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

在安大略省南部，志留纪白云岩带从尼亚加拉悬崖延伸到布鲁斯县，是一个主要的基岩含水层，为大（圭尔夫，剑桥）和小（弗格斯，奥兰治维尔）社区的大约100万人提供饮用水。圭尔夫市井场由23口市政抽水井组成，为该市提供饮用水。其中两口井受到三氯乙烯（TCE）的威胁，三氯乙烯是一种前工业溶剂和人类致癌物。虽然三氯乙烯的水平符合饮用水准则，但尚不清楚三氯乙烯的浓度将如何受到长期抽水、抽水速率变化、补给的季节性变化、该地区其他水井抽水的影响以及含水层内的化学过程的影响。了解这些相互关联的影响对纽约市长期管理安全和可持续的饮用地下水供应至关重要。拟议的研究将整合高分辨率现场和实验室表征和监测技术，这些技术是由圭尔夫大学的Beth Parker博士开发和改进的，被称为DFN现场方法和DFN数值模拟技术。DFN现场方法利用多种证据线，包括：岩石取心、岩心的物理和化学测试、井眼衬管的安装、开放和衬管的水力和水物理测试、井眼衬管的安装、多层地下水监测系统的安装、多层系统的物理和化学测试、地下水流动系统和污染物的流向和运输的建模。本研究的新颖方面包括“智能”多级地下水监测系统原型、三维捕获区模型的开发以及岗哨井监测程序设计的改进方法。研究结果将使圭尔夫含水层系统中TCE污染物的行为更加确定，为地下水社区提供基于科学的、可辩护的政策，以可持续地管理安全的饮用水供应，并改善加拿大地下水行业的知识库和最佳实践方法。**************

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.**************