Long-term Experimental and Management Plan (LTEMP)

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The Long-term Experimental and Management Plan (LTEMP)

Glen Canyon Dam was authorized by the Colorado River Storage Project Act of 1956 and completed by the Bureau of Reclamation (Reclamation) in 1963. Below Glen Canyon Dam, the Colorado River flows for 15 miles through the Glen Canyon National Recreation Area, which is managed by the National Park Service (NPS). Fifteen miles below Glen Canyon Dam, Lees Ferry, Arizona, marks the beginning of Marble Canyon and the northern boundary of Grand Canyon National Park.

The major function of Glen Canyon Dam is water storage and flood control. The dam is specifically managed to regulate releases of water from the Upper Colorado River Basin to the Lower Colorado River Basin to satisfy provisions of the 1922 Colorado River Compact and subsequent water delivery commitments, and thereby allow states within the Upper Basin to withdraw water from the watershed upstream of Glen Canyon Dam and utilize their apportionments of Colorado River water. Another function of Glen Canyon Dam is the generation of hydroelectric power.

The Grand Canyon Protection Act of 1992 (Pub. L.102–575) (GCPA) addresses potential impacts of dam operations on downstream resources in Glen Canyon National Recreation Area and Grand Canyon National Park. The GCPA required the Secretary of the Interior to complete an EIS evaluating alternative operating criteria that would determine how Glen Canyon Dam would be operated "to protect, mitigate adverse impacts to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established." The first EIS on Glen Canyon Dam operations was published in March 1995. The Preferred Alternative of the 1995 EIS (Modified Low Fluctuating Flow Alternative) was selected as the best means to operate Glen Canyon Dam in a record of decision (ROD) issued on October 9, 1996. In 1997, the Secretary adopted operating criteria for Glen Canyon Dam (62 FR 9447) as required by Section 1804(c) of the GCPA.

Additionally, the GCPA required the Secretary to undertake research and monitoring to determine if revised dam operations were achieving the resource protection objectives of the final EIS and ROD. These provisions of the GCPA were incorporated into the 1996 ROD and led to the establishment of the Glen Canyon Dam Adaptive Management Program (GCDAMP), administered by Reclamation, and of the Grand Canyon Monitoring and Research Center within the U.S. Geological Survey (USGS). The LTEMP will be coordinated with the existing Glen Canyon Dam Adaptive Management Program.

The GCDAMP includes a federal advisory committee known as the Glen Canyon Dam Adaptive Management Work Group (AMWG), a technical work group, a scientific monitoring and research center administered by the USGS, and independent scientific review panels. The AMWG makes recommendations to the Secretary concerning Glen Canyon Dam operations and other management actions to protect resources downstream of Glen Canyon Dam consistent with the GCPA and other applicable provisions of federal law.

The decision by the Secretary to develop the Glen Canyon Dam Long-Term Experimental and Management Plan EIS is a component of its efforts to continue to comply with the ongoing requirements and obligations established by the GCPA and recommendations of the AMWG. Reclamation and NPS are joint-leads on the LTEMP EIS because Reclamation has primary responsibility for operation of Glen Canyon Dam and NPS has primary responsibility for managing the resources of the Grand Canyon National Park, Glen Canyon National Recreation Area, and Lake Mead National Recreation Area. [1]

Long-term Experimental and Management Plan (LTEMP)
The LTEMP provides the basis for decisions that identify management actions and experimental options that will provide a framework for adaptively managing Glen Canyon Dam operations over the next 20 years
LTEMP Science Plan
The LTEMP Science Plan describe a strategy by which monitoring and research data in the natural and social sciences will be collected, analyzed, and provided to DOI, its bureaus, and to the GCDAMP in support of implementation of LTEMP.
Core Monitoring Plan
The GCMRC Core Monitoring Plan (CMP) describes the consistent, long-term, repeated measurements using scientifically accepted protocols to measure status and trends of key resources to answer specific questions. Core monitoring is implemented on a fixed schedule regardless of budget or other circumstances (for example, water year, experimental flows, temperature control, stocking strategy, nonnative control, etc.) affecting target resources.
Monitoring and Research Plan
The GCMRC Monitoring and Research Plan (MRP) specifies (1) core monitoring activities, (2) research and development activities, and (3) long-term experimental activities consistent with the strategies and priorities established in this SSP to be conducted over the next 5 years to address some of the strategic science questions associated with AMWG priority questions.
Budget and Work Plan
The GCMRC Triennial Work Plan (TWP) identifies the scope, objectives, and budget for monitoring and research activities planned for a 3-year period. When completed, the TWP will be consistent with the MRP.


