What Is an Aquifer? Not a Lake, Not a River, Not a Cave

Ask anyone to picture an aquifer and they draw a cave or an underground river. That picture is wrong almost everywhere on Earth, and correcting it carefully is where hydrogeology starts. This video covers: water in the pore space, and why porosity alone never makes an aquifer; the aquifer / aquitard / aquiclude / aquifuge family; the unsaturated zone, the capillary fringe and the exact definition of the water table; unconfined versus confined aquifers and the potentiometric surface; artesian and flowing artesian wells; why specific yield and storativity differ by a thousand times, and what that does to the cone of depression; perched and leaky aquifers; and then the four geological families that actually make aquifers — sand and gravel, sandstone, limestone and dolomite, and fractured crystalline and volcanic rock. Ends with transmissivity and how to read a real site. Subtitles in English, Korean, Chinese (Simplified), Spanish, Japanese and Hindi.