Glen Canyon Dam AMP - New pages [en]

LTEMP Metrics

2026-09-08T19:44:29Z

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[[Image:Metrics.jpg|300px|link=Metrics]]


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==LTEMP Metrics==
Section 6.1 (c) of the 2016 LTEMP ROD states that “The DOI, in consultation with the Adaptive Management Working Group, will develop monitoring metrics for the goals and objectives using those in Appendix C of the FEIS as a starting point” (DOI, 2016b). Appendix C refers to a suite of “performance metrics” developed by Runge and others (2015) for evaluating the relative merits of the seven alternatives evaluated in the 2016 EIS. Those metrics were “intended to be objective measures of the performance of alternatives relative to goals for each affected resource being evaluated in the LTEMP EIS” (Runge and others, 2015). Comparisons of the performance of those metrics, among other considerations, ultimately led to selection of Alternative D as the preferred alternative.

The performance metrics developed by Runge and others (2015), while suitable for comparing draft alternatives, were not designed nor intended to measure resource outcomes based on empirical observations of resource condition following implementation of the LTEMP. In 2019, the DOI’s Assistant Secretary for Water and Science directed the Bureau of Reclamation Glen Canyon Dam Adaptive Management Program (GCDAMP) to identify a set of “metrics” for assessing how well the selected alternative was meeting the goals and objectives stated in the LTEMP (DOI, 2016b). In fiscal years 2021-2023, Reclamation coordinated with the U.S. Geological Survey (USGS) Grand Canyon Monitoring and Research Center (GCMRC) to work with GCDAMP stakeholders in developing a new set of performance metrics for tracking progress towards attaining the resource goals specified in the LTEMP, using the previous performance metrics as a starting point. [https://gcdamp.com/images_gcdamp_com/3/3b/USGS_GCMRC_Status_of_LTEMP_Metrics_Report_Dec11_2025-508Comp.pdf]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3bfb1; text-align:left; color:#000; padding:0.2em 0.4em;">Resource Goals and Metrics</h2>
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==[https://gcdamp.com/index.php?title=CULTURAL '''Cultural and Archaeological Resources''']==

===Resource Goal===
*Maintain the integrity of potentially affected NRHP-eligible or listed historic properties in place, where possible, with preservation methods employed on a site-specific basis.

===Metrics===
*Integrity
*Topographic Change at a Sample of Sites
*Change in Vulnerability to Loss of Integrity

==[https://gcdamp.com/index.php?title=ECOSYSTEM '''Natural Processes''']==

===Resource Goal===
*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.

===Metrics===
*Deviation from Natural Flow Metric ( with “sub-metrics”: spring-early summer, late summer-fall, and winter deviation from natural flows)
*Sub-daily Flow Fluctuation Metric
*Springtime Gross Primary Productivity
*Percent EPT Metric

==[https://gcdamp.com/index.php/Humpback_Chub_Page '''Humpback Chub''']==

===Resource Goal===
*Meet humpback chub recovery goals, including maintaining a self-sustaining population, spawning habitat, and aggregations in the Colorado River and its tributaries below the Glen Canyon Dam.

===Metrics===
*Current Biological Opinion tier of humpback chub in the Little Colorado River (LCR) Aggregation
*Grand Canyon-wide abundance of adult humpback chub
*Proportion of Grand Canyon Ecosystem with evidence of all three life stages of humpback chub

==[https://gcdamp.com/index.php/HYDROPOWER '''Hydropower and Energy ''']==

===Resource Goal===
*Maintain or increase Glen Canyon Dam electric energy generation, load following capability, and ramp rate capability, and minimize emissions and costs to the greatest extent practicable, consistent with improvement and long-term sustainability of downstream resources.

===Metrics===
*Glen Canyon Dam Energy Production
*Economic Value of Glen Canyon Dam Energy Production
*Marketable Capacity of Glen Canyon Dam Energy

==[https://gcdamp.com/index.php/FISH '''Other Native Fish Species''']==

===Resource Goal===
*Maintain self-sustaining native fish species populations and their habitats in their natural ranges on the Colorado River and its tributaries.

===Metrics===
*Proportion of Grand Canyon Ecosystem (GCE) with evidence of all 3 life stages of Bluehead Sucker (Catostomus discobolus), Flannelmouth Sucker (Catostomus latipinnis), Razorback Sucker (Xyrauchen texanus)
*Proportion of GCE with Speckled Dace (Rhinichthys osculus) (any life stage)
*Proportion of GCE with extirpated species (any life stage)

==[https://gcdamp.com/index.php?title=RECREATION '''Recreational Experience''']==

===Resource Goal===
*Maintain and improve the quality of recreational experiences for the users of the Colorado River Ecosystem. Recreation includes, but is not limited to, flatwater and whitewater boating, river corridor camping, and angling in Glen Canyon.

