Measuring infiltration rate and hydraulic conductivity in a dry well in a thin overburden

Infiltration rate and hydraulic conductivity are immensely important parameters for evaluating the hydrology of subsurface environments. Specifically, in disposal wells schemes and in artificial recharge plans both properties must be correctly assessed to better analyze the performance of these installations. In a new research, tanker water and rainfall runoff were injected into a 22.5 m deep well dug in a 15 m thick dry overburden and the underlying impermeable marl bedrock (7.5 m) to evaluate the feasibility of using the well to store winter runoff in the overburden for recovery in the summer. Rates of rise and fall in the hydraulic head were measured, and infiltration rate in various depths were calculated. Also, hydraulic conductivity of the overburden was calculated using particle distribution curves of the overburden samples. Infiltration rate showed close correlation with the hydraulic conductivity. Maximum infiltration rate occurs at depths of 10-11 m; depth of 10 m is the most conductive interval. New findings have come out of this experience including 1. negative correlation between maximum head generated in a specific injection event and the rate of infiltration and 2. the important role of the contact zone between bedrock and the overburden in draining the injected water.