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

[9420686] MAGILLIGAN地理学和相关学科的许多研究都考察了人类活动对自然系统的影响方式。进行这种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和附近土地使用模式的改变所造成的间接影响对侵蚀和沉积过程产生了深远的影响。然而，对消除人类活动影响后所发生的过程的关注相对较少。这个合作研究项目将通过一个有效的对照实验来研究河道从慢性人为干扰中恢复的情况。该项目将记录在俄勒冈州中部和东部一些河流沿线的牧场取消放牧后，河流河道恢复的速度、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、鱼类生境特征和河流过程指标的数据。还将从书面资料和遥感器收集关于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开发通道恢复模型。在第二年，实地工作将扩大到检查附近最近建立围场的地点，以及沉积物、地质和溪流生态条件更多样化的地点。该项目将为河床恢复过程提供有价值的新见解。它将记录在恢复和未恢复的河流之间的形态和水力特征的差异。它将测试关于不同因素在恢复过程的不同阶段的反应方式的假设，并将确定实现恢复所需的时间。这些资料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。由于该项目的部分资金是通过本科生研究经验计划获得的，因此该项目将为有前途的学生提供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.