Laserfiche WebLink
<br />4. Write a final report of all findings. <br /> <br />IX. Accomplishments/Initial Findings and Shortcomings: <br /> <br />1. No mechanistic models currently available to determine <br />incremental relationships between flow and river conditions <br />favorable to the endangered fishes are sufficiently well- <br />developed to be used exclusive of many other ecological <br />measures. "River ecosystems are too complex to be described by <br />simple deterministic models or constructs of individual <br />attributes. Ecosystem components are N-dimensional, inherently <br />variable (stochastic) in time and space and interact in complex <br />ways that cannot be predicted from simple, logistic equations. <br />Construction of an ecosystem model that describes all of the' <br />dynamic processes...is likewise unreasonable as a predictive <br />tool." "A general (simple application in different streams) <br />incremental flow-biomass model that is statistically precise <br />(repeatable) and accurate (describes reality) is likely not <br />attainable, especially in large rivers like the Upper Colorado <br />where ecosystem structure and function is complex and poorly <br />known," <br /> <br />2. The "prudent alternative (to models) is to use all available <br />ecological information to derive and implement a flow regime <br />for the upper Colorado River basin ecosystem and quantify <br />variables...that describe whether the ecosystem is changing in <br />a way that favors recovery of the fishes." <br /> <br />3~ "The state of the ecological knowledge in the Upper Colorado <br />River Basin is sufficient to justify endorsement of interim <br />flows," <br /> <br />4~ Critical Uncertainties (Issues) <br /> <br />a. Flows may not be the only limiting factor. Predation by <br />nonnatives and/or contaminants may prevent recovery. <br /> <br />b. There may not be enough. water to both recover the fishes <br />and meet compact entitlements. <br /> <br />c. Channel and floodplain morphology in time and space is not <br />a simple stage-area relationship. (because of sediment <br />movement). <br /> <br />d. Tradeoffs among spring flow regimes (in terms of larval <br />drift, nonnative predation, etc.) need to be evaluated. <br /> <br />e. Effects of hydropower-induced flow fluctuations on varial <br />zone food webs needs to be determined. <br /> <br />f. Shifts in rithron-potamon transition zones as a function <br />of recommended flow regimes needs to be determined. <br />