Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/hess-2017-645
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
09 Nov 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Hydrology and Earth System Sciences (HESS).
Analysis of three-dimensional unsaturated-saturated flow induced by localized recharge in unconfined aquifers
Chia-Hao Chang1, Ching-Sheng Huang2, and Hund-Der Yeh1 1Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan
2State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Center for Global Change and Water Cycle, Hohai University, Nanjing, China
Abstract. In the process of groundwater recharge, surface water usually enters an aquifer by passing an overlying unsaturated zone. Up to now, little attention has been given to the effect of unsaturated flow on the hydraulic head within the aquifer due to recharge. This paper develops a mathematical model to depict three-dimensional transient unsaturated-saturated flow in an unconfined aquifer with localized recharge on the ground surface. The model contains Richards’ equation for unsaturated flow, a flow equation for saturated formation, and the Gardner constitutive model describing the behavior of unsaturated soil properties. Both flow equations are coupled through the continuity conditions of the head and flux at the water table. The semi-analytical solution to the coupled flow model is derived by the methods of Laplace transform and Fourier cosine transform. A sensitivity analysis is performed to explore the head response to the change in each of the aquifer parameters. A quantitative tool is presented to assess the recharge efficiency signifying the percentage of the water from the recharge to the aquifer. We found that the effect of unsaturated flow on the saturated hydraulic head is negligible if two criteria associated with the unsaturated soil properties and initial aquifer thickness are satisfied. The head distributions predicted from the present solution match well with those from finite element simulations. The predictions of the present solution also agree well with the observed data from a field experiment at an artificial recharge pond in Fresno County, California.

Citation: Chang, C.-H., Huang, C.-S., and Yeh, H.-D.: Analysis of three-dimensional unsaturated-saturated flow induced by localized recharge in unconfined aquifers, Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2017-645, in review, 2017.
Chia-Hao Chang et al.
Chia-Hao Chang et al.
Chia-Hao Chang et al.

Viewed

Total article views: 215 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
171 40 4 215 0 1

Views and downloads (calculated since 09 Nov 2017)

Cumulative views and downloads (calculated since 09 Nov 2017)

Viewed (geographical distribution)

Total article views: 215 (including HTML, PDF, and XML)

Thereof 209 with geography defined and 6 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 19 Nov 2017
Publications Copernicus
Download
Short summary
Existing analytical solutions associated with groundwater recharge are only applicable to the studies of saturated flow in aquifers. This paper develops an analytical solution for 3D unsaturated-saturated flow due to localized recharge into an unconfined aquifer. The effects of unsaturated flow on the recharge process are analyzed. The present solution agrees well with a finite element solution. Solution's predictions also match well with observed data obtained by a field experiment.
Existing analytical solutions associated with groundwater recharge are only applicable to the...
Share