HR: 11:35h
AN: H22C-05    [Abstracts]
TI: Impact of Source Mass Depletion on the Contaminant Flux Distribution at the Source Control Plane
AU: * Basu, N B
EM: nbasu@ufl.edu
AF: University of Florida, Soil and Water Science Department 2169 McCarty Hall, Gainesville, FL 32611, United States
AU: Rao, P C
EM: pscr@purdue.edu
AF: Purdue University, Department of Civil Engineering, West Lafayette, IN 47906, United States
AU: Jawitz, J W
EM: jawitz@ufl.edu
AF: University of Florida, Soil and Water Science Department 2169 McCarty Hall, Gainesville, FL 32611, United States
AU: Annable, M D
EM: annable@ufl.edu
AF: University of Florida, Department of Environmental Engineering Sciences, Gainesville, FL 32611, United States
AU: Hatfield, K
EM: khatf@ce.ufl.edu
AF: University of Florida, Department of Civil and Coastal Engineering, Gainesville, FL 32611, United States
AB: The impact of source depletion on the contaminant flux distribution (J) at the source control plane (CP) was investigated using model simulations and data from a field study. DNAPL dissolution and transport in three- dimensional, heterogeneous, spatially correlated, random permeability fields with emplaced sources were simulated with two numerical codes (ISCO3D and T2VOC). The DNAPL and J distributions were characterized using population statistics (mean, standard deviation, coefficient of variation) and spatial statistics (centroid, second moments, variograms). The mean and standard deviation of the Sn and J distributions decreased with source mass depletion by dissolution. The decrease in mean and standard deviation was proportional for the J distribution resulting in a constant coefficient of variation (CV), while for the Sn distribution, the mean decreased faster than the standard deviation. The spatial distributions exhibited similar behavior as the population distribution, i.e., the CP flux distribution was more stable (defined by temporally constant second moments and range of variograms) than the Sn distribution. These observations appeared to be independent of the heterogeneity of the permeability (k) field (variance of the lnk distribution = 1 and 2.45), correlation structure (positive vs. negative correlation between the k and Sn domains) and the DNAPL dissolution model (equilibrium vs. rate limited), for the cases studied. The temporal invariance of the contaminant flux distribution was also observed in the results from a flux monitoring field study (Hill Air Force Base, Utah) at a DNAPL source CP before and after source remediation. These observations suggest that the temporal evolution of the contaminant flux distribution can be estimated if the initial distribution is known. However, the findings are preliminary and broader implications to sampling strategies for remediation performance assessment and expected plume behavior need to be evaluated in additional modeling and experimental studies.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2007 Joint Assembly