Improving Prediction of Subsurface Flow and Transport through Exploratory Data Analysis and Complementary Modeling

通过探索性数据分析和补充建模改进地下流动和输送的预测

• 批准号: 0943627
• 负责人: Albert Valocchi
• 金额: $ 40万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943627&HistoricalAwards=false
• 关键词: Improving; Prediction; Subsurface; Flow; Transport

Abrasion by Bedload and Suspended Load: Experimental StudyRiver incision into rock plays an important role in diverse problems ranging from practical to academic. From dam spillway design, to river management planning including maintenance of suitable aquatic habitats in mountain rivers and river restoration efforts, to the long-term controls on the slope, width, and roughness of mountain rivers, a quantitative understanding of the mechanics of river incision into rock is essential and of broad interest. There has been substantial progress in the past decade on understanding the interactions among climate, topography, erosion, and tectonics; recognition of the central role of river incision into rock has been a key insight. Exploration of the role played by bedrock channels, however, has been accomplished primarily with simplified stream power models (generic rule sets for river incision that lump together a diverse set of erosional mechanisms). Refined, and more realistic, model predictions require advances in our quantitative understanding of erosion processes. Field-based investigation of bedrock incision processes is essential, but does not allow the investigator full control of critical variables. Controlled laboratory experiments have increasingly been used to explore fundamental aspects of the physics of river incision, to test existing models, and to guide their refinement. This research project at ASU includes flume experiments, data analysis, and theoretical development. The experiments will be designed to complement and extend previous flume studies. The primary controlling variables (flux and size distribution of sediment; channel slope; water discharge; and substrate hardness) will be varied in a systematic exploration of conditions, including the transition from bedload to suspended load transport. Bed morphology will be allowed to evolve naturally, and the critical feedbacks between bed morphology, fluid dynamics, sediment flux, and local erosion rate will be quantified. Based on preliminary experiments, field observations, and previous numerical studies, we formulate quantitative hypotheses that can and will be tested by direct measurement of erosion rate, bed topography, grain saltation trajectories, sediment transport rate, and fluid flow conditions, thus allowing refinement of current theory. The results from this research project will have important implications for basic science and a number of practical concerns of societal relevance. Advances in the understanding of the linkages between bedrock lithology, sediment characteristics and channel morphology are of potentially great value in solving applied problems of minimizing and mitigating for landuse impacts and restoring damaged riverine habitat and ecosystems. Engineering planning and management demand understanding of the processes that govern channel changes, including bed roughness and alluvial cover characteristics. A postdoctoral researcher, a graduate student and several undergraduates will receive invaluable training from this research project. Also, laboratory demonstrations will be developed for use in undergraduate courses and for public outreach events.

河床与悬浮力的磨蚀实验研究河流切入岩石在实践和理论等诸多问题中发挥着重要作用。从大坝泄洪道设计，到河流管理规划（包括维护山地河流中适宜的水生栖息地和河流恢复工作），再到对山地河流的坡度、宽度和粗糙度的长期控制，对河流切入岩石的力学的定量理解是必不可少的，也是广泛关注的。在过去的十年里，在了解气候、地形、侵蚀和构造之间的相互作用方面取得了实质性进展；认识到河流切入岩石的核心作用是一个关键的洞见。然而，对基岩河道所起作用的探索主要是通过简化的水流动力模型（将多种侵蚀机制组合在一起的河流切割通用规则集）来完成的。更精确、更现实的模型预测要求我们对侵蚀过程的定量理解取得进展。基岩切割过程的现场调查是必不可少的，但不允许研究者完全控制关键变量。控制实验室实验越来越多地用于探索河流切割物理的基本方面，测试现有模型，并指导其改进。这个在亚利桑那州立大学的研究项目包括水槽实验、数据分析和理论发展。这些实验将用于补充和扩展以前的水槽研究。主要控制变量（泥沙通量和粒径分布、河道坡度、水量和基材硬度）将在系统探索条件中发生变化，包括从顺质输运到悬质输运的转变。河床形态将允许自然演变，河床形态、流体动力学、泥沙通量和局部侵蚀速率之间的关键反馈将被量化。基于初步实验、实地观察和先前的数值研究，我们制定了定量假设，这些假设可以并且将通过直接测量侵蚀速率、床地形、颗粒跳跃轨迹、沉积物输送速率和流体流动条件来验证，从而允许改进当前的理论。这项研究项目的结果将对基础科学和一些与社会相关的实际问题产生重要影响。在了解基岩岩性、沉积物特征和河道形态之间的联系方面取得的进展，对于解决减少和减轻土地利用影响以及恢复受损的河流生境和生态系统的应用问题具有潜在的巨大价值。工程规划和管理需要了解控制河道变化的过程，包括河床粗糙度和冲积覆盖特征。一名博士后、一名研究生和几名本科生将从该研究项目中获得宝贵的培训。此外，将开发用于本科课程和公共宣传活动的实验室演示。