Difference between revisions of "2017 Knowledge Assessment"

• 2019-20 Knowledge Assessment (KA)
• Knowledge Assessments, Annual Reporting Meetings, and SCORE Reports Page
• FY18-20 GCDAMP Triennial Work Plan
• The Long-term Experimental and Management Plan (LTEMP) Page
• Science Advisors Page

• Science Advisors Program-Executive Coordinator Final Report on FY 2017 Knowledge Assessment (4/30/17)

• Status & Trends Tables
• Drivers & Constraints Tables
• Effects of LTEMP Experimental and Management Actions Tables

• Knowledge Assessment Update
• 2017 Knowledge Assessment Webinar 2017-04-06 ppt
• TWG: Review of the 2017 ARM and Discussion of Knowledge Assessment

Aquatic Food Base

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Archaeological & Cultural Resources

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Humpback Chub

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Hydropower & Energy

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Invasive Fish Species

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Other Native Fish Species

• still to be completed

Rainbow Trout Fishery

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Recreational Experience

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Riparian Vegetation

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Sediment

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

Tribal Cultural Values

• still to be completed

Water Quality

• Status & Trends
• Drivers & Constraints
• Effects of Experimental & Management Actions

What to Assess and When

• Establish a regular schedule of knowledge assessments, integrated with the development of at least the triennial work plans and the cumulative findings of the Annual Reporting cycle.
• The TWG and GCMRC need not repeat the assessment of knowledge about the potential effects of the LTEMP experimental and management actions.
• Every effort should be made to include the assessment of “Other Native Fishes” in all future KAs.
• Every effort should be made to ensure that future KAs include the assessment of “Tribal Resources,” however these come to be defined.
• The TWG and GCMRC should consider expanding the assessment of the “Natural Processes” resource topic to include processes other than the two included in the FY 2017 KA.
• The LTEMP and its ROD limit the “Nonnative Invasive Species” resource topic to invasive aquatic organisms, but do not limit it to fishes. The TWG and GCMRC should consider expanding the assessment of this topic to include other aquatic invasive species if ecologically appropriate.

Assessment Structure and Process

• The TWG should make clear from the outset precisely what objectives the expert teams should to use for each resource topic, against which to assess status and trend.
• The process and its guidance need to be improved to encourage the expert teams to address a smaller number of truly “key” resource characteristics for each focal resource.
• The expert teams need to be encouraged to read and follow the formal guidance for the KA – and conversely to provide feedback on how the guidance could be improved.
• Integration of the work of the individual expert teams could be improved by developing a standard, master list of drivers and constraints.
• The FY 2017 KA did not address or could have better addressed some environmental factors that recent Annual Reporting Meetings, past KAs, and GCMRC publications have identified as potentially relevant to the GCDAMP.
• Integration of the results from repeated KAs would also benefit from the development of standardized lists of resource characteristics for each focal resource topic, the GCDAMP FY 2017 Knowledge Assessment Final Report, Executive Coordinator for the Science Advisors Program examination of which could be repeated in successive KAs.
• The KA process would benefit from the formal inclusion of the effort in annual or triennial work plans, so that all participating experts know this will be an expected matter of attention.
• The schedule for each KA should include a more formally recognized period or opportunity for all stakeholders to provide feedback to the expert teams.
• The TWG has proposed, and Reclamation and the SAP-EC have requested in the draft FY 2018-2020 Triennial Work Plan and Budget, that the GCDAMP re-establish a “Standing Panel” as part of the SAP, to provide routine review services to the GCDAMP.

Spreadsheet Tool

• The FY 2017 KA expert teams – or at least the team leaders – should be polled for feedback on the spreadsheet tool, on ways in which the tool or its associated guidance might be improved.
• The spreadsheet should include places where the expert teams can or record or find several additional pieces of information, including:

1. Explicit documentation of the objectives and benchmarks used for assessing status and trend
2. The definitions of all resource characteristics and technical measures addressed in the KA
3. The definitions of all drivers and constraints addressed in the KA (see recommendations above on Knowledge Assessment Structure and Process)
4. Citations for important reference works relevant to ratings and considered in rationale narratives.

• The “Unknown” category for status, trend, strength, and direction could be split into two variants to recognize two possibilities: there may not be enough evidence with which to even attempt an assessment, or the available evidence, while perhaps nominally sufficiently plentiful, may be too “noisy” to support any firm conclusion.
• The guidance provided with the spreadsheet tool, and the Data Validation functions incorporated into the tool, should be improved to promote greater consistency in how the expert teams fill in the tables in the tool.

