Stream Channel Stability and Watershed Resilience of Geomorphic Recovery

受到人类活动和自然灾害干扰的河流系统往往对流域和当地社区产生严重影响。该研究项目将量化河流如何根据流量和泥沙通量的变化重建平衡河道特征。研究人员将对以下断言进行检验：水道的平衡形式不能被唯一地定义，而水道的性质取决于沉积物的主要运输模式。对河道平衡的清晰认识对河流的管理和恢复至关重要。项目结果将为区域规划者、流域管理者、非政府组织和其他各方提供新的方法，以便确定流域恢复的优先次序，并从河流系统中寻求更好的生态和经济效益。该项目还将通过研究生参与的特殊机会和女性科学家指导计划，为改善科学、技术、工程和数学（STEM）领域的教育做出贡献。流域管理者和政策制定者目前缺乏必要的分析指标来衡量河流扰动的程度，以确定恢复活动是否有效地促进处于平衡状态的地貌稳定的河流。在这个项目中，研究人员将通过使用沉积物示踪剂、河道断面和水流模型以及河道内沉积物测量来确定流域动态平衡中各种可能的地貌表达。他们将使用泥沙床载信息来量化表征河道从干扰中恢复的协变和非奇异路径，他们将采用数学模型来模拟沿河道纵向剖面泥沙供应变化的系统中的河道恢复。通过该项目获得的见解对于理解流域的弹性以及实施河流系统的恢复和恢复工作至关重要。

NATIONAL SCIENCE FOUNDATIONGEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAMABSTRACTRiver systems that have been disturbed by human activities and natural disasters often have severe impacts on watersheds and local communities. This research project will quantify how rivers reestablish equilibrium channel characteristics in response to changes in flow and sediment flux. The investigators will test the assertion that the equilibrium form of a channel cannot be uniquely defined and that channel properties depend on the dominant mode of sediment transport. A clear understanding of river channel equilibrium is vital for river management and restoration. Project findings will provide regional planners, watershed managers, nongovernmental organizations, and others with new methodologies for prioritizing watersheds for restoration and for seeking better ecological and economic advantages from river systems. The project also will contribute to improved education in science, technology, engineering, and mathematics (STEM) fields through special opportunities for the involvement of graduate students and mentoring programs for female scientists.Watershed managers and policy makers currently lack the necessary analytical metrics to gauge the magnitude of river disturbance to determine whether restoration activities are effective in promoting geomorphologically stable rivers that are in equilibrium. In this project, the investigators will identify the various possible geomorphic expressions of watersheds in dynamic equilibrium through the use of sediment tracers, channel transects and flow modeling, and in-channel sediment measurements. They will use sediment bedload information for quantifying the covariant and non-singular pathways that characterize channel recovery from disturbances, and they will employ mathematical models for simulating channel recovery in systems with varying sediment supply along longitudinal profiles of stream channels. The insights developed through this project will be essential for understanding the resiliency of watersheds and for the implementation recovery and restoration efforts of river systems.