Improving Groundwater Recharge by Ventilation of Unsaturated Zone

Groundwater recharge is affected by the entrapment of air in the unsaturated zone. During the infiltration process, air phase moves ahead of the wetting front and confined air mass resists wetting front propagation. This study aims at assessing the feasibility of improving groundwater recharge by providing ventilation in the unsaturated zone through the removal of entrapped air. In a laboratory sand column, ponded infiltration tests were carried out by providing vents of different diameters. Increase in diameter and number of vents improved the infiltration rate. Thus, simple pipes of any diameter inserted within the unsaturated zone beneath the recharge structures such as check dams, percolation ponds, surface spreading, etc. will lead to rapid increase in infiltration rate.