A finite-element model of artificial recharge with an impedance layer above the water table
Due to the great demand for groundwater storage for irrigation and municipal use, aquifer storage has been exhausted and a practical means of replenishment is needed. The aquifer can be recharged artificially by spreading methods (i.e., by flooding a basin, ditch and furrow; also by natural channel or irrigation). The main objective of artificial recharge is to allow water to infiltrate the soil in the unsaturated zone from a relatively large area, over an extended period of time. The objective of the present study is to analyze the effect of an impedance layer on the growth of the resulting groundwater mound. A Variably Saturated two-dimensional transient flow model (VSAT) was developed to study the flow in the saturated/unsaturated zones of the porous media. The model is based on the Galerkin finite element approximation, and uses triangular elements and linear shape functions. It was formulated using a linking scheme to exchange the recharge and storage information between the unsaturated Groundwater Infiltration Two-dimensional flow model (GWINF2D), and the saturated Groundwater Flow model (GWFLOW). The model solves the modified Richard's equation in a cross-sectional plane (x-z plane) for the change of pressure head and the groundwater flow equation in an areal plane (x-y plane) for the water table elevation. The nonlinearity of the solution was treated by using an iterative numerical scheme. A finer mesh at the impedance layer and underneath the recharge basin was constructed in such a way as to obtain more accurate results. The groundwater mound's growth due to recharge from a basin at the ground surface, and under the influence of an impedance layer, was analyzed. The results showed that the mound's height is affected by the permeability of the layers as well as its location from the basin.
- Research Organization:
- Colorado State Univ., Fort Collins, CO (USA)
- OSTI ID:
- 7152877
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540310* -- Environment
Aquatic-- Basic Studies-- (1990-)
AQUIFERS
COMPUTER CODES
DATA
EXPERIMENTAL DATA
FINITE ELEMENT METHOD
G CODES
GROUND WATER
HYDROGEN COMPOUNDS
HYDROLOGY
IMPEDANCE
INFORMATION
MATHEMATICAL MODELS
NUMERICAL DATA
NUMERICAL SOLUTION
OXYGEN COMPOUNDS
RECHARGE
V CODES
WATER
WATER TABLES