===Metrics===
*Economic Value of Recreation Experience

==[https://gcdamp.com/index.php?title=GCDAMP_Sediment '''Sediment''']==

===Resource Goal===
*Increase and retain fine sediment volume, area, and distribution in the Glen, Marble, and Grand Canyon reaches above the elevation of the average base flow for ecological, cultural, and recreational purposes.

===Metrics===
Performance Metric:
*Sand Bar Volume (includes multiple “sub-metrics”, e.g., normalized sandbar volume by type, mean sand bar response to HFEs)

Surveillance Metrics:
*Sand Supply By River Segment (Sand Mass Balance)
*Silt & Clay Retention by River Segment (Turbidity)

==[https://gcdamp.com/index.php/Tribal_Resources '''Tribal Perspectives''']==

===Resource Goal===
*Maintain the diverse values and resources of traditionally associated Tribes along the Colorado River corridor through Glen, Marble, and Grand Canyons.

===Metrics===
*Is the Colorado River ecosystem healthy? Please explain why or why not.
*How well is LTEMP doing at meeting its goals? Please explain the basis for your assessment.
*Overall, is the Grand Canyon doing better, worse, or about the same as last year? Please explain the basis for your assessment.

==[https://gcdamp.com/index.php?title=FISHERY '''Rainbow Trout Fishery''']==

===Resource Goal===
*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.

===Metrics===
*Trout Angler Catch Rate
*Rainbow Trout (Oncorhynchus mykiss) Abundance

==[https://gcdamp.com/index.php/Nonnative_Invasive_Aquatic_Species '''Nonnative Invasive Species''']==

===Resource Goal===
*Minimize or reduce the presence and expansion of aquatic nonnative invasive species.

===Metrics===
*Average number of “risky species” per Habitat Segment in Grand Canyon Ecosystem
*Average number of “risky species” with evidence of recent recruitment per Habitat Segment in Grand Canyon Ecosystem

==[https://gcdamp.com/index.php/Riparian_Vegetation '''Riparian Vegetation''']==

===Resource Goal===
*Maintain native vegetation and wildlife habitat, in various stages of maturity, such that they are diverse, healthy, productive, self-sustaining, and ecologically appropriate.

===Metrics===
*Total Plant Cover
*Native Plant Richness
*Native to Non-native Plant Species Cover Ratio

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*[[Media:USGS GCMRC Status of LTEMP Metrics Report Dec11 2025-508Comp.pdf| 2025 LTEMP Metrics Report]]
*[https://gcdamp.com/index.php/GCDAMP_Planning GCDAMP Planning and Guiding Documents]
*[https://gcdamp.com/index.php/Long-term_Experimental_and_Management_Plan_(LTEMP) The Long-term Experimental and Management Plan (LTEMP)]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">Metrics Posters</h2>
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*[https://gcdamp.com/images_gcdamp_com/4/40/Tango_ARM2024_Poster_IPDS.pdf Cultural and Archaeological Resources]
*[https://gcdamp.com/index.php/File:Goal_2_Natural_Processes_Metrics.jpg Natural Processes]
*[https://gcdamp.com/images_gcdamp_com/2/2e/BAO_Approved_POSTER_Dzul_IP-186132_HBC_Metrics_2025_v3%2C1-28-2026.pdf Humpback Chub]
*[[Media:BAO_Approved-Hydropower_Metrics_Poster-MAnderson_20260122_1511.pdf|Hydropower and Energy]]
*Other Native Fish
*[[Media:BAO_Approved-Recreation_Metrics_Poster-MAnderson_20260122.pdf|Recreational Experience]]
*Sediment
*[[Media:BAO_Approved-Tribal_MetricsPoster,MAnderson_20260128_1022.pdf|Tribal Perspectives]]
*Rainbow Trout Fishery
*Nonnative Invasive Species
*[https://gcdamp.com/index.php/File:Goal_11_Riparian_Vegetation.jpg Riparian Vegetation]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">Presentations and Papers</h2>
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*[https://www.usbr.gov/uc/progact/amp/twg/2025-12-11-twg-meeting/uc-gcdamp-twg-ltempmetrics-statusreport-508-20251211.pdf Status Report on the Long-Term Experimental & Management Plan (LTEMP) Metrics for the Glen Canyon Dam Adaptive Management Program]
*[https://www.usbr.gov/uc/progact/amp/amwg/2025-08-21-amwg-meeting/uc-gcdamp-amwg-monitoringmetricsfutureuse-508-20250821.pdf Monitoring Metrics Future Use]
*[https://www.usbr.gov/uc/progact/amp/amwg/2025-08-21-amwg-meeting/uc-gcdamp-amwg-draftperformancemetrics-508-20250821.pdf Final Draft Performance Metrics for the Long-Term Experimental & Management Plan]
*[https://www.usbr.gov/uc/progact/amp/twg/2025-04-10-twg-meeting/uc-gcdamp-twg-arm-monitoringmetricssummarytable-508-20250410.pdf Monitoring Metrics Summary Table]
*[https://www.usbr.gov/uc/progact/amp/twg/2025-04-10-twg-meeting/uc-gcdamp-twg-arm-goal1metrics-fy2024-508-20250410.pdf Update on the Status of Goal 1 Metrics for FY2024]
*[https://www.usbr.gov/uc/progact/amp/twg/2021-10-14-twg-meeting/20211014-ExampleMetricsLong-TermExperimentalManagementPlan-Presentation-508-UCRO.pdf Example Metrics for the Long-Term Experimental and Management Plan]
*[https://www.usbr.gov/uc/progact/amp/twg/2021-06-17-twg-meeting/20210617-MonitoringMetrics-DraftPlan-508-UCRO.pdf Monitoring Metrics Draft Plan ]

