U.S. Geological Survey
U.S. Geological Survey
In this paper we describe the key features of the holistic approach for assessing the environmental flow requirements of riverine ecosystems. We identify the fundamental features of the natural hydrological regime which are of ecological importance, each of which would require an allocation of water, and then describe how these individual water allocations are used to rebuild a modified flow regime. In taking this approach, we have identified many deficiencies in our understanding of ecological responses to streamflow, and have outlined some of th emost important and demanding topics for further research. Finally, we stress the need for closer collaboration among ecologists, hydrologists, engineers and water managers in the development of water allocation strategies and environmentally sound approaches to river management.
American Rivers produced abstract
We evaluated sampling variability of stream habitat sampling methods used by the USDA Forest Service and the USDI Bureau of Land Management monitoring program for the upper Columbia River Basin. Three separate studies were conducted to describe the variability of individual measurement techniques, variability between crews, and temporal variation throughout the summer sampling season. We quantified the variability between crews and through time, and described the percent of the total variability attributed between crew and seasonal variability. We then estimated the number of samples needed to detect change between managed and reference sites. Differences among streams accounted for a larger share of the total variability than did differences among observers. Stream variability was greater than 80 percent of the total variability for 12 of the 16 variables measured. This is somewhat surprising given the similarities between the study streams. Observer variability was minimal for stream habitat methods describing reach, streambank, and cross-section variables. Conversely, variability was higher for pool, large woody debris, and substrate variables. Seasonal variation was minimal for stream channel variables with the exception of substrate particle sizes. Sample sizes derived from both observer and stream variability (type I error 0.1, type II error 0.9, minimum detectable change 10 percent) ranged from 10 to 3,502 sites to detect changes between two populations. We believe that these estimates represent an unambiguous and powerful way to display the consequences of variability to scientists and managers.
USDA Forest Service