Lecture topic: Flow and Transport Properties of Fractured Bedrock Aquifers in the Vertical Direction.
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Assessing the ability of an unconfined bedrock aquifer to transmit infiltrating water and contaminants vertically downwards has long been a difficulty for practicing hydrogeologists. Typically, the conduits for flow are vertical fractures or joints that may intersect the ground surface or subcrop beneath a thin veneer of soil. Although this setting is widely recognized to pose a risk to the quality of water in the aquifer, we actually know very little about the fluid and transport processes across the bedrock surface. In this talk, the results of studies conducted recently at two field sites, one set in sedimentary rock and the other in a gneissic terrain, will be presented. The studies include the development of pumping and pulse interference methods for estimation of vertical hydraulic conductivity, and the completion of tracer experiments from a surficial source to depth in a pumped well for the estimation of transport porosity. The results point out the significant importance of vertical fracture geometry, spacing and aperture in determining bulk vertical hydraulic conductivity and vertical transport porosity, and the difficulty we have in estimating these properties. In particular, the methods typically used in porous media to estimate vertical hydraulic properties, such as the pumping test, fail in fractured bedrock settings due to uncertainty in the estimates for specific yield and vertical specific storage. Similarly, the extremely low primary porosity contained by the fractures and the complexity in fracture geometry subvert the interpretation of vertical transport processes beyond the simple detection of primary pathways in these settings.
Dr. Kent Novakowski
Head, Department of Civil Engineering, Queen’s University
Kent Novakowski obtained his PhD from the University of Waterloo in 1992. He joined the Department of Civil Engineering at Queen’s University, Kingston, Canada in August of 2000 and was appointed Head of the Department in 2009. Prior to Queen’s, Dr. Novakowski led the Groundwater Contamination Project at the National Water Research Institute in Burlington, Ontario. Dr. Novakowski has more than 25 years experience in the characterisation and modelling of groundwater flow and contaminant transport in both crystalline and sedimentary fractured rock. He has published more than 200 papers and abstracts in a variety of proceedings and refereed journals, including 60 articles in journals such as Water Resources Research (WRR), the Journal of Hydrology, and the Journal of Contaminant Hydrology (JCH). Dr. Novakowski is a past Associate Editor of WRR, the Journal of Groundwater and the Canadian Geotechnical Journal, and a current Associate Editor of JCH. Dr. Novakowski has participated in the presentation of numerous professional short courses given at venues in Canada, the US, South Africa and Australia. He has served on three expert panels and chaired a fourth which was focused on Sustainable Water Well Infrastructure in Ontario. He is currently the Director of the Water Research Centre, an affiliation of more than 45 water researchers from a wide variety of disciplines across Queen’s and the Royal Military College. He has also served as a consultant to various private companies and agencies in North America and abroad.