Download
1 / 31
310 likes | 317 Views
Learn about the causes and consequences of floods, as well as the various methods used to control and manage them, including storm drains, levees, dams, reservoirs, and floodways.
E N D
Chapter 3Managing Earth’s Changes Flooding
Essential Question: How can floods be controlled?
Lesson 1 Vocabulary • flood • storm drain • floodway • levee • dam • reservoir
Floods – occurs when water flows or collect over land that is usually dry. Floods are caused by: heavy rainfall over many days overflowing rivers severe storms
Savannah River 2013 Flooding
Tuckasee King Landing Clyo, GA July 2013 Flooding
Floods can damage: • crops • destroy buildings & homes • drown people & animals
Steps to a flood: Rain goes in the ground Ground gets very wet Water flows over the ground = runoff
Nature has its own way of controlling floods – Wetlands soak up extra water. There are many laws to protect wetlands. Even with these laws, wetlands are disappearing. Water cannot soak through paved parking lots, roads, and highways.
How do we control flooding? storm drains levees dams and reservoirs floodways
Storm Drain = a system of pipes or channels that carry away storm water
levee = a wall along the banks of a river or other body of water that serves to keep water behind it.
dam = a wall across a river that controls the flow or river water reservoir = an artificial lake, often formed when water collects behind a dam.
full at 330 feet Thurmond Dam Clarks Hill, GA
People control how