Difference between revisions of "FY21-23 Triennial Budget and Workplan"

Project A: Streamflow, Water Quality, and Sediment Transport and Budgeting in the Colorado River Ecosystem

The primary linkage between Glen Canyon Dam operations and the characteristics of the physical, biological, and cultural resources of the Colorado River ecosystem (CRe) downstream from Glen Canyon Dam is through the stage, discharge, water quality, and sediment transport of the Colorado River. This project makes and interprets the basic measurements of these parameters at locations throughout the CRe. The data collected by this project are used to implement the High-Flow Experiment (HFE) Protocol (i.e., trigger and design HFE hydrographs), to evaluate the reach-scale sand mass-balance response to the HFE Protocol (U.S. Department of Interior, 2011; Grams and others, 2015), and to evaluate the downstream effects of releases conducted under the Long-Term Experimental and Management Plan (LTEMP) Environmental Impact Statement (EIS) (U.S. Department of Interior, 2016a, b).

The data collected by this project are also used by many of the other physical, ecological, and socio-cultural projects funded by the Glen Canyon Dam Adaptive Management Program (GCDAMP). In addition to supporting the LTEMP sediment goal, the basic data collected by this project supports the following nine LTEMP goals: aquatic food base, archaeological and cultural resources, humpback chub, hydropower and energy, invasive fish species, natural processes, rainbow trout fishery, recreational experience, and riparian vegetation. Most of the project funds support basic data collection at USGS gaging stations, with the remainder funding data interpretation. Roughly 64% of the proposed budget covers basic data collection, with the remaining 36% supporting salaries for serving the data and for interpretive work (i.e., publications). The funds requested under this proposal cover ~75% of the costs required to collect data at the network of U.S. Geological Survey (USGS) gaging stations used by this project. An additional $203,000 to support this network is provided directly to the USGS Arizona Water Science Center from funds appropriated by Congress for the USGS, the Bureau of Reclamation, and the Bureau of Land Management, and from funds provided by the Arizona Department of Environmental Quality (AZDEQ), the Navajo Nation, and Peabody Energy. Project A is designed to provide measurements of stage (i.e., water-surface elevation), discharge (i.e., streamflow), water quality, and suspended sediment at sufficiently high temporal resolutions (~15-minute) to resolve changes in these parameters and to allow accurate determination of suspended-sediment loads for use in sediment budgeting (Grams and others, 2019; Topping and others, in press). The proposed monitoring under this project is similar to that conducted over the last 18 years. Work conducted under the previous workplan, currently provisionally accepted at the Journal of Geophysical Research pending minor revision, indicates that sand storage in the channel and sandbars of the CRe is not likely sustainable unless tributary sand inputs remain well above average and dam releases remain slightly below average. The work proposed in this current workplan is therefore that required to address this important conclusion.

Project B: Sandbar and Sediment Storage Monitoring and Research

The purposes of this project are to: 1) track the effects of individual HFEs on sandbars and campsites (funded), 2) monitor the cumulative effect of successive HFEs and intervening dam operations on sandbars (funded) and sand conservation (partially funded), 3) investigate the interactions between dam operations, sand transport, and channel dynamics (funded as Project O.2), and 4) develop predictive models for streamflow and sandbar changes that can be used for evaluating dam operations scenarios (not funded).

One of the stated goals in the Record of Decision (ROD) for the LTEMP (U.S. Department of the Interior, 2016) is to "increase and retain fine sediment volume, area, and distribution...for ecological, cultural, and recreational purposes." Expectations of improved deposition on sandbars and conservation of sediment were among the criteria used in the selection of the preferred alternative. One of the central components of the selected alternative is the continued implementation of HFEs for building sandbars. The LTEMP extended the program initiated with the Environmental Assessment for Development and Implementation of a Protocol for HighFlow Experimental Releases from Glen Canyon Dam (HFE Protocol; U.S. Department of the Interior, 2011) which asked the question, "Can sandbar building during HFEs exceed sandbar erosion during periods between HFEs, such that sandbar size can be increased and maintained over several years?" In other words, does the volume of sand aggraded into eddies and onto sandbars during controlled floods exceed the volume eroded from sandbars during intervening dam operations? In addition, condition-dependent experiments were included in the preferred alternative, with objectives related to sandbar building and sediment conservation. Project B includes elements that are designed to evaluate whether the sediment-related goals of the LTEMP are met (partially funded), provide the information that is needed to proceed with or abort LTEMP experimental activities (funded), evaluate the effectiveness of implemented experiments (funded), and develop predictive models for future planning efforts (not funded). The sandbar monitoring program described here was outlined in the LTEMP Science Plan and provides the data required to answer the fundamental question of the HFE Protocol and LTEMP by monitoring changes in sandbars over many years, including a period that contains several controlled floods. The program is a continuation of the monitoring implemented in previous work plans and is based on annual measurements of sandbars, using conventional topographic surveys supplemented with daily measurements of sandbar change using ‘remote cameras’ that autonomously and repeatedly take photographs. These annual measurements and daily photographs are included in Project Element B.1 (funded). Because these long-term monitoring sites represent only a small proportion of the total number of sandbars in Marble and Grand canyons, Project Element B.2 (partially funded) includes periodic measurements of nearly all sandbars within individual 50 to 130 km sediment budget reaches (see Project A for description of sediment budget reaches).

The other critical information that is needed to evaluate the outcome of the HFE Protocol and the LTEMP is the change in total sand storage in long river reaches. HFEs build sandbars by redistributing sand from the low-elevation portion of the channel to sandbars in eddies and on the banks. The sand available for deposition is the sand that is in storage on the channel bed, which is the sum of the sand contributed by the most recent tributary inputs, any sand that may have accumulated since Glen Canyon Dam (GCD) was completed, and any sand that remains from the pre-dam era. The goal of the HFE Protocol is to accomplish sandbar building by mobilizing only the quantity of sand most recently contributed by the Paria River, thereby preventing depletion of pre-dam era sand. For this reason, conservation of sand was one of the criteria used to evaluate and select the preferred alternative in the LTEMP ROD. Measured trends in sand storage along the channel bed combined with trends in exposed sandbars will provide the necessary information on which to base future decisions about dam operations and other potential management options. If sand storage is maintained or increased, we expect the response to future HFEs to be similar or better than that observed following recent HFEs. In contrast, depletions of fine sediment in the active channel are potentially irreversible if sand supply from tributaries is consistently less than downstream transport. This situation would threaten the long-term ability to maintain sandbars. These long-term trends are measured in Project Element B.2 (partially funded), which includes two channel mapping campaigns. In 2021, we propose collecting a baseline map for the segment between RM 87 and RM 166, which has never been mapped. In 2023, we propose making a repeat map in Upper Marble Canyon to collect data that will be used in the 10-year assessment of LTEMP to be completed in future work plans, however this field work is not supported in the current project budget. Project Element B.3 includes work on the control network in support of this project, the remote sensing overflight project, and other work plan projects.

Project B also includes two research components and several experimental components. The first research component is proposed to investigate river channel adjustment to HFEs and redistribution of reservoir delta sediment on the Colorado River within the CRe in western Grand Canyon. This project was initially proposed as Project Element B.4 but is now included in this draft of the work plan as Project Element O.2 (experimental fund). Project Element B.5 (not funded) is a modeling project to produce flow models that predict the inundation extent and flow velocities for dam operations and HFEs in Marble Canyon and improve capabilities for predicting sandbar response to dam operations. Although this element is not supported in the current budget, we will attempt to make progress on modeling objectives if other funding sources are found. Project Element B.6 (experimental fund) describes studies that will be conducted to monitor and evaluate the condition-dependent experiments that affect sandbars and sediment resources, including extended duration HFEs, proactive spring HFEs, and variations in HFE downramp rate.