Aquatic food base

• Consider 3 consecutive years of macroinvertebrate production flows to see if reduced egg mortality during weekends leads to higher drift concentrations during weekday hydropeaking.
• Consider additional studies of interrelationships between discharge fluctuations and drift.
• Consider testing spring timed HFEs, because the timing of HFEs may influence substrate quality. Recent fall HFEs appear to be promoting colonization by aquatic macrophytes, which provide habitat for invasive New Zealand mudsnails. Spring HFEs likely knock back macrophytes to a greater degree than fall HFEs.
• Consider how timing of spring HFEs might actually be used to mitigate strong trout recruitment response (i.e., would April HFE stimulate food base and not create as many small trout as compared to early March HFE?).
• Consider assessing shorter-term effects of HFEs on foodbase, rather than year-averaged trends.
• Consider studies that compare habitat quality of cobble/gravel in Glen vs. Grand Canyon and that include direct manipulations of substrates (power washing cobbles, scraping cobbles).
• In the absence of a switch in HFE timing, consider studies that disturb macrophytes in spring and/or fall (e.g., by raking or dredging) to understand how HFE timing affects macrophyte response.
• TMFs are unlikely to be positive for food base. Given that fish in the GCD tailwater are food-limited, do not recommend TMFs as a way to improve food base diversity.
• Consider modeling what effect low summer steady flows might have on drift concentrations and bioenergetics of fish.
• Complete analysis of longterm drift monitoring data.
• Ensure robust monitoring is in place during next equalization flow.
• Continued monitoring of invertebrate drift combined with dissolved oxygen monitoring will help resolve effects of DO on drift. Consider additional, direct studies on DO effects on invertebrates.
• Continued drift and light trap monitoring in Glen, Marble, and Grand Canyon will help clarify role of turbidity in constraining secondary production (drift and emergence production).
• Begin monitoring nutrients downstream. Evaluate feasibility of nutrient supplementation program.
• Consider regular stable isotope analysis of aquatic insects captured in light traps and drift nets to clarify trophic-basis of insect production (i.e., leaf litter vs. algae) in Lees Ferry and Grand Canyon.
• Consider repatriation of native Colorado River invertebrates such as caddisflies from Davis and Parker to "jump start" colonization.
• Consider new research at Hoover, Davis and Parker Dams to better understand life history of the caddisflies that are abundant in Davis and Parker segments, which have substantially greater hydropeaking than in Glen.
• Consider investigating temperature tolerances of Tapeats invertebrates.
• Conduct stress tests of invertebrate assemblages (growth experiments over extreme range of water temperatures on current "Big 4" taxa) to identify how the nearctic assemblages present downstream of Glen Canyon Dam will respond to the very warm water temperatures that may occur in the future.
• Consider benthic monitoring in FY18-20 to track downstream progression of quagga.
• Consider new research studies of macrophyte-invertebrate interactions to better understand role of macrophytes in driving changes in invertebrate prey base, especially in LF.

Archaeological and cultural resources

• Resume monitoring w/NPS and Tribes. Re-establish monitoring program using NPS/ASMIS protocols.
• Expand stage elevation model for HFEs to include GLCA Reach.
• Establish and implement targeted monitoring pre and post HFE's.
• Support NPS and Tribal monitoring efforts and coordination with GRCA CRMP and law enforcement patrol; integrate monitoring information with education and mitigation efforts.
• Continue submerged monitoring of Spencer Steamboat.

Humpback chub

• none provided

Hydropower and energy

• Make sure to consider hydrology and water use and how they affect resource characteristics. Make sure these resources are considered when planning for changes in water use.
• Keep the analysis updated past LTEMP.
• Move forward on cost/benefit analysis on adding generation on the bypass tubes.
• Look for ways of increasing reservoir elevation at Lake Powell.
• Look for ways to conduct experiments coincident with power production.
• Identify maintenance costs for bypass tubes/valves and clarify funding source for this maintenance.
• Evaluate whether extended duration HFEs result in larger and longer‐lasting sandbars in critical reaches

Invasive fish species

• Maintain or reduce current spawning numbers of Brown Trout in Lees Ferry Reach to protect Rainbow Trout and Humpback Chub fishery
• Reduce conditions that promote increased recruitment and numbers of Brown Trout
• Continue fish weir at Bright Angel Creek, and possibly other tributaries if Brown Trout spawning/recruitment is occurring there
• Continue monitoring for rare-nonnatives

