Collaborative Research on Processes and Timing of Geomorphic and Hydraulic Adjustments During Stream Channel Recovery

点击翻译按钮获取中文摘要

9412310 McDOWELL Many studies in geography and related disciplines have examined the ways that human activities impact on natural systems. One of the locales where such studies have been undertaken are streambeds, where direct human alteration of channel characteristics and indirect impacts resulting from changing patterns of land use on nearby lands have had profound impacts on processes of erosion and deposition. Relatively little attention has been focused, however, on the processes that occur when the impact of human activities are removed. This collaborative research project will examine stream channel recovery from chronic human disturbance through what is effectively a controlled experiment. The project will document the rate, magnitude, and processes of stream channel recovery following the elimination of cattle grazing from pasture lands along a number of streams in central and eastern Oregon. During the first year of work, data on channel morphology, streambed sediment characteristics, fish habitat characteristics, and indicators of fluvial processes will be gathered from six stream segments. Historical data on the nature and timing of land uses from written sources and remote sensors also will be gathered, with special attention given to the establishment of enclosures that prevented cattle grazing on nearby lands. These data will be analyzed and used to develop models of channel recovery. During the second year, field work will be expanded to examine sites for which nearby enclosures were established more recently and for which sediment, geologic, and ecological conditions of streams are more varied. This project will provide valuable new insights into streambed recovery processes. It will document differences in morphologic and hydraulic characteristics between restored and unrestored reaches of streams. It will test hypotheses about the ways that different factors respond during different phases of the recovery process, and it wi ll determine the amount of time necessary to achieve restoration. This information will not only have significant value to researchers, but it will have considerable immediate utility to land managers in both the public and private sectors. Because part of the funding for this project is being made through the Research Experiences for Undergraduates Program, the project will provide an excellent opportunity for promising students to directly participate in a high-quality research project.