Project C: Riparian Vegetation Monitoring and Research

Riparian vegetation affects physical processes and biological interactions along the river channel downstream of GCD in ways that are integrally linked to flow regime. Reduced peak flows and increased base flows resulting from GCD operations have promoted riparian vegetation expansion close to the river (Sankey and others, 2015), but favor some species over others. Daily fluctuating flows have been shown to decrease germination and growth of riparian plants (Bejarano and others, 2020; Gorla and others, 2015) and is likely impacting the species composition in the CRe. Flow patterns designed to enhance other important resources, such as HFE’s, have a collateral impact on riparian vegetation cover and composition (Kennedy and Ralston, 2011; Ralston, 2011; Rood and others, 2005). Changes to species proportions and cover result in altered ecosystem functions, since riparian plant species differ in their structure (e.g., tall trees vs. short grasses), morphological traits (thorns, leaf size), and function (shade, soil stabilizer) (Butterfield and others, 2020; Merritt and Bateman, 2012). Through vegetation changes, dam operations can impact wildlife habitat (Ralston, 2005), sediment scour and deposition (Butterfield and others, 2020), visitor experience (Hadley and others, 2018), cultural resources (Cook and others, 2019), and many other natural processes.

The purpose of this project is to monitor the status and trends of riparian vegetation, examine mechanisms behind trends in riparian vegetation change as they relate to LTEMP flows, and apply existing and new knowledge to LTEMP vegetation management. The four elements of this project assess riparian vegetation status in the CRe (Element C.1, partially funded), test mechanisms by which flow regime impacts species of interest (Element C.2, fully funded), synthesize data to anticipate changes to vegetation (Element C.3, fully funded), and assist nonflow management actions directed by the LTEMP (Elements C.2, C.3, C.4; fully funded, Figure 1). For a description of budget cuts to Project C, see section 8. Elements and Activities Proposed, but not Funded in the Work Plan.

Project D: Effects of Dam Operations and Vegetation Management for Archaeological Sites

The construction and subsequent 50+ years of operation of GCD has profoundly altered the downstream aquatic and terrestrial ecosystem of the Colorado River corridor in lower Glen Canyon, Marble Canyon, and Grand Canyon. Among many effects, dam construction and operation have affected geomorphic processes responsible for the formation and preservation of the Holocene age, fluvially-derived sediment deposits in which numerous archaeological sites and other resources of cultural importance are embedded. The affected archaeological resources are valued not only for their information potential to archaeologists, but also as the homes and resting places of the ancestors of several Native American Tribes who reside in the region today. They are also valued as tangible records of indigenous peoples’ tenure in this landscape. Other resources of cultural value in the CRe include the plants that grow on the Holocene deposits, the birds that nest in the vegetation, the reptiles and mammals that inhabit the riparian zone, as well as the myriad kinds of aquatic life that live in the river. This project focuses specifically on studying and documenting the dam’s effects to the terrestrial riparian environment of the CRe and its associated archaeological resources, while recognizing the linkages this work has for other culturally valued resources as well.

During the past three decades, researchers affiliated with the USGS and various academic institutions have monitored and researched GCD effects on cultural resources in the CRe, including specifically the dam’s physical effects on archaeological sites. While it is recognized and acknowledged that the dam and its operation are not the only sources of change affecting the CRe and associated archaeological sites, this project focuses on researching and monitoring dam effects, in keeping with the mandates of the Grand Canyon Protection Act (GCPA). Furthermore, while it is also recognized and acknowledged that Native American Tribes affiliated with Grand Canyon view the effects of dam operations as being broader than just physical impacts to the ecosystem, and they believe that dam effects can potentially include impacts to traditional spiritual values as well as indigenous societies more generally, this project focuses on impacts which are amenable to investigation by scientific methods, with the understanding that those impacts which are not amenable to scientific investigation are best identified and addressed by the specifically-affected cultures at risk.

From a physical perspective, GCD has reduced downstream sediment supply to the Colorado River by about 95% in the reach upstream of the Little Colorado River confluence and by about 85% downstream of the confluence (Topping and others, 2000). Operation of the dam for hydropower generation has additionally altered the flow regime of the river in Grand Canyon, largely eliminating pre-dam low flows (i.e., below 5,000 ft3/s) that historically exposed large areas of bare sand (U.S. Department of the Interior, 2016a; Kasprak and others, 2018). At the same time, the combination of elevated low flows coupled with the elimination of large, regularly-occurring spring floods in excess of 70,000 ft3/s has led to widespread riparian vegetation encroachment along the river, further reducing the extent of bare sand (U.S. Department of the Interior, 2016a; Sankey and others, 2015). Kasprak and others (2018) report that the areal coverage of bare sand has decreased by 45% since 1963 due to vegetation expansion and inundation by river flows. Kasprak and others (2018) forecast that the areal coverage of bare sand in the river corridor will decrease an additional 12% by 2036. The changes in the flow regime, reductions in river sediment supply and bare sand, and the proliferation of riparian vegetation have affected the condition and physical integrity of archaeological sites and resulted in erosion of the upland landscape surface by reducing the transfer (termed “connectivity”) of sediment from the active river channel (e.g., sandbars) to terraces and other river sediment deposits in the adjoining landscape (U.S. Department of Interior, 2016a; Draut and Rubin, 2006, 2008; Draut and others, 2008, 2010; Draut, 2012; East and others, 2016, 2017; Kasprak and others, 2018; Sankey and others, 2018a, b; Cook and others, 2019). Many archaeological sites and other evidence of past human activity are now subject to accelerated degradation due to reductions in sediment connectivity under current dam operations and riparian vegetation expansion which are tied to regulated flow regimes (U.S. Department of the Interior, 2016a; East and others, 2016, 2017; Cook and others, 2019). The GCD Long-Term Experimental and Management Plan Environmental Impact Statement (LTEMP EIS) predicts that conditions for achieving the goal of preservation for archaeological resources, termed “preservation in place,” will be enhanced as a result of implementing the selected alternative (U.S. Department of Interior, 2016a). HFEs are one component of the selected alternative that will be used to resupply sediment to sandbars in Marble and Grand canyons, which in conjunction with targeted vegetation removal, is expected to resupply more sediment via wind transport to archaeological sites, depending on site-specific riparian vegetation and geomorphic conditions. However, HFEs have been shown to directly erode terraces that contain archaeological sites in Glen Canyon National Recreation Area (GLCA; East and others, 2016; U.S. Department of Interior, 2016a).

HFEs have also been shown by Sankey and others (2018b) to rebuild or maintain sandbars that provide sand to resupply aeolian dunefields containing archaeological sites throughout Marble and Grand canyons. Aeolian dunefields were resupplied with sand at deposition of rates of 2-8 cm per year from HFE deposits in half of the flood-site instances monitored after the 2012, 2013, 2014, and 2016 HFEs (Sankey and others, 2018b). Sankey and others (2018b) also found evidence for cumulative increases in sediment resupply of dunefields when annual HFEs are conducted consistently in consecutive years.

Project E: Controls on Ecosystem Productivity: Nutrients, Flow, and Temperature

Aquatic primary production is an important energy source for riverine food webs, converting sunlight, carbon dioxide and water into simple carbohydrates via photosynthesis. In the Colorado River downriver of Glen Canyon Dam, fish are food limited (Cross and others, 2011) and energy (carbon) produced within the river is a preferred food source relative to energy from tributaries and riparian inputs (Wellard Kelly and others, 2013). Aquatic primary production, and the aquatic insect community this production supports, is the main source of fish production in Glen Canyon throughout the year (Cross and others, 2011). Primary producers (specifically diatoms) are also a preferred food source downstream, although the role of non-algal (tributary/terrestrial) carbon sources can also be an important driver of the food availability during flood pulses such as occur during monsoon season (Cross and others, 2011; Wellard Kelly and others, 2013; Sabo and others, 2018).

There are several lines of evidence that link both nutrient concentrations and primary productivity to higher trophic levels throughout the Colorado River. Outside of periods when tributaries are flooding for extended periods, the availability of aquatic insect drift and the condition of native fish are positively related to seasonal rates of gross primary production (GPP) near the LCR, highlighting the important role for aquatic primary production even 120 km downstream of the dam (Deemer, 2020). Primary production at Diamond Creek (235 km downstream of the dam) also appears linked to juvenile production of flannelmouth suckers, the most common species in this area, further highlighting the importance of in situ production to fish communities in the western canyon (Yackulic, 2020). While total primary production is not significantly related to metrics of fish production in Glen Canyon, the availability of phosphorus (P), an important limiting nutrient, is correlated with chlorophyll a, a metric of diatom and other non-macrophyte-based primary production. Furthermore, P predicts rainbow trout recruitment better than flow-based metrics used to predict recruitment for the LTEMP EIS (U.S. Department of Interior, 2016; Yackulic, 2020).

