Rivers and Bridges. Earth processes. All of the earth's rivers contain only about 0.0001% of the earth's water .
That doesn't sound like very much, but rivers can do some amazing things. The water in rivers comes from many different sources. Rivers can begin in lakes or as springs that bubble up from underground. Other rivers start as rain or melting snow and ice high up in the mountains. Geography Essentials - Investigating rivers. Other small streams and rivers, called tributaries, flow into the river and it increases in size as it travels along.
The river eventually slows down, curving around to make large bends called meanders. The river ends its journey when it flows into the sea, or a large lake. Some rivers are frozen for part of their journey. These are called glaciers. Cities, towns and villages have grown up on or near rivers because people use the water for many purposes. Investigating rivers websites.