| A | B |
|---|
| saturated zone | a layer of permeable rock or soil in which cracks and pores are totally filled with water |
| permeable | characteristic of materials that allow water to easily pass through |
| water table | the top of the saturated zone, or depth to the groundwater in an aquifer |
| groundwater | freshwater below Earth's surface; water that fills the pores in underground soil and rock layers |
| aquifer | An underground layer of rock or soil that holds wayer |
| porosity | a measure of how much space there is between grains of sand, gravel, etc. |
| impermeable | a charcteristic of materials through which water does not easily pass |
| unsaturated zone | a layer of rock and soil above the water table in which the pores contain air as well as water |
| aquitard | an impermeable earth material |
| watershed | the entire land and water area that drains into a stream, river, lake, or ocean |
| residence time | the amount of time a water molecule stays in a reservoir |
| reservoir | a storage location for water (example: ocean, glacier, atmosphere, etc.) |
| point source | pollution that flows from pipes or comes from specific points (example: sewage treatment plants, industrial plants) |
| non-point source | pollution that does not result from a discharge at a specific, single location, but generally results from land runoff, drainage or seepage, after a rain event (example: fertilizer, pesticides, oils, grease, trash, etc. |
