River Systems

1. River Systems chapter 15 Holt

2. 1. The continuous movement of water from the atmosphere to the land and oceans and back to the atmosphere is called the water cycle. • 2. A region’s water budget is affected by temperature, vegetation, wind, and the amount and duration of rainfall. • 3. The availability of fresh water can be enhanced through conservation efforts. • Water cycle, 375 • Evapotranspiration, 376 • Condensation, 376 • Precipitation, 376 • Desalination, 378

3. 4. A river system is made of a main stream and feeder streams, called tributaries. • 5. A watershed is the area of land that is drained by a river system. • 6. The erosive ability of a river is affected by stream load, stream discharge, and stream gradient. • 7. A bend in a low-gradient stream or river is called a meander. • 8. A river that is composed of multiple channels that divide and rejoin around sediment bars is called a braided stream. • Tributary, 379 • watershed, 379 • stream load, 380 • discharge, 380 • Gradient, 380 • meander, 381 • braided stream, 382

4. 9. Where a stream slows significantly, it can deposit its stream load to form deltas and alluvial fans. • 10. In floodplains, flooding commonly brings in new, rich soil for farming but can cause property damage. • 11. Floods can be controlled through forest and soil conservation and by building structures such as levees and dams. • delta, 383 • Alluvial fan, 383 • Floodplain, 384