Potential LTEMP Experiments

Spring/Summer 2022 

Technical Work Group Meeting

 Traynham, Bureau of Reclamation

 Kennedy, USGS, Southwest Biological Science Center, 

April 13, 2022 

Grand Canyon Monitoring and Research Center
 

 

 

LTEMP Process for Experiments 

• Annual Reporting and TWG meetings 

• Notification and Consultation to Tribes & PA Parties 

• Implementation / Planning Team Recommendation 

• DOI decision 

3 
 

 

 

 

 

Potential LTEMP Flow Experiments 

Water Year 2022 

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∆

Proactive Spring HFE∆◊

Trout Management Flows 

up to 96 hours 

24 hours** 

up to 3 cycles/month for 4 months 

March – April 

April – June 

May – August 

Macroinvertebrate Flows target 2-3 replicates May – August 

* First test not to exceed 192 hours ∆ no Spring HFE in same WY as extended duration Fall HFE

** First test 24 hours ◊ no proactive Spring HFE in same WY as sediment-driven Spring HFE 

*** After first test, up to 250 hours 

4 

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 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Review – 2021 Bug Flows 

• Recommendation #2: 

To inform discussion of potential future implementation of the Bug

Flows experiment, the PI Team recommends, by consensus, the 

following next steps for DOI to consider: 

o The PI Team commits to document its considerations in a memo to DOI and the 

LTEMP Leadership Team. 

Request that GCMRC state resource implications for non-implementation of Bug 

Flows in WY 2021. 

Request that GCMRC complete a report by January 2022 summarizing 

experimental findings and discuss how the observations of non-implementation 

compared to the predictions. 

Request that WAPA provide additional information regarding purchase power 

cost estimates, including assumptions and uncertainty, such that effects to 

hydropower are minimized if Bug Flows are implemented in the future. 

Request that the Science Advisors Program establish and convene an 

independent review panel to evaluate the Bug Flows experiment in achieving its 

objective and to develop opportunities for further experimentation. 5 
 

 

 

Goal 2. Natural Processes 

 Restore, to the extent practicable, ecological patterns and processes 

within their range of natural variability, including the natural abundance, 

diversity, and genetic and ecological integrity of the plant and animal

species native to those ecosystems. 

Regulated Flows 

Natural Flows 

Natural 

Processes? 

Annual 

Seasonal 

Daily pattern 

all different 
- - - - -

-

-

-

-

-

- -

-

 

 

30 years of Adaptive Management Experimentation:1990-2020

HFE Protocol Established 2004 HFE 2008 HFE 2011 1996 HFE (Nov ’12, Nov ’13, Nov ’14, Nov ’16, Nov ’18) (November) (March) Equalization (March/April) High Flow Experiments Operations 

(HFEs) 

2000 Low Summer Steady 

Flow Experiment. 2008 2012 Fall 

Steady Flow 

2018 2020 Bug Flow 

Dam operations 

constrained Experiments 

Low steady releases from Steady Flow experiment. Low steady 

June August. Experiment. Low releases on weekends, 

steady releases in May August 

September October (THIS REPORT) 

Start of Key Monitoring 

Datasets Evaluated 2012 GPP, Community science insect monitoring 2008 Invertebrate drift 

in Report 

2009 Juvenile native 

fish monitoring 
-

 

 

 

Low Summer Steady Flow Experiment-2000 

 ~120 days of steady flow 

 Target: juvenile native fish 

 Food web monitoring relied

on static metrics 

 algae biomass 

 benthic invertebrates (larvae) 

 Large impact to hydropower 

 High demand summer months 

 Exacerbated by energy market 

manipulation (ENRON) 

fish length, abundance 

From Ralston 2011, USGS Open File Report 2011 1220 
 

 

 

 

Fall Steady Flow Experiment-2008 to 2012 

 60d/yr steady flow for 5 years 

 Target: juvenile native fish 

 New tools for food web 

monitoring developed 

 2008-Invertebrate drift 

 2009-Juv. native fish growth/surv 

 Lower impact to hydropower

than 2000 experiment 

 2012-GPP, comm. light trapping 

 Low demand months 

 Fewer days/yr 

GPP Adult midge abundance From Hall and others 2015, Limn.& Ocean. 
 

