Groundwater extraction from a geomorphically active river:field calibration of deterministic and stochastic models

• Main Authors: Yu-Chou Chiang, 姜毓洲
• Other Authors: Hervé Capart
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/44898051272398410490

碩士 === 國立臺灣大學 === 土木工程學研究所 === 100 === The thesis explores the potential of groundwater extraction as a method of water derivation from a geomorphologically active river. The case chosen is the Qingho derivation of Laonong River, where large elevation changes have been recorded. Due to Typhoon Morakot, for instance, the river bed rose 20 meters in a single event. For such condition we evaluate different groundwater extraction schemes. To characterize potential river elevation change, we propose a stochastic model calibrated with long term geological data and modern hydrological observations. A deterministic 3D groundwater flow model is constructed to simulate flow through the alluvial fill. The model is based on the method of fundamental solutions and takes the water table as a free boundary. Field calibration and verification is done based on a full-scale drawdown test conducted at a bridge pier near the site. Finally, we apply the tools to evaluate the performance of different groundwater extraction schemes, under changing river conditions.