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2027-2028 Operating Guidelines

2026-08-21T20:43:49Z

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[[File:IMG_4472.JPG|center|300px]]
The post placed in the 1920s by the USGS at "Lee Ferry" marking the division of the upper and lower basins

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==2027-2028 Operating Guidelines==
Several reservoir and water management decisional documents and agreements that govern the operation of Colorado River facilities and management of the Colorado River are scheduled to expire at the end of 2026. These include the 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead (2007 Interim Guidelines), the 2019 Drought Contingency Plans, as well as international agreements between the United States and Mexico pursuant to the United States-Mexico Treaty on Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande (1944 Water Treaty).

The Post-2026 process was a multi-year NEPA process that set out to develop long-term successor operating guidelines for Lake Powell and Lake Mead to replace expiring agreements. The process was formally initiated in June 2023 with the Notice of Intent to prepare an Environmental Impact Statement (EIS). Throughout the process, extensive stakeholder engagement occurred, with a particular focus on developing a range of alternatives over a two‑and‑a‑half‑year period. Six alternatives were developed and evaluated to capture a broad range of operational concepts and potential environmental impacts, though consensus on long‑term operations was not reached. After the publication of the Final EIS on July 31, 2026, the process is concluding with issuance of the Record of Decision on August 21, 2026, which adopts the Preferred Alternative’s "Decision Framework." Pursuant to the Record of Decision, the first set of guidelines—the 2027–2028 Operating Guidelines—were also issued.[https://www.usbr.gov/ColoradoRiverBasin/post2026/index.html]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3bfb1; text-align:left; color:#000; padding:0.2em 0.4em;">Framework</h2>
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==Lake Powell operations:==

For the August 24-Month study, perform Exhibit Runs using the following potential release volumes [with LTEMP monthly volumes] in descending order to determine an initial Water Year release volume that maintains a minimum Lake Powell elevation of 3510' throughout the WY. [[File:LakePowellOperations.png|right|400px]]

===Upper Elevation Range: ===
If the October 1 elevation is at or above 3565' start with a release volume of 8.23 maf

===Mid-Elevation Range: ===
If between 3540' and 3565' start with release volumes of 8.0 maf, then 7.5 maf, then 7.0 maf the release volume will be the first that maintains 3510' throughout the WY

===Low Elevation Infrastructure Protection Range: ===
If below 3540' start with a release volume of 7.0 maf

If the August 24-Month study with a release volume of 7.0 maf shows elevations below 3510' during the WY follow the Determinations Table:
*Release volume will be between 6.0 and 7.0 maf
*Move monthly volumes from October through April to May through September to maintain at least 3510' in March of the current WY
*Run two 24-Month Studies for release volumes of 6.0 maf and 7.0 maf
*In the 6.0 maf run, include supplemental releases from CRSP Upper Initial Units for May of the current year through April of the following year
*Determine March elevation for the 7.0 maf run

If the March elevation is:
* >3510' then the release is 7.0 maf and there are no releases from the CRSP upper units
* <3510' then determine what releases from the CRSP upper units coupled with reductions in Powell releases (down to 6.0 maf) will keep the March elevation above 3510'

From October to April, evaluate monthly projections.