Understanding the controls on Colorado River primary production is an important step towards better managing the aquatic food base. Disentangling the drivers of both rates and types of riverine primary production, and their link back to fish production, is particularly challenging given interactive and delayed effects and given different levels of information on the potential drivers. For example, monsoonal storm pulses that place temporary light availability constraints on rates of primary production (Hall and others, 2015) may also be delivering significant amounts of phosphorus to the mainstem. In a second example, at times of high phosphorus outflow from Glen Canyon Dam, elevated production of a dominant food source, diatoms, may suppress macrophyte production (via shading) obscuring the link between overall productivity and higher trophic levels.

This project aims to disentangle some of these drivers by combining the highly resolved longterm information about riverine turbidity, silt and clay concentrations, solar inputs, discharge, and gross primary productivity (via continuous oxygen and temperature measurements – data that are collected as parts of the Interagency Lake Powell Water Quality Monitoring project (Appendix 1), Project A.2, and Project E) with improved additional information about phosphorus, gas transfer and the relative role of diatoms in affecting whole river production (Elements E.1 and E.2). Project E is designed to capture and link changes in productivity to changes in bottom-up drivers such as light, flow, and nutrients and to further develop links between these bottom-up drivers and higher trophic levels.

Key to linking primary production to higher trophic levels is developing a better understanding of how much production is required to meet fish metabolic demands. This understanding will help us to develop ecosystem models that incorporate data collected at multiple trophic levels (Element E.3). Element E.3 involves both laboratory work and ecosystem modeling. Laboratory work will quantify the standard and active metabolic rates of the dominant native fishes in the ecosystem (i.e., humpback chub and flannelmouth sucker). Past bioenergetics work done in the 2000s (Petersen and Paukert, 2005; Paukert and Petersen, 2007) assumed humpback chub had metabolism like other Gila spp. because it has never been directly measured in humpback chub. However, recent observations in both the lab and the field suggest that humpback chub may have abnormally low metabolisms that enable them to persist through periods of food shortage (e.g., Dibble and others, 2017). By estimating these standard and active metabolic rates and absolute fish population abundances for Colorado River reaches, we can determine how much carbon (i.e., energy) is being consumed and how this relates to the amount of carbon produced by primary production through an ecosystem model.

Project F: Aquatic Invertebrate Ecology

The primary focus of Project F is continuation of long-term monitoring needed to track ecosystem response to “Bug Flows” and other LTEMP experiments. Research by our group has demonstrated that the scarcity of mayflies, stoneflies, and caddisflies from the Colorado River is partly due to acute mortality of insect eggs arising from hourly changes in discharge associated with hydropower generation (Figure 1). In May–August 2018–2020, Glen Canyon Dam operations were experimentally modified to try to increase the production and diversity of aquatic insects in the CRe. These experimental Bug Flows involved hourly flow fluctuations for hydropower generation during weekdays, coupled with steady, low flows on weekends to reduce aquatic insect egg desiccation and mortality. In FY2021-23, our group will track ecosystem response to the Bug Flows experiment and other ongoing or potential management actions using citizen science monitoring of aquatic insects (F.1), monitoring of invertebrate drift (F.1 and F.2), monitoring of invertebrate communities in Bright Angel Creek in response to fisheries management actions (F.3), through diet and stable isotope analysis of fish feeding habits (F.4), and through monitoring and research associated with spring flow disturbances (O.1).

Research and monitoring of invertebrates described in Project F also provides essential context and data that are used by other projects. For example, invertebrate monitoring data are used by Project E (controls on ecosystem productivity) to identify the extent to which changing nutrient levels are propagating up through the food web. Invertebrate monitoring data also aid interpretation of seasonal and annual trends in humpback chub (Project G) and rainbow trout (Project H), because aquatic invertebrates represent the food base for both species of fish. Project F also integrates and uses data from other projects, particularly Project A (streamflow, water quality, and sediment transport), to identify how changing environmental conditions affect invertebrate populations.

Project G: Humpback Chub Population Dynamics throughout the Colorado River Ecosystem

During FY2021-23, we will continue monitoring activities mandated by the 2016 Biological Opinion (BiOp; USFWS, 2016) associated with the LTEMP EIS (U.S. Department of the Interior, 2016), while focusing research on improving our understanding of abundance and the drivers of humpback chub population dynamics throughout the lower CRe. In the proposed budget, mark-recapture research in western Grand Canyon (G.6) would cease in FY2023, making it less likely that we would determine drivers of chub dynamics there (missing an opportunity to learn about this population while it is still thriving and potentially failing to meet a conservation measure). However, the TWG recommended that this project be funded in FY2023 by prioritizing savings and carry-over for continuation of Project Element G.6. The LCR-spawning portion of the population has been a stronghold for humpback chub since emplacement of Glen Canyon Dam in the 1960s. This portion of the population experienced a decline in the late 1990s and early 2000s but has been stable or increasing ever since then (Coggins and others, 2006; Van Haverbeke and others, 2013; Yackulic and others, 2018). However, monitoring of juvenile fish indicates the LCR-spawning portion of the population has displayed decreased juvenile production since 2012. As a result, we expect adult abundance to decline in the near term; however, the magnitude of this decline is less certain (Figure 1). During FY2021-23, we will continue to estimate juvenile production and test hypotheses regarding drivers of juvenile production. We will also continue to resolve our understanding of how rainbow trout, temperature, turbidity, and food limitation drive growth, survival, and fish condition in the mainstem Colorado River.

For many decades, humpback chub that spawned in the LCR formed the vast majority of the overall CRe population. Since 2014, however, the catch of humpback chub in western Grand Canyon has been increasing (Van Haverbeke and others, 2017) and it is likely a larger portion of the overall CRe population is now found in western Grand Canyon. While our understanding of the drivers of the LCR population has matured in recent years following intensive demographic studies, we lack a similar understanding for the western Grand Canyon. Available data suggests that recent increases may be driven by only a few years of high juvenile production. During this workplan, we will continue studies of chub demography in the western Grand Canyon, which will allow us to determine baseline rates of growth and survival and allow us to estimate abundance in this expanding population segment. We are optimistic that we will continue to learn about drivers of juvenile production and overall chub vital rates with an ultimate goal of developing predictive models for chub in the western Grand Canyon that are similar to the ones used in the LTEMP EIS for chub that spawn in the LCR.

To satisfy BiOp Conservation Measures, test hypotheses about drivers, and estimate adult abundance, we will monitor humpback chub in the LCR-spawning population by sampling the LCR and juvenile chub monitoring (JCM-east) reach in the Colorado River (G.2, G.3) in all years. We also will monitor the western Grand Canyon population via continuation of mark recapture in the Fall Canyon reach (JCM-west) during all three years, if funding can be made available for FY2023 (G.6), allowing us to continue to meet an objective listed in the BiOp Conservation Measures. Maintaining JCM-west is particularly important because we will be discontinuing seining trips (not funded, G.8) in all years of the workplan. Extensive sampling via the aggregation sampling (G.5) will continue in all 3 years, albeit with less effort in FY2022 than originally proposed. Mark-recapture data from these trips will be supplemented with data from autonomous passive integrated transponder (PIT) tag antennas, such as the LCR multiplexer cross-channel array (MUX) in the LCR and portable antennas, as these technologies have proven effective at detecting larger adults which are often difficult to capture using other methods such as hoop netting and electrofishing (G.4). Lastly, since models developed under the previous workplan suggest that Chute Falls translocations help augment the LCR-spawning adult population, we propose continuation of Chute Falls translocations and monitoring by the US Fish and Wildlife Service (USFWS; G.7). We do not currently plan to analyze otoliths from incidental mortalities of age-0 fish collected over the last few years in the LCR to improve understanding of hatch dates, which would have helped us understand the degree to which LCR hydrology effect juvenile production. Data collected from the abovementioned field efforts will be analyzed to help learn more about humpback chub life history and to guide management efforts (G.1).

