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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754863
• 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.

从土壤表面延伸到区域地下水位以下的地下水的关键区域支持着几乎所有的陆地生命并包含大部分陆地生物量，我们更好地定量预测地下水流、化学运动和气体交换的能力至关重要。鉴于控制水的运动以及化学污染物在土壤和地下水中的归宿和迁移的机制和过程的更好的基本了解变得更加紧迫。当空气（气相）和水（多相流体）在地下共存时，我们对即将发生的气候变化对温度和降水的影响的最佳估计仍然受到严重限制。这是在关键区域的不饱和土壤和浅层地下水中截留​​的空气中的情况，并且当土壤和岩石的润湿性/排斥性是动态的（与时间相关的）时特别受到限制。当溢出时则受到严重限制。污染物具有表面活性（表面活性剂）特性，特别敏感的土壤包括有机物含量高的防水干燥土壤、野火后土壤以及受石油产品和工业溶剂污染的土壤。润湿性和毛细管现象随时间变化。由于许多环境污染物和天然存在的化合物充当表面活性化合物（表面活性剂），它们大大改变了空气-水界面的表面张力、固体的润湿性和接触角，这一事实使情况变得复杂我在溶质浓度依赖性毛细管现象、接触角动力学和分数润湿性对土壤水行为的影响方面拥有丰富的研究经验和长期的国际声誉。这些贡献、知识和专业知识是拟议研究的基础。该方法将结合仪器仪表齐全的基于实验室的流动池实验、数学模型开发和现场研究，未来 5 年的主要目标成果将是开发概念验证数据集、概念模型、一阶动态水力函数和定量。水的一阶数学模型该研究将为专家和非专家（例如环境修复专家、林业工作者、生态水文学家）生成简单的一阶实用模型，以便能够计算出更准确和可靠的水渗透。 、污染物迁移行为以及由此产生的土壤保水、地下水补给和污染物迁移和归宿。