Ground Water Modeling and Fate and Transport Analysis

The movement of water in the subsurface, while well understood conceptually, varies a great deal based upon site conditions. For this reason, several ground water models have been developed that use complex mathematical calculations in an attempt to account for conditions that can affect ground water movement. These models can vary from relatively simple one-dimensional flow to complex flow fields that incorporate numerous features of the subsurface and require extensive calibration and validation.

Ground Water Model Applications

Ground water models may be necessary for numerous purposes including:

  • Determining the direction and velocity of ground water flow.
  • Determining the impacts of changes in ground water withdrawal on the movement of ground water.
  • Evaluation of Well interference due to changes in ground water withdrawals and the proximity of wells.
  • Determining the impacts of changes to ground water recharge, such as increased impervious cover and stormwater systems.
  • Determining the movement of contaminants dissolved in ground water.
  • Determining potential exposure pathways to contaminants migrating with ground water.
  • Determining source(s) of ground water contamination based upon ground water flow direction and velocity.

Contaminant Fate and Transport Modeling

A commonly used extension of ground water modeling is the modeling of the fate and transport of contaminants. Fate and transport modeling addresses the migration of the contaminant in ground water as well as changes in contaminant concentrations due to dilution and degradation of the contaminant. Fate and transport modeling is commonly a regulatory requirement for determining exposure and associated risk. Fate and transport modeling permits an assessment of the likely success of various remedial activities and thereby is useful in optimizing remedial strategies. Fate and transport modeling can also be used to assess potential sources for observed ground water conditions including allocation of responsibility among potentially responsible parties (PRPs).

Fate and transport modeling begins with ground water modeling that requires a sophisticated understanding of the interaction between ground water and the environment through which it is migrating. Additionally, the contaminant fate and transport modeling requires a sophisticated understanding of the interactions between the contaminant and the subsurface that can change the rate at which a contaminant migrates and its ground water concentrations, and contaminant degradation and daughter product generation.

Modeling Services

GeoServices, Ltd. is proficient in the application of numerous ground water models and fate and transport models. GeoServices has successfully applied ground water models and fate and transport models to regulatory issues, such as impacts of ground water withdrawals, well interference studies, site characterization, site remediation, risk assessment, Pennsylvania Land Recycling (Act 2) projects and Brownfields closure, the justification of institutional controls, and justification for the use of engineering controls. Fate and transport modeling has also been successfully applied in litigation to assess responsibility and damages. We have the experience and expertise to accurately help navigate these complex technical issues.


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