Advanced characterization and monitoring for improved wellhead protection in a fractured and porous dolostone bedrock aquifer

在安大略南部，从尼亚加拉悬崖延伸到布鲁斯县的志留纪白云岩带是一个主要的基岩含水层，为大型（圭尔夫、剑桥）和小型（费尔格斯、奥兰治维尔）社区的大约100万人提供饮用水。圭尔夫市的井场包括23个市政抽水威尔斯井，为城市提供饮用水。其中两口威尔斯井受到三氯乙烯（TCE）的威胁，三氯乙烯是一种前工业溶剂，也是一种人类致癌物质。虽然三氯乙烯的含量符合饮用水准则，但目前尚不清楚三氯乙烯的浓度将如何受到长期抽水、抽水率变化、补给的季节性变化、该地区其他威尔斯井抽水的影响以及含水层内化学过程的影响。了解这些相互关联的影响是至关重要的城市的安全和可持续的饮用地下水供应的长期管理。拟议的研究将整合高分辨率的现场和实验室表征和监测技术，由圭尔夫大学的Beth帕克博士开发和完善，并被称为DFN现场方法和DFN数值模拟技术。DFN现场方法利用多条证据线，包括：岩石取芯、岩心的物理和化学测试、钻孔内衬的安装、露天和内衬钻孔的水力和水文物理测试、钻孔内衬的安装、多级地下水监测系统的安装、多级系统的物理和化学测试以及地下水流系统和污染物归宿和迁移的建模。这项研究的新方面包括一个“智能”的原型多级地下水监测系统，开发的3-D捕获区模型和改进的方法设计的岗哨井监测程序。研究结果将产生更多的确定性TCE污染物的行为在圭尔夫含水层系统，提供地下水社区以科学为基础，防御政策，可持续地管理安全的饮用水供应，并提高知识基础和加拿大地下水行业的最佳实践方法。

In southern Ontario, the Silurian dolostone belt extending from the Niagara escarpment to Bruce County is a major bedrock aquifer supplying approximately 1 million people with drinking water in large (Guelph, Cambridge) and small (Fergus, Orangeville) communities. The City of Guelph wellfield comprises 23 municipal pumping wells that supply the city with potable water. Two of the wells are threatened by the occurrence of trichloroethene (TCE) a former industrial solvent and a human carcinogen. While the levels of TCE meet drinking water guidelines, it is not known how the concentrations of TCE will be affected by long term pumping, changing rates of pumping, seasonal variations in recharge, impacts from pumping of other wells in the area, and chemical processes within the aquifer. Understanding these interrelated impacts are critical to the City's long term management of secure and sustainable potable groundwater supplies. The proposed research will integrate high resolution field and laboratory characterization and monitoring techniques developed and refined by Dr Beth Parker at the University of Guelph and referred to as the DFN field approach and DFN numerical modelling techniques. The DFN field approach utilizes multiple lines of evidence including: rock coring, physical and chemical testing of the core, installation of borehole liners, hydraulic and hydrophysical testing of the open and lined borehole, installation of borehole liners, installation of multilevel groundwater monitoring systems, physical and chemical testing of the multilevel systems and modelling of the groundwater flow system and contaminant fate and transport. The novel aspects of this research include a "smart" prototype multilevel groundwater monitoring system, development of 3-D capture zone model and improved methodology for designing a sentry well monitoring program. The results of the research will generate more certainty about TCE contaminant behaviour in the Guelph aquifer system, provide groundwater communities with scientific-based, defensible policies for managing secure potable water supplies sustainably and improve the knowledge base and best practice methods of the Canadian groundwater industry.