SGER: Influence of postglacial rebound on river longitudinal profiles in Sweden

该奖项将探索影响河流纵向剖面发展的变量之间的相互作用。首席调查员将使用瑞典大范围冰川引起的隆起提供的自然实验，其中包含一系列具有相似特征但基准面历史略有不同的河流。PI将测试一系列五个假设，重点是流域面积和流量(H1)、底物特性(H2、H3)和提升率(H4)对河流纵向剖面和河道几何形状的影响，以及水流功率定律是否足以描述河流切割，其中存在急流(而不是瀑布)形式的临界点(H5)。第二个目标是利用碎屑运动和基岩切割的阈值结合超过这些阈值的水流频率估计每条河流选定地点的相对侵蚀率。这项建议中概述的研究将使PI能够测试水流功率定律在具有陡峭急流形式的临界点的河流上的适用性，以及之前调查人员的推断，即对隆起的响应与流域面积成比例。拟议的研究将为研究生和本科生提供实地经验。这项研究还将促进与瑞典河岸生态学家的合作，并增加对冰川消融后河流调整的历史和机制的了解，这是已知影响河岸群落结构和多样性的因素。

This award will explore interactions among variables that influence the development of a river's longitudinal profile. The Principal Investigator will use the natural experiment provided by the widespread glacially induced uplift in Sweden, which contains a series of rivers with similar characteristics but slightly different base level histories. The PI will test a series of five hypotheses that focus on the influence of drainage area and discharge (H1), substrate properties (H2, H3), and uplift rate (H4) on river longitudinal profile and channel geometry, and on the adequacy of a stream power law to describe river incision where knickpoints in the form of rapids (rather than waterfalls) are present (H5). A second objective is to estimate relative erosion rates at selected sites along each river using thresholds for clast motion and bedrock incision combined with the frequency of flows exceeding these thresholds. The research outlined in this proposal will allow the PI to test the applicability of the stream power law along rivers with knickpoints in the form of steep rapids, and the inference of previous investigators that response to uplift scales with drainage area.Broader Impacts. The proposed research will provide field experience for graduate and undergraduate students. The research will also foster collaboration with Swedish riparian ecologists, and increase understanding of the history and mechanics of river adjustment following deglaciation, which are known to influence riparian community structure and diversity.