Other Native Fish Species

• none provided

Rainbow trout fishery

• Continue monitoring the recruitment of age0 fish that disperse from Lees Ferry into Marble Canyon during the late-summer and fall at Houserock Reach.
• Monitor trout population dynamics in response to changes in nutrients. This appears to be a promising area of research to better understand what drives RBT abundance, growth, and condition.
• Continue to monitor trout population dynamics both in the LCR inflow area and the Lees Ferry Sport Fishery
• This analysis suggests that higher flow in winter and lower flow in spring increases the number of trout in a system. If managers wish to decrease recruitment, they may wish to increase flow volume in spring during a time when trout are spawning or when they are in their early life history stages.
• Need to determine the efficacy of TMFs (magnitude, duration, frequency).
• This analysis suggests that fish density does have a negative influence on trout size, so if managers wish to increase adult rainbow trout size they might take steps to decrease density/recruitment into the population
• Consider actions which likely increase benthic production of invertebrates (the ultimate source of invertebrate drift), including the role nutrients play.
• Consider implementation of Macroinvertebrate production flows and experimentally examine how flows influence the foodbase, which influences invertebrate drift availability and ultimately trout growth.
• Use targeted trout management flows to test hypothesis, when conditions are appropriate (i.e. Brown trout control).
• Research is needed to determine what is the major factor determining variation in aquatic preybase. As a response variable, trout need to be monitored for effects from high flow experiments and reservoir nutrient dynamics.
• Annual recruitment of Age0 trout is a critical information for determining the likely trends in population growth. Need to reconcile the differences in recruitment found between RTELLS catch indices and mark-recapture estimates. Suggest re-estimating RTELLS capture probabilities since these have not been revised since 2007.
• We suggest monitoring the movement of age-0 trout into Marble Canyon to assess future increases in trout abundance due to recruitment in Marble Canyon, as well as efficacy of Trout Management Flows to reduce recruitment events in Lees Ferry.
• Discontinue Redd counts and place greater emphasis on sampling and estimating abundance and survival of Age0 recruits.
• Evaluate the relationship between Rainbow Trout Maximum Size and Prey-size and abundance and Temperature in CR could be very valuable for understanding the factors that control this resource: 1). Continue monitoring the resource characteristic by field sampling efforts designed to estimate maximum size. 2). Apply modelling tools (such as drift-foraging bioenergetics or Net Energy Intake models) to predict how changing biological or physical conditions influence the maximum size that rainbow trout can attain. 3). Use both empirical studies and modeling approaches to build an explicit understanding of how management actions influence the resource. 4). Consider whether to reduce or simplify study, given angler perceptions that bioenergetic model results are already solid.

Recreational experience

• Minimize duration and magnitude of experimental flows that create access issues while still accomplishing downstream resource objectives.
• Keep mean daily flows at a minimum of 12kcfs
• Minimize percent of daily fluctuations, especially during months with lower releases.
• Consider minimum flows/ fluctuations at 6,000-9,000cfs.
• Weekend water flows, holiday flows, MPF should be equivalent to mean daily flow for a given month, consider 8 kcfs as the minimum flow.
• Design operational flows to minimize impacts to and manage for foodbase and rainbow trout recruitment while addressing downstream resource objectives
• Minimize daily mean flows different than 10 kcfs and flow ranges greater than 5 kcfs during operational and experimental flows while meeting downstream resource objectives. Increase experimental flow education and outreach to anglers.
• Operate Glen Canyon Dam in such a manner to manage rainbow trout recruitment and promote and foodbase to meet rainbow trout specific condition measure. Implement measures to identify rainbow trout catch greater than 16 inches.
• Based on results from 2017 ARM meeting, consider phosphate inputs to boost macroinvertebrate production.
• In TMF design, consider 8 kcfs as the minimum flow, and slowing down ramp rates as much as reasonable for this experiment to be effective.
• Conduct HFEs whenever conditions are appropriate. Whitewater boaters recognize the positive beach building effects even with the inconvenience of very high flows
• Although HFE's build sandbars, they do not scour vegetation, which continues to expand into usable campsites. Consider non-native vegetation removal, within certain stretches. Vegetation management may be required to change campsite area. Develop plan for vegetation management that targets sites where re-establishment is least likely and monitor results. If campsite areas continue to decline, consider actions in addition to high flows if larger campsites are required. Short-duration high flows are effective for increasing usable campsite area.
• Conduct a cost benefit analysis on effects to hydropower to operate dam without daily fluctuations.
• During equalization years, spread high monthly releases throughout summer months to minimize the amount of sediment eroded out of the Canyon.
• Research needed on management action recommended to improve wilderness characteristics of Glen and Grand Canyons.
• Helicopter use should be for emergencies only

