ARK's experience in multi-dimensional groundwater and containment modeling has covered the gamut from funded and non-funded research and development of computer programs to site application and expert witness testimony. ARK utilizes well-known, regulatory-accepted computer models for a variety of purposes, the majority of which are included in the following general categories:

• Evaluating, simulating, and predicting the performance of hydrogeologic regimes;
  
• Designing optimal, cost-effective remediation systems; and
  
• Evaluating the health risks associated with alternative remedial options.

In addition, ARK has developed ten programs to perform both analytical and numerical analyses of groundwater flow and multi-component transport problems, including finite element and finite difference analyses.

Though computer modeling is not required for all remediation projects, it can provide a sound technical basis upon which to make significant financial and regulatory decisions. ARKs approach is to use only the modeling effort necessary to provide the appropriate technical support for those decisions. Examples of specific hydrologic and hydrogeologic tasks for which ARK may utilize computer models include those fisted below:

• Calculating the changes in potentiornetric head that result from hydraulic influences such as dewatering, deep well injection, and underground drains.
  
• Simulating the effects of various types of waste disposal facilities and other land uses on groundwater in the region.
  
• Forecasting the effects on strearn flow rates, flooding, sediment transfer, and strearn quality within a drainage basin as caused by a variety of land uses.
  
• Computing chemical migration (including organic chemicals, radionuclides, heavy metals, and nutrients) in groundwater, considering factors such as attenuation caused by soil adsorption, acid neutralization, and biological activity.