The LTEMP Purpose and Need [2]

The purpose of the proposed action is to provide a comprehensive framework for adaptively managing Glen Canyon Dam over the next 20 years consistent with the GCPA and other provisions of applicable Federal law. The proposed action will help determine specific dam operations and actions that could be implemented to improve conditions and continue to meet the GCPA's requirements and to minimize, consistent with law-adverse impacts on the downstream natural, recreational, and cultural resources in the two park units, including resources of importance to American Indian Tribes.

The need for the proposed action stems from the need to use scientific information developed since the 1996 ROD to better inform DOI decisions on dam operations and other management and experimental actions so that the Secretary of the Interior may continue to meet statutory responsibilities for protecting downstream resources for future generations, conserving species listed under the Endangered Species Act (ESA), avoiding or mitigating impacts on National Register of Historic Places (NRHP)-eligible properties, and protecting the interests of American Indian Tribes, while meeting obligations for water delivery and the generation of hydroelectric power. [3]

LTEMP Resource Goals

Reclamation and NPS developed resource goals considering public input and Desired Future Conditions (DFCs) previously adopted by the Adaptive Management Work Group (AMWG). The following resource goals were identified:

  1. Archaeological and Cultural Resources. 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.
  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.
  3. Humpback Chub. 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.
  4. Hydropower and Energy. 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.
  5. Other Native Fish Species. Maintain self-sustaining native fish species populations and their habitats in their natural ranges on the Colorado River and its tributaries.
  6. Recreational Experience. 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.
  7. Sediment. 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.
  8. Tribal Resources. Maintain the diverse values and resources of traditionally associated Tribes along the Colorado River corridor through Glen, Marble, and Grand Canyons.
  9. Rainbow Trout Fishery. 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.
  10. Nonnative Invasive Species. Minimize or reduce the presence and expansion of aquatic nonnative invasive species.
  11. Riparian Vegetation. Maintain native vegetation and wildlife habitat, in various stages of maturity, such that they are diverse, healthy, productive, self-sustaining, and ecologically appropriate.[4]

LTEMP BiOp Triggers for Humpback Chub (LTEMP BA Appendix D)

Tier 1 Trigger – Early Intervention Through Conservation Actions:

  • 1a. If the combined point estimate for adult HBC (adults defined ≥200 mm) in the Colorado River mainstem LCR aggregation; RM 57-65.9) and Little Colorado River (LCR) falls below 9,000 as estimated by the currently accepted HBC population model (e.g., ASMR, multi-state).

-OR-

  • 1b. If recruitment of sub-adult HBC (150-199mm) does not equal or exceed estimated adult mortality such that:
  1. Sub-adult abundance falls below a three-year running average of 1,250 fish in the spring LCR population estimates, or
  2. Sub-adult abundance falls below a three-year running average of 810 fish in the mainstem Juvenile Chub Monitoring reach (JCM annual fall population estimate; RM 63.45-65.2).

Tier 1 Trigger Response:

  • Tier 1 conservation actions listed below will be immediately implemented either in the LCR or in the adjacent mainstem. Conservation actions will focus on increasing growth, survival and distribution of HBC in the LCR & LCR mainstem aggregation area.

Tier 2 Trigger - Reduce threat using mechanical removal if conservation actions in Tier 1 are insufficient to arrest a population decline:

Mechanical removal of nonnative aquatic predator will ensue:

  • If the point abundance estimate of adult HBC decline to <7,000, as estimated by the currently accepted HBC population model.

Mechanical removal will terminate if:

  • Predator index (described below) is depleted to less than 60 RBT/km for at least two years in the JCM reach and immigration rate is low (the long term feasibility of using immigration rates as a metric still needs to be assessed),

-OR-

  • Adult HBC population estimates exceed 7,500 and recruitment of sub-adult chub exceed adult mortality for at least two years.
PredatorIndexTable.jpg

If immigration rate of predators into JCM reach is high, mechanical removal may need to continue. These triggers are intended to be adaptive based on ongoing and future research (e.g., Lees Ferry recruitment and emigration dynamics, effects of trout suppression flows, effects of Paria River turbidity inputs on predator survival and immigration rates, interactions between humpback chub and rainbow trout, other predation studies).

