Navajo Unit Operations

Coordination Meeting

April 23rd 2024

1:00 PM

Farmington Civic Center / Microsoft Teams
• Introductions

• WY 2024 Operations to date

• Seasonal Weather Outlook– Erin Walter, NWS

• Spring Runoff Forecast– Ashley Nielson, CBRFC

• WY 2024 planned operations

• NMISC and TNC release update – Colleen Cunningham, NMISC

• Maintenance Update

• SJRIP Update

• Comments and Reports

Agenda
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Oct Nov Dec Jan Feb Mar Apr May

Pool Eleva�on (�)

Flow (cfs)

Navajo Reservoir Opera�ons WY 2024

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

San Juan River Flows WY 2024

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)
Reclamation Hydro Data 

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


Water Year 2024 is October 1, 2023-September 30, 2024

So far this water year:

• Navajo Modified Unregulated Inflow has totaled 161 kaf (54% avg 

for this date)

• Navajo Release has totaled 158 kaf (72% avg for this date)

• Calculated Evaporation has totaled 7 kaf 

• NIIP has diverted 28 kaf 

• San Juan-Chama has diverted 9 kaf

Water Year 2024 Totals
3 Grand Junction, CO

NRCS & CBRFC as of April 22nd 2024

Modeled SWE by Basin
4 Grand Junction, CO Upper San Juan River Basin
5 Grand Junction, CO Piedra Subbasin
6 Grand Junction, CO Upper San Juan Subbasin
7 Grand Junction, CO Animas Subbasin
8 Grand Junction, CO

Temperature/Precipitation Anomaly Since April 1
9 Grand Junction, CO

Drought Monitor
11 Grand Junction, CO

7-Day Forecast Over the San Juan Basin
12 Grand Junction, CO

7-Day Forecast Over the San Juan Basin
13 Grand Junction, CO Forecast Precip Over the San Juan Basin
15 Grand Junction, CO

Climate Prediction Center

6 to 10 Day Outlook
16 Grand Junction, CO

Climate Prediction Center

8 to 14 Day Outlook
17 Grand Junction, CO

Climate Prediction Center

One Month Outlook: May
18 Grand Junction, CO

Climate Prediction Center

Seasonal Outlook
19 Grand Junction, CO

Thank You!

email: erin.walter@noaa.gov

office phone: 970-256-9463

cell phone:720-384-7792
Soil Moisture Impacts on Water Supply / Runoff

Below normal soil moisture conditions → negative impact

 (decreased runoff efficiency)

Runoff Efficiency

● Soil moisture deficit must be fulfilled before runoff can occur.

● Timing/magnitude of runoff is ultimately a result of:

○ Spring Weather (precipitation/temperature)

○ Snow Conditions

○ Soil Moisture Conditions

○ Dust conditions

A few reminders.....

Fall 2023 Modeled Soil Moisture
Fall Modeled Soil Moisture Conditions Streamflow Conditions
2024 Water Year Precipitation

Observed precipitation is averaged by CBRFC defined basin elevation zones.

Above Navajo Reservoir: 90%

Animas River Basin: 90%
April Precipitation and Temperature 

April 1-22 Precipitation 

Observed precipitation is averaged by CBRFC defined basin elevation zones.

April Observed Daily Temperatures

 Durango
Snow Conditions: SNOTEL and CBRFC Model Snow

Model snow includes areas above and below SNOTEL sites.

● SNOTEL locations range from ~8,500-11,500’ 

● Modeled basins range from ~4600-14,000’

○ Modeled snow below 7500’ is not being shown on the map/plot.

April 22 SWE Conditions

NRCS SNOTEL Observed (Squares)

CBRFC Model (Significant Areas)
BLUE: >11000’

RED: 9500’-11000’

GREEN:6500-9500’’

DASHED:91-20 Median

Snow Conditions: CBRFC Model

BLUE: >11000’

RED: 9500’-11000’

GREEN:6500-9500’’

DASHED:91-20 Median

● Snow above 11000’: below normal

● Snow between 9500-11000’: near normal

● Snow below 9500’: below normal peak

● Melt has occurred at all elevations but significant melt below 11000’
April 22 Water Supply Volume Forecasts: San Juan River Basin

 50% exceedance forecasts range from ~60-75% average.

April-July Volume 

KAF / % 1991-2020 Average

*MP 50=Most Probable/50% Exceedance Forecast

*
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

Green solid: 1991-2020 average April-July volume

Green dotted: 1991-2020 median April-July volume

Brown dotted: Average observed

Orange dashed: 2024 Observed Streamflow

 Observed: 60 KAF (provisional)

90% chance of exceeding 320 KAF / 51% avg

 (dry spring weather)

Mid-Month Forecasts:

 50% chance of exceeding 410 KAF / 65% avg

 50% chance of NOT exceeding 410 KAF / 65% avg

 Apr 1 Forecast: 420 KAF / 67% 

10% chance of exceeding 615 KAF / 98% avg

 (wet spring weather)

NOTE: 20% chance that the April-July runoff will fall outside of the forecast range.
Navajo Reservoir Inflow

April 1st 50% Forecast 1991-2023

Mar 1st average error: 22% 

Apr 1st average error: 18% 

May 1st average error: 15% 

Navajo Reservoir Inflow Forecast Verification

Over forecast

Under forecast

Primary Sources of Forecast Error:

● Future Weather

○ Uncertainty in precipitation and temperature forecasts

○ Extreme dry/wet events results in larger errors

■ Rarely forecast in advance

● Model States: Is the model representative of reality?

