GCDAMP FLAHG Page

Flow Experiments Ad Hoc Group (FLAHG) ESTABLISHED JANUARY 15, 2020, Status: Active Charge In accordance with direction provided by the AMWG at its August 18, 2018 meeting, and the Secretary Designees August 14, 2019 guidance to BOR and GCMRC, the FLAHG is charged with working with GCMRC to evaluate opportunities for conducting higher spring releases that may benefit high value resources of concern to the GCDAMP (recreational beaches, aquatic food base, rainbow trout fishery, hydropower, humpback chub and other native fish, cultural resources, and vegetation), fill critical data gaps, and reduce scientific uncertainties. As a starting point, the FLAHG shall consider the benefits of and opportunities for conducting higher spring releases within power plant capacity. The FLAHG and GCMRC will report their initial findings to the TWG in April 2020 so that the TWG and GCMRC can report their conclusions to the AMWG in May 2020. The FLAHG is also charged with working with GCMRC to develop and propose a project element in the FY 2021-2023 Triennial Budget and Work Plan to identify other spring high flow options that may be allowed under the current LTEMP ROD (as determined by DOI) that may benefit high valued resources of concern to the GCDAMP (defined above), fill critical data gaps, and reduce scientific uncertainties. Members Peggy Roefer (chair), Jeff Arnold, Jan Balsom, Cliff Barrett, Rob Billerbeck, David Brown, Peter Bungart, Kelly Burke, Shane Capron, Winkie Crook, Craig Ellsworth, Charlie Ferrantelli, Clarence Fullard, Michelle Garrison, Paul Harms, Brian Healy, Leslie James, John Jordan, Vineetha Kartha, Ted Kennedy, Jakob Maase, Ryan Mann, Craig McGinnis, Jessica Neuwerth, Clayton Palmer, Bill Persons, Richard Powskey, Ben Reeder, Peggy Roefer, Scott Rogers, Seth Shanahan, Larry Stevens, Jim Strogen, Lee Traynham, Steve Wolff, Kirk Young. Invited technical advisors: Helen Fairley, Heather Patno, Mike Moran, Scott VanderKooi

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Spring Disturbance Flows To test both spring and fall HFEs, the HFE protocol proposed using two sediment accounting periods. These sediment accounting periods are used to track the quantity of new Paria River sand available for building beaches in Marble Canyon during an HFE, and HFEs are only triggered if the quantity of new sand is large. This sediment accounting approach to triggering HFEs, coupled with state-of-the-art sediment monitoring (Topping and Wright 2016), eliminates the possibility of unintentionally scouring sediment resources from Marble Canyon during HFEs. When the HFE protocol was first proposed, it was estimated that sediment-triggered fall HFEs would occur approximately two out of every three years and sediment-triggered spring HFEs would occur approximately once every three years (Wright and Kennedy 2011). [1] Although Sediment-Triggered Spring HFEs and Proactive Spring HFEs are now possible, analysis of Paria River discharge data indicates that Sediment-Triggered Spring HFEs may occur less frequently than originally estimated (Grams and Topping 2018). Sediment accounting data available since the HFE protocol was operationalized in 2012 bear this out. Specifically, since 2012 the sediment trigger for a fall HFE has been reached 6 times (i.e., 2012-2016, 2018; no HFE occurred in 2015 owing to green sunfish) while the sediment trigger for a spring HFE has never been reached (Grams and Topping 2020). Testing of 5 fall HFEs over the past 8 years has benefitted sediment resources and reduced uncertainties concerning sandbar response to HFEs in general (Figure 2). However, regular testing of fall HFEs since 2012 is also correlated with a growing population of brown trout in Lees Ferry (Runge and others 2018) and critical uncertainties concerning the role of spring HFEs in achieving biological resource objectives remain unanswered (Figure 2). By May 2020, the FLAHG and GCMRC completed design of a conceptual hydrograph that included a high spring release that was within power plant capacity. The FLAHG hydrograph capitalizes on a unique low flow of 4,000 ft3 /s for 5 days, which is needed to conduct maintenance on the apron of Glen Canyon Dam (see Figure 3). The FLAHG hydrograph proposes to follow this low flow disturbance with a high flow disturbance that will culminate in a discharge of up to 25,000 ft3 /s for 82 hours. This combination of desiccation at low flows followed by scour at high flows is hypothesized to disturb benthic habitats to a much greater extent than either the low or high flows alone (Kennedy and others 2020). [2] Below we present predicted effects of the FLAHG hydrograph on the 11 LTEMP Resource Goals using the Knowledge Assessment rubric from 2019 (http://gcdamp.com/index.php?title=Portal:GCDAMP_Knowlege_Assessments). For comparison, and to anchor predictions concerning the FLAHG hydrograph, we also used the Knowledge Assessment framework to predict effects of Spring and Fall HFEs on LTEMP Resource Goals. To simplify analysis of hydrograph impacts, the FLAHG narrowed consideration of testing this hydrograph to sometime in March based on the following two