A view toward the future of subsurface characterization: CAT scanning groundwater basins

Abstract

[1] In this opinion paper we contend that high-resolution characterization, monitoring, and prediction are the key elements to advancing and reducing uncertainty in our understanding and prediction of subsurface processes at basin scales. First, we advocate that recently developed tomographic surveying is an effective and high-resolution approach for characterizing the field-scale subsurface. Fusion of different types of tomographic surveys further enhances the characterization. A basin is an appropriate scale for many water resources management purposes. We thereby propose the expansion of the tomographic surveying and data fusion concept to basin-scale characterization. In order to facilitate basin-scale tomographic surveys, different types of passive, basin-scale, CAT scan technologies are suggested that exploit recurrent natural stimuli (e.g., lightning, earthquakes, storm events, barometric variations, river-stage variations, etc.) as sources of excitations, along with implementation of sensor networks that provide long-term and spatially distributed monitoring of excitation as well as response signals on the land surface and in the subsurface. This vision for basin-scale subsurface characterization faces many significant technological challenges and requires interdisciplinary collaborations (e.g., surface and subsurface hydrology, geophysics, geology, geochemistry, information and sensor technology, applied mathematics, atmospheric science, etc.). We nevertheless contend that this should be a future direction for subsurface science research.

Inherent Limitations of Hydraulic Tomography

“…This approach goes by the name of data fusion or data integration. A considerable amount of current research is aimed at integrating hydraulic, geophysical, geological, chemical, and other sources of information for aquifer characterization (Vasco et al 2001; Vasco and Finsterle 2004; Rubin and Hubbard 2005; Hyndman et al 2007; Yeh et al 2008; Vasco et al 2010). This is also an active area of research in the context of petroleum reservoir characterization (Caers 2005; Coburn et al 2006).…”

“…In the context of this study, hydraulic tomography refers to the simultaneous analysis of head responses, measured at a number of locations, produced by a sequence of hydraulic tests stressing different portions of an aquifer (see Butler [2005] for an overview of hydraulic tomography in the context of other hydraulic testing methods). Recently, Yeh et al (2008) advocated extending the concept to analyze head responses to natural stimuli, thus continuing a long tradition among groundwater hydrologists of exploiting natural stimuli for aquifer characterization. Given the large number of papers that have been published on hydraulic tomography in the last decade, we feel compelled to add a cautionary note to the discussion.…”

Dealing with Landscape Heterogeneity in Watershed Hydrology: A Review of Recent Progress toward New Hydrological Theory

“…To estimate the parameters of such random fields, pumping tests are very useful. In quasi‐steady‐state analyses of well responses at constant discharge, for example, Monte Carlo simulations are combined with geostatistical inversion to yield detailed ‘tomographic’ estimates of how the parameters vary in space (Yeh et al. 2008).…”

Robotic Perception Amalgamated with Autonomic Computing for Ground Water Level Detection

“…In the similar fashion, ground water level detection is also one of the vital problems in the environmental science [7], [12]. Here, a robot working on the proposed model and performing automated learning serves the same purpose as the NASA curiosity robot.…”