A digital model for the transport of trichloroethylene in an alluvial aquifer, Tucson, Arizona
AuthorCross, Mark Manthei.
Trichloroethylene -- Environmental aspects -- Arizona -- Pima County -- Data processing.
Trichloroethylene -- Environmental aspects -- Arizona -- Tucson -- Data processing.
Trichloroethylene -- Environmental aspects -- Arizona -- Pima County -- Mathematical models.
Trichloroethylene -- Environmental aspects -- Arizona -- Tucson -- Mathematical models.
Groundwater -- Pollution -- Arizona -- Pima County -- Data processing.
Groundwater -- Pollution -- Arizona -- Tucson -- Data processing.
Groundwater -- Pollution -- Arizona -- Pima County -- Mathematical models.
Groundwater -- Pollution -- Arizona -- Tucson -- Mathematical models.
Committee ChairSimpson, Eugene S.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractConcentrations of trichloroethylene (TCE) have been detected in groundwater from wells in several areas south of Tucson, Arizona. A two-dimensional finite difference model was compiled from hydrogeologic data for an area of about 55 square miles, and was calibrated to reproduce historical water level data and compute seepage velocities for the period 1952 to 1980. The model uses the method of characteristics to solve the advection-dispersion equation. Contaminant sources were imposed at a group of TCE disposal sites at an industrial facility. Changes in concentration in the upper zone of the regional aquifer were simulated for the period 1952 to 1982. The model successfully reproduces TCE concentrations measured in groundwater from the upper zone in the area of the facility and northwest of the facility. Results for 1982 indicate that the 10 ppb contour of TCE concentration extended about 4,000 feet to the northwest of the facility.
Degree ProgramHydrology and Water Resources
Degree GrantorUniversity of Arizona
Showing items related by title, author, creator and subject.
Linking a hydrologic model for small urban watersheds to a geographic information system.Hu, Zhengyu.; Guertin, D. Phillip; Hawkins, Richard H.; Lopes, Vicente L. (The University of Arizona., 1994)A series of approaches were developed for integrating the TR-55, a hydrologic simulation model for small urban watersheds, with two grid based geographic information systems--IDRISI and Map Analysis Package. A geographic information system database for a small urban experimental watershed was developed. Thirty storm rainfall-runoff events were used to test the integration of hydrological model and GIS. It was found that the simulated runoff from geographic information system was much better than that from conventional methods.
Gaseous transport in the vadose zone : computer simulations using the discrete state compartment modelSeidemann, Rick Hugh,1960-; Simpson, Eugene S.; Evans, Daniel D.; Bently, Harold (The University of Arizona., 1988)Past disposal practices of TricNoroethylene (ICE) and other halogenated hydrocarbons have resulted in the contamination of groundwater in part of the Tucson Basin, Tucson, Arizona. At the Carranza site, known to overlie a ICE groundwater contamination plume, a nest of gas sampling piezometers was constructed to measure the vertical distribution of TCE vapor in the vadose zone. The distribution of TCE vapor in the vadose zone was found to be nonmonotonically decreasing from the water table to the atmosphere. To investigate this ICE concentration profile, simulation studies were performed using the Discrete State Compartment model to test various hypotheses concerning the transport mechanisms of TCE vapor in the vadose zone. The studies showed that unless a high permeable column by which diffusing gas could by-pass low permeable layers was included in the simulation molecular diffusion alone could not produce the concentrations measured at the Carranza site. The simulation also showed that a nonmonotonic concentration profile similar to the measured concentration profile could be produced if multiple sources are assumed in the vadose zone. Soil gas advection by barometric pressure fluctuations was shown to increase concentrations at all depths in the vadose zone but the effect was minor compared with the effect of the high permeability column bypass for TCE diffusional transport.