main reasons: 1) both the 1996 and 2008 Spring HFEs also occurred in March, which will simplify evaluation and comparison of new biological data that might be collected around a FLAHG hydrograph to earlier data from those spring HFEs, and 2) a March test of the FLAHG hydrograph will minimize adverse impacts of the low flow to Recreational Experience by avoiding the start of the commercial river trip motor season in April. Knowledge Assessment groups often evaluated multiple specific measures to capture all the facets of a given LTEMP goal. For example, the goal for Rainbow Trout Fishery is, “Achieve a healthy high-quality recreational rainbow trout fishery in GCNRA and reduce or eliminate downstream trout migration consistent with NPS fish management and ESA compliance.” To capture both facets of this goal, the Knowledge Assessment team considered two specific measures: rainbow trout abundance in Lees Ferry, and rainbow trout abundance at the Little Colorado River confluence. The predicted resource responses to a given action often varied, depending on which specific measure was considered. We capture this variation in predictions by presenting bookend, “lowest performing” and “highest performing”, scenarios gleaned from the assessments and their differing specific measures. Note that the assessment summaries and graphs are based on detailed assessments for each resource that were performed by multiple subject matter experts (see section V. Acknowledgements for a complete list of participants). Those detailed assessments are contained in a spreadsheet for each resource that accompany this document. The detailed resource assessments were based on consideration of peer-reviewed literature, modelling, and other quantitative science as well as more qualitative expert opinions, similar to previous Knowledge Assessments. [3]

Links The HFE page DOI Direction page GCDAMP Budget page BAHG page Projects Project Element O.1. Does Disturbance Timing Affect Food Base Response? Project Element O.2. Bank Erosion, Bed Sedimentation, and Channel Change in Western Grand Canyon Project Element O.3. Aeolian Response to a Spring Pulse Flow Project Element O.4. Riparian Vegetation Physiological Response Project Element O.5. Mapping Aquatic Vegetation Response to a Spring Pulse Flow Project Element O.6. Brown Trout Early Life Stage Response to a Spring Pulse Flow Project Element O.7. Native Fish Movement in Response to a Spring Pulse Flow Project Element O.8. Do Disturbance Flows Significantly Impact Recreational Experience? Project Element O.9. Are There Opportunities to Meet Hydropower and Energy Goals with Spring Disturbance Flows? (funded in N.1). Project Element O.10. Sandbar and Campsite Response to Spring Disturbance Flow (funded in B.1).  Project Element O.11. Decision Analysis Presentations and Papers Draft AMWG Agenda - NOV20 FLAHG Charge AMWG Motions Action Items FINAL FLAHG Predicted Effects document Final BAHG recommendation Project O TWG Motions Action Items Project O - AMWG November Version Project O - AMWG November Version - Track Changes 2020 Flow Ad Hoc Group Update Ecological Significance of Diminished Spring Freshets Process May 2019 AMWG Action Item It was suggested that the TWG take up consideration of the remaining “HFE Assessment” action item, which reads, “A next step would be for GCMRC to identify experimental flow options that would consider high valued resources of concern to the GCDAMP (i.e., recreational beaches, aquatic food base, rainbow trout fishery, hydropower, humpback chub and other native fish, and cultural resource), fill critical data gaps, and reduce scientific uncertainties.” The AMWG did not object to the remaining action item passing from GCMRC to the TWG. DOI Direction Dr. Petty Guidance Memo – Page 3 – “In response to stakeholder input at recent AMWG meetings, the feasibility of conducting Spring High Flow Experiments (HFE), along with modeling for improvements and efficiencies that benefit resources including natural, cultural, recreational, and hydropower should be explored. As a potential starting point, I encourage you to consider opportunities to conduct higher spring releases within power plant capacity, along with spring HFEs that may be triggered under the current LTEMP Protocol” 2021-2023 Triennial Budget and Work Plan TWG Motion The TWG recommends that the AMWG recommend for approval to the Secretary of Interior the Triennial Work Plan and Budget FY 2021-2023 as provided to the TWG on June 23, 2020 and as requested to be revised by the TWG during their meeting on June 23 and 24, 2020. Revisions requested by the TWG on June 23 and 24, 2020: Include the GCMRC B.4 work element in the budget ($58,000 for first 2 years and $64,000 for year 3). Remove and/or reduce GCMRC D.2 (approximately $39,000 in year 1, $36,000 in year 2, and $54,000 in year 3) and GCMRC D.3 (approximately $28,000 in year 1, $29,000 in year 2, and $0 in year 3). Include Havasu Creek and LCR-mouth gage in GCMRC A.1 at 17,000/year. Please change GCMRC Project N verbiage (Pg 294) from “For example, modeling a change in ramp rates to maintain or improve the hydropower and recreational