Tributaries

The Amazon is fed by a large number of tributaries.

Most tributaries' waters end up in the middle of the stream.

The Altmühl, Naab and Regen tributaries meet the Danube from the left.

Salmon and steelhead start their lives in freshwater streams and tributaries. They then migrate downstream, rearing and maturing, before they reach the ocean. They live in the ocean for 2 to 5 years, migrating thousands of miles, before beginning the journey upstream to their natal streams where they spawn to produce the next generation of fish.

You are aware—or probably, in this half-educated age, you are not aware—that the country round some parts of the Amazon is still only partially explored, and that a great number of tributaries, some of them entirely uncharted, run into the main river.

More than 250 fish species use the Chesapeake Bay and tributaries for some portion of their life cycles, including American and hickory shad, river herring, striped bass, eel, weakfish, bluefish, flounder, oysters, and blue crabs. More than 300 migratory bird species can also be found in the watershed.

The flood-prone Yangtze river, which runs from Yunnan in the southwest to Jiangsu and Shanghai on the east coast, has seen a massive increase in water volumes, causing flooding in many of its tributaries and bringing water volumes in the giant Three Gorges reservoir close to record levels.

Mounting research blames a confluence of rising sea levels driven by global warming and the damming and dredging of key rivers and their tributaries for the rapid sinking and shrinking of Asia's seven major delta systems, from the Indus in Pakistan to the Pearl in China.

Name the Danube's largest tributaries.

The Potomac River was a meeting place for Native Americans long before European exploration. The Indians traded goods and occasionally warred with rival tribes along its tributaries. The watershed is littered with arrowheads and spear points and discarded oyster shells from these early peoples.