*Adjust release volume down to no less than 6.0 maf to avoid falling below 3510' through March of the following WY
*Adjust release volume up if projected to end the current WY is above 3565' such that half the difference in volume from the projected September 30 Lake Powell storage at elevation 3565' is added to the release.

===Extraordinary Circumstances:===
If Lake Powell is projected to decline below 3500' in March of the following year (see Sec. 5.1.D)

Consult with Basin States
*If the volume needed to protect 3500' in March of the following year is >2.0 maf
*If any Basin State believes there is inequity between volumes available in the CRSP Upper Units and reductions in Powell releases
*If Powell releases <6.0 maf are needed to maintain 3500' in March of the following year

==Lake Mead operations:==

===Elevation between 1125' and 1220' (full pool)===
If the most probable rises above 1125' in the next 12 months[[File:LakeMeadOperations.png|right|700px]]
*Consult to increase apportionment above 6.25 maf

===Shortage Condition Determination and Lower Basin Reductions: Elevation between 1010' and 1125'===
Lower Basin Reductions
*Apportion 6.25 maf (1.25 maf reduction)
*Conserve an additional 700 kaf voluntarily

===Elevation between 895' (dead pool), 950' (minimum power pool), and 1010'===
If the most probable falls below 1010' in the next 12 months
*Consult to consider potential actions

===Intentionally Created Surplus (ICS)===
Extended through 2028

In the year ICS is created
*0% deduction of the volume
*3% annual evaporation assessment until delivered

No ICS delivery if Mead is less than 1000'
*Consultation if Mead is between 1000' than 1025'

ICS delivery is limited to 800 kaf (2026-2028)

Limits on annual creation, delivery, and accumulation (see table)

===Federally Managed Water Resources Pool (FMWRP)===
*Indian Water Rights Settlement
*450 kaf within ICS

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*[https://www.usbr.gov/ColoradoRiverBasin/post2026/index.html Reclamation Site: Colorado River Post-2026 Operations]
*[https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/2027-2028OperatingGuidelines_Final.pdf Colorado River Guidelines for Coordinated Operations of Lake Powell and Lake Mead for Operating Years 2027 and 2028]
*[https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/P26_BiologicalOpinion_Final.pdf Biological Opinion for Glen Canyon Dam Operations (2026–2036)]
*[https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/P26_RecordofDecision_Final.pdf ROD-Decision Framework for Colorado River Guidelines: Coordinated Operations of Lake Powell and Lake Mead (2027–2036)]
*[https://www.usbr.gov/ColoradoRiverBasin/post2026/final-eis/index.html Post-2026 Operational Guidelines and Strategies for Lake Powell and Lake Mead – Final Environmental Impact Statement]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">Past Operating Guidelines</h2>
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*[https://www.usbr.gov/ColoradoRiverBasin/interimguidelines/seis/index.html 2024 Supplemental Environmental Impact Statement (SEIS) for Near-term Colorado River Operations]
*[https://www.usbr.gov/ColoradoRiverBasin/dcp/index.html Drought Contingency Plans]
*[https://gcdamp.com/index.php/Interim_Guidelines 2007 Interim Guidelines for Lower Basin Shortages]
*[https://www.usbr.gov/lc/region/pao/pdfiles/opcriter.pdf 1970 Long-Range Operating Criteria (LROC)]

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">Presentations and Papers</h2>
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*[https://www.usbr.gov/lc/region/g4000/riverops/coriver-projections.html Colorado River System Projections Overview]
*[https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/FutureColoradoOperations_Factsheet.pdf Future Colorado River Operations Fact Sheet]

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The 1997 Habitat Maintenance Flow (HMF)

2026-08-19T20:36:45Z

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== [http://www.riversimulator.org/Resources/GCDAMP/AMWG1997to1999/Jan98/Attachment%205.pdf The 1997 Habitat Maintenance Flow (HMF)] ==

=== Introduction ===

The Bureau of Reclamation and the Grand Canyon Monitoring and Research Center conducted a test of a "Habitat Maintenance" style flow from Glen Canyon Dam on 3-5 November 1997. The Introduction flow peak reached approximately 30,600 cfs for this 2-day test. This memo outlines the impacts of that flow event on resources through Grand Canyon.

