Groundwater flow measurement in unconsolidated glacial deposits using fluorometer analysis of dispersed and adsorbed fluorescein dye

This paper describes the development of a testing technique to determine groundwater flow direction and velocity in a single well. A series of experiments were performed using a device designed specifically to fit into a 152.4 mm (6 inch) diameter well casing. A test apparatus was assembled of polyvinyl chloride (PVC) pipes using porous stones to simulate groundwater flow conditions in an aquifer. The measurement device released fluorescein dye into the center of the simulated well using a dye release mechanism consisting of a glass vial with a salt plug suspended in modeling clay at its base. A small hole in exposed the top and bottom of the salt plug allowed the exchange of dye with the groundwater flowing past the dye outlet hole. The dye released into the well was subsequently adsorbed onto the surface of carbon rods located at eight equally spaced points around the perimeter of the well. The relative amount of the fluorescein dye remaining in the dye release vial, as well as the amount adsorbed on the carbon rods, was measured by the intensity of fluorescence detected by a fluorometer. (Abstract shortened by UMI.)...