LTEMP BiOp Conservation Measures [5] (2016)

Humpback Chub

Ongoing actions:

Reclamation would continue to support the NPS, FWS, GCMRC, and GCDAMP in funding and implementing translocations of humpback chub into tributaries of the Colorado River in Marble and Grand Canyons, and in monitoring the results of these translocations, consistent with agencies’ plans and guidance (e.g., NPS Comprehensive Fisheries Management Plan [CFMP], FWS Humpback Chub Genetics Management Plan and Translocation Framework, and GCMRC Triennial Work Plan). Translocations allow for opportunities to expand the area occupied by humpback chub and improve the overall status of the species. Specifically, the following would occur:

  • Humpback chub would be translocated from the lower reaches of the Little Colorado River to areas above Chute Falls in an effort to increase growth rates and survivorship.
  • Monitoring would be conducted annually, or as needed, depending on the data required, to determine survivability, population status, or genetic integrity of the Havasu Creek humpback chub population. Intermittent translocations of additional humpback chub in Havasu Creek would be conducted if the FWS and NPS determine it is necessary to maintain genetic integrity of the population.

Reclamation would continue to fund a spring and fall population estimate annually, or at a different frequency as deemed appropriate in consultation with FWS, using a mark recapture based model for the Little Colorado River or the most appropriate model developed for the current collecting techniques and data. Monitoring the chub population allows us to determine its status (whether it is stable, increasing, or decreasing).

Reclamation would continue to fund control or removal of nonnative fish in tributaries prior to chub translocations depending on the existing fish community in each tributary. Reclamation, NPS, and FWS would lead any investigation into the possibility of using a chemical piscicide, or other tools, as appropriate. Tributaries and the appropriate control methods would be identified by the FWS, NPS, Reclamation, and GCMRC, in consultation with the Arizona Game and Fish Department (AGFD). Depending on the removal methods identified, additional planning and compliance may be necessary. Removal of nonnative fishes improves the status of chub and other native fishes by reducing competition and predation. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation would continue to fund the FWS in maintenance of a humpback chub refuge population at a federal hatchery (Reclamation has assisted the FWS in creating a humpback chub refuge at the Southwestern Native Aquatic Resources and Recovery Center [SNARRC]) or other appropriate facility by providing funding to assist in annual maintenance (including the collection of additional humpback chub from the Little Colorado River for this purpose). In the unlikely event of a catastrophic loss of the Grand Canyon population of humpback chub, the refuge would provide a permanent source of sufficient numbers of genetically representative stock for repatriating the species.

Reclamation would continue to assist the FWS, NPS and the GCDAMP to ensure that a stable or upward trend of humpback chub mainstem aggregations can be achieved by:

  • Continuing to conduct annual monitoring of the Little Colorado River humpback chub aggregation (e.g., juvenile chub monitoring parameters). Periodically, an open or multistate model should be run to estimate abundance of the entire Little Colorado River aggregation inclusive of mainstem fish.
  • Supporting annual monitoring in the mainstem Colorado River to determine status and trends of humpback chub and continuing to investigate sampling and analytical methods to estimate abundance of chub in the mainstem.
  • Conducting periodic surveys to identify additional aggregations and individual humpback chub.
  • Evaluating existing aggregations and determining drivers of these aggregations, for example, recruitment, natal origins, spawning locations, and spawning habitat (e.g., consider new and innovative methods such as telemetry or the Judas-fish approach) (Kegerries et al. 2015).
  • Exploring means of expanding humpback chub populations outside of the Little Colorado River Inflow aggregation. Evaluate the feasibility of mainstem augmentation of humpback chub that would include larval collection, rearing, and release into the mainstem at suitable areas outside of or within existing aggregations.

Reclamation would, through the GCDAMP, conduct disease and parasite monitoring in humpback chub and other fishes in the mainstem Colorado. The GCMRC is currently conducting parasite monitoring in the Little Colorado River. However, in order to better understand how/if disease and parasites (primarily Asian tapeworm) are affecting chub and how temperature differences may affect parasite occurrence, this work would be expanded to include investigations of parasites in humpback chub (and surrogate fish if necessary) in the mainstem. Ensuring adequate protection from diseases and parasites is an identified management action needed in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

New actions:

Reclamation would collaborate with the FWS, GCMRC, NPS, and the Havasupai Tribe to conduct preliminary surveys and a feasibility study for translocation of humpback chub into Upper Havasu Creek (above Beaver Falls). The implementation of surveys and translocations, following the feasibility study, would be dependent on interagency discussions, planning and compliance, and resulting outcomes of tribal consultation. As stated above, translocations of chub into currently unoccupied habitat aid in expanding the area occupied by the species. In addition, using a tributary to the Colorado River, such as Upper Havasu Creek, protects translocated fish from the effects of dam operations in the mainstem, but still allow for chub in Havasu Creek to contribute to the mainstem population.