Project H: Salmonid Research and Monitoring

The LTEMP (U.S. Department of Interior, 2016) provides the necessary long-term framework for assessing specific operations at Glen Canyon Dam (GCD), as well as other types of management actions conceived during and implemented over the next 20-year period. For this reason, the Salmonid Research and Monitoring Project was developed having the long view, with a means to revise and respond to unanticipated and emerging risks (e.g., brown trout). The study design described in the previous work plan remains relevant for the same management questions posed in the LTEMP, and likely, other work plans developed in the future. As such, this type of experimental approach is appropriate for understanding large and complex ecosystems, particularly when quantifying trout population dynamics. Clearly, population responses are sometimes confounded by extrinsic factors (e.g., nutrients, see Project E) that act independent of flows or because of multiple management actions that have been applied concurrently within a given year (e.g., 2018 ‘Bug Flows’ and fall HFEs).

These circumstances make it difficult for resolving cause and effect relationships in a timely fashion. Although monitoring programs (e.g., Project Element H.1) are important for documenting long-term population trends and characteristics such as catch-per-unit-effort, size distribution, and occurrence and trends, monitoring as a sole method of data collection is not an effective approach in time or cost for determining causation, particularly when quantifying and separating out effects from complex interactions that occur among multiple factors (e.g., flow, fish density, nutrients). In order to study multiple flow treatments and avoid potential confounding factors, we propose to continue using a seasonal sampling design described in the FY2018-20 Triennial Work Plan (TWP) with spatial replication to assess trout responses to experimental flows and other factors within and across years (Project Element H.2). However, due to budget constraints in the FY2021-23 TWP, we initially proposed decreasing sampling effort from three Trout Reproductive and Growth Dynamics (TRGD) sub-reaches to one sub-reach per trip starting in FY2022. Stakeholders raised concerns in the June 23-24, 2020 GCDAMP TWG Meeting about this approach and the loss of information related to the increasing brown trout population. The TWG requested a revision of the work plan in their motion to the AMWG, stating they: “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.” To accommodate this request from GCDAMP Stakeholders, (Arizona Game and Fish Department) AGFD and GCMRC are currently in discussions that will continue over this 3-year work plan to integrate the two programs to the extent practicable, knowing that both programs will need to compromise to attain this goal given the budget allotted in the FY2021-23 TWP for trout monitoring and research. Since an integrated study design will be developed and tested based on discussions over the next year or so, we have kept the narratives and budgets for Project Elements H.1 and H.2 separate in the final draft of this work plan for the sake of clarity. Additional details on our initial approach to better integrate these programs while retaining some of the study objectives for each program are outlined in Section 5.4.

As a goal, protection of the endangered humpback chub near the LCR is one of the highest priorities of the GCDAMP, but a concurrent priority is to maintain a high-quality rainbow trout sport fishery upstream from Lees Ferry in Glen Canyon. As such, rainbow trout were an important component in the development of LTEMP for GCD operations, and thus were a major consideration in the flow decisions in the selected alternative in the LTEMP ROD (U.S. Department of Interior, 2016b). Yet, high trout abundance is not the only factor that limits humpback chub abundance at the LCR (e.g., temperature, prey, and turbidity) (Yackulic, 2018), as a population has survived multiple periods of high trout abundance (1998-2001, 2008-2009, 2011-2014, 2017-2019) (Coggins and others, 2011; Korman and Yard, 2020).

Trout Management Flows (TMFs) proposed in the LTEMP were designed to limit rainbow trout recruitment and dispersal out of Lees Ferry (Korman and others, 2011a; Korman and others, 2011b; Korman and others, 2016; Yard and others, 2016) with a goal of maintaining the balance between the sport fishery and the humpback chub population downstream. However, ecosystems are dynamic and there has been a large increase in brown trout recruitment upstream from Lees Ferry over the past few years (2015-2019).

Given this new development, it is unclear whether the expansion of brown trout will disrupt the balance between salmonids and endangered native fishes downstream, the rainbow trout fishery in Glen Canyon, and the degree to which flow manipulations can be used to manage rainbow and brown trout.

A major component of the proposed study elements, described herein, focus on how experimental flows will influence recruitment, growth, survival, and dispersal of rainbow trout in Glen and Marble canyons. However, management of the rainbow trout fishery cannot occur in a vacuum given the recent increase of brown trout in Glen Canyon. Small numbers of brown trout have been present in the canyon since the dam was built (Minckley, 1991), but have increased following a time period associated with frequent fall HFEs (Runge and others, 2018). It is currently unclear whether this flow relationship is causal or coincidental, but research is needed to further examine if the proposed flow manipulations help or hinder the expansion of brown trout.

Other aspects of the flow regime and non-flow factors can also explain recent increases in brown trout. These include increases in macrophyte abundance due to reductions in diel variation in flow starting in the early 1990s (McKinney and others, 1999), and warmer water temperatures due to low reservoir elevations from the persistent 21st century drought may provide a physiological advantage for brown trout as an apex predator (Korman and others, in review). However, good comparative studies of temperature tolerances made between rainbow trout and brown trout are uncommon, and at best thermal differences are nuanced (e.g., prey availability and prey size).

Brown trout are superior competitors in other tailwater systems and typically are not stocked past their initial introduction (Dibble, unpublished data), and are known to be voracious predators of small-bodied native fishes (Yard, 2011). It is therefore prudent and necessary to not only evaluate the effect of experimental flows on rainbow trout, but also to examine how brown trout populations may respond to such flow manipulations. Furthermore, competitive interactions between brown trout and rainbow trout may impact each other’s survival and recruitment rates. Good growth and condition of rainbow trout occurred in late 2016 and 2017, which contributed to high rainbow trout recruitment in 2017, and its likely downstream movement. The only year since 2015 without a substantive catch of age-1 brown trout occurred in 2017, which was also the year with elevated recruitment of rainbow trout. Therefore, it is possible that a larger or healthier population of rainbow trout could help keep the brown trout population in Glen Canyon in check. It could be that higher levels of rainbow trout spawning in winter and spring of 2017 reduced recruitment of brown trout by redd (i.e., spawning bed) superimposition or other competitive effects (Scott and Irvine, 2000; Nomoto and others, 2010).

Thus, policies aimed at reducing rainbow trout recruitment in Glen Canyon have the potential to backfire if they inadvertently lead to an increase in brown trout abundance. A better understanding of the interaction between rainbow and brown trout in Glen Canyon is therefore critical, and a major aim of the revisions made in the proposed work plan, herein.

Project I: Warm-water Native and Nonnative Fish Monitoring and Research

Maintaining self-sustaining native fish populations within the Colorado River and minimizing the presence and expansion of aquatic invasive species are two specific resource goals outlined in the LTEMP EIS and associated BiOp for the operation of Glen Canyon Dam (U.S. Department of Interior, 2016a, b). These two resource goals are closely linked together in that introduced warm-water fish are largely incompatible with Colorado River native fish (Marsh and Pacey, 2005; Minckley and Marsh, 2009). Introduced warm-water sport fish prey upon juvenile native fish, and once established, can cause rapid disappearance of native fish (Moyle and others, 1986). In both the upper and lower Colorado River Basins, warm-water predatory fish are implicated in the lack of recruitment and subsequent population declines in native fish (Mueller, 2005; Martinez and others, 2014). Control methods are typically the most cost effective and successful when invasions are detected early (Leung and others, 2002; Dawson and Kolar, 2013). A robust monitoring program increases the likelihood that a new invasion will be detected early and that management actions can be taken to control pest species.

