 Erosion  process by which wind, water, ice, or gravity transports soil and sediment from one location to another

 Water cycle  continuous movement of water from the ocean to the atmosphere to the land and back to the ocean

 Tributary  stream that flows into a lake or larger stream

 Channel  path that a stream follows

 Divide  boundary between drainage areas that have streams that flow in opposite directions

 Load  materials carried by a stream

 Deposition  process by which material is laid down

 Watershed  area of land that is drained by a water system

 Alluvial fan  fan shaped mass of material deposited by a stream when the slope of the land decreases sharply

 Floodplain  area along a ricer that forms from sediments deposited when the river overflows its banks

 Water table  upper surface of underground water

 Delta  fan-shaped mass of material deposited at the mouth of a stream

 Porosity  percentage of the total volume of a rock or sediment that consists of open spaces

 Aquifer  body of rock or sediment that stores groundwater and allows the flow of groundwater

 Point-source pollution  pollution that comes from a specific site

 Permeability  ability of a rock or sediment to let fluids pass through its open spaces, or pores

 Artesian spring  spring whose water flows from a crack in the cap rock over the aquifer

 Recharge zone  area in which water travels downward to become part of an aquifer

 Sewage treatment plant  facility that cleans waste materials found in water that comes from sewers or drains

 Non point source pollution  pollution that comes from many sources rather than one single, specific site

 Septic tank  tank that separates solid wastes from liquids and that has bacteria that break down the solid waste