• For more detailed analysis, variations in flow velocity and flow depth are more important than flow discharge for evaluating ecological requirements because it is the depths and velocities that create habitats.

  • Climate and water-resources developments can have strong influences on river flow distributions. Water-resources development affects river flows substantially in the upper Platte River, and its effects extend to the central Platte River. The relative importance of climate influences and water-resources development on channel characteristics should be analyzed and should encompass a record of several decades.

  • Restoration of the central Platte River should include water processes and forms, control of invasive species, and some grazing and fire if research shows these phenomena to be important aspects of the pre-European river.

  • More emphasis should be placed on the management of the Platte River as an ecosystem, rather than keeping the focus exclusively on listed species.

In summary, the committee’s review of DOI’s efforts to explain and model the connections among ecosystem components of water, sediment, morphology, and vegetation leads us to conclude that these efforts are underlain by valid science. Likewise, DOI’s instream-flow requirements are grounded in scientific understanding of the system and in the technology of model construction that was state-of-the-art when the decisions and recommendations appeared. Science and engineering are making progress, however, and new technology is becoming available. New advances are needed because of the braided, complex nature of the Platte River, a configuration that is unlike that of the streams where others often apply the models. Current DOI model developments, including the emerging SEDVEG model, are likely to be helpful and useful in both understanding and managing the Platte River. DOI’s determination of suitable habitat rests on the best available science. The committee also recognizes, however, that there has been no substantial testing of the predictions of DOI’s modeling work,1 and we urge that calibration of the models be improved and that monitoring of the effects of recommended flows and vegetation management be built into a continuing program of adaptive management. In such a system, monitoring can indicate whether recommendations and determinations are valid and can suggest further adjustments to the recommendations and determinations on the basis of observations.

1  

The committee did not consider USGS’s in-progress evaluation of the models and data used by USFWS to set flow recommendations for whooping cranes.



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