Long-term monitoring allows the ability to detect trends and test hypotheses in regard to temporal variation in fish populations, but its strength also lies in the ability to interpret and detect unexpected trends or surprises (Lindenmayer and others, 2010; Dodds and others, 2012; Melis and others, 2015). When designed properly, a long-term monitoring program is a powerful tool for quantifying the status and trends of key resources, understanding system dynamics in response to stressors, and investigating the efficacy of alternative management actions. Without long-term monitoring, science-based decisions for fisheries management are often not possible (Walters, 1986). This project will continue long-term, standardized monitoring conducted by Arizona Game and Fish Department (AGFD) throughout the Colorado River from Lees Ferry (RM 0) to Pearce Ferry (RM 281) for the combined purposes of tracking the status of native fish as well as identifying new invasive aquatic species. This is the only project that tracks all native and nonnative fishes throughout the length of the Colorado River in the project area.

AGFD will conduct one spring system-wide fish monitoring trip in FY2021, one trip in FY2022, and two trips in FY2023 from Lees Ferry to Diamond Creek using electrofishing, angling and hoop netting. For the monitoring that takes place in the Fall downstream from Diamond Creek, AGFD will only monitor the last 15 miles of river upstream from Pearce Ferry (3 nights of sampling in each year) because of budget constraints and the need to reduce logistics costs. Other fish monitoring efforts which focus on humpback chub (Project G), and monitoring of small bodied fished conducted by the NPS downstream of Bright Angel Creek (funded by the Bureau of Reclamation outside of the GCDAMP also provide important additional detection information of new invasive aquatic species, and all of these efforts together provide a robust monitoring program to track changes in native fishes and detect new problematic invasive aquatic species. Water levels in Lake Powell have decreased in recent years because of ongoing drought. This causes warm surface waters to be entrained into the penstocks and released downstream. While warmer water provides better thermal conditions for native Colorado River fishes, it also increases the likelihood that warm-water introduced fishes will become established and negatively impact populations of native fishes. Management and removal of invasive aquatic species can be difficult once a species becomes established because problems typically become large in scale quickly and few effective tools are available for managing aquatic invasive species (Dawson and Kolar, 2013).

This creates the need to both detect invasive species early and understand which species pose the greatest threats so that efforts can be prioritized. Assessing the risks posed by existing or new warm-water invasive fish provides managers with the scientific information needed to make decisions about what management activities are warranted. Hilwig and Andersen (2011), compiled a literature review of the potential risks posed by individual species, but those risks need to be validated and quantified based on existing environmental conditions, species abundances, and expected future conditions in the LCR and CRe. In previous work plans risks related to rainbow and brown trout were evaluated (FY2016-17) as well risks posed by other invasive warm-water fishes (FY2018-20). Channel catfish and green sunfish were identified as two invasive species that pose particularly high risks to Colorado River native fish (Ward, 2020). In surveys conducted in FY2018-20, channel catfish were found to exist in higher abundance within the LCR than previously known, with a majority of the fish being large in size, averaging 408 mm (Figure 1). There are no catfish species native to the Colorado River, therefore native Colorado River fishes did not evolve mechanisms to avoid catfish predation. Native fishes are particularly vulnerable to predation by catfish predators (Ward and Figiel, 2013), especially under turbid conditions (Ward and Vaage, 2019).

Green sunfish were also identified as a particularly high-risk species because of their aggressive nature, high piscivory and known ability to rapidly colonize new environments and displace native fish (Ward, 2015). In this workplan we propose to focus specifically on quantifying the risks posed by these two species.

Laboratory studies will be conducted to quantify size specific predation risk from channel catfish and green sunfish. These laboratory studies in conjunction with abundance estimates for channel catfish from the LCR, will allow managers to determine if invasive catfish present more or less of a predation threat to juvenile chub than predation by trout or other warm-water predators. This information gives context from which to evaluate potential management actions such as mechanical removal and will ensure that any future aquatic invasive species removal efforts are focused only on those species that pose the highest threat to humpback chub populations.

In addition to evaluating the risks posed by invasive fishes we will also continue to evaluate the risks posed by infestation of Asian fish tapeworm (Bothriocephalus acheilognathi) in humpback chub. Asian fish tapeworm is an invasive species that infests warm-water cyprinid fish. Asian fish tapeworm monitoring took place in 2005 and 2006 and has occurred annually at a low level within the LCR since 2015.

Additional monitoring will continue in this work plan to evaluate the prevalence of Asian fish tapeworm in humpback chub inhabiting the mainstem Colorado River as identified in the 2016 BiOp. Asian fish tapeworm has been identified as one of six potential threats to the continued existence of endangered humpback chub (USFWS, 2002). It is potentially fatal to new host species (Hoffman and Schubert, 1984).

Asian fish tapeworm was first documented in the LCR in Grand Canyon in 1990 (Minckley, 1996) and was hypothesized to be a cause of long-term declines in condition of adult humpback chub from the LCR (Meretsky and others, 2000). Monitoring Asian fish tapeworm infestation in humpback chub in the mainstem Colorado River in addition to the LCR will provide a baseline context and relative risk assessment with which to evaluate the potential impacts of this invasive parasite on humpback chub populations.

In the FY2018-20 Triennial Work Plan (TWP) we identified the need to develop a new tool to detect rare nonnative species invasions prior to population expansion. Responding quickly to invasions before populations become large and established is the least expensive and most effective way to control invasive species (Leung and others, 2002). Early detection tools are in the process of being developed to detect the presence of rare species and their spatial extent across a riverscape at a molecular level (Schwartz and others, 2007; Carim and others, 2016a). In aquatic environments, fish shed cellular material into the water via reproduction and feces that can persist in the environment for several weeks. This cellular material can be collected via water sample and environmental DNA (eDNA) extracted from cells collected in the environment in which an organism lives, rather than directly from animals themselves.

Since the quantity of eDNA in a sample scales with fish biomass, relative abundance metrics can be calculated (Klymus and others, 2015). This approach can have higher sensitivity relative to traditional sampling methods, since hoop nets and standard electrofishing may not detect rare species at the early stages of invasion (e.g., smallmouth bass), species that may not be susceptible to capture (e.g., channel catfish), or species residing in deeper areas outside of the range of standard methods. Molecular analyses can also be associated with lower costs than traditional staff-heavy sampling methods, since a filtered water sample is all that is needed (Carim and others, 2016a). As such, this tool lends itself nicely to answering questions in the Grand Canyon related to both the presence and distribution of rare nonnative species and is a critical first step in early detection so that management actions can be targeted to prevent spread. We used seed money in the FY2018-20 TWP in combination with funding from the USBR and USFWS to commence a project to collect eDNA samples at 300 spatially distributed sites throughout the Colorado River, at tributary junctions, and in Lakes Mead and Powell. This trip was scheduled to launch in May 2020 but was postponed due to the COVID-19 pandemic and closure of the Colorado River in Grand Canyon in spring 2020. This sampling may be postponed to June 2020 or rescheduled entirely to May 2021.

In the FY2021-23 TWP, we propose to use data on any nonnative species detections from the 2020 eDNA sampling trip to target reaches where problematic nonnative species detections occur. The objective of this second sampling trip is twofold: 1) determine whether invasive species of interest have geographically expanded; and 2) determine whether relative abundance has increased (or decreased) in the interim time period. This information will be used to help the NPS implement strategies that respond to new or expanded invasions, should they occur.

Project J: Socioeconomic Research

Project J contains research elements that collect and integrate socioeconomic information with data and predictive models from ongoing long-term physical and biological monitoring and research led by the USGS GCMRC. The project elements improve the ability of GCDAMP resource managers and stakeholders to evaluate management actions and prioritize monitoring and research. This project involves three interrelated socioeconomic research elements that address novel resource management challenges and build on research in the FY2018-20 TWP (Bureau of Reclamation, and U.S. Geological Survey, 2017):

• The development and integration of predictive biological and physical models with economic metrics to evaluate and prioritize monitoring of, and research on, resources downstream of Glen Canyon Dam (GCD), including the anticipated success (or lack thereof) of proposed flow experiments in the LTEMP EIS (U.S. Department of Interior, 2016a) (Element 1);
• The design, implementation, and monitoring of the impacts of an incentivized harvest program to reduce brown trout abundance in Lees Ferry (Element 2); and
• The survey of recreational angler and whitewater boater’s preferences for flow attributes, in accordance with GCD maintenance and LTEMP EIS experimental flows (Element 3).