resource objectives is a possible application of GCMRC Project N.” to: “For example, modeling a change in ramp rates to improve the hydropower resource objective is a possible application of Project N.” In accordance with direction provided by the AMWG as described in the FLAHG charge, include a project and/or project element to support the FLAHG charge, and provide funding if necessary. Remove Reclamation B.4, TWG Chair reimbursement (25,000 for FY 2021) Propose AGFD and GCMRC look to integrate work efforts to allow for an additional TRGD site to be monitored. Cost estimate for going from 1 TRGD to 2 TRGD sites is approximately 67,000. Prioritize the use of available, unprogrammed and unspent funds from FY 2020, 2021 and 2022 towards funding GCMRC G.6 (JCM-West) in 2023. August 2020 AMWG budget recommendation AMWG recommends to the Secretary of the Interior the Glen Canyon Dam Adaptive Management Program Triennial Budget and Work Plan—Fiscal Years 2021-2023 (July 29, 2020 draft), subject to the following: Removal from GCMRC Project N the following verbiage: "Past research into changes in regional energy costs attributed to alteration of GCD operations have shown that no changes occur in hourly prices (U.S. Department of Interior, 2016b). Specifically, hourly energy prices at the regional hub important to GCD (Palo Verde) remain approximately the same with variation in production of energy at GCD. In addition, the analysis of experiments is a short-run analysis, assuming that demand for energy is inelastic (demand does not change with small changes in prices) and surplus power capacity exists. Therefore, changes in $/MW and $/MWh are accurate representations of the changes in consumer and producer surplus when evaluating minor, short-run changes in GCD operations. However, long- run changes in the energy sector may lead to a different economic outcome and a more complete modeling approach would be required. The evaluation of GCD operation and long-run changes in the electricity sector such as the integration of renewable energy, repurposing of federal hydropower resources, or power system capacity expansion would require a significant increase in research scope." Consideration of GCMRC Project O is deferred, but will be included in the 2021-2023 Triennial Budget and Work Plan as a proposal to be considered for the Reclamation C.5 Experimental Management Fund, pending revisions to be made by GCMRC and the Bureau of Reclamation and review by the Technical Work Group. After consideration and if recommended by AMWG, a springtime disturbance flow will be planned to occur in coordination with Glen Canyon Dam apron repairs, to ensure sufficient time to integrate the information and learning about the importance of springtime high flows into the 2021-2023 TWP, subject to an evaluation of the resource conditions described in the LTEMP ROD. AMWG acknowledges and appreciates the effort to develop Project O in response to elements of the TWG Recommendation for the 2021-2023 Triennial Budget and Work Plan, consistent with guidance from the Secretary’s Designee (memo issued August 14, 2019), and in support of the Flow Ad Hoc Group charge. GCMRC is commended for their effort. AMWG members will submit written comments to GCMRC and Reclamation on Project O no later than Friday, September 4, 2020. GCMRC and Reclamation will make revisions based on comments received and will submit the revised Project O plan for TWG consideration by Wednesday, October 7, 2020, for discussion at the October 2020 TWG meeting. AMWG directs the TWG to review the revised Project O and to forward a revised Project O recommendation for AMWG consideration no later than Friday, October 30, 2020. The AMWG will act on the TWG recommendation no later than Friday, November 20, 2020. BAHG Recommendation (10/08/2020) The BAHG expresses support for a Project O that evaluates the effects of the proposed FLAHG hydrograph. The BAHG recommends to the TWG the following elements outlined in Project O (July 2020 draft) be prioritized in the following rank order for funding a first year of work effort: Tier 1 Projects (Weighted mean rankings from BAHG rating exercise: 9.3 and 8.6). The BAHG identified that these project elements are the most important for understanding the effects of the proposed FLAHG hydrograph. Project Element O.1. Does Disturbance Timing Affect Food Base Response? Project Element O.5. Mapping Aquatic Vegetation Response to a Spring Pulse Flow Tier 2 Projects (Weighted mean rankings from BAHG rating exercise: 6.8, 5.7, and 3.9). The BAHG identified that these project elements are very important for understanding the effects of the proposed FLAHG hydrograph. Project Element O.6. Brown Trout Early Life Stage Response to a Spring Pulse Flow Project Element O.2. Bank Erosion, Bed Sedimentation, and Channel Change in Western Grand Canyon Project Element O.7. Native Fish Movement in Response to a Spring Pulse Flow Tier 3 Projects (Weighted mean rankings from BAHG rating exercise: ≤ 0). The BAHG identified that these project elements are important for understanding effects of the proposed FLAHG hydrograph. Project Element O.11. Decision Analysis Project Element O.4. Riparian Vegetation Physiological Response Project Element O.8. Do Disturbance Flows Significantly Impact Recreational Experience? Project Element O.3. Aeolian Response to a Spring Pulse Flow The BAHG acknowledges that the following projects are already funded in the TWP as Projects N.1 and B.1, thus a recommendation on rank priority is unnecessary: Project Element O.9. Are There Opportunities to Meet Hydropower and Energy Goals with Spring Disturbance Flows? (funded in N.1). Project Element O.10. Sandbar and Campsite Response to Spring Disturbance Flow (funded in B.1).  