Numerical study on tide-driven submarine groundwater discharge and seawater recirculation in heterogeneous aquifers |
| |
| Authors: | Xinya Li Bill X Hu Juxiu Tong |
| |
| Institution: | 1.Pacific Northwest National Laboratory, Hydrology,Richland,USA;2.Department of Ecology,Jinan University,Guangzhou,People’s Republic of China;3.College of Water Resources and Environmental Sciences,China University of Geosciences,Beijing,People’s Republic of China;4.Department of Earth, Ocean and Atmospheric Science,Florida State University,Tallahassee,USA |
| |
| Abstract: | There are many factors affecting submarine groundwater discharge (SGD). However, systematic study of the influences of these factors is still limited. In this study, numerical modeling is performed to quantitatively explore the influences of various factors on SGD in a coastal aquifer. In such locations, tidal and terrestrial hydraulic gradients are the primary forces driving fresh and salt water movement. Unlike steady-state flow, dynamic fresh and salt water mixing at the near-shore seafloor may form an intertidal mixing zone (IMZ) near the surface. By constructing a general SGD model, the effects of various model components such as boundary conditions, model geometry and hydraulic parameters are systematically studied. Several important findings are obtained from the study results: (1) Previous studies have indicated there will be a freshwater discharge tube between the classic transition zone and the IMZ. However, this phenomenon may become unclear with the increase of heterogeneity and anisotropy of the medium’s conductivity field. (2) SGD and IMZ are both more sensitive to the vertical anisotropy ratio of hydraulic conductivity (Kx/Kz) than to the horizontal ratio (Kx/Ky). (3) Heterogeneity of effective porosity significantly affects SGD and IMZ. (4) Increase of the storage coefficient decreases fresh water discharge but increases mixing salt water discharge and total SGD. The increase will also change the shape of the IMZ. (5) Variation of dispersivities does not affect SGD, but significantly changes the distributions of the IMZ and the whole mixing zone. These findings will be helpful to the sampling design of field studies of SGD and to the application of dynamic SGD models to field sites for model development and calibration. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
