Difference between revisions of "2017 Knowledge Assessment"

Introduction

The FY 2017 KA addressed three broad spheres of knowledge for each of these eleven focal resource topics:

• Status and Trend: How closely does the condition of the resource currently approach management objectives and, if the current condition shows any trend, is this a trend toward or away from management objectives?
• Drivers and Constraints: What environmental factors, including human actions and basic dam operations, most strongly affect resource status and trend, how strong are these effects, and do these effects constrain or drive resource condition toward or away from management objectives?
• LTEMP Experimental and Management Actions: Which LTEMP experimental and management actions are expected to affect resource condition and trend, how strong are these effects expected to be, and are these effects expected to drive resource condition toward or away from management objectives?

More specifically, the FY 2017 KA posed three sets of core questions for each of the eleven focal resource topics:

• Status and Trend

1. What is the present understanding of the status of the condition(s) addressed by the topic?
2. What is the present understanding of the direction of any trend(s) in these conditions?
3. How certain or uncertain is this understanding?

• Drivers and Constraints

1. What is the present understanding of the drivers and constraints that most significantly shape the status and trends in these conditions?
2. What is the present understanding of the strength and direction of these effects?
3. How certain or uncertain is this understanding?

• Effects of Experimental and Management Actions

1. What is the present understanding of the ways in which each type of LTEMP experimental or management action could affect the status and trends in these conditions?
2. What is the present understanding of the likely strength and direction of these effects?
3. How certain or uncertain is this understanding?

The last of these three sets of questions focused on eleven specific experimental management actions identified in the LTEMP FEIS and ROD as features of the Preferred Alternative:

• Fall High-Flow Experiments (HFEs) > 96‐hr duration but ≤ 45,000 cfs in October or November
• Fall HFEs < 96‐hr duration but ≤ 45,000 cfs in October or November
• Humpback chub translocation
• Larval humpback chub head-start program
• Macroinvertebrate production flows
• Mechanical removal of invasive fish species
• Mechanical removal of rainbow trout from the Little Colorado River (LCR) reach
• Proactive Spring HFEs ≤ 45,000 cfs in April, May, or June
• Riparian vegetation restoration
• Spring HFEs ≤ 45,000 cfs in March or April
• Trout management flows

The Preferred Alternative in the LTEMP FEIS and ROD also includes summer low flow experiments. However, these will not be attempted until during the second 10 years of implementation of the LTEMP. The FY 2017 Knowledge Assessment focused on topics that might bear on the GCDAMP Triennial Work Plan for FY 2018-2020 and therefore did not address the potential effects of summer low-flow experiments.

Through its answers to the three sets of core questions presented above, the FY 2017 Knowledge Assessment sought to:

• Summarize information on status, trends, and the state of knowledge for the eleven focal resource topics.
• Document the state of knowledge of how antecedent conditions (external drivers and constraints) may affect the outcomes of different management actions.
• Identify potential needs for continuing, increasing, reducing, revising, or adding monitoring, research, and other information-gathering efforts to address potentially crucial gaps in knowledge.

Status and Trends

The experts for the other ten resources assessed the current status of seven overall as meeting the criteria for “Moderate Concern,” and assessed two, aquatic food base and recreational experience, as meeting the criteria for “Significant Concern” overall. Only one resource, invasive fish species (nonnative invasive species), received an overall rating of “Good Condition.” Since this last resource topic focuses on a threat, its status indicates that, nonnatives, invasive fish species overall currently pose only a limited threat to other species in the system. However, the expert teams consider six of the ten assessed resources currently to be experiencing either no net trend in status, and four – aquatic food base, archaeological and cultural resources, hydropower and energy, and the recreational experience – to be experiencing deteriorating trends in status. The experts did not identify any resource as currently experiencing a net improving trend in status. Tables outlining status and trends for each resource characteristic can be found here.

Drivers and Constraints

The assessment of drivers and constraints identified numerous factors that influence the status of the ten assessed focal resources. These factors fall into thirteen proposed overarching categories: aquatic food base dynamics (primary and secondary production), aquatic invasive species, archaeological site disturbance, boat and aircraft launches, dam design and operational constraints, humpback chub dynamics, Lake Powell conditions, rainbow trout dynamics, riparian vegetation dynamics, river flow variation, river water quality, river water temperature, and sediment dynamics (above and below baseflow stage).

Unfortunately, there is no simple way to summarize these results. As explained earlier (see Roll-Up Method, above), it is not meaningful to average the rating values for the drivers and constraints affecting an entire resource topic across all associated resource characteristics. In addition, each expert team independently developed its own list of drivers and constraints. This produced a total of 88 different driver and constraint names, with no two expert teams using the same names for any drivers and constraints. As a result, it is not possible to directly compare the ratings for individual drivers across resource topics.

However, it is possible to organize the 88 drivers and constraints into a smaller number of categories. Table 10 identifies 13 categories or types of drivers and constraints, incorporating all 88 original “raw” types identified by the ten expert teams (see Appendix C). Other groupings are possible (see Recommendations, below). Table 10 also shows the numbers of individual drivers and constraints in each category, both overall and for each affected resource. Table 10 lists the proposed driver/constraint categories in order based on their overall frequency of identification across all resource topics.

Effects of LTEMP Experimental and Management Actions

The results in Table 12 indicate that the expert teams expect the net effects of the various LTEMP experimental and management actions (across all resource characteristics for the ten resources) to be a “mixed bag.” Each action is expected to have a mixture of net positive to negative and net strong to weak effects on each of the ten resources, on average across all the individual resource characteristics for each resource. No single action is expected to consistently provide a net benefit to all resources. Similarly, with the exception of recreational experience, no single resource is expected to be affected consistently by all actions. In the case of recreational experience, the results indicate that the expert team expects the net effects of all actions on all resource characteristics to be neutral (neither positive nor negative). However, the tables in Appendix D show that these average effects mask a range of variation in effects across individual resource characteristics.

The assessments of status and trend, drivers and constraints, and the potential effects of LTEMP experimental and management actions for the ten assessed resources also identified numerous gaps and areas of uncertainty in critical knowledge. The resources with the highest frequencies of such gaps and uncertainties were (in descending order of frequency): water quality, riparian vegetation, the rainbow trout fishery, the aquatic food base, humpback chub, invasive fish species, and sediment. The raw spreadsheet entries indicate that the expert teams reported these gaps and uncertainties because of difficulties with unclear or undefined management objectives for individual resource characteristics; temporal or spatial gaps in the available data; insufficient numbers of suitable data points; or high temporal or spatial variability in the available data. These findings highlight topics that could benefit from improved management objectives, continuing and/or improved monitoring, and/or research to address critical gaps and uncertainties.

The concluding recommendations identify needs and opportunities for the TWG and GCMRC to improve the assessment methods and their implementation under five headings: What to assess and when, assessment structure and process, the spreadsheet tool, the scorecard display system, and the default method used to average together the findings across multiple lines of evidence for each resource topic.