Geoelectrical Characterization of Mobile/Immobile Exchange: New Technologies for Field Testing and Data Analysis
Abstract
The classical advective-dispersive transport model inadequately describes the migration of contaminants or other chemicals in groundwater in many geologic settings, particularly in heterogeneous aquifers and fractured rock. Alternative models, including the mobile/immobile model, are necessary to explain contaminant rebound at the end of pump-and-treat operations, extremely slow rates of contaminant removal, and other phenomena attributed to back diffusion. In the mobile/immobile model, the geologic medium comprises dual overlapping domains (Figure 1), one in which water and chemicals move through advection and dispersion (the mobile domain), and the other in which water is stagnant and chemicals are stored and slowly released (the immobile domain). Contamination trapped in the immobile domain acts as a long-term source, as it slowly diffuses back into the mobile domain where it is measured or observed in groundwater samples. The mobile/immobile model is widely used and supported in popular computer codes for contaminant transport including the U.S. Geological Surveys MODFLOW 6 (Langevin et al., 2017) and the MT3D family of codes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 27, 2021
- Accession Number
- AD1202940
Entities
People
- Lee D. Slater
- Neil Terry
- Ramona Iery
- Steven Hammett
Organizations
- Naval Facilities Engineering Systems Command
- Rutgers University–Newark