The proposed project elements address the LTEMP Record of Decision (ROD) (U.S. Department of Interior, 2016b) resource goals related to humpback chub, sediment, invasive fish, and hydropower, as specified in Section 4.

Project K: Geospatial Science, Data Management and Technology

A crucial component of any long-term adaptive management program is the proper management and accessibility of its data resources necessary for measuring the status, trends, and experimental results related to the program’s objectives. The data collected through the USGS GCMRC are a vital resource used to determine the status of the natural resources identified through the GCDAMP and to make timely decisions on dam operations. The primary purpose of this project is to provide high-level support to GCDAMP-funded science efforts in the disciplines of geospatial science, data management, database administration, and emerging information technologies.

Shifts in the geospatial and information technology industries are pushing the boundaries on how data can be managed and made accessible to outside entities. Much of this change is driven by advances in technology—from improved sensors for monitoring the Earth, to increased digital data storage capacity, to newer computer systems designed for processing large data sets more efficiently, and to the greater emphasis of the “Internet of Things” where the reliance of webbased technologies have revolutionized our world. A common thread for the different aspects of this project is to continue to advance GCMRC’s ability to leverage many of these new technologies for the benefit of the GCMRC, the science projects described within this work plan, and the larger GCDAMP. While some of the work elements described within this project discuss the use of newer technologies and methods for managing, analyzing and providing access to the Center’s data resources, the concepts that this work serves are not new and have been part of the GCDAMP since the beginning. By standardizing our data resources, streamlining workflows and leveraging new technologies, we can fulfill these important needs of the program more efficiently, and ultimately, for much lower costs than would occur if each project were instead left to develop their own closed systems. Work performed within this project makes it possible to share important information about trends in resources of the CRe to the GCDAMP through web-based, interactive tools and mapping products, allowing the GCDAMP to make better informed, time-sensitive decisions on experimental and management actions under the 2016 LTEMP and the (ROD (U.S. Department of Interior, 2016a, b).

Project L: Overflight Remote Sensing in Support of GCDAMP and LTEMP

This project seeks to acquire high-resolution multispectral imagery and a digital surface model (DSM) of the Colorado River and riparian area from the forebay of Glen Canyon Dam downstream to Lake Mead, and along the major tributaries to the Colorado River. The proposed schedule for this data collection mission is in May 2021, during the first year of the FY2021-23 TWP. The data sets derived from remote sensing overflights (Table 1 and Figure 1) have proven to be extremely valuable to most of the research projects conducted by GCMRC over the past two decades. Importantly, scientific research which relied heavily on these data were the basis for the 2016 LTEMP (U.S. Department of Interior, 2016a). Data derived from the 2021 overflights will be used in the LTEMP ROD implementation process (U.S. Department of Interior, 2016b).

GCMRC’s Scientific Monitoring Plan in support of LTEMP, notes that the ROD “calls for a comprehensive, decadal-scale assessment of the impact of dam operations on sandbar resources and on the status of humpback chub” (VanderKooi and others, 2017). Given that the most recent overflight was previously conducted in 2013, and given the physical, geographic and logistical constraints of the Colorado River in Grand Canyon, system-wide remotely-sensed data are necessary to complement ground-based data collection and assist with the GCMRC’s efforts to effectively assess these impacts for the entire river ecosystem over decadal time frames. The imagery and derivative data products from overflight remote sensing are used either directly or indirectly by every science project proposed in this TWP to address every resource goal of the LTEMP.

While this proposed work is discussed within the context of the FY2021-23 TWP, the nature and justifications for conducting the overflight are directed at the GCMRC’s ability to respond to and deliver information for the LTEMP implementation process that tracks decadal-scale changes to resources system-wide. As such, the overflight is a scientific effort that has both an immediate and a longer-term payoff; future LTEMP studies will require similar information that can be effectively derived from remotely-sensed data acquired over coming decades. For these reasons, this project is mission critical to successfully inform the GCDAMP on performance of the LTEMP ROD.

Project M: Leadership, Management, and Support

The Leadership, Management, and Support budget covers salaries for a budget analyst, librarian, a part-time library assistant, three members of the logistics support staff, as well as leadership and management personnel for GCMRC. Leadership and management personnel salaries include those for the GCMRC Chief and Deputy Chief as well as half the salary for one Principal Investigator and half the salary for one data specialist. Most of the travel and training costs for administrative personnel are included in this project as well as the cost of GCMRC staff to travel to AMWG and TWG meetings. Cooperator funding is for support of the Partners in Science Program with Grand Canyon Youth. Operating expenses include:

1. GSA vehicle costs including monthly lease fees, mileage costs, and any costs for accidents and damage;
2. DOI vehicle costs including gas, maintenance, and replacements costs;
3. GCMRC’s Information Technology equipment costs; and
4. A $20,000 annual contribution to the equipment and vehicles working capital fund.

Project N: Hydropower Monitoring and Research

The LTEMP (U.S. Department of the Interior, 2016a) states that the objective of the hydropower and energy resource goal is to, “maintain or increase Glen Canyon Dam (GCD) 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.” Project N will identify, coordinate, and collaborate with external partners on monitoring and research opportunities associated with operational experiments at GCD designed to meet hydropower and energy resource objectives, as stated in the LTEMP EIS and its ROD (U.S. Department of the interior, 2016a, b), and guided by the memorandum (Guidance Memo) from the Secretary's Designee, dated August 14, 2019 (Petty, 2019).

Operational experiments include proposed experiments in the LTEMP EIS (U.S. Department of Interior, 2016b), and other identified operational scenarios at GCD to improve hydropower and energy resources, while consistent with improvement and long-term sustainability of other downstream resources. Project N will prioritize research associated with operational experiments at GCD designed to meet hydropower and energy resource objectives. Project N will also conduct monitoring and research of proposed experiments in the LTEMP EIS and consider impacts on hydropower and energy as part of the experimental design. Coordinated project implementation and development will occur between Reclamation, Western Area Power Administration (WAPA), and other collaborators to utilize and build on existing hydropower and energy models and data, specifically those from Appendix K in the LTEMP EIS (U.S. Department of Interior, 2016b).

Project O

The purpose of Project O is to evaluate whether a spring-timed disturbance flow will improve resources in the Colorado River Ecosystem (CRe). The proposed spring-timed disturbance flow is not to be confused with the sediment-triggered High Flow Experiments (HFEs), which are one of the principal experimental flows recognized in the Long-Term Experimental and Management Plan Final Environmental Impact Statement (LTEMP FEIS; U.S. Department of Interior, 2016a) and its associated Record of Decision (LTEMP ROD; U.S. Department of Interior, 2016b). The cornerstone of this project is a potential test of a spring disturbance flow hydrograph developed by the FLow Ad Hoc Group (FLAHG). The FLAHG hydrograph is a direct outgrowth of the group’s December 2019 charge, which states the FLAHG shall work: 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 proposed hydrograph is a 5-day low flow necessary for maintenance on Glen Canyon Dam (GCD) followed by a 4.5-day high flow pulse within base operations constraints specified by the ROD (Figure 1). This combination of desiccation at low flows followed by scour at higher flow is hypothesized to disturb benthic habitats to a much greater extent than either the low or higher flow alone (Kennedy and others 2020).

The hydrograph developed and recommended by the FLAHG will be used to evaluate whether a spring-timed disturbance flow enhances resources in the CRe. The FLAHG hydrograph may also be used to: 1) evaluate whether an extended period of low flows in the spring windy season, followed by a pulse flow, enhances transport of sand to inland dunefields and archaeological sites (Project Element O.3); 2) track physiological responses of key riparian plant species and identify how physiological responses to flows may favor some riparian plant species over others (Project Element O.4); 3) evaluate native and invasive fish response (Project Elements O.6 and O.7); 4) estimate the impact of a low flow disturbance to recreational angling (Project Element O.8), hydropower (Project Element O.9), and sandbars and campsites (Project Element O.10); and 5) use of decision support tools to help synthesize findings and identify logical next steps in adaptive management experimentation (Project Element O.11; note that funding for O.11 is being sought from a different source than other project elements, see Budget Justifications). The period of work for this project will be two fiscal years that begin in the fiscal year the spring disturbance flow is implemented. For planning purposes here, we define these as Year 1 and Year 2. In Year 1 this project seeks funding mainly from the C.5 Experimental Management Fund. Note that Reclamation retains decision-making authority for the allocation of funds from the C.5 Experimental Management Fund. In Year 2 we will seek funding from TWP carryover funds from prior years, or through annual review of the TWP, or through other Reclamation considerations (see Budget Tables in Budget Justifications). 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).

