Impact of glaciation on groundwater vulnerability

冰川作用对地下水脆弱性的影响

• 批准号: RGPIN-2019-04990
• 负责人: Arnaud, Emmanuelle
• 金额: $ 1.82万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680770
• 关键词: Impact; glaciation; groundwater; vulnerability

Source water protection is a priority as population growth, climate change and contaminants have put pressures on groundwater producing wells. Approximately 11.5 million Canadians and 2 billion people worldwide rely on groundwater for drinking and daily use, with additional significant use by agriculture (60% of groundwater withdrawn) and industry (20%). These vulnerable resources are found in glacial deposits or bedrock of previously glaciated regions in Canada and around the world. Managing and protecting water wells requires a robust geological model that identifies the geometry of hydraulically relevant features at the well field or contaminant plume scale. Creating this type of model is challenging in previously glaciated settings, where texture is not the primary driver controlling groundwater flow or contaminant pathways. The last glaciation had a profound impact not only on texture, but also on the variable distribution of subsurface materials, the surface topography, and the underlying bedrock surface. In addition, the permeability of bedrock was affected through fracture and dissolution feature or karst development associated with crustal rebound and glacial and post-glacial hydraulics. This geological history plays a key role in determining modern contaminant pathways and plume evolution, volume and depth of aquifers, integrity of aquitards, and consequently, flow system characteristics, well productivity and susceptibility to contamination. While geological surveys and the environmental sector have made strides in creating regional scale models, the heterogeneity of glacial deposits at the well field scale remains a challenge.******The proposed research addresses this by 1) identifying typical sedimentation styles or architecture in specific glacial settings, and assessing its influence on water quality; and 2) examining the interactions between glacial processes and the underlying bedrock and how this has impacted karst distribution in bedrock aquifers. Numerous high-resolution core and water quality data will be examined to test if certain landscapes and subsurface sediment profiles are more susceptible to contamination than others, thus improving delineation of wellhead protection areas. The relationship between glacial processes and bedrock will be explored by examining a) the geological evolution of a buried bedrock valley and its relationship to the occurrence of productive karstic bedrock aquifers and b) the geological properties of the sediment-bedrock interface to shed light on subglacial processes and to assess if there are any predictive relationships useful for subsurface modelling and protection of contact aquifers.******Research findings and 5 graduates with the much-needed skills of applying glacial geology to hydrogeology will have a significant impact on Canada's ability to protect groundwater at the well-field scale, by advancing our understanding of the geological history of these previously glaciated landscapes.

由于人口增长、气候变化和污染物对地下水生产威尔斯井造成压力，水源保护是一个优先事项。全球约有1150万加拿大人和20亿人依赖地下水饮用和日常使用，农业（抽取地下水的60%）和工业（20%）也大量使用地下水。 这些脆弱的资源在加拿大和世界各地的冰川沉积物或以前冰川地区的基岩中发现。 管理和保护水威尔斯井需要一个强大的地质模型，确定在井场或污染物羽流规模的水力相关功能的几何形状。 在以前的冰川环境中创建这种类型的模型是具有挑战性的，在那里纹理不是控制地下水流或污染物路径的主要驱动力。末次冰期不仅对质地产生了深刻的影响，而且对地下物质的分布、地表地形和下伏基岩表面也产生了深刻的影响。 此外，基岩的渗透性受到断裂和溶解特征或与地壳回弹和冰后期水力学相关的岩溶发育的影响。 这一地质历史在确定现代污染物路径和羽流演变、含水层的体积和深度、含水层的完整性以及流动系统的特征、油井生产力和对污染的敏感性方面发挥着关键作用。虽然地质调查和环境部门在创建区域尺度模型方面取得了长足的进步，但井场尺度的冰川沉积物的异质性仍然是一个挑战。拟议的研究通过以下方式解决这一问题：1）确定特定冰川环境中的典型沉积类型或结构，并评估其对水质的影响; 2）研究冰川过程与底层基岩之间的相互作用，以及这如何影响基岩含水层中的岩溶分布。 将检查许多高分辨率岩心和水质数据，以检验某些地貌和地下沉积物剖面是否比其他地貌和地下沉积物剖面更容易受到污染，从而改进井口保护区的划定。 将通过以下方式探讨冰川过程与基岩之间的关系：a）研究埋藏基岩山谷的地质演变及其与富产性岩溶基岩含水层出现的关系; B）研究沉积物-基岩界面的地质特性，以阐明冰下过程，并评估是否存在任何可用于地下建模和保护接触含水层的预测关系。研究结果和5名毕业生具有将冰川地质学应用于水文地质学的急需技能，将对加拿大在井场规模保护地下水的能力产生重大影响，通过推进我们对这些以前冰川景观的地质历史的理解。