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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741337
• 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 water retention, groundwater recharge and contaminant migration and fate.

延伸的临界区域将土壤表面向下形成到区域地下水位下方的地下水，几乎所有陆地寿命都包含大部分陆地生物量。我们在地下中更好地预测水流，化学运动和气体交换的能力对于准确评估许多环境问题以及相关的管理和/或补救方案是必不可少的。鉴于我们对气候变化对温度和精确度的影响，对控制水运动以及土壤和地下水中化学污染物的命运和运输的机制和过程的基本了解变得更加紧迫。我们当前的知识和定量预测水流的能力，当空气（气相）和水中的水（多相流体）在地下时，污染物的运输仍然受到严重限制。在不饱和土壤和临界区浅水区域的空气中，这种情况是这种情况，当土壤和岩石的润湿性/驱虫性是动态的（时间依赖性）时，尤其有限。当溢出的污染物具有表面活性（表面活性剂）特性时，它受到严重限制。异常敏感的土壤的例子是驱逐有机物含量，野火土壤和被石油产品和工业溶液污染的土壤。随着时间的流逝，润湿性和毛细血管变化的问题使许多环境污染物和天然化合物充当表面活性化合物（表面活性剂），从而实质上改变了空气水界面处的表面张力，固体表面上的润湿性和接触角。我在创新的研究和关于固体浓度依赖性毛细血管，接触角动力学和分数润湿性对土壤水行为的影响方面的创新研究和出版物中拥有丰富的国际声誉。这些贡献，知识和专业知识是拟议研究的基础。科学方法将结合仪器基于实验室的流动细胞实验，数学模型开发和现场研究。在接下来的5年中，主要的目标结果将是建立概念数据集的证明，概念模型，一阶动态氢化功能以及在表达动态润湿性和毛细管性的土壤中的水浸润和保留的定量一阶数学模型。这项研究将为专家和非专家（例如，环境修复专家，外国人，生态流行病学家）生成简单的一阶实践模型，以便能够计算出更准确，可靠的水渗透，污染物的运输行为以及所得的土壤保留，地下水恢复和污染物的迁移和污染物。