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LTEMP Flow 

Experiments

Lee Traynham, Bureau of Reclamation

Joel Sankey, USGS GCMRC

Technical Work Group Meeting

January 13, 2022
LTEMP Experiments

“The overall approach attempts to strike a balance 

between identifying specific experiments and 

providing flexibility to implement those experiments 

when resource conditions are appropriate.”

“...rather than proposing a prescriptive approach to 

experimentation, an adaptive management-based 

approach that is responsive and flexible will be used 

to adapt to changing environmental and resource 

conditions...”

--2016 LTEMP ROD, p. B-9
LTEMP Process for Experiments

• Annual Reporting and TWG meetings

• Notification and Consultation to Tribes & PA Parties

• Implementation / Planning Team Recommendation

• DOI decision

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Resource Considerations 

1. Water quality and water delivery

2. Humpback Chub

3. Sediment

4. Riparian Ecosystems

5. Historic properties and traditional cultural properties

6. Tribal Concerns

7. Hydropower production and WAPA’s assessment of the 

status of the Basin Fund

8. Rainbow Trout Fishery

9. Recreation

10. Other Resources

Reference: 2016 LTEMP ROD, p. B-8,

Section 1.3 Implementation Process for Experiments Under Alternative D

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Potential LTEMP Flow Experiments 

GCD Experimental Flow Duration Implementation 

Window

Fall HFE up to 96 hours October - November

Extended Duration Fall HFE 97- 192* or 97-250 hours*** October - November

Spring HFE∆ up to 96 hours March – April

Proactive Spring HFE∆◊ 24 hours** April – June

Trout Management Flows up to 3 cycles/month for 4 months May – August

Macroinvertebrate Flows target 2-3 replicates May – August

* First test not to exceed 192 hours

** First test 24 hours

*** After first test, up to 250 hours

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WY 2022 Related Activities:

• Drought Response Ops at GCD – Lower winter releases, reallocation

• Consultation w/ Tribes re: Trout Management Flows – Jan kickoff

• Planning/Implementation Process Review 

∆ no Spring HFE in same WY as extended duration Fall HFE

◊ no proactive Spring HFE in same WY as sediment-driven Spring HFE
Current Activities & Next Steps

• Spring High Flow Experiment

o Jan-Mar - Evaluating sediment inputs for trigger conditions 

Planning/Implementation Team assessment 

• Bug Flows

 Oct 2021 – GCMRC Draft Synthesis Report & WAPA assessment of purchase power costs 

 Dec 2021 – Science Advisors Review 

o Jan 2022 – ARM, TWG Review and Discussion 

• Trout Management Flows

o Jan 2022 – Consultation w/ Tribes (Jan kickoff)

o TBD 2022 – GCMRC Literature Review (Jan TWG summary)

o TBD 2022 – BOR White Paper 

o TBD 2022 – Potential lab-based or small-scale studies

o TBD 2022 – Review of Upper Basin spike flow experiment 

• Spring Disturbance Flow

 Dec 2021 – GCMRC documents findings in Annual Report

o Jan 2022 – ARM, TWG Review and Discussion 

o TBD 2022 – O.1 and O.2 continued, O.11 

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Sand Budget Model Results

LTEMP Monthly Release Pattern

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-143 Ktons remain at end 

of accounting window
Sand Budget Model Results

DROA Monthly Release Pattern

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-103 Ktons remain at end 

of accounting window
Experiments Potentially 

Occurring in FY22
Potential Spring HFE -

FY22

 Currently within Spring accounting 

window (Dec. 1, 2021 – June 30, 

2022)

 Sand inputs from Paria not 

significant to date
Paria River Discharge and Sand 

Inputs

USGS Preliminary Data, 2022. Do Not Cite. 

(https://www.gcmrc.gov/discharge_qw_sediment/station/GCDAMP/09382000)

December 1, 2021 – January 13, 2022

Cumulative Sand Load ~ 20,959
Upper Marble Canyon Sand Mass 

Balance

USGS Preliminary Data, 2022. Do Not Cite. 

(https://www.gcmrc.gov/discharge_qw_sediment/reach/GCDAMP/09380000/09383050)

December 1, 2021 – December 31, 2021

Zero Bias Value = -18,000

Lower Uncertainty Bound = -28,000
December 1, 2021 – December 31, 2021

Zero Bias Value = 22,000

Lower Uncertainty Bound = 19,000

Lower Marble Canyon Sand Mass 

Balance

USGS Preliminary Data, 2022. Do Not Cite. 

(https://www.gcmrc.gov/discharge_qw_sediment/reach/GCDAMP/09383050/09383100)
Questions?