As with LTEMP flow experiments, the process to plan and implement the spring disturbance flow would involve evaluation of resource conditions and expected effects by the Glen Canyon Technical Team followed by Glen Canyon Leadership Team consideration. Research and monitoring proposed herein may change if conditions warrant. The decision of whether to implement the spring disturbance flow will be made by the Secretary of the Interior or their Designee.

Appendix 1. Lake Powell Water Quality Monitoring

GCMRC has an existing five-year agreement with the Bureau of Reclamation (IA R18PG00108) to continue Lake Powell water quality monitoring through calendar year 2022. The Grand Canyon Monitoring and Research Center (GCMRC) will be continuing its long-term water-quality monitoring program of Lake Powell reservoir. This program has been in existence since 1965 and United States Geological Survey (USGS) has conducted the monitoring program since 1996. The monitoring program measures water-quality conditions in the forebay and tailwater of the reservoir monthly and throughout the entire reservoir on a quarterly basis. Water temperature, specific conductance, dissolved oxygen; pH, redox potential, chlorophyll florescence and turbidity are measured throughout the water column at 30 sites, with samples of major ionic constituents , nutrients, dissolved organic carbon, phytoplankton, and zooplankton being collected at selected sites. Physical and Chemical information from this program was published-as USGS Data Series Report DS-471. An updated revision to this report is currently in review. All information from this program is stored in the Water Quality Database (WQDB).

• GCDAMP Planning
• GCDAMP Budget and Workplan Page
• Budget AdHoc Group Page
• FLAHG Page

• GCMRC FY21 Annual Project Report
• DOI approval letter of the FY21-23 TWP
• FY21-23 TWP Final (Approved by Secretary)
• FY21-23 TWP Final Draft for AMP review (Sept 2020)
• Project O
• GCMRC FY21-23 TWP AMWG Draft (July 2020)
• Reclamation FY21-23 TWP AMWG Draft (July 2020)
• GCMRC FY21-23 TWP First Draft (April 2020)
• Reclamation FY21-23 TWP First Draft (April 2020)
• GCDAMP Triennial Budget and Work Plan Process (Updated October 19, 2016)
• Conservation Measures Extracted from the Nov. 28, 2016 USFWS LTEMP Biological Opinion
• Appendix D Draft Final Proposed Action Triggers for the Management of Humpback Chub, Colorado River, Grand Canyon

2022

• Technical Work Group Budget Motion
• June 2022 TWG Budget Motion
• AMWG FY23 Budget Recommendation Language
• GCMRC FY2023 Budget Overview
• GCDAMP FY23 Budget and Work Plan: Reclamation
• GCDAMP FY23 Budget and Work Plan: Reclamation
• GCMRC FY2023 Budget Overview

2021

• Fiscal Year 2022 Proposed Budget and Work Plan – Reclamation
• Recommendation from the Budget Ad Hoc Group for the Fiscal Year 2022 Budget and Work Plan
• Proposed Fiscal Year 2022 Budget and Work Plan
• Fiscal Year 2021 Priorities Update
• GCDAMP Fiscal Year 2022 Budget and Work Plan: Reclamation
• Three-Year Federal Appropriations Process
• GCMRC Fiscal Year 2022 Budget Overview
• GCDAMP FY22 Budget and Work Plan: Reclamation

2020

• GCMRC FY 2021-23 Triennial Workplan and Budget – 4th Draft
• GCDAMP Fiscal Year 2021-2023 Triennial Budget and Work Plan : Reclamation
• Triennial Budget and Work Plan Fiscal Year 2021-2023
• Science Advisors Review of the 2nd draft GCMRC 2021-2023 Work Plan
• External Review of Fiscal Year 2021-23 Triennial Plan Draft of May 19, 2020
• Draft Fiscal Year 2021-23 Triennial Budget and Work Plan (Reclamation): Development & Comments
• GCMRC Fiscal Year 2021-23 Triennial Workplan and Budget – 3rd Draft
• GCMRC FY 2021-23 Triennial Workplan and Budget – Budget introduction presentation
• GCMRC FY 2021-23 Triennial Workplan and Budget – 2nd Draft
• Preliminary GCDAMP Fiscal Year 2021-23 Triennial Workplan and Budget presentation
• Reclamation Budget Process
• Triennial Budget and Work Plan Fiscal Year 2021-23 – Budget introduction presentation

Resource Topics for 2021-23 TWP

Based on ROD Resource Categories (see page 6 of the ROD)

• Archaeological and Cultural Resources
• Humpback Chub
• Hydropower and Energy
• Other Native Fish Species
• Recreational Experience
• Sediment
• Tribal Resources
• Rainbow Trout Fishery
• Riparian Vegetation
• Water Quality and Food Base (added, part of KA)
• Invasive Fish Species (added, part of KA)

• Natural Processes: Not used (is an evaluation of above resources as related to “natural” benchmarks)

Humpback Chub

Ongoing actions:

• Translocations of humpback chub into tributaries of the Colorado River in Marble and Grand Canyons
• Spring and fall humpback chub population estimate
• Control or removal of nonnative fish in tributaries prior to chub translocations
• Humpback chub refuge population at a federal hatchery
• Ensure that a stable or upward trend of humpback chub mainstem aggregations can be achieved by:

1. Annual monitoring of the Little Colorado River humpback chub aggregation (e.g., juvenile chub monitoring parameters).
2. Annual monitoring in the mainstem Colorado River to determine status and trends of humpback chub.
3. Periodic surveys to identify additional aggregations and individual humpback chub.
4. Evaluate existing aggregations and determining drivers of these aggregations.
5. Explore means of expanding humpback chub populations outside of the Little Colorado River Inflow aggregation.

• Disease and parasite monitoring

New actions:

• Feasibility study for translocation of humpback chub into Upper Havasu Creek (above Beaver Falls).
• Evaluate other tributaries for potential translocations.

Razorback Sucker

Ongoing actions:

• Larval and small-bodied fish monitoring.

Actions to benefit all native aquatic species

Ongoing actions:

• Investigate the possibility of renovating Bright Angel and Shinumo Creeks with a chemical piscicide.
• 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.

New actions:

• 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.
• Preventing the passage of deleterious invasive nonnative fish through Glen Canyon Dam.
• Fund the NPS and GCMRC on the completion of planning and compliance to alter the backwater slough at River Mile (RM) 12.
• Develop a plan for implementing rapid response control efforts for newly establishing or existing deleterious invasive nonnative species.
• Experimental use of TMFs to inhibit brown trout spawning and recruitment in Glen Canyon

Southwestern willow flycatcher and Yuma Ridgway’s rail

• Conduct Yuma Ridgway’s rail surveys
• Conduct southwestern willow flycatcher surveys

• Spring HFEs ≤  45,000 cfs in March or April
• Proactive Spring HFEs ≤ 45,000 cfs in April, May, or June
• Fall HFEs ≤ 45,000 cfs in October or November
• Fall HFEs > 96‐hr duration in October or November
• Trout management flows from May to August
• Macroinvertebrate production flows from May to August
• Humpback chub translocations (mainstem and tributaries)
• Larval humpback chub head‐start program
• Mechanical removal of rainbow trout from LCR reach
• Mechanical removal of invasive fish species
• Riparian vegetation restoration

2022

The Technical Work Group recommends that the Adaptive Management Work Group (AMWG) recommend for approval to the Secretary of Interior, the Fiscal Year 2023 budget as shown on the budget worksheets presented to the Technical Work Group (TWG) on June 15, 2022; furthermore, as funds become available, the Technical Work Group recommends those funds are used to fund the work items listed below in priority order:

Priority 1 – Given the historic release temperatures from Glen Canyon Dam and the possibility of invasive fish establishment in the Colorado River ecosystem (CRE) with the potential to harm Endangered Species Act listed fish and the rainbow trout fishery, the Department of Interior should prioritize funds, including the use of the Reclamation C.6 Native Fish Conservation Contingency Fund and the C.5 Experimental Management Fund, and prioritize activities such as evaluation of operational alternatives or other CRE management and monitoring, to address this concern. These activities might require budgetary adjustments. Such actions will be coordinated with the TWG and AMWG. The Glen Canyon Dam Adaptive Management Program sees the potential establishment of nonnative fish as an emergency situation that warrants swift and decisive mitigation action.

