Artificial Ground-Water Recharge with Capillarity

The effect of capillarity on the transient response of the water table to recharge was evaluated by a numerical and a porous media model. The numerical model was developed to simulate the growth and spread of ground-water mounds taking into consideration the flow and storage in the capillary region. The contribution from the capillary region was described analytically in terms of recharge rates and the measureable soil properties of bubbling pressure, pore-size distribution index, and hydraulic conductivity. The numerical model was verified by comparing its predictions for various flow conditions with the result obtained from the porous media model. The effects of bubbling-pressure head, pore-size distribution index, initial saturated depth, depth to water table, and recharge rate on the predicted mound height were determined. It was shown that the effect of the capillary region significantly influences the growth and spread of ground-water mounds.