Riparian vegetation

• Continued ground-survey and aerial image monitoring of changes to herbaceous and woody species and non-native spp. to track shifts in Tamarix defoliation and subsequent infilling by other species. Compare the CRe flora to that of Cataract Canyon to get an general idea of how these somewhat similar sections of the Colorado River compare - would require extra field work and collaboration with Canyonlands NP and the Northern Colorado Plateau Network. Measures of community heterogeneity need to be tied to a specific management question, so an appropriate measure can be used.
• Continue work using flow-response guilds to examine likely functional group changes due to different flow regimes and likely functional group changes that impacted historic sandbar change (two current projects). Study functional group response/shifts and model using flow scenario.
• Continue research and monitoring that improves our understanding of how vegetation impacts fluvial and aeolian sediment transport.
• Reexamine the areal extent and composition of marsh habitats using the more recent areal imagery and ground-surveys.
• Develop a science-based vegetation management (e.g., restoration, rehabilitation, or other active management) plan with measurable goals. Allocate time and money based on goals to track success. What to do with the dead, standing Tamarix may be a topic to consider in the future.
• Using genetic studies and field data, we could examine if HFE's are selecting for clonal species and genotypes.

Sediment

• Continue monitoring and expand sample sizes to increased confidence in strength and direction determinations.
• Develop study plan for proactive and extended duration HFE's before implementation.
• If vegetation management occurs, monitor sandbar response in future high flows.
• Continue monitoring sand storage. If persistent declines in storage occur, considering revising action.

Tribal Cultural Values

• none provided

Water quality

• Reinstall temperature string on the Lake Powell side of GCD. Monitor forebay of GCD on a monthly basis to determine trends and analyze data collected in the past. It is difficult to assess a status and trend without identifying specific scenarios of concern. Gather data necessary to determine lake hydrodynamics including temperature data at the inflows (Colorado River and San Juan River). Utilize the results of an Protocols Evaluation Panel or Science Advisors Panel to determine location and frequency.
• Monitor forebay of GCD on a monthly basis to determine trends. Monitor Lake Powell at an interval determined by the results of an Protocols Evaluation Panel or Science Advisors Panel, analyze data collected in the past with special emphasis on metalimnetic oxygen minima and CBOD. More thoroughly monitor DO concentrations in Lake Powell during HFE (e.g., twice daily data, coupled with profile at dam)-- jet tubes significantly increase the DO in the river, would be good to understand the combination of DO from penstock and DO from jet tubes.
• Monitor Lake Powell at an interval determined by the results of an Protocols Evaluation Panel or Science Advisors Panel, analyze data collected in the past. Measure conductivity of inflow of Lake Powell at Colorado River and San Juan River.
• Analyses for nutrients should be routinely collected monthly (as scheduled) above and below GCD (forebay and Lees Ferry.. and further downstream). Timing of riverine nutrient sampling should be standardized. Given the extremely low concentrations of phosphorus in this system, the contract laboratory should be consulted to see if a new method might be able to lower the detection limits. More time should be spent analyzing the historical nutrient data collected in Lake Powell. Some protocol should also be developed to establish the representativeness of the Lake Powell-Wahweap station penstock depth sample in reflecting the water chemistry and biology exiting Lake Powell. Follow PEP recommended targeted sampling to better understand the drivers of nutrient patterns in the lake and the nutrient limitation regime below GCD.
• Samples for phytoplankton, zooplankton, and chlorophyll should be collected monthly above and below GCD. Monitor Lake Powell at an interval determined by the results of an Protocols Evaluation Panel or Science Advisors Panel, analyze data collected in the past at key locations to determine the impact of quagga mussels on the reservoir and other trends. There is a need to determine whether the data collected in Lake Powell is correlated to the data at Lees Ferry.
• Data should be collected above and below GCD and in Lake Powell at an adequate frequency to determine status and trends as determined by the results of an Protocols Evaluation Panel or Science Advisors Panel. Analyze data collected in the past. Explore work conducted by other researchers on mercury in Lake Powell.
• Monitor Lake Powell at an interval determined by the results of an Protocols Evaluation Panel or Science Advisors Panel, analyze data collected in the past at key locations to determine trends.