Erosion Runoff carries loose soil with it causing erosion. Thousands of acres of top soil are lost each year. The fields in Pennsylannia had 2 feet of top soil before people started farming, now some ares have only 7 inches left. Shed The area of land that drains into a specific river system. Topography is the shape of the land formed by high and low places.
Drainage divides Higher elevations of land that outline the edges of the water shed.
The top edge of the ground water. A geological formation that stores water in sufficient quantity to constitute a usable supply for people's uses. Artesian Wells come from a confined aquifer. This is an aquifer that has layers of impermeable material both above and below it and is under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer. A pump is not needed to draw the water up.