DETERMINING THE CONNECTIVITY OF FRACTURES BETWEEN MULTIPLE BEDROCK WELLS USING DISSOLVED OXYGEN AS A TRACER

When contamination affects a water supply, flow conditions must be assessed to maximize recovery. The behavior and characteristics of groundwater flow conditions in fractured crystalline bedrock are difficult to assess in a cost effective manner. Chlebica and Robbins (2013) developed a method for characterizing fractures in a bedrock well using dissolved oxygen as a tracer. The dissolved oxygen method simplifies traditional methods for identifying water-contributing fractures, determining flow direction, and selecting locations for water quality sampling. We have expanded on this method to determine how multiple wells are interconnected. Following the aeration of a well, the movement of dissolved oxygen is tracked in a connecting well through individual fractures. Dissolved oxygen concentrations can be used to quantify dispersion properties of oxygenated water and flow velocity within a well. Using the dissolved oxygen method to identify interconnected fractures in bedrock wells provides a more economical alternative for site investigation and remediation.