Doctoral Dissertation Research: The Role of Large Woody Debris in a Midwestern Low-Energy Stream: Implications for Stream Naturalization

博士论文研究：大型木质碎片在中西部低能量溪流中的作用：对溪流自然化的影响

• 批准号: 0002450
• 负责人: Bruce Rhoads
• 金额: $ 0.93万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0002450&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Role; Large

When examining the factors that influence the geomorphic structure and dynamics of stream channels, attention tends to focus on interactions between water and sediments. A number of external factors can influence these fluvial dynamics, however, including plant material that falls into and along stream beds. Although increasing attention is being given to the impact of biota on stream dynamics and related channel morphology, most research has been done in locations where fast-moving streams flow through non-urban areas. The overall goal of this doctoral dissertation research project is to advance the understanding of the interactions between large woody debris (LWD) and the geomorphic structure and function of low-gradient meandering streams. The project will explore process-based interactions between LWD storage and transport, organic matter retention, and a variety of fluvial processes, including sediment transport, three-dimensional flow structure, and bar form development, and it will to inform stream naturalization efforts by developing a set of management guidelines about LWD that are consistent with extant biotic-fluvial processes. Specific research questions to be examined in this project include: (1) How is LWD spatially distributed within a meandering stream?, (2) What geomorphic and hydrologic factors affect the dynamics of woody debris in this type of fluvial system?, and (3) How do woody debris obstructions affect bed material characteristics, local patterns of erosion and deposition, three-dimensional flow structure, and organic matter standing stock at the scale of individual meander bends? The project design and methodologies will be informed by research on three-dimensional flow in meander bends, bedform and planform development in meandering streams, and the influences of LWD on stream ecosystems. Field data are will be collected in a 600-meter meandering section of Poplar Creek, a tributary of the Fox River in Kane County in northeastern Illinois. This study site is located directly upstream of a straightened reach that is the focus of a de-channelization project that will attempt to re-establish a naturally functioning meandering system with diverse in-stream morphology and habitats. Among components of the field study are characterization of land-use change within the watershed, GIS-facilitated analysis of historical changes in channel position at the research site, and analysis of available historical hydrologic data. Special attention will be given to process-based field investigations focusing on LWD dynamics and organic matter retention throughout the 600-meter reach and interactions between LWD obstructions and geomorphological processes within three meander bends. This research project will contribute to the general understanding of the geomorphological dynamics of meandering streams, especially process interactions between biotic and abiotic components of these systems. This improved understanding will provide a more reliable framework of knowledge on which to base stream naturalization plans for low-energy meandering streams with abundant LWD. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

在研究影响河道地貌结构和动态的因素时，人们的注意力往往集中在水和沉积物之间的相互作用上。 然而，许多外部因素会影响这些河流动力学，包括落入河床和沿着河床的植物物质。 尽管人们越来越关注生物群对河流动力学和相关河道形态的影响，但大多数研究都是在快速流动的河流流经非城市地区的地方进行的。 该博士论文研究项目的总体目标是增进对大型木质碎片（LWD）与低梯度蜿蜒溪流的地貌结构和功能之间相互作用的理解。 该项目将探索随钻测井储存和运输、有机质保留和各种河流过程之间基于过程的相互作用，包括沉积物运输、三维流动结构和坝形发展，并将通过开发一套与现有生物河流过程一致的随钻测井管理指南。 本项目要研究的具体研究问题包括：（1）随钻测井在蜿蜒河流内的空间分布如何？（2）哪些地貌和水文因素影响此类河流系统中木质碎屑的动态？（3） ) 木质碎屑障碍物如何影响河床物质特征、局部侵蚀和沉积模式、三维流动结构以及单个曲流弯曲范围内的有机质积存量？ 项目设计和方法将通过对曲流弯曲中的三维流动、曲流溪流中的床形和平面发育以及随钻测井对溪流生态系统的影响的研究来提供信息。 现场数据将在伊利诺伊州东北部凯恩县福克斯河的支流 Poplar Creek 600 米蜿蜒河段收集。 该研究地点位于直河段的直接上游，该河段是去河道化项目的重点，该项目将尝试重建具有多种河内形态和栖息地的自然功能的蜿蜒系统。 实地研究的组成部分包括流域内土地利用变化的特征、GIS 辅助的研究地点河道位置历史变化分析以及现有历史水文数据分析。 将特别关注基于过程的现场调查，重点关注整个 600 米范围内的随钻测井动力学和有机物滞留以及三个曲折弯内随钻测井障碍物与地貌过程之间的相互作用。 该研究项目将有助于对蜿蜒河流的地貌动力学的一般理解，特别是这些系统的生物和非生物成分之间的过程相互作用。 这种加深的理解将提供一个更可靠的知识框架，以此为具有丰富随钻测井的低能量曲流溪流的归化计划奠定基础。 作为博士论文研究改进奖，该奖项还将为有前途的学生建立强大的独立研究生涯提供支持。