Grantee Research Project Results
2000 Progress Report: A Method for Characterizing the Vadose Zone and Monitoring Solute Transport
EPA Grant Number: R827114Title: A Method for Characterizing the Vadose Zone and Monitoring Solute Transport
Investigators: Yeh, Tian-Chyi J. , Warrick, Arthur W.
Institution: University of Arizona
EPA Project Officer: Aja, Hayley
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
Project Amount: $359,955
RFA: Exploratory Research - Physics (1998) RFA Text | Recipients Lists
Research Category: Land and Waste Management , Air , Safer Chemicals
Objective:
The objective of this research project is to develop new techniques for identifying distributions of heterogeneity and contaminants in the subsurface.Progress Summary:
Several tasks were accomplished during the last funding period. First, we have developed a new aquifer test method, hydraulic tomography, for characterizing aquifer heterogeneity. During a hydraulic tomography experiment, water is sequentially pumped from or injected into an aquifer at different vertical portions or intervals of the aquifer. During each pumping or injection, hydraulic head responses of the aquifer at other intervals are monitored, yielding a set of head/discharge (or recharge) data. By sequentially pumping (or injecting) water at one interval and monitoring the steady-state head responses at others, many head/discharge (recharge) data sets are obtained.We have developed a sequential inverse approach to interpret results of hydraulic tomography. The approach uses an iterative geostatistical inverse method to yield the effective hydraulic conductivity of an aquifer, conditioned on each set of head/discharge data. To efficiently include all the head/discharge data sets, a sequential conditioning method is employed. It uses the estimated hydraulic conductivity field and covariances, conditioned on the previous head/discharge data set, as prior information for next estimations using a new set of pumping data.
This inverse approach was first applied to hypothetical, two-dimensional, heterogeneous aquifers to investigate the optimal sampling scheme for the hydraulic tomography (i.e., the design of well spacing, pumping, and monitoring locations). The effects of measurement errors and uncertainties in statistical parameters required by the inverse model were also investigated. Finally, the robustness of this inverse approach was demonstrated through its application to a hypothetical, three-dimensional, heterogeneous aquifer.
Future Activities:
Based on our inverse methodology for hydraulic tomogrpahy, we are developing a new interpretation scheme for the electrical resistivity tomography (ERT) survey. This new scheme will make the ERT a cost-effective tool for measuring a large amount of moisture content of a large volume of geological formations. Such a large amount of moisture information can assist our inverse model for the vadose zone. Thus, we can correctly forecast migration of water and contaminants in the vadose zone.Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 5 publications | 5 publications in selected types | All 5 journal articles |
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Yeh TCJ, Liu SY. Hydraulic tomography: Development of a new aquifer test method. Water Resources Research 2000;36(8):2095-2105. |
R827114 (2000) R827114 (2001) |
Exit Exit |
Supplemental Keywords:
hydraulic tomography, aquifer tests, sequential and geostatistical inversion., Scientific Discipline, Water, Waste, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Physics, Restoration, Ecology and Ecosystems, Aquatic Ecosystem Restoration, Engineering, Chemistry, & Physics, Groundwater remediation, hydraulic properties, sloute transport monitoring, moisture content, solute transport monitoring, remediation, aquatic ecosystems, environmental rehabilitation, pressure distribution, groundwater contamination, electrical resistivity tomography, vadose zone, groundwater pollutionRelevant Websites:
http://www.hwr.arizona.eduProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.