Adaptive Fusion of Stochastic Information for Imaging Fractured Vadose Zones (Yeh, Lee, Hsue, et al., 2008, Ni and Yeh, 2008, Hao et al, 2008, Yeh et al., 2008, Yeh and Zhu, 2007) A stochastic information fusion methodology is developed to assimilate electrical resistivity tomography, high-frequency ground penetrating radar, mid-range-frequency radar, pneumatic/gas tracer tomography, and hydraulic/tracer tomography to image fractures, characterize hydrogeophysical properties, and monitor natural processes in the vadose zone. The information technology research will develop: (1) mechanisms and algorithms for fusion of large data volumes; (2) parallel adaptive computational engines supporting parallel adaptive algorithms and multi-physics/multi-model computations; (3) adaptive runtime mechanisms for proactive and reactive runtime adaptation and optimization of geophysical and hydrological models of the subsurface; and (4) technologies and infrastructure for remote (pervasive) and collaborative access to computational capabilities for monitoring subsurface processes through interactive visualization tools. The combination of the stochastic fusion approach and information technology can lead to a new level of capability for both hydrologists and geophysicists enabling them to "see" into the earth at greater depths and resolutions than is possible today. Furthermore, the new computing strategies will make high resolution and large-scale hydrological and geophysical modeling feasible for the private sector, scientists, and engineers who are unable to access supercomputers, i.e., it is an effective paradigm for technology transfer.
Hydraulic tomography (Yeh and Liu, 2000 and Liu, Yeh and Gardner, 2000) is a recently developed method for analyzing aquifers using several pumping and monitoring locations. The concept of hydraulic tomography is similar to that used in any tomographic investigation (ERT or CAT scans, etc.). Hydraulic tomography can be used to discern the anisotropy and heterogeneity inherent in the hydraulic parameters at a site, while 'textbook' pumping test solutions (i.e. Theis or Cooper-Jacob) assume homogeneity implicitly.
Currently my research group is working on transient hydraulic tomography which will use both steady-state and early time drawdown observations to estimate the 3-D distribution of hydraulic conductivity and specific storage throughout the aquifer.
See this poster for an example using hydraulic tomography with data collected at a field site in Italy.