There are four types of geological formation: Aquifer Aquifer are geological formation which contains water and can yield water. They are porous as well as pervious. They are water bearing strata from which underground water is generally extracted. Aquitard Aquitard are geological formation which contains water but yield is very less as compared to aquifer. They are porous strata but less pervious than aquifer. Aquiclude The geological formation which contains water but doesn’t allow extraction of water is called aquiclude. […]