Sediment Storage at the Transition Between Debris-Flow and Fluvial Processes

泥石流和河流过程过渡阶段的沉积物储存

• 批准号: 0545768
• 负责人: Stephen Lancaster
• 金额: $ 28.93万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0545768&HistoricalAwards=false
• 关键词: Sediment; Storage; Transition; Between; Debris

Sediment Storage at the Transition Between Debris-Flow and Fluvial Processes Project AbstractBroad Explanation. In order to better understand deposition, retention, and evacuation mechanisms and the sediment budget in valleys strongly affected by debris-flow deposition, the proposed research will characterize volumes, ages, and sedimentology of sediment storage and their relationships to contributing drainage basin and local valley characteristics in headwater streams of the Oregon Coast Range. This project will address a key interface in the source-to-sink flow of sediment off landscapes. An important goal in modern geomorphology is to determine the first-order rate laws that govern fluxes in geomorphic systems, and this projectl specifically addresses this issue. To reach an informed compromise in mountainous areas between exploitation and conservation, it is vital to understand the natural mechanisms mediating downstream effects of episodic disturbances such as forest fires and associated debris flows. The research will contribute to the scientific and political debate around forest practices and habitat in the Pacific Northwest and elsewhere by elucidating the downstream attenuation of debris-flow-derived sediment pulses and presenting that information to managers and policy-makers. Technical Description. What are the mechanisms, rates, and volumes of sediment deposition, retention, and evacuation in mountain streams, and how do these mechanisms, rates, and volumes change downstream? How are they related? How are they affected by climate change? Investigations will encompass streams at varying positions along the transition between debris-flow and fluvial processes, from valleys where both debris-flow scour and deposition are important, through valleys where debris-flow scour appears unimportant but debris-flow deposits predominate, to valleys where debris-flow deposition from tributaries merely punctuates otherwise fluvial deposits. Specific research activities will include (1) mapping and measurement of sediment volumes throughout headwater networks with airborne laser swath mapping (ALSM) and ground-based mapping and testing of the method with ground-based surveying; (2) characterization and mapping of deposit sedimentology and stratigraphy, deposit radiocarbon age distributions, and strath terraces to elucidate retention and evacuation mechanisms, evacuation times, and changes due to climate change; and (3) analysis of digital elevation models (DEMs) to find the dependence of deposit volumes and characteristics and valley morphology (e.g., strath terraces) on network structure and topography.Field sites will be in parts of the Oregon Coast Range (OCR) underlain by an Eocene sandstone formation (Tyee) because prior studies provide knowledge of geomorphic processes and paleoclimate; debris flows dominate sediment delivery to storage in headwater valleys; Quaternary climate change has not changed the dominant geomorphic processes; the OCR is the focus of debate between advocates of exploitation and conservation, respectively; and this area is readily accessible.

碎屑流和河流过程之间的过渡中的沉积物存储项目AbstractBroad解释。 为了更好地理解沉积，保留和疏散机制以及山谷中的沉积物预算，受碎屑流沉积的强烈影响，拟议的研究将表征沉积物存储的量，年龄和沉积学及其关系及其关系，以促进排水盆地和俄勒冈海岸海岸水流的本地山谷特征。该项目将解决沉积物从景观中的源流量流中的关键接口。现代地貌学的一个重要目标是确定控制地貌系统中通量的一阶费率定律，该项目专门解决了这个问题。为了在剥削和保护之间达到山区的知情妥协，了解介导情节干扰（例如森林火灾和相关碎屑流）的下游影响的自然机制至关重要。这项研究将通过阐明碎屑流衍生的沉积物脉冲的下游衰减，并向管理人员和政策制定者介绍这些信息，从而为太平洋西北和其他地方的森林实践和栖息地的科学和政治辩论做出贡献。技术描述。 山流中沉积物沉积，保留和疏散的机制，速度和量是什么？这些机制，速率和体积如何在下游变化？他们如何关系？它们如何受到气候变化的影响？调查将涵盖沿着碎屑流和河流过程之间过渡的不同位置的流，从碎屑流的冲刷和沉积都很重要的山谷中，通过杂物 - 流冲洗的山谷，这些山谷似乎并不重要，但碎屑被沉积在debris-flisters the debris-fully fullys fullys fullys fullys fullise fullyed culties fullyed serforties to to to to to to to to to to to to to to there fullys fullyed culties to to there fullys fullys fuly to to。具体的研究活动将包括（1）用空气中的激光饰面映射（ALSM）的映射和测量整个源头网络的沉积物量以及通过基于地面测量的方法对方法进行地面映射和测试； （2）表征和映射沉积沉积学和地层学，沉积放射性碳年龄分布以及Strath Terraces，以阐明保留和疏散机制，疏散时间以及由于气候变化而引起的变化； （3）分析数字高程模型（DEMS），以查找对网络结构和地形的矿床量和特征的依赖性以及山谷形态（例如Strath Terraces）。场地将在俄勒冈州海岸范围（OCR）的部分地区（OCR）属于二元砂岩形成（Tyee）的部分，因为先前的研究提供了地质过程的知识，因此可以提供地质层次的知识。碎片流占主导地位的沉积物，以在源头山谷中存储；第四纪气候变化并没有改变主要的地貌过程。 OCR分别是剥削和保护倡导者之间辩论的重点。而且该区域很容易访问。