15 – June 26 ramp-down

• Total volume over base 242.2 kaf

• Jicarilla Apache Nation Subleased Water to The Nature Conservancy 

and New Mexico Interstate Stream Commission:

• June 13- June 15 

• 4,000 cfs for 48 hours

• Total volume over base 14.7 kaf

• Total Release over base release: 256.9 kaf

Spring 2023 High Flow Release Volumes 
Reclamation Hydro Data 

https://www.usbr.gov/uc/water/hydrodata/reservoir_data/site_map.html https://www.usbr.gov/uc/water/hydrodata/reservoir_data/920/charts/pool_elevation.html

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5990

5995

6000

6005

6010

6015

6020

6025

6030

6035

6040

6045

6050

6055

6060

6065

6070

Release (cfs)

Reservoir Eleva�on (�)

Navajo Reservoir Forecast Eleva�on and Release

as of August 2022 24-Month Study

Release based on Min Probable Forecast Release based on Most Probable Forecast Release based on Max Probable Forecast

Reservoir Eleva�on based on Min Probable Forecast Reservoir Eleva�on based on Most Probable Forecast Reservoir Eleva�on based on Max Probable Forecast

September 30, 2023

Max Probable 6048 �

Most Probable 6045 �

Min Probable 5993 �

WY-2023

MIN probable min

eleva�on of 6010 �

WY-2023

SJRIP- Recom Spring Ops:

Max Probable: 51-day SPR

Most Probable: No SPR

Min Probable: No SPR

September 30, 2022

Max Probable 6031 �

Most Probable 6022 �

Min Probable 6015 �

WY-2023

MIN probable min

eleva�on of 5992 �

How did 

the Ops 

forecast 

from last 

August do?

Presented Aug 23, 2022
0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5990

5995

6000

6005

6010

6015

6020

6025

6030

6035

6040

6045

6050

6055

6060

6065

6070

Release (cfs)

Reservoir Eleva�on (�)

Navajo Reservoir Forecast Eleva�on and Release

as of August 2022 24-Month Study 

Release based on Min Probable Forecast Release based on Most Probable Forecast

Release based on Max Probable Forecast Reservoir Eleva�on based on Min Probable Forecast

Reservoir Eleva�on based on Most Probable Forecast Reservoir Eleva�on based on Max Probable Forecast

Actual Pool Eleva�on Actual Release

How did 

the Ops 

forecast 

from last 

August do?

• MIN PROBABLE – There is a 90% chance the inflow will be higher than 

this

• MOST PROBABLE – There is a 50% chance the inflow will be higher 

than this and a 50% chance the inflow will be lower than this.

• MAX PROBABLE – There is a 10% chance the inflow will be higher 

than this

• This captures 80% of the uncertainty. There remains a 10% chance the 

inflow will be lower than the Min Probable and a 10% chance that the 

inflow will be higher than the Max Probable. How wide this range is 

can give an indication of the level of uncertainty.

Forecast Probabilities Refresher
August 22nd, 2023

Seasonal Outlook

Navajo Reservoir
2023 Seasonal Outlook

30-Day & 7-Day Departure from Normal Temperature
30-Day & 7-Day Departure from Normal Precipitation

2023 Seasonal Outlook
2023 Seasonal Outlook

Soil Moisture Drought Monitor
US Drought Monitor

2023 Seasonal Outlook
NWS Max Temperature Forecasts

2023 Seasonal Outlook
7

72-Hr Precipitation Estimate Ending Saturday 6 PM MDT

2023 Seasonal Outlook
Climate Prediction Center: 6 to 10 Day Outlook

2023 Seasonal Outlook
Climate Prediction Center: 8 to 14 Day Outlook

2023 Seasonal Outlook
Climate Prediction Center: September Outlook

2023 Seasonal Outlook
Current ENSO Status & Predictions: Updated August

El Nino conditions are anticipated to continue through the Northern Hemisphere winter (greater than 95% through Dec, 2023 - Feb, 2024)

Current ENSO Alert System Status: El Nino Advisory

95% chance of El Nino 

continuing Dec - Feb, 2024

2023 Seasonal Outlook
Seasonal Outlook

So what does 

that mean in terms 

of weather??...
Seasonal Outlook

“Typical” ENSO Patterns & Impacts
Climate Prediction Center: Seasonal Outlook Oct - Dec

Seasonal Outlook
Climate Prediction Center: Seasonal Outlook Dec - Feb

Seasonal Outlook
Thank you!

