Tetra Tech houses one of the largest, most experienced pool of expert groundwater modelers in the country. Over 50 modelers, with an average of 12 years of experience, apply their expertise to our clients’ projects. Our staff have performed groundwater modeling services in many complex hydrogeologic situations, including the Department of Energy’s (DOE) Nevada Test Site, Savannah River Site, and Love Canal. We have conducted numerous groundwater modeling projects to help delineate the nature and extent of contamination at hazardous waste sites and analyze the effectiveness of remedial actions. Our modeling results have been accepted by regulators and by judges (when models have been used in trial).
Tetra Tech uses groundwater modeling to support site characterization activities, water resource evaluations, remedial design, mine pit dewatering, geostatistical analysis, and database formulation. We have a proven ability to expedite remediation and closure using modeling tools. For example, Tetra Tech has used modeling, GIS, and regulatory negotiation tools to achieve faster, more efficient site remediation and closure at sites across the country. Some of our innovative modeling approaches include the integration of modeling with GIS databases to focus data collection, development of combined groundwater-surface water models, and the use of optimization techniques for well placement and pumpage. We also assist our clients in taking advantage of emerging regulatory policies and guidance, including the use of risk-based corrective action, negotiation of technical impracticability waivers, evaluating monitored natural attenuation, and the development of Alternate Concentration Limits where appropriate.
Evaluating the performance and cleanup effectiveness of alternative corrective actions at hazardous waste sites is a specialty of our firm. This allows cost-effective testing of remedial alternatives prior to the expense of field implementation, and allows us to deal with such issues as water management, treatment plant size, and the location of injection/extraction wells. Often our analysis of cleanup effectiveness is used to provide industry and regulators with realistic expectations for the performance of remedial activities.
Our expertise in the remedial modeling area is perhaps best demonstrated by our model reviews to assess state-of-the-art remediation technologies.
- The EPA guidance document entitled Soil Vapor Extraction Technology: Evaluation of Models for the Remediation of VOC-Contaminated Soils
- Subsurface Remediation Modeling - A State-of-the-Art Review, for the E.I. duPont de Nemours and Company; this document analyzes the strengths and weaknesses of models to assess the effectiveness of such remedial actions as bioremediation, chemical oxidation/reduction, chemical fixation, in-situ vitrification, pump-and-treat, free-phase NAPL recovery, soil vapor extraction, air sparging, soil flushing, thermal desorption, electro-osmosis, and low permeability barriers
- Review of Commonly Used Subsurface Flow and Transport Models for a confidential client
We have an in-house library of 250 codes, many of which were developed by Tetra Tech, including MODFLOWT, which extends the popular MODFLOW flow model to include contaminant transport, and FTWORK, which was released as a public domain code by DOE in 1989. Both codes have been used at numerous sites. Our modeling staff encompasses more than 50 geologists, hydrogeologists, and engineers and we offer a corporate-level research and development group that specializes in solving modeling and data management challenges.
Using visualization software to create
geologic layering and the plume
delineation of trichloroethylene.
- Aquifer test analyses
- Well drilling oversight
- Water supply development
- Groundwater modeling
- Site characterization
- Contaminant fate and transport modeling
- DNAPL (chlorinated solvents) and LNAPL (petroleum) issues
- Database services
- Groundwater and soil remediation
- Brownfields services
- Litigation support
- Deep-well injection modeling support