What are the different kinds of aquifer?
TOM: One way of classifying an aquifer is by looking at the material that it’s made of. The most common is porous material, porous rock, which is sands and gravels deposited over the years. Another is fractured rock, and this is more hard rocks, the salts, that have become fractured through ages; water flows through them. There’s still another way of classifying aquifers, and that is whether an aquifer is a free surface aquifer—which means that if you were to put in a well, the water would flow up to that point where the water table is in the well—and a confined aquifer, where if you put in a well, the water is essentially under pressure and would be forced upward. If it actually comes to the surface, a confined aquifer is sometimes called an Artesian aquifer. Interviewer: What are the interactions between ground water and surface water? TOM: There’s a two-way interaction between ground water systems, and the aquifer, and the surface water system. First of all, the surface water system
