Craig Swanson, age 12, of Middletown, Ohio, for his question:
WHICH RIVER IS THE WORLD'S LONGEST?
Africa's Nile River is the longest river in the world. It starts in the northeastern part of Africa and flows from south to north for a distance of 4,157 miles. It travels mainly through the Sudan and Egypt.
Without a doubt, the Nile is one of the most important and most famous waterways in the world. Along its shores some of man's earliest civilizations started. The fertile Nile Valley provided all of the abundance that man needed to have a good life.
There are actually two main streams and sources of the Nile River. The White Nile obtains its waters from the plateau sections of Uganda, Kenya, Tanzania and Zaire.
The Blue Nile is the second source. It receives its waters from the mountains of Ethiopia.
A Scottish explorer named James Bruce found the source of the Blue Nile in the hills southwest of Lake Tana in Ethiopia in 1770. He followed the Blue Nile to the spot where it joins the White Nile at Khartoum in Sudan.
It wasn't until almost 100 years later, in 1856, that a British explorer named John Spoke found that the source of the White Nile was at Lake Victoria in Uganda.
The main arms of the White Nile are the Bahr el Jebel, the Bahr al Ghazal and the Sobat River. Near the junction of the Bahr al Jabal and Bahr al Ghazal is the As Sudd Region. This is an expansive, swampy section where the river channels are choked with floating plant life.
Much of the water that is in the Bahr al Jabal comes from Lake Mobuto Ses Seko, which was formerly known as Lake Albert, and Victoria. Both lakes act as great reservoirs.
The White Nile does not affect the annual rise of the Nile River since it has an even flow throughout the year. During April and May, when the water in the lower Nile is low, most of the water comes from the White Nile.
During the season of high water on the Nile River, most of the water comes from the Blue Nile. The flood crest on the Nile River is caused by the heavy rains and melting snows in the Ethiopian Mountains.
Many dams and canals have been built along the Nile to make year round irrigation possible, and also to keep floods under control.
The Aswan Dam is just above the First Cataract and four miles to the south is the larger and newer Aswan High Dam.
The Nile River offers a very important way to travel and transport goods is Egypt and Sudan. However, a series of six cataracts in southern Egypt and Sudan, and at the As Sudd Region in southern Sudan, prevent boats from going the full length of the river.
The Nile can be traveled without problems between the Mediterranean Sea and the Aswan Dam.
The Nile Delta starts at Cairo, where the river divides into two main channels. The water finally enters the Mediterranean Sea at Rosette and Damietta, two cities that are almost 100 miles apart.