Any Questions?

email: erin.walter@noaa.gov

office phone: 970-256-9463

cell phone: 720-384-7792
0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

6040

6045

6050

6055

6060

Release (cfs)

Reservoir Eleva�on (�)

Navajo Reservoir Forecast Opera�ons Fall and Winter 2023

as of August 2023 CBRFC Forecast

Release based on Min Probable Forecast Release based on Most Probable Forecast

Release based on Max Probable Forecast Reservoir Eleva�on based on Min Probable Forecast

Reservoir Eleva�on based on Most Probable Forecast Reservoir Eleva�on based on Max Probable Forecast

Actual Eleva�on Actual Release

End of water year pool eleva�on 

will likely be between 6050 � and 

6055 �.

Summer releases dependent on 

irriga�on, weather, and available 

hydrology. Likely will range 

between 500 and 800 for 

remainder of season, depending 

on weather. 

Winter releases will likely be 

near 300 cfs, depending on 

weather

The August Inflow forecast was for 

20 kaf at the �me of this model run. 

The Mid-August update downgraded 

the forecast to 5 kaf.

As of August 21st, -2.3 kaf has been 

observed. Weather plays a huge role!
Based on current streamflow conditions, storage levels, and statistical 

outlooks based on 30 years of historical hydrology,

• Runoff projections for WY 2024 range from 465 kaf (51% avg) – 1,500 

kaf (165% avg) with a median projection of 845 kaf (93% avg).

• 60% chance of having sufficient available water to conduct a spring 

peak release

• <3% chance of falling below 5990 ft (min active storage)

Projected Operations WY 2024
• WY 2023 April-July runoff was well above average throughout the San Juan River 

Basin. Navajo Modified Unregulated Inflow totaled 1,028 kaf which was 163% of 

average.

• The current elevation is 6053.85 ft with a live storage of 1,216 kaf (74% full) and an 

active storage of 590 kaf (58% full). This is 94% of average for this time of year.

• A spring peak release was conducted that totaled 257 kaf over base, accomplishing 

three of four ESA goals. 

• Summer and early Fall releases will likely range between 500 and 800 cfs during 

irrigation, subject to weather at the time. Late fall and winter releases will be lowered 

likely near 300 cfs as long as the downstream target baseflow can be satisfied.

• The current outlook for WY 2024 is wide, ranging from 51% of average to 165% of 

average. 

Summary Next Meeting January 2023
• Navajo Project Notices: https://www.usbr.gov/uc/wcao/water/rsvrs/notice/nav_rel.html

• Navajo Monthly Forecast Update: https://www.usbr.gov/uc/water/crsp/cs/nvd.html

• UC Water Operations Home: https://www.usbr.gov/uc/water/index.html

• Teacups: https://www.usbr.gov/uc/water/basin/index.html

• 24-Month Study: https://www.usbr.gov/uc/water/crsp/studies/index.html

• DROA: https://www.usbr.gov/dcp/droa.html

Links
Reclamation Contacts:

Marc Miller – Water Management Group Chief

970-385-6541 mbmiller@usbr.gov

Susan Novak Behery – Hydrologic Engineer

970-385-6560 sbehery@usbr.gov

To be added to Navajo Dam notices email list, send an email to 

westcoloareaoffice@usbr.gov 

Useful Links

Reclamation: www.usbr.gov/uc

USGS: water.usgs.gov/nwis

CBRFC: cbrfc.noaa.gov