Dynamic Repellency, Wettability and Capillarity as Primary Drivers for Water Flow and Chemical Transport in Soils and Groundwater in the Critical Zone

动态排斥性、润湿性和毛细管作用是关键区域土壤和地下水中水流和化学物质输送的主要驱动力

• 批准号: RGPIN-2020-06614
• 负责人: Smith, James
• 金额: $ 1.82万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718068
• 关键词: Dynamic; Repellency; Wettability; Capillarity; Primary

The critical zone which extends form the soil surface down to groundwater below the regional water table supports almost all terrestrial life and contains most of the terrestrial biomass. Our ability to better quantitatively predict water flow, chemical movement and gas exchange in the subsurface is essential and foundational to accurately assessing many environmental problems and associated management and/or remediation schemes. A better fundamental understanding of mechanisms and processes controlling the movement of water and the fate and transport of chemical contaminants in the soil and groundwater is ever more urgent given our best estimates of pending climate change impacts on temperatures and precipitation. Our current knowledge and ability to quantitatively predict water flow, contaminant transport remain critically limited when both air (gas-phase) and water coexist (multi-phase fluids) in the subsurface. This is the case in unsaturated soils and entrapped air in shallow groundwaters of the critical zone, and particularly limited when the wettability/repellency of the soils and rocks is dynamic (time-dependent). It is critically limited when spilled contaminants have surface active (surfactant) properties. Examples of soils which are exceptionally sensitive are water repellent dry soils with high organic matter contents, post wildfire soils, and soils contaminated by petroleum products and industrial solvents. The problem of wettability and capillarity changing over time are complicated by the fact that numerous environmental contaminants and naturally occurring compounds act as surface active compounds (surfactants) which substantially change the surface tension at the air water interface, the wettability and contact angle at solid surfaces. I have extensive research experience and a long international reputation for my innovative research and publications on solute concentration dependent capillarity, contact angle dynamics and fractional wettability effects on soil water behavior. Those contributions, knowledge and expertise are foundational to the proposed research. The scientific approach will combine well instrumented laboratory-based flow cell experiments, mathematical model development, and field studies. The primary targeted outcomes over the next 5 years will be to develop proof of concept data sets, conceptual models, first-order dynamic hydraulic functions and quantitative first-order mathematical models of water infiltration and retention in soils expressing dynamic wettability and capillarity. The research will generate simple first-order practical models for specialists and non-specialists (e.g. environmental remediation specialists, foresters, eco-hydrologists) to be able to calculate more accurate and reliable water infiltration, contaminant transport behaviours and resultant soil

从土壤表面向下延伸到 区域地下水位以下的地下水支持着几乎所有的陆地生命 并且包含了大部分的陆地生物量。我们有能力更好地 定量预测地下水的流动、化学运动和气体交换 地下对于准确评估许多环境至关重要 环境问题和相关的管理和/或补救方案。一 更好地从根本上了解控制气候变化的机制和过程， 水的运动和土壤中化学污染物的归宿和迁移 而地下水的需求则更加迫切，因为我们对未来气候的最佳估计 气候变化对气温和降水的影响。我们现有的知识和 定量预测水流、污染物输运的能力仍然至关重要 当空气（气相）和水（多相流体）共存时， 地下。 在非饱和土壤中就是这种情况， 临界区的浅层地下水，特别是当 土壤和岩石的润湿性/排斥性是动态的（依赖于时间）。它 当溢出的污染物具有表面活性时， （表面活性剂）性质。 土壤的例子， 敏感的是具有高有机质含量的斥水性干燥土壤， 野火土壤，以及石油产品和工业污染的土壤 溶剂. 润湿性和毛细作用的问题 由于许多环境污染物 和天然存在的化合物作为表面活性化合物（表面活性剂） 其实质上改变了空气-水界面处的表面张力， 固体表面的润湿性和接触角。我做了大量的研究 经验和长期的国际声誉，我的创新研究和 关于溶质浓度依赖性毛细作用、接触角 动态和部分润湿性对土壤水分行为的影响。那些 贡献、知识和专长是拟议的 research. 科学的方法将联合收割机 基于仪器化实验室的流动池实验，数学模型 发展和实地研究。未来5年的主要目标成果 多年的时间将用于开发概念数据集，概念模型， 一阶动态水力函数和定量一阶 土壤水分入渗和持水数学模型 动态润湿性和毛细作用。 这项研究将产生简单的一阶 专家和非专家的实用模型（如环境 补救专家、林业人员、生态水文学家）能够计算 更准确和可靠的水渗透，污染物传输行为 以及由此产生的土壤