| A | B |
|---|
| erosion | the process by which wind, water, ice, or gravity transports soil and sediment from one location to another |
| water cycle | the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean |
| tributary | a stream that flows into a lake or into a larger stream |
| watershed | the area of land that is drained by a water system |
| divide | the boundary between drainage areas that have streams that flow in opposite directions |
| deposition | the process in which material is laid down |
| delta | a fan-shaped mass of material deposited at the mouth of a stream |
| alluvial fan | a fan-shaped mass of material deposited by a stream when the slope of the land decreases sharply |
| floodplain | an area along a river that forms from sediments deposited when the river overflows its banks |
| water table | the upper surface of underground water; the upper boundary of the zone of saturation |
| aquifer | a body of rock or sediment that stores groundwater and allows the flow of groundwater |
| porosity | the percentage of the total volume of a rock or sediment that consists of open spaces |
| permeability | the ability of a rock or sediment to let fluids pass through its open spaces, or pores |
| recharge zone | an area in which water travels downward to become part of an aquifer |
| artesian spring | a spring whose water flows from a crack in the cap rock over the aquifer |
| point-source pollution | pollution that comes from a specific site |
| nonpoint-source pollution | pollution that comes from many sources rather than from a single, specific site |
| sewage treatment plant | a facility that cleans the waste materials found in water that comes from sewers or drains |
| septic tank | a tank that separates solid waste from liquids and that has bacteria that break down the solid waste |
