GROUNDWATER MODELING

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Earth Data Incorporated scientists have substantial experience in the development and application of analytical and numerical models of complex groundwater flow and contaminant transport. Digital models describing groundwater flow and contaminant migration can be used for practical studies of wellfield design and scale up, including details such as well interference, off-site receptor risk analysis, and wellhead protection studies. The models include groundwater flow, mass balances and chemical reaction mechanisms of varying degrees of complexity. To address conceptual limitation, closed form analytical solutions are used to predict aquifer response in simple hydrogeologic systems whereas whereas well interactions and/or complex chemical mechanisms are generally studied with more robust numerical modeling tools.
Earth Data Incorporated does not believe that computer simulations alone can be used as a deterministic tool to yield absolute answers. Instead, Earth Data Incorporated believes that:
  • Models are tools, they may raise more questions than they answer;
  • Modelers do not prescribe an answer, but work with and for those who know the site best and seek to incorporate their conceptualization of site geology and groundwater interactions into a consistent numerical simulation; and
  • Models and the modeling process should be founded on a firm geologic/hydrogeologic conceptual model and built using regimented and well documented procedures.
Utilizing these principals, Earth Data Incorporated applies the modeling tool to:
  • Optimize solutions;
  • Extrapolate trends (prediction);
  • Demonstrate processes (Natural Attenuation);
  • Illuminate inconsistencies in interpretations;
  • Help to find data gaps; and
  • Visualize complex interactions

MODELING TOOLS

Earth Data Incorporated utilizes and adapts diverse modeling tools as appropriate on a project-specific basis. Existing groundwater flow codes utilized by Earth Data Incorporated include: MODFLOW-2000 which describes steady state as well as transient groundwater flow in a single or multi-layered aquifer system with various possible boundary conditions; FEMWATER, which describes groundwater flow in a manner similar to MODFLOW, but utilizes a finite element approach which is useful in heat transfer or density dependent (such as salt-water intrusion) studies; MT3DMS and RT3D which describe contaminant migration and attenuation within a groundwater flow system with differing degrees of relative transport, adsorption, diffusion, and advection. Earth Data Incorporated utilizes advanced pre-processor tools such as MODELCAD and Groundwater Modeling System (GMS) version 6.0, to organize, analyze, and visualize the modeling data.

In addition to an extensive survey of numerical modeling tools, Earth Data Incorporated also utilizes several different analytical tools such as Aqtesolv and IsoAqx for isotropic analysis of hydrogeologic data. AniAqx is utilized for anisotropic analysis. These tools, in conjunction with extensive experience in their application to hydrogeologic studies in the Coastal Plain as well as fractured rock, gives Earth Data Incorporated subastantial capability in groundwater simulation.

DATA MANAGEMENT TOOLS
Earth Data Incorporated utilizes relational databases as well as Geographic Information Systems (GIS) to store, analyze, and present diverse data types which evolve during our project work. Some of the specific software utilized includes ESRI Software, Manifold GIS, AutoCAD, ChemPoint/ChemStat, as well as SQL server. Leveraging this flexibility, Earth Data can accept most any existing dataset as input and provide diverse output as required by clients and regulators.

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