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

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

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

5.  Channel  path that a stream follows

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

7.  Load  materials carried by a stream

8.  Deposition  process by which material is laid down

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

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

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

12.  Water table  upper surface of underground water

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

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

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

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

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

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

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

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

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

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