Opportunity at U.S. Environmental Protection Agency (EPA)
Multiscale Groundwater Modeling of Flow and Transport for Safe and Sustainable Waters
National Exposure Research Laboratory, Exposure Methods & Measurement Division (GA)
||Athens, GA 306052720
|Kraemer, Stephen R.
This opportunity involves the development and testing of multiscale (field, watershed, basin, region) computer models based on semi-analytic (e.g., analytic element) and numerical (e.g., finite difference, finite element) techniques for groundwater flow. The solutions seek to characterize the shallow groundwater flow as controlled by areal recharge as the forcing function and subsequent drainage to streams (or other surface water bodies), and deep aquifer flow and characterization of leakage through semi-confining layers. We are interested in the influence of shallow pumping wells and deep injection wells on the water balance and advective flow field. The discharge vector field within heterogeneous porous and fractured media defines the advection-dispersion pathways for solutes. Analyses of subsurface residence times have applications in defining wellhead (source water) protection areas, and in mapping landscape sensitivity and vulnerability to non-point source pollution for EPA total maximum daily load (TMDL) accounting in streams. The water balance and velocity fields may be used by more detailed transport solutions accounting for geochemical retardation and transformation. The role of ground water and headwater stream networks and excess nutrient assimilation is an important ecological service to understand through modeling and observation. Another interest area of the EPA underground injection control (UIC) program is the characterization of the zone of endangerment to drinking water sources from the deep injection of hazardous waste or the injection of supercritical CO2 for geosequestration. Also of interest is the impact of hydraulic fracturing for unconventional natural gas on drinking water resources. We recognize the importance of testing research codes with field observations. We recognizes the importance of uncertainty characterization, whether associated with conceptual/structural uncertainty or parameter uncertainty. The ground water models developed in this project are designed to be available for inclusion in integrated multimedia (air, watershed, stream) modeling frameworks.
Groundwater modeling; Analytic element method; Watershed hydrology; Source water protection; Carbon capture storage-CO2 geologic sequestration; Area of review; Hydraulic fracturing; Water acquisition; Ecological services; Sustainability;
Open to U.S. citizens, permanent residents and non-U.S. citizens
Open to Postdoctoral and Senior applicants