 

 

Bug Flow Experiment-2018-2020 

 ~36d/yr steady flow for 3 years 

 Targeted egg laying process 

 Lower cost than 2008-2012 

experiment 

 Fewer days/yr 

 Low demand weekends 
 

 

 

 

Bug Flows Synthesis

Key Findings 

 Enhanced natural processes 

and improved food base 

 More egg laying substrates 

 More insect emergence 

 More caddisflies 

 But not more midges 

 More algae (GPP) 

 Enhanced rainbow trout fishery 

 Higher catch rates

“Objective: Improve food base productivity 

and abundance or diversity of mayflies, stoneflies, 

and caddisflies” LTEMP Table 4. 

Unpublished data, subject to change, 

do not cite. 
 

 

 

 

UPDATED RESULTS  Cessation of Bug Flows 

associated with: 

~50% decline in midges 

Consistent with hypothesis that Bug Flows 

was improving conditions for midges 

~25% decline in caddisflies 

Tough to untangle what this means -no direct benefits to larvae or emergence in ‘21 -But preceded by 3 years of good egg laying 

Unpublished data, subject to change, 

do not cite. 

10 
GCMRC Recommendation 

 1) Repeat weekend experiment—May to August 

 Solid design, easy comparison, reduce uncertainties 

 2) Expand, add months—March to October 

 More of a good thing 

 3) Start earlier—March to June 

 Focus on GPP and larval benefit, lower cost 

 3) Start earlier, add fall mo.—March to June, 

Sept to Oct 

 Longer experiment yet reduces impact to hydropower 

 4) Shorten experiment (e.g., May-June only) 

 Lower cost 

?? 
Conclusion 

 The best available science 

continues to indicate Bug 

Flows were successful at 

Enhancing Natural Process 

that sustain the Colorado River 

ecosystem 
 

 

Planned monitoring—2022 

 Community Science light traps 

 ~ 750 samples per year, throughout Canyon 

 Robust dataset for tracking insect response 

 Fish diet and food web studies 

 Q: Are changes in food base benefitting native fish? 

 Non-lethal methods to honor tribal values 

 Stable isotopes 

 Fecal e-dna 

 Lavage (stomach pumping) where possible 

Kennedy et al. 2016 

BioScience 

Unpublished data, subject to change, do not cite. 

?? 
 Notify GCDAMP stakeholders, 

public 

TWG Meeting 

Draft Report distributed 

AMWG/TWG for PI Team review 

Webinar 

Tech Team Call #4.5 Tech Team Call #5 

Draft Report review Final Report 

Leadership Team mtg; 

DOI decision 

Leadership Team 
 

 

 

 

 

 

Potential Hydrograph Alternatives 

• Hydrograph characteristics: 

o Implementation window May 1 – August 31 

o Steady weekend lows, fluctuating weekday

releases 

o Weekend lows “H” cfs higher than weekday lows 

o Weekly, Monthly, and Annual release volumes

would not change. 

• FY22 Hydrograph Alternatives* 

o Alt 1: H level  Base Hydrograph, H750** 

o Alt 2: H level  H1 (zero offset) 

o Alt 3: H level  H -250 (negative offset) 

* All alternatives feature 36 days of steady flows 

** H750 - Weekend releases are 750 cfs higher than weekday lows 6 
7 
 

 

 

 

 

 

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  Other Considerations 

9. Recreation • Ops uncertainty – annual 

• Ops uncertainty – monthly 10. Other Resources 

• Non-native fish 

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

Section 1.3 Implementation Process for Experiments Under Alternative D 

8 
 

 

 

 

Basin Fund Status & Impacts 

• Projected Basin Fund Decline 

o  $83M by end of FY22 

• Projected costs of FY22 Bug Flows: about $1.4M 

• Prior year costs 

o FY18 – actual $165K (estimated $335K) (H1000) 

o FY19 – actual $327K (estimated $332K) (H750) 

o FY20 – actual TBD ($750K-$1M) (estimated $407K) (H750) 9 
Stakeholder Feedback 

• AMWG/TWG Informational webinar (3/30) 

o Request for comments by Friday, April 8 

• Support 

o Fly Fishers International/Trout Unlimited Recreational Anglers 

• Opposed 

o Colorado River Energy Distributors Association 

11 
Technical Recommendation 

• Summary 

o Implement Bug Flows May 1 – Aug 31, 2022 

o Adverse effects to hydropower; defer on “unacceptable” 

o Uncertainty in hydrology, operations, resources 

 Bi-weekly PI Team coordination May – August 

 New conditions, unanticipated effects, potential off-ramps 

o Further consideration of design improvements 

•Team Perspectives (of 15) 

o Support (10) 

o Opposed (1) 

o Abstained (2) 

o Absent (2) 

10 
THANK YOU ! ! !