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

9420686马格里根地理学和相关学科的许多研究都研究了人类活动对自然系统的影响方式。进行这类研究的地点之一是河床，在那里，人类对河道特征的直接改变以及附近土地上土地利用模式的变化所产生的间接影响对侵蚀和沉积过程产生了深远的影响。然而，相对较少的注意力集中在消除人类活动影响时发生的过程上。这个合作研究项目将通过一个有效的受控实验来检查流水道从慢性人类干扰中的恢复。该项目将记录在俄勒冈州中部和东部一些溪流沿线的牧场上消除放牧牛后，溪流河道恢复的速度、规模和过程。在第一年的工作中，将从六个河段收集有关河道形态、河床沉积物特征、鱼类栖息地特征和河流演变指标的数据。还将从书面来源和遥感器收集有关土地使用性质和时间的历史数据，并特别注意建立围栏，防止牛群在附近土地上放牧。这些数据将被分析并用于建立渠道恢复模型。在第二年，将扩大实地工作，以检查附近围栏最近建立的地点，以及河流的沉积物、地质和生态条件变化较大的地点。该项目将为流床回收过程提供有价值的新见解。它将记录河流恢复和未恢复河段之间在形态和水力特性方面的差异。它将测试关于不同因素在恢复过程的不同阶段做出反应的假设，并将确定实现恢复所需的时间量。这些信息不仅对研究人员有重大价值，而且对公共和私营部门的土地管理人员也有相当大的直接效用。由于这个项目的部分资金是通过本科生研究体验计划获得的，该项目将为有前途的学生提供一个直接参与高质量研究项目的绝佳机会。

9420686 MAGILLIGAN 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 will 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.