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SIMULATION OF A METHYL TERT-BUTYL ETHER (MTBE) PLUME WITH MODFLOW, MT3D AND THE HYDROCARBON SPILL SCREENING MODEL (HSSM)
Citation:
Earle, R. AND J W. Weaver. SIMULATION OF A METHYL TERT-BUTYL ETHER (MTBE) PLUME WITH MODFLOW, MT3D AND THE HYDROCARBON SPILL SCREENING MODEL (HSSM). Presented at MODFLOW 2001 and Other Modeling Odysseys Conference, Golden, CO, September 11-14, 2001.
Impact/Purpose:
The objective of this research is to develop a multicomponent, mass-balance-based model for simulating transport of spilled oils with and without dispersant treatments.
Description:
An MTBE plume in the Upper Glacial Aquifer of Long Island, NY was simulated by combining MODFLOW and MT3D with a semi-analytical model for a gasoline release. The first step was to develop and calibrate a 3-dimensional steady-state numerical ground water flow model of the aquifer using MODFLOW. The most important large scale features of the flow system that were captured in the MODFLOW model were the pattern of aerial recharge and the interaction of ground water with surface waters at one end of the plume. Historical site data and the observed contaminant distribution were then used to generate a gasoline release scenario that was simulated by the Hydrocarbon Spill Screening Model (HSSM). HSSM was used to simulate emplacement of gasoline over a three-year period and the resulting dissolution of MTBE into the aquifer. Both the MTBE concentration in ground water and the size of the source zone change with time as the fuel weathers and the lens expands. These results form a boundary condition for transport in the aquifer, which was simulated by using MT3D and the calibrated MODFLOW model. The simulation was in close agreement with field observations, including observed detachment of the MTBE plume from the gasoline source, and plume diving under the influence of aerial recharge.