Site Assessment, Remediation, and Redevelopment: Projects
Groundwater Modeling, Environmental Data Management/Internet Access System Development, and Groundwater Contaminant Evaluation and Remediation, Eastern North Carolina
Client
Confidential Industrial Client
Description
We provide comprehensive environmental consulting service to a confidential industrial client located above a multiple-aquifer system in the eastern Coastal Plain of North Carolina. In addition to a complex hydrogeologic setting, the site is complicated by multiple waste sources and associated organic and inorganic groundwater contaminant plumes. The evaluation and remediation of these groundwater problems have included performing extensive monitoring and well installation, groundwater sampling and analysis, soil boring and pore-water samplings, soil-gas sampling, and geophysical surveys, and designing and installing groundwater pump-and-treat systems.
Groundwater Modeling. In support of several remedial investigations and corrective actions undertaken at the site, we developed groundwater flow and contaminant fate and transport models. For simulating groundwater flow, we developed 3-D, block-centered, finite-difference numerical models using the U.S. Geological Survey (USGS) code MODFLOW. The MODFLOW pre- and post-processor, Visual MODFLOW, was used to prepare input files and analyze the results. Input parameters and boundary conditions were based on the results of extensive field investigation and testing, including aquifer-analysis slug tests and pumping tests, and hydrogeologic surveys and infiltration tests designed to evaluate seepage flux between aquifers and surface water features. Flow calibration results indicated very good agreement between measured and simulated groundwater elevations.
We included the results of contaminant fate and transport modeling for one of the site's volatile organic contaminant plumes in a Corrective Action Plan and received approval from state regulators to implement a monitored natural attenuation corrective action. A second transport model was prepared for a nitrate contaminant plume, and the proposed monitored natural attenuation corrective action is still under review. For these investigations/corrective actions, we used the transport model code, MT3D96, which is a 3-D, block-centered, finite-difference numerical model developed by S.S. Papadopulos & Associates, Inc. MT3D96 directly uses results from MODFLOW for the flow field. The MT3D96 pre- and post-processor, Visual MODFLOW, was used to prepare input files and analyze the results. We also used Environmental Visualization System 3-D software to animate the modeling results in 3-D, which were later presented.
Environmental Data Management/Internet Access System Development. The complexity and large amount of environmental data being managed for the client required the development of a well-designed, comprehensive, and expandable relational database. The client needed an efficient and easy-to-use system to access its data. Geode, our Internet data querying and mapping tool, allows users to evaluate the data in a spatial or nonspatial context and it is readily expandable, so it can be customized to meet the client's specific needs. Currently, Geode instantly provides data tables and maps to the client via Web-based queries. Automated reporting options and viewing of groundwater contaminant isoconcentration contours, historical technical reports, and project calendars are features under development and scheduled for the next version of the software. In developing Geode, we used a combination of database development, Web programming, and GIS programming. We developed the mapping application using MapObjects and Internet Map Server software and developed the Web application using a combination of Microsoft (MS) Active Server Pages, JavaScript, and HTML programming.
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