HR: 08:00h
AN: H31F-01    [Abstracts]
TI: Estimating Vertical Groundwater Velocities Using Groundwater Thermal Gradients
AU: * Arriaga, M A
EM: marriaga@ensr.aecom.com
AF: ENSR Corporation, 27755 Diehl Road, Suite 100, Warrenville, IL 60555, United States
AU: Leap, D I
EM: mountains2oceans@insightbb.com
AF: Purdue University, 550 Stadium Mall Drive , West Lafayette, IN 47907, United States
AU: Petruccione, J L
EM: jpetruccione@ensr.aecom.com
AF: ENSR Corporation, 27755 Diehl Road, Suite 100, Warrenville, IL 60555, United States
AB: An understanding of vertical groundwater flow through unconsolidated deposits is a component for predicting fate and transport of contaminants in the saturated zone. Groundwater movement through heterogeneous glacial deposits common to northern Indiana (USA) provided a test setting for determining if measured vertical groundwater thermal gradients could aid in calculating vertical groundwater velocity estimates. Field procedure was conducted by collecting stratified groundwater temperatures from a series of cased monitoring wells previously advanced through glacial till and outwash sedimentary sequences. Groundwater thermal gradients (temperature-depth profiles) were plotted and matched using automated computer modeling software (Microsoft Excel Solver) with published type curves to derive a dimensionless parameter for estimating vertical groundwater velocities. Data results matched predictions, to include an increase in vertical groundwater velocities during the seasonally wetter Spring; and, higher calculated vertical groundwater velocities for the finer-grained till aquitards when compared to aquifers comprised of coarser-grained outwash deposits. This study shows promise and has gathered interest both in the scientific community and environmental consulting practice for estimating vertical migration rates of contaminants (specifically those affected by advection) within the saturated zone. Government agencies or consultants, for instance, could also potentially apply this estimation technique to measure and map localized recharge rates for developing more accurate wellhead protection zones.
DE: 1828 Groundwater hydraulics
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2007 Joint Assembly