Reclamation would, in cooperation with the FWS, NPS, GCMRC, and AGFD, explore and evaluate other tributaries for potential translocations.

Razorback Sucker

Ongoing actions:

Reclamation would continue to assist the NPS, FWS, and the GCDAMP in funding larval and small-bodied fish monitoring in order to:

  • Determine the extent of hybridization in flannelmouth and razorback sucker collected in the western Grand Canyon.
  • Determine habitat use and distribution of different life stages of razorback sucker to assist in future management of flows that may help conserve the species. Sensitive habitats to flow fluctuations could be identified and prioritized for monitoring.
  • Assess the effects of TMFs and other dam operations on razorback sucker.

Actions to benefit all native aquatic species

Ongoing actions:

Reclamation, in collaboration with the NPS and FWS, and in consultation with the AZGFD, would investigate the possibility of renovating Bright Angel and Shinumo Creeks with a chemical piscicide, or other tools, as appropriate. Additional planning and compliance, and tribal consultation under Section 106 of the NHPA, would be required. This feasibility study is outlined in the NPS CFMP (2013; see “Feasibility Study for Use of Chemical Fish Control Methods”). The action benefits humpback chub and other native fish by removing nonnative fish that can predate upon and compete with humpback chub. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation would continue to fund efforts of the GCMRC and NPS to remove brown trout (and other nonnative species) from Bright Angel Creek and the Bright Angel Creek Inflow reach of the Colorado River, and from other areas where new or expanded spawning populations develop, consistent with the NPS CFMP. After 5 years of removal efforts are completed (in 2017), an analysis of success would be conducted. Piscicides may be considered for removal of nonnative species if determined to be appropriate and following completion of the necessary planning and compliance actions. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

New actions:

Reclamation would explore the efficacy of a temperature control device at the dam to respond to potential extremes in hydrological conditions due to climate conditions that could result in nonnative fish establishment. Evaluations would be ongoing for all current and evolving technological advances that could provide for warming and cooling the river in both high- and low-flow discharge scenarios, and high and low reservoir levels. These studies should include evaluating and pursuing new technologies, an analysis of the feasibility, and a risk assessment and cost analysis for any potential solutions. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation would pursue means of preventing the passage of deleterious invasive nonnative fish through Glen Canyon Dam. Because Glen Canyon Dam release temperatures are expected to be warmer under low reservoir elevations that may occur through the LTEMP period, options to hinder expansion of warmwater nonnative fishes into Glen and Grand Canyons would be evaluated. Potential options to minimize or eliminate passage through the turbine or bypass intakes, or minimize survival of nonnative fish that pass through the dam would be assessed (flows, provide cold water, other). While feasible options may not currently exist, technology may be developed during the LTEMP period that could help achieve this goal. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation would, in consultation with the FWS and AGFD, fund the NPS and GCMRC on the completion of planning and compliance to alter the backwater slough at River Mile (RM) 12 (commonly referred to as “Upper Slough”), making it unsuitable or inaccessible to warmwater nonnative species that can compete with and predate upon native fish, including humpback chub. Depending on the outcome of NPS planning and compliance, Reclamation would implement the plan in coordination with the FWS, AGFD, NPS and GCMRC. Additional coordination would be conducted to determine and access any habitats that may support warmwater nonnatives. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation would support the GCMRC and NPS in consultation with the FWS and AGFD on the completion of planning and compliance of a plan for implementing rapid response control efforts for newly establishing or existing deleterious invasive nonnative species within and contiguous to the action area. Control efforts may include chemical, mechanical, or physical methods. While feasible options may not currently exist, new technology or innovative methods may be developed in the LTEMP period that could help achieve this goal. Rapid response to new warmwater fish invasions may become a more frequent need in the future with lower reservoir elevations and warmer dam releases. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Reclamation, will consider, in consultation with the GCDAMP, the experimental use of TMFs to inhibit brown trout spawning and recruitment in Glen Canyon, or other mainstem locations. Inhibiting brown trout spawning and recruitment will benefit chub by reducing the potential for brown trout to predate upon humpback chub. The regulation and control of nonnative fish is a management action identified in the Humpback Chub Recovery Goals (USFWS 2002a) and Razorback Sucker Recovery Goals (USFWS 2002b).

