January 2000: DNAPL Parameter and Fate and Transport Modeling Florida
Hazlett-Kincaid was contracted by the Florida Department of Environmental Protection (FLDEP) to review the results of a fate and transport model developed by another consultant for an industrial client in Florida. Hazlett-Kincaid Inc. (HKI) was asked to evaluate the possibility that the existing TCE plume configuration could have resulted from a singular source of contamination. Specifically, HKI was tasked with the development of interpolative models of TCE and Cis-1,2-Dichloroethene (DCE) data provided to FLDEP by the company and an independent fate and transport model for the migration of TCE between the industrial site and a nearby river, to the east.
The purpose of the interpolative models was to visually evaluate TCE and DCE plume configurations in terms of probable source locations and develop a clearer picture of the down-gradient plume segmentation. The fate and transport model was developed to provide the means by which alternative scenarios for plume migration from a single source of contamination located on the industrial property could be evaluated in terms of impact to the plume configuration that could lead to the observed down-gradient segmentation.
The scope of work provided for:
1) Development of three EarthVision® parameter models of the most recent data describing the distribution of TCE concentrations, DCE concentrations, and the ratio DCE:TCE between the industrial site and a nearby river.
2) Export and delivery of views from the parameter models as computer image files delivered to the client on CD-ROM and a secure website and the delivery of one encrypted parameter model for stand-alone viewing.
3) Development of a fate and transport model of TCE migration between the industrial property and the nearby river in which three possible scenarios would be tested: time-variability in the TCE source concentration at the industrial property intended to simulate variability in the release of contamination to the groundwater environment; fluctuations in the hydraulic gradient across the site; and variable pumping rates at a well located approximately 500m east of the industrial property.
4) Export and delivery of views from the fate and transport model as computer image files delivered to FLDEP on CD-ROM and a secure website.
5) A written report describing the modeling process, interpretations of the modeling results, and an evaluation of the possibility that the existing TCE and DCE plume configurations could have resulted from a single source of contamination.
In addition to the original scope of work, four additional EarthVision® parameter models were created to address questions brought up by FLDEP during the project period. The additional models addressed the: TCE and DCE concentrations, and the ratio of DCE:TCE for the period between January 1997 and March 1997, and the three-dimensional distribution of hydraulic conductivity throughout a part of the industrial property.
Above - Z-Slice of a model of log DCE concentrations at and down-gradient of the industrial facility.
Below - Y-Slice of a model of the ration DCE:TCE at and down-gradient of the industrial facility used to evaluate the probability of a single source of contamination.
