Tian-Chyi Jim Yeh

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Gray system theory uses a black-gray-white color spectrum to describe a complex system whose characteristics are only partially known or known with uncertainty. In this study, we use gray system theory to investigate the relation between precipitation and spring flows in a karst region in China. The gray incidence analysis was applied to the Liulin Springs,(More)
There are approximately 470,000 km(2) of karst aquifers that feed many large springs in North China. Turbulent flow often exists in these karst aquifers, which means that the classical ground water model based on Darcy's law cannot be applied here. Ground water data are rare for these aquifers. As a consequence, it is difficult to quantitatively investigate(More)
Over the past few decades, enormous effort has been expended on conducting traditional aquifer tests and model calibration for characterizing aquifers. Traditional aquifer tests generally involve pumping at one well and using the observed drawdown data at another well to estimate aquifer hydraulic properties. Analysis of the test is built upon Theis' or(More)
[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(More)
In China, 9Ð5% of the landmass is karst terrain and of that 47,000 km 2 is located in semiarid regions. In these regions the karst aquifers feed many large karst springs within basins of thousands of square kilometres. Spring discharges reflect the fluctuation of ground water level and variability of ground water storage in the basins. However, karst(More)
One of the largest karst springs in North China, the Jinci Springs, dried up and has remained dry since 1994. We develop a correlation analysis with time-lag and a regression analysis with time-lag to study the relation between spring flow and precipitation. This allows us to obtain a better understanding of karst hydrological processes by differentiating(More)
While tomographic inversion has been successfully applied to laboratory- and field-scale tests, here we address the new issue of scale that arises when extending the method to a basin. Specifically, we apply the hydraulic tomography (HT) concept to jointly interpret four multiwell aquifer tests in a synthetic basin to illustrate the superiority of this(More)
The representative anisotropic parameters for an aquifer located at the campus of the National Yunlin University of Science and Technology in Taiwan have been acquired. A constant-rate pumping test was carried out, and drawdown-time data were collected from ten observation wells. Applications of the conventional aquifer test analysis, which assumes aquifer(More)
The karst hydrological processes are the response of karst groundwater system to precipitation. This study provided a concept model of karst hydrological processes. The hydraulic response time of spring discharge to precipitation includes the time that precipitation penetrates through the vadose zone, and the subsequent groundwater pressure wave propagates(More)