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

点击翻译按钮获取中文摘要

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.