The Role of Fractional Dynamic Wettability as a Primary Determinant for Flow and Transport in Soils and the Vadose Zone.

分数动态润湿性作为土壤和包气区流动和传输的主要决定因素的作用。

• 批准号: RGPIN-2014-04214
• 负责人: Smith, James
• 金额: $ 2.19万
• 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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633877
• 关键词: Role; Fractional; Dynamic; Wettability; Primary

In some soils when water is applied to the surface by rain or other means the water beads on the surface and runs off. Then, over time the soil changes to become able to soak up the water. This process is called dynamic fractional wettability or soil water repellency. Dynamic fractional wettability drastically changes the behaviour of water and its availability in soils for plant growth, nutrient cycling, and it role in contaminant transport. The process of changing wettability of soils is very complex and unpredictable under many important environmental conditions. For example, after a forest wildfire the soil is commonly rendered highly repellent leading to excessive runoff of rain with resultant erosion. Also, the amount of water that is retained in repellent soil is greatly reduced which directly affects plant growth, seed germination, soil evapotranspiration, and soil temperature. Water that does pond on the surface due to the repellency can drain down fractures and large pores in the soil (like old root channels) and bypass the shallow soil and most plant roots to subsequently arrive in groundwater much more quickly. Similar concerns of dynamic fractional wettability below ground surface occur in soils after petroleum spills or at old industrial sites (Brown Fields). Unfortunately, our current scientific knowledge and ability to predict how water moves and is stored or released from soils that have the tendency to repel water to varying degrees over time (dynamic fractional wettability) is critically lacking. The current state of our scientific knowledge is such that there are currently no mechanistic computer models that can accurately describe water behaviour in these complex dynamic soils and/or resultant recharge and transport of contaminants to ground waters under these conditions. Research over the last few decades has revealed that soil water fractional wettability/repellency is far more common than previously known/recognised and is potentially a primary driver for water movement under a number of important environmental conditions. The objectives of this NSERC Discovery Grant research program are to advance our fundamental conceptual understanding and ability to mathematically model and predict water flow and contaminant transport in soils expressing dynamic fractional wettability/water repellency. This will be done through field experiments, highly instrumented laboratory testing/experiments, pore-scale imaging in representative soil materials, and model development. The outcome will be new/better models of soil water flow, soil water storage, and related contaminant transport in soil and groundwater that can be used to help solve many related and pressing environmental problems subject to the primary effects of dynamic fractional wettability.

在某些土壤中，当水通过雨或其他方式将水施加到表面上时，意味着表面上的水珠并逃跑。然后，随着时间的流逝，土壤会变化以吸收水。该过程称为动态分数润湿性或土壤水的驱除态度。动态分数润湿性会大大改变水的行为及其在土壤中的植物生长，养分循环以及IT在污染物运输中的作用的可用性。在许多重要的环境条件下，改变土壤润湿性的过程非常复杂且无法预测。例如，在森林野火之后，土壤通常会导致高度驱虫剂，导致雨水过多，从而导致侵蚀。同样，保留在驱虫剂土壤中的水量大大减少，这直接影响植物生长，种子发芽，土壤蒸散量和土壤温度。由于驱虫而在地面上池塘的水会耗尽土壤中的裂缝和大毛孔（如旧的根通道），并绕过浅层土壤和大多数植物根，以便更快地到达地下水。在石油溢出后或旧工业地点（棕色田地）的土壤中，地面下的动态分数润湿性的类似关注点也发生在土壤中。不幸的是，我们目前的科学知识和预测水如何移动和释放的能力是从具有随着时间的时间驱除水（动态分数润湿性）趋势的土壤中的。我们的科学知识的当前状态使得目前尚无机械计算机模型可以准确描述这些复杂的动态土壤中的水行为和/或在这些条件下污染物到地面水域的充分充电和运输。在过去的几十年中，研究表明，土壤水分的润湿性/驱虫性比以前已知/认可的更为普遍，并且在许多重要的环境条件下可能是水流动的主要驱动力。该NSERC发现赠款研究计划的目标旨在提高我们基本的概念理解和数学上的能力，以模拟和预测表达动态分数润湿性/水的土壤中的水流和污染物的运输。这将通过现场实验，高度仪器的实验室测试/实验，代表性土壤材料中的孔尺度成像以及模型开发来完成。结果将是土壤水流，土壤储存和土壤和地下水中相关污染物的新模型，可用于帮助解决许多相关和紧迫的环境问题，但要受到动态分数润湿性的主要影响。