Southwestern willow flycatcher and Yuma Ridgway’s rail

Reclamation would partially assist in funding NPS to conduct Yuma Ridgway’s rail surveys once every three years for the life of the LTEMP.

Reclamation would partially assist in funding NPS to conduct southwestern willow flycatcher surveys once every two years for the life of the LTEMP.

LTEMP Experimental Actions [6]

Experimental treatments are grouped under three categories: (1) Sediment-Related Experimental Treatments; (2) Aquatic Resource-Related Experimental Treatments; and, (3) Native and Nonnative Plant Management and Experimental Actions. The specific types of experimental treatments included under each category are described below.

Sediment-Related Experimental Treatments (BA, pages 24-30) [7]

Spring and fall HFEs would be implemented when triggered, based on the estimated sand mass balance resulting from Paria River sediment inputs during the spring and fall accounting periods, to rebuild sandbars. These HFEs include sediment-triggered HFEs in spring or fall, proactive spring HFEs as triggered by high annual release volume (> 10 maf), and extended duration (>96 hr) fall HFEs.

Aquatic Resource-Related Experimental Treatments (BA, pages 30-41) [8]

Nonnative fish control actions would be implemented if the Little Colorado River humpback chub population declined and proactive conservation actions failed to reverse declining populations.

Mechanical removal of nonnative species is a controversial issue in the Colorado River through Glen and Grand Canyons. A spring 2015 meeting of Grand Canyon biologists (NPS, FWS, AGFD, GCMRC) to assess current trout removal triggers resulted in a concept of early conservation measure intervention to maximize conservation benefit to humpback chub and minimize the likelihood of mechanical predator removal. Under the preferred alternative, mechanical removal of nonnative rainbow and brown trout (and other nonnative predators) would be implemented through a triggered, tiered approach (see Appendix D in BA) near the confluence of the Little Colorado River and the Colorado River if conservation actions designed to reverse declines in the Little Colorado River humpback chub aggregation were ineffective. Two different tiers of population metrics would be used to trigger responses such as actions to increase growth and survival of humpback chub (Conservation Actions, Tier 1), or mechanical nonnative fish control (Tier 2), which would only be implemented when Tier 1 conservation actions (actions would focus on increasing growth, survival and distribution of chub in the Little Colorado River and LCR mainstem aggregation area) fail to slow or reverse the decline in the humpback chub population (see Appendix D in BA, Young et al. 2015). In addition, if humpback chub decline and the identified actions are not working, the FWS, in coordination with action agencies and traditionally associated Tribes, will identify future appropriate actions (among other caveats specified in Young et al. 2015).

Experimental Trout Management Flows (TMFs) could be used to control annual rainbow trout production in the Glen Canyon reach for the purposes of managing the rainbow trout fishery and for limiting emigration to Marble Canyon and the Little Colorado River reach. TMFs would be tested early in the experimental period, preferably in the first 5 years.

Low summer flows may be tested in the second 10 years of the LTEMP period, for the purpose of achieving warmer river temperatures (> 14°C) to benefit humpback chub and other native species. Under low summer flows, daily fluctuations would be less than under base operations (e.g., approximately 2,000 cfs). Investigating the anticipated effects of and options for providing warmer water temperatures in the mainstem Colorado River through Grand Canyon is an identified management action in the Humpback Chub Recovery Goals (USFWS 2002a).

Low steady weekend flows (“bug flows”) would be conducted to test whether the flows would increase insect abundance. On an experimental basis, for example, flows would be held low and steady for two days per week (weekends) from May through August to attempt to improve the productivity of the aquatic food base, and increase the diversity and abundance of mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), which are collectively referred to as EPT.

Native and Nonnative Plant Management and Experimental Treatments (BA, pages 41-42) [9]

Experimental riparian vegetation treatment activities would be implemented by NPS under the proposed action and would modify the cover and distribution of riparian plant communities along the Colorado River. All activities would be consistent with NPS Management Policies (NPS 2006) and would occur only within the Colorado River Ecosystem in areas that are influenced by dam operations. NPS would work with tribal partners and GCMRC to experimentally implement and evaluate a number of vegetation control and native replanting activities on the riparian vegetation within the Colorado River Ecosystem in GCNP and GCNRA. These activities would include ongoing monitoring and removal of selected nonnative plant species, systematic removal of nonnative vegetation at targeted sites, and native replanting at targeted sites, which may include complete removal of tamarisk (both live and dead) and re-vegetation with native plants. Treatments would include the control of nonnative plant species and revegetation with native plant species.

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