HR: 0800h
AN: H21B-1021    [Abstracts]
TI: Groundwater Response To Stream Stage In Coastal Aquifer
AU: * Kim, K
EM: kykim@kigam.re.kr
AF: Korea Institute of Geoscience and Mineral Resources, 30, Gajeong-dong, Yuseong-gu, Daejeon, 305-350 Korea, Republic of
AU: Kim, T
EM: katzura@kigam.re.kr
AF: Korea Institute of Geoscience and Mineral Resources, 30, Gajeong-dong, Yuseong-gu, Daejeon, 305-350 Korea, Republic of
AU: Kim, Y
EM: yjkim@kigam.re.kr
AF: Korea Institute of Geoscience and Mineral Resources, 30, Gajeong-dong, Yuseong-gu, Daejeon, 305-350 Korea, Republic of
AU: Woo, N
EM: ncwoo@ysgeo.yonsei.ac.kr
AF: Yonsei University, 134, Shinchon-dong, Seodaemonn-gu, Seoul, 120-749 Korea, Republic of
AB: A two-dimensional semi-analytical solution is presented to analyze the stream-aquifer interaction in a coastal aquifer where groundwater responds to tidal effect. The conceptual model considered in this study is a two-dimensional subsurface system bounded by stream and coastline in right angle. The stream is semi-infinitely long in longitudinal extent bounded by coastline, and the streambed partially penetrates the aquifer. The dimensional and non-dimensional boundary value problems are solved for groundwater level in the aquifer with a successive use of Laplace and Fourier transform technique, and the results are obtained by the numerical inversion of the transformed solution. The solution derived herein is verified by reducing the solutions to known one-dimensional problems. Hypothetical examples are used to examine the characteristics of groundwater level variations due to the stream-aquifer interactions and the tidal fluctuations. As the distance increases from coastline the tide effect damps gradually and the effect of stream stage variation prevails. On the contrary, as the distance increases from stream the stream boundary effect decreases and the tide effect prevails. The area of influence caused by stream boundary has increased during the simulation, while the influence zone of coastal boundary was relatively constant. The groundwater level near the zone where two boundary conditions meet may rise by the action of combined effect of the two boundaries or may not change by cancelling the effect of each boundary. Thereafter, care must be taken when hydraulic parameters are estimated using sinusoidal oscillations of hydraulic head in coastal aquifers. An evaluation of parametric sensitivity of the solutions is also conducted to show the impact of stream bed leakance, stream penetration ratio to the aquifer, and storage coefficient of aquifer. The leakance value does not influence the amplitude of groundwater fluctuation, however, the effect of stream boundary increases with increasing leakance value. The sensitivity analysis also implies that the impact of stream penetration on groundwater level increases with stream width, and groundwater level variation due to stream and tide boundaries is very sensitive to storage coefficient.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting