Rivers are nature's supply of fresh water. Most originate at the top of mountains and flow down to join oceans and lakes. Rivers begin their journeys as streams and springs. Some become large rivers flowing between river banks; the large ones are called rivers, the smaller ones creeks, brooks or rivulets. Rivers form part of what is termed a hydrological cycle. The water in a river is generally collected from surface runoff, springs, groundwater recharge, ice and snow packs.
Amazon River, South America
The Amazon River has been called the greatest in the world. Where the river opens at its estuary, it is an amazing 325 km wide. In the dry season, its widest point is about 11 km wide. It carries the largest volume of freshwater, about 20 percent of the total discharge into oceans. It is one of the longest rivers in the world, measuring about 6,500 km. In dry seasons the Amazon covers an area of 11,000 square km of land; in wet seasons it covers roughly 35,000 square km of land. The mouth of the Amazon at the point where it meets the sea is so large that ocean-going ships have actually navigated its waters to travel inland.
Congo River (Zaire River), Africa
The Congo River's width varies from about 0.5 miles to 10 miles at different points along its course. The river forms the major part of the border between the Republic of Congo and Zaire. The Congo River is divided into three sections: the upper Congo, the middle Congo and the lower Congo. The Congo River is the second-largest river in the world in terms of volume discharged, after the Amazon River. Its deepest point is about 750 feet, and it is 4,700 km long.
Yangtze River, China
The Yangtze River's width varies at different points along its course, from 30 meters at its narrowest point to 650 meters at its widest point. In some places the width ranges from 200 to 300 meters, in other 300 to 500 meters, and still others 500 to 650 meters. The Yangtze River is China's largest river, and it is considered the third-largest river in the world. The river runs a more-than 6,000-km long course. It plays an important role in the country's agricultural and mineral industries. The river is also a major water transport artery for China and has more than 700 tributaries.
Volga River, Russia
The Volga River is the longest river in Europe. It forms Western Russia's principal waterway. Rising in the Valdai Hills, it flows through more than 3,500 km to empty into the Caspian Sea. The width of the Volga River varies at different points along the route; at times it is 65 km wide, at other points its branches stretch from 520 to 3,500 yards. The river is important to the Russian people and is fondly referred to as Mother Volga.