=== Physical Resource Impacts ===

GCMRC coordinated pre- and post-event videography of the river corridor, and those images are being examined for backwater habitat changes.

Using the methods of Parnell et al. (1996), detailed topographic surveys of 35 sand bar monitoring sites were conducted immediately following the November 1997 test flow by members of the Northern Arizona University Department of Geology sand bar studies office. Information gathered from these surveys is compared to previous surveys conducted in August 1997 in order to quantify sand bar change. Based on this preliminary data, the November test flow benefitted the sediment resources by depositing sediment at higher elevations. The higher elevation areas of sand bars contain critical riparian habitats that are of particular interest to management agencies. Following the 1996 45,000ft'/s test flow, erosion has steadily decreased the volume of sediment contained in the upper elevations of sand bars. Preliminary results show that the November 1997 test flow slightly increased the volume of sand bars (above the 20,000 ft¥/s stage elevation), calculated as a percentage of the pre-1996 test flow, from 87% to 91%. High flows above powerplant capacity are the only means by which the volume of the upper levels of sand bars can be maintained.

The U.S. Geological survey (G. Fisk, D.Topping, D.Rubin and S.Weile) monitored mainstream streamflow and suspended sediment at the Lees Ferry, Above Little Colorado River, Grand Canyon and Diamond Creek gauges once/day before, during and after the flow event. Bedload sampling was conducted in the mainstream and in eddies at selected sites following the high flow. Bar sedimentology, grain size, deposit thickness was conducted with the NAU effort immediately following the high flow.

===Biological Resources Impacts===

On November 6, 1997 the Arizona Game and Fish Department (AGED) surveyed cobble bars in the Lee’s Ferry reach to assess rainbow trout stranding post downramp. AGED evaluated stranding by dividing each cobble bar examined into quadrants and obtaining a total count of stranded fish by examining total area of the bars. AGFD also noted stranding of macroinvertebrates. Cobble bars selected for evaluation were representative of this habitat type in the Lees Ferry reach and were in areas which receive preferential use by fishing guides and fishermen. Observations: At RM -14, no stranding of rainbow trout and no apparent stranding of Gammarus lacustris or other macroinvertebrates was observed. At RM -12.8, one dead rainbow trout (60mm) was observed to have been stranded and low concentrations of Gammarus were observed stranded in a few shallow pools, no other stranded macroinvertebrates noted. At RM -8, two live rainbow trout (90 mm and 400 -500 mm) were observed stranded in a large pool, Gammarus (>1,000) of diverse size range were observed stranded in one small pool, and several thousand snails (Physidae) were observed stranded on two small sand habitats associated with sedges nearshore. At RM -2.5, one dead adult flannelmouth sucker (Catostomus latipinnis) was observed in approximately 3 ft of water just inside mouth of backwater. This was judged not to be a stranding-related mortality.

Concern over endangered species, particularly endangered Kanab ambersnail, prompted development of a U.S. Fish and Wildlife Service Biological Opinion on this federal action. A 2-3 October 1997 habitat and population survey at Vaseys Paradise revealed that 29.8 m? of potential KAS habitat lay downslope from the 934 m/s (33,000 cfs) flood stage. Five habitat patches were predicted to be inundated and potentially scoured by the planned November Test Flow, but it was considered unlikely that the inundated vegetation would be completely eliminated. The habitat in the flood zone was estimated to support approximately 181 KAS (<1% of the estimated total population). Immediately prior to the November Test Flow, the Arizona Game and Fish Department salvaged habitat and 14 KAS from the inundated zone and is presently holding that material at the Phoenix Zoo. A GCMRC survey crew reported new sand and driftwood on the inundated habitat patches immediately following the event. Although losing 14.4% of the flood zone habitat to scour, the Test Flow did not completely eliminate vegetation in the habitat patches of concern. No impacts were anticipated or observed on endangered southwestern willow flycatcher habitat. Impacts on endangered humpback chub were not considered to be detectable, and hence no effort was made to monitor that species.

===Conclusions===

These preliminary results indicate that top-of-powerplant flows can be used to rebuild low-lying sand bar platforms, and result in little disruption of terrestrial endangered species. A flow of this magnitude is probably insufficient to create or substantially rejuvenate backwater habitats, which serve as nursery habitats for native and non-native fish. Although some sand bars increased in area and volume, this flow may not have been of sufficient duration to maximize sand bar rebuilding.[http://www.riversimulator.org/Resources/GCDAMP/AMWG1997to1999/Jan98/Attachment%205.pdf]

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