In our deliberations of Project O, the BAHG recommends that the Experimental Fund (Reclamation C.5) should not be used to support the following items and, to the extent that a proposed project element includes an item, that item should be removed from the project element:  Multi-year commitments because the decision to use the Experimental Fund is made on a year-by-year basis; Monitoring for experiments or activities that occur with a level of regularity or certainty that would lend themselves to be planned for and funded through the TWP because this is counter to the intent of the Experimental Fund; and Salaries for positions lasting more than one year (i.e. anything more than a one-year term position or contract) because this may lead to unreasonable expectations of work security. The BAHG also recommends that prioritizing elements in Project O for funding through the Experimental Fund should be made in context with other requests from the Experimental Fund and vice versa. October 2020 TWG Flow Ad Hoc Group (FLAHG) Hydrograph Motion The TWG recommends that the AMWG recommend to the Secretary of the Interior, to implement, when conditions warrant and consistent with the LTEMP protocol for implementing flow experiments, the spring disturbance flow hydrograph developed by the FLAHG in coordination with the GCMRC, as described in the FLAHG Predicted Effects document and associated presentations to the TWG on October 14, 2020. October 2020 TWG Project O Motion The TWG recommends that the AMWG recommend to the Secretary of the Interior GCMRC’s “Project O” proposal, as provided to the TWG on October 7, 2020, for inclusion in the 2021-2023 Triennial Budget and Workplan, but with the following revisions and areas of emphasis: Reclamation retains decision-making authority for the allocation of funds from the C.5 Experimental Management Fund. Requests to support Project O through the Experimental Management Fund should be considered in context with other requests from the Experimental Management Fund (i.e. including, but not limited to Projects A.4, B.6.1-5, and J.3) and vice versa. Consideration of funding for Project O elements should be in accordance with the recommendation developed by the BAHG on October 8, 2020. Elements O.1 and O.2 – Funding requests for Year 2 should come from TWP carryover funds from prior years or through annual review of the TWP. Element O.11 – Funding requests for Year 1 and Year 2 could come from TWP carryover funds from prior years or through annual review of the TWP or other Reclamation considerations. References to specific years (e.g. FY2021) will be replaced with general references to Year 1 and Year 2 to accommodate uncertainty regarding implementation timing. Opportunities to leverage external resources and support from Program partners will be considered and explored by GCMRC and Reclamation. November 2020 AMWG Flow Ad Hoc Group (FLAHG) Hydrograph Motion The AMWG recommends to the Secretary of the Interior, to implement, when conditions warrant and consistent with the LTEMP protocol for implementing flow experiments, the spring disturbance flow hydrograph developed by the FLAHG in coordination with the GCMRC, as described in the FLAHG Predicted Effects document (dated October 6, 2020) and associated presentations to the AMWG on November 17, 2020. November 2020 AMWG Project O Motion The AMWG recommends to the Secretary of the Interior GCMRC’s “Project O” proposal, as provided to the AMWG on November 10, 2020, for inclusion in the 2021-2023 Triennial Budget and Workplan, with the following areas of emphasis: Reclamation retains decision-making authority for the allocation of funds from the C.5 Experimental Management Fund. Requests to support Project O through the Experimental Management Fund should be considered in context with other requests from the Experimental Management Fund (i.e. including, but not limited to Projects A.4, B.6.1-5, andJ.3) and vice versa. Consideration of funding for Project O elements should be in accordance with the recommendation developed by the BAHG on October 8, 2020. Elements O.1 and O.2 – Funding requests for Year 2 should come from TWP carryover funds from prior years or through annual review of the TWP. Element O.11 – Funding requests for Year 1 and Year 2 could come from TWP carryover funds from prior years or through annual review of the TWP or other Reclamation considerations. Opportunities to leverage external resources and support from Program partners will be considered and explored by GCMRC and Reclamation.