I. Geoterms • A. Hydroelectric potential: the electrical power that can be generated from flowing water • B. Perennial irrigation: a system that allows for the year-round watering of crops • C. River basin: the area drained by a river and its tributaries. These tributaries are the smaller streams that flow into the main river. Rain falling anywhere in a river basin will eventually flow into the main river.
D. Water cycle: the movement of water from the surface of Earth to the atmosphere and back again. During this cycle, water evaporates from rivers, lakes, and oceans, rises and condenses into clouds, and then falls back to Earth as rain, hail, sleet, or snow. This process is also known as the hydrologic cycle.
II. The Geographic Setting • A. The World’s Longest River • 1. Nile River has two branches • A. White Nile (longest = 4,160 miles) • B. Blue Nile • C. Source is the highlands of Burundi
2. Nile River rises and falls with the seasons B. The Gifts of Water, Transportation, and Power 1. Nile provides water for washing, cooking, drinking, and crops 2. Seasonal flooding leaves deposits of rich silt on river banks 3. Nile is useful for transportation and energy (hydroelectric plants)
III. The Beginnings of the Nile • A. From Rainwater to Rivers: The Water Cycle • 1. Evaporation • 2. Water vapor • 3. Condensation • 4. Precipitation • 5. Infiltration • 6. Runoff
B. Lake Tana: source (headwaters) of the Blue Nile • 1. As water flows rapidly out of the lake, it picks up lots of soil that is later deposited on farmlands downstream • 2. Source of the Blue Nile discovered in the 1600s C. Lake Victoria: Source of the White Nile 1. Discovered by England in 1850s. 2. From its source, it flows rapidly through two more lakes and over a large waterfall before slowing down on the plains of Sudan
IV. Two Niles Meet: Confluence and Cataracts • A. The White and Blue Niles Meet at Khartoum • 1. Confluence is the coming together of the two Nile Rivers • 2. The Blue Nile grows more due to the seasonal rains, causing flooding downstream B. Rough Waters Slow River Travel 1. The Nile has six cataracts (rapids) 2. The cataracts slows trade and travel on the river.
V. Through the Desert: Wadis and Dams • A. An Arid Landscape 1. The Nile travels through Sahara Desert and Nubian Desert 2. Wadis are dry riverbeds that can experience flash floods if there is rain B. Controlling the Nile: The Aswan High Dam 1. Lake Nasser is a reservoir built in 1970 a. One purpose was hydroelectric power b. Second purpose was to control the flow of the Nile (avoid flood destruction, provides even flow year round, makes travel easier)
2. Negative effects • A. The dam traps the silt from flowing downstream • B. Egyptian farmers now have to use artificial fertilizers.
VI. Across Egypt: Floodplains and Delta • A. A Narrow Strip of Farmland Lines the River • 1. The floodplains (land between the river and the low cliffs on either side of the river) is prime farmland • 2. Rather than taking water from the Nile, water is coming from Lake Nasser which allows farmers to irrigate more land.
B. Water for Rapidly Growing Cairo • 1. Cairo (10 million people) is consuming more water • 2. Cairo is discharging sewage and industrial waste into the river causing pollution and putting a strain on the water supply C. The River’s Final Gift: The Nile Delta 1. The delta is about 155 miles wide as it flows into the Mediterranean Sea. 2. The delta is very fertile and excellent for farming
VII. Beginning to Think Globally • A. Nile is the longest river in the world • B. Amazon River in South America is the second longest river, having its source in the Andes • C. Yangtze River in Asia has its source in the Tibetan Plateau = #3 largest river • D. Ohio-Mississippi-Missouri River system in North America has its source in the Rocky Mountains and Appalachian Mountains • E. All rivers change as they flow across the surface of Earth (some natural, some man-made)
VIII. Global Connections • A. What are the main benefits of building hydroelectric dams? • B. What are the main costs of building hydroelectric dams? • C. Do the benefits of damming rivers outweigh the costs?