○ Snow

■ SNOTELs and satellite images used to verify 

○ Soil moisture

■ Extensive analysis done in Fall
Peak Flow Forecast: Animas- Durango

Animas-Durango Peak Flow Forecast

Daily Peak Flow Forecast Magnitude

Peak Flow Forecast Overview

Zoom in on plot to see all historical years.

● Peak flow magnitude and timing will depend on Spring weather. 

● As flows increase and time of peak nears, the 10-day forecast 

hydrograph is a better source of information.
10-Day Streamflow Forecasts

https://www.cbrfc.noaa.gov/lmap/lmap.php?interface=river

● 10-day streamflow forecasts use:

○ 7-day precipitation forecast

○ 10-day temperature forecast

● Updated daily by ~10 am

● Include any known upstream reservoir release plans.
Contact Info

Contact Information

• Ashley Nielson - San Juan River Forecaster

• ashley.nielson@noaa.gov

• 801-524-5130 x333 

• Operational Hydrologist: in office

• 801-524-4004

• cbrfc.operations@noaa.gov

CBRFC Webpage

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

CBRFC Water Supply Presentations

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

Contact Info
Official 2024

Water Supply Forecast

(April-July)

as of mid-April 2024

Navajo: 410 kaf (65%* avg)

Vallecito: 135 kaf (76% avg)

Lemon: 34 kaf (71% avg)

Animas: 285 kaf (74% avg)

McPhee: 170 kaf (67% avg)

Powell: 5,400 kaf (85% avg)

*average of the 1991 – 2020 time period
Spring Operations 

Calculations

• Reclamation calculates how 

much water could be “available” 

for a spring peak release. 

• Calculation is based on the 

Decision Tree in the San Juan 

River Recovery Program’s(SJRIP) 

modified Flow Procedures 

(2018)
Spring Operations 

Calculations

• Forecast inflows into Navajo

• Expected contract fulfillment 

and ESA obligations for 

downstream target baseflows

• Calculate the forecast storage in 

the reservoir above the 

elevation of 6050 ft that will be 

on Sept 30th (end of water year)
Spring Operations 

Calculations

• The SJRIP will take the results of 

the Decision Tree into account, 

along with several other factors, 

when making their Spring 

Operations recommendation to 

Reclamation

• Reclamation will operate in 

accordance with the ROD (2006) 

to coordinate with SJRIP on the 

implementation of the 

recommendation.
Based on the current streamflow conditions, storage levels, and statistical outlooks 

based on 30 years of historical hydrology,

• Navajo Reservoir April-July runoff projections range from 330 kaf (53% of avg) to 

575 kaf (92% of avg) with a median of 410 (65% of avg)

• Current storage and projected runoff are insufficient to conduct a spring peak 

release as per the SJRIP Flow Recommendations.

• The SJRIP has recommended that no spring peak release be made in 2024.

• Releases in spring and summer 2024 will be made to target the SJRIPrecommended baseflows.

• Releases for the NMISC-TNC subcontracted JAN water will be made in two 10kaf 

increments in late summer and early winter.

Projected Operations WY 2024
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Apr 2024 May 2024 Jun 2024 Jul 2024 Aug 2024 Sep 2024 Oct 2024 Nov 2024 Dec 2024

Release (cfs)

Reservoir Eleva�on (�)

Navajo Reservoir Forecast Eleva�on and Release WY 2024

as of mid-April 2024 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

NIIP.Diversion cfs

End of WY Storage likely 

between 6030 and 6062 �

Reservoir likely to peak 

between 6050 and 6060 �

Spring release 350 cfs through 

June.

Summer releases will vary 

based on hydrology and 

weather and are likely to range 

between 500 and 1200 cfs.

NMISC and TNC have requested 

their JAN subcontracted 20 kaf 

be released as two 10 kaf 

events, one in late summer and 

one in early winter.
• An exploratory drilling project is underway on the dam face.

• You may see drill rigs and official personnel working along the face 

and crest of the dam through 2025.

• Periodic extended road closures will occur on NM 511 (crossing the 

dam) and NM 539 (dam crest).

• No road closures are planned during the summer recreational season 

(between Memorial Day and Labor Day). NM 539 will reopen on May 

16, 2024 and road work will resume in the Fall of 2024.

Maintenance Update 
• 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

Next Meeting Tues, August 20th
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