| A | B |
|---|
| tributaries | streams that join larger streams |
| river system | the main river and all its tributaries |
| drainage basin | the land area from which a river system gets its water |
| erodes | wears away rock and soil |
| sediment | rock and soil carried by water |
| headwaters | the beginning of a river |
| moraine | a ridge formed when a glacier deposits its sediments |
| floodplain | a low-lying area formed when a stream overflows |
| groundwater | water in the ground near Earth's surface |
| aquifer | a layer of rock in which groundwater can accumulate and flow freely |
| water table | the top of an aquifer |
| geyser | a fountain of hot water and steam that erupts when groundwater lies close to hot volcanic rock or magma, and gets heated too much |
| glacier | a large mass of moving ice |
| meanders | looping bends formed by a river that erode the sides of the valley and make it wider |