Priority 2 – Continue Project Element G.6, Juvenile Chub Monitoring-West

Priority 3 – Continue sampling at two sub-reaches for Project Element H.2, Experimental Flow Assessment of Trout Recruitment

Priority 4 – Begin the Grand Canyon portion of the water quality synthesis requested by the Adaptive Management Work Group at their February 9-10, 2022 meeting

Priority 5 – Investigate an aquatic vegetation removal pilot project in Lees Ferry to reduce brown trout habitat

Priority 6 – Continue two monitoring trips for Project Element C.1, Ground-based Riparian Vegetation Monitoring

Priority 7 – Continue Project Element B.5, Streamflow and Sandbar Modeling

In addition, should an emergency arise that would require budgetary adjustment, the TWG is notifying the AMWG that we may make necessary budgetary recommendations at a later date. Motion made by Kelly Burke, GCWC, Seconded by Erik Stanfield, Navajo Nation, To adopt the motion as written above on 6/16/2022. The motion was approved by consensus.

2021

Developed and Approved Budget Recommendation to TWG The Budget Ad Hoc Group (BAHG) recommends that the Technical Work Group (TWG) recommend to the Adaptive Management Work Group (AMWG), the Triennial Work Plan and Budget FY2021-2023 as revised by the BAHG during their meeting on May 27, 2021. All proposed projects will be considered as appropriate sources of funding (e.g. TWP carryover funds from prior years or through annual review of the TWP or other Reclamation considerations) become available. Revisions include addition of a Dissolved Oxygen Risk Assessment to be completed by Reclamation in 2022. In addition, the proposed revisions include the following prioritized list of GCMRC projects, as described in the attached spreadsheets dated May 27, 2021:

1. JCM-West (2023)
2. Additional TRGD Site (2023)
3. Aquatic Vegetation Removal Pilot in Lees Ferry (202?) (Subject to additional proposal detail and completion of compliance requirements.)
4. Project O.11 and Bug Flow Review. (Additional proposal detail requested following Science Advisor review.)
5. Project O.1 (2022)
6. Project O.2 (2022) [3]

2020

Motion made by Kevin Dahl, seconded by Larry Stevens, and approved by consensus 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:

1. Include the GCMRC B.4 work element in the budget ($58,000 for first 2 years and $64,000 for year 3).
2. 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).
3. Include Havasu Creek and LCR-mouth gage in GCMRC A.1 at 17,000/year.
4. 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.”
5. 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.
6. Remove Reclamation B.4, TWG Chair reimbursement (25,000 for FY 2021)
7. 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.
8. Prioritize the use of available, unprogrammed and unspent funds from FY 2020, 2021 and 2022 towards funding GCMRC G.6 (JCM-West) in 2023.[4]

• BAHG notes for FY23 calls

2020

• BAHG Call #1: Discussion of Priorities and Areas of Emphasis
• BAHG Call #2: Humpback Chub, Nutrients, Water Quality, Sediment
• BAHG Call #3: Foodbase, Rainbow Trout Fishery, Other Native Fish Species (other than HBC), and Nonnative Invasive Species
• Slides for Foodbase
• BAHG Call #4: Riparian Vegetation, Cultural Resources, Tribal Resources, Socioeconomics, Recreation, Hydropower, Overflight Remote Sensing and GIS
• Slides for Socioeconomics, Recreation, Hydropower
• April TWG meeting budget discussion notes
• BAHG Call #5: Rainbow (and Brown) Trout Fishery, GIS, Other Native Fish Species (other than HBC), and Nonnative Invasive Species
• BAHG Call #6: Tribal and Cultural Resources, Riparian Vegetation, Overflight Remote Sensing, Socioeconomics, Recreation, Hydropower
• BAHG Call #7: Humpback Chub, Nutrients and Water Quality, Foodbase, and Sediment

• October 21-22: TWG meeting
• October 21-January 14: Complete Knowledge Assessment (KA)
• October 21-December 20: GCMRC to prepare annual report
• December 20: Annual Report due to TWG
• January 13-15: Annual Reporting and TWG meeting to review budget and provide initial guidance to GCMRC and Reclamation
• January 20-March 18: GCMRC/Rec. to meet with tribes and Federal Family for input and prepare TWP Initial Draft
• February 6, 11am-noon (MST): BAHG call with GCMRC to discuss guidance, priorities, and areas of emphasis, sustainable funding: how to absorb increase in overhead and CPI increases,
• February 12-13: AMWG meeting to discuss initial priorities and DOI and Federal family input
• February 20, 1-4pm (MST): BAHG call to discuss 1st draft: Humpback Chub, Nutrients, Water Quality, Sediment
• February 25, 1-4pm (MST): BAHG call to discuss 1st draft: Foodbase, Rainbow Trout Fishery, Other Native Fish Species (other than HBC), and Nonnative Invasive Species
• February 28, 8am-noon (MST): BAHG call to discuss 1st draft: Tribal and Cultural Resources, Riparian Vegetation, Socioeconomics, Recreation, Hydropower, Overflight Remote Sensing and GIS
• March 3, 1-3pm (MST): BAHG call with GCMRC to discuss priorities and areas of emphasis post-AMWG
• March 17: TWP Initial Draft (collection of abstracts) due to DOI and Designee
• March 18-April 22: DOI/Designee review/comment period
• April 2: TWP Initial Draft due to TWG (BAHG/SA too)
• April 2-April 22: TWG/BAHG/SA review/comment period
• April 15-16: TWG meeting to consider draft TWP, including anticipated funding sources
• April 17, 1-4 pm (MST/AZ): BAHG call to discuss 1st draft:, GIS, Rainbow Trout Fishery, Other Native Fish Species (other than HBC), and Nonnative Invasive Species
• April 20, 1-4 pm (MST/AZ): BAHG call to discuss 1st draft: Tribal and Cultural Resources, Riparian Vegetation, Socioeconomics, Recreation, Hydropower, Overflight Remote Sensing
• April 21, 1-4 pm (MST/AZ): BAHG call to discuss 1st draft: Humpback Chub, Nutrients and Water Quality, Foodbase, and Sediment
• April 23-May 18: GCMRC/Rec. to prepare TWP 2nd Draft
• May 18: TWP 2nd Draft (full document) due to BAHG/SA/DOI/tribes
• May 20: AMWG webinar
• May 20-June 8: TWG/BAHG/SA review comment period
• June 8 - June 22: GCMRC/Rec. prepare TWP 3rd draft
• June 16, 12-3pm (AZ/PDT), 1-4pm (MDT): BAHG call - SA presentation, discuss with GCMRC/Rec. on how issues identified in 2nd draft were resolved, identify any issues that would block a BAHG recommendation to the TWG
• June 17, 12-2pm (AZ/PDT), 1-3 (MDT): BAHG call - develop recommendation to the TWG
• June 22: TWP 3rd draft due to TWG
• June 23-24: TWG meeting to provide a budget recommendation to the AMWG
• June 23-July 29: GCMRC/Rec. prepare Final Draft
• July 29: TWP Final Draft due to AMWG
• July 29-August 19: AMWG review/comment period
• August 19-20: AMWG meeting to provide a budget recommendation to the SOI
• September: SOI reviews the budget and work plan
• October: Fiscal Year begins under the new TWP guidance
• November: Consumer Price Index becomes available. Science and management meeting with DOI and cooperators
• December: Budget is finalized