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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Characterizing Subsurface Hydraulic Characteristics at Zhuoshui River Alluvial Fan, Taiwan

Wang, Yu-Li Eric, Wang, Yu-Li Eric January 2016 (has links)
The objective of this study is to estimate 2-D spatial distribution of hydraulic conductivity (Ks) of Zhuoshui River alluvial fan, Taiwan, using groundwater level data from 88 wells and stream stage data from 4 gauging stations. In order to accomplish this analysis, wavelet analysis is first carried out to investigate the periodic cycles of groundwater level, precipitation, and stream stage. The results of the analysis show that variations of groundwater level and stream stage are highly correlated in terms of seasonal and annual periods. Subsequently, seasonal variations of groundwater level in response to stream stage variation are utilized to estimate the Ks spatial distribution by spatiotemporal cross correlation analysis, cokriging, and river stage tomography. Prior to applications of these methods to the alluvial fan, performances of each approach are evaluated and compared with reference field of a noise free synthetic experiment. It is found that all of the approaches could yield similar general spatial pattern of Ks. Nevertheless, river stage tomography seems to reveal a higher resolution of spatial Ks distribution. When the geologic zones are provided in river stage tomography analysis as prior information, the accuracy of estimated Ks values improves. Finally, results of the applications to data of the alluvial fan reveal that the apex and southeast of the alluvial fan are regions with relative high Ks and the Ks values gradually decrease toward the shoreline of the fan. These two areas are considered as the possible main recharge regions of the aquifer. It is also observed that Ks at northern alluvial fan is slightly larger than that at southern. These findings seem consistent with the geologic evolution of this alluvial fan.
2

Analýza vzájemného vztahu dvou metod terénního měření infiltrace vody do půdy / Analysis of the mutual relationship between two methods of field measurement of water infiltration into the soil

Larišová, Lucie January 2012 (has links)
This thesis deals with the theoretical description of the infiltration process and field measurements of infiltration in the cadastral territory of Bohaté Málkovice. The research work carried out in 2011 in an experimental area on Haplic Chernozem/FAO, medium-heavy loam soil. The experimental area was divided into two parts, the topsoil layer on these surfaces was processed by both classic and minimization technologies. The plots were sown by spring barley. The applied measurements of water infiltration into the soil were two-cylinder method and MiniDisc. Within the vicinity of the infiltration experiments with intact soil were collected samples for laboratory determination of saturated hydraulic conductivity. From the field measurements and laboratory experiments were determined values of hydraulic conductivity (saturated and unsaturated), and other infiltration characteristics, the cumulative infiltration and infiltration rate. To evaluate the infiltration of the heats was used three-paramether Philp type equation that provides a good estimate of saturated hydraulic conductivity. For the evaluation of the MiniDisc there was used the Zangova method that provides the unsaturated hydraulic conductivity. The laboratory evaluation of the saturated hydraulic conductivity was compared with the estimated values obtained from the field measurements. The values of the saturated hydraulic conductivity from the laboratory measurements are closely comparable with estimates obtained from the steady infiltration rates from the field experiments. The research results also showed that medium-heavy loam soil, when being processed by minimization including modification of the soil surface by digging, have a positive effect on the infiltration of water into the soil. This fact leads to a higher protection plants in the vegetative period and improvement of the retention and storage capacity of soil.

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