47. Integration of Surface and Borehole Geophysical Methods in the Characterization of Hydrologic Systems

Geophysical measurements obtained at a variety of scales can be analyzed to understand the structure and physical properties of the shallow subsurface. This information, in turn, can be used to interpret conditions that control movement of groundwater as it interacts with the geological environment. Developing accurate conceptual models of aquifers and their characteristics based upon well-devised field studies is a key goal of U.S. Geological Survey (USGS) hydrologic research.

The USGS owns and maintains a broad collection of geophysical instruments that are available to conduct borehole and surface-based hydrologic investigations. Many of these tools have different volumes of investigation, penetration depths, and response functions that may be dictated by the geologic media. The coherent integration of these data sets can provide information related to depositional processes, in situ stress and deformation, the nature and frequency of fractures, porosity and hydraulic connectivity, lithostratigraphy, and preferential flow pathways. The successful candidate will be given access to a wide variety of geophysical logging tools and surface-geophysical instrumentation from which to examine tool responses and principles of operation in order to advance the interpretation of field data within the context of hydrologic studies.

Groundwater hydrology is one of the main research disciplines of the USGS. Within this category are more specialized scientific topics such as the hydrology of fractured rocks, the hydraulic properties of sedimentary-rock aquifers, and the physics of contaminant flow. The Fellow will have the opportunity to tailor a well-conceived research approach to a specific field site and apply innovative geophysical techniques in a manner that advances our understanding of groundwater systems.

There is considerable room for individual creativity in this Research Opportunity, with the general scientific approach being guided by the particular hydrogeologic environment of the chosen field site. Suggested topics include, but are not limited to, the following areas:

1. Characterizing the hydrology of fractured-rock aquifers through the use of geophysical measurements and the application of rock-mechanics principles to link stress and deformation to groundwater transport through fracture pathways.
2. Characterizing the hydrology of porous media through the integration of geophysical measurements and the application of analogous electric transport models to understand the role of petrophysical properties in controlling groundwater flow.
3. Evaluating the utility of a variety of borehole, cross-hole, and surface geophysical measurements as well as inversion methods in developing two- and three-dimensional models of the shallow subsurface.
4. Developing numerical flow and transport models that incorporate results of geophysical surveys and/or directly incorporate geophysical measurements as inversion/optimization constraints.

Proposed Duty Station: Denver, CO; Storrs, CT

Areas of Ph.D.: Geophysics, hydrology, geology (candidates holding a Ph.D. in other disciplines but with knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet one of the following qualifications: Research Geophysicist, Research Hydrologist, Research Geologist

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Research Advisor(s): Roger Morin, (303) 236-5915, rhmorin@usgs.gov; John Lane, (860) 487-7402, ext.13, jwlane@usgs.gov

Human Resources Office contact: Janet Presley, (303) 236-9573, jpresley@usgs.gov

Summary of Opportunities