An aquifer system, showing both unconfined and confined aquifers. The unconfined aquifer lies just below the water table, receiving water directly from precipitation or surface water like rivers and lakes. Beneath a layer of impermeable clay, the confined aquifer is trapped under pressure, and water in it can rise through an artesian well without pumping. The diagram also shows how surface features like rivers and lakes are interconnected with groundwater systems, highlighting how water moves through porous layers above bedrock in a continuous underground cycle.