River Environments 1

3. The speed at which water flows in a river, measured in metres per second (m/s).
4. The area of land drained by a river and its tributaries. All precipitation falling within it eventually flows to the same river or outlet is called drainage . . ..
6. The volume of water passing a given point in the river in a given time, measured in cumecs (m³/s). Calculated as cross-sectional area × velocity.
7. The process by which liquid water is changed into water vapour (gas) by heat energy from the sun.
10. The total length of all streams and rivers in a drainage basin divided by the area of the basin (km of channel per km²). High density suggests impermeable rock or heavy rainfall is called . . . density.
11. A smaller river or stream that flows into a larger (main) river.
12. The point where two rivers or streams meet and join together.
14. The boundary (usually a ridge or area of high ground) that separates one drainage basin from another.
15. A model describing how river characteristics change downstream. Channel width, depth, discharge, velocity and load quantity increase downstream, while load particle size, gradient and channel roughness decrease is called . . . model.

1. A cross-section showing the gradient of a river from its source to its mouth. It is typically concave, steep in the upper course and gentle near the mouth.
2. Water that falls from the atmosphere to the Earth’s surface as rain, snow, sleet, hail or drizzle.
5. The lateral movement of water downslope through the soil, towards a river channel.
8. A body of permeable rock that stores and transmits groundwater (e.g. chalk, sandstone).
9. The process by which water vapour cools and changes into liquid water droplets, forming clouds.
13. The continuous circulation of water between the oceans, atmosphere and land through processes such as evaporation, condensation, precipitation and runoff is called . . . cycle..