2. Rivers and streams A river and stream can be defined as. a natural stream of water that flows through land and empties into a body of water such as an ocean or lake

3. Geography Drain most of the landscapes of the world. River basins are areas of the land that are drained by rivers Rivers eventually flow out to sea or to an internal basin lake Basins are separated from each other by water sheds (the area of land that drains in to a river)

4. Geography continued

5. Structure Rivers and streams can be divided into three dimensions 1) wetted channel: contains water year round 2) active channel: is usually flooded once a year 3) riparian zone: is a transition between the aquatic environment to the terrestrial environment

6. Physical Conditions Light: amount of light penetration is affected by two main factors organic and inorganic material that is washed into or blown in to them from the land and sediment that is suspended in the water Temperature: closely tracks air temperature but does not reach the extremes of terrestrial habitats Water Movements: is dependent on where the river or stream is located at

7. Chemical Conditions Salinity: the amount of salt dissolved in river water reflects the prevailing climate in its basin Oxygen: is inversely correlated with its temperature

8. Biology Both fauna and flora vary greatly Is dependent on the location of the river or stream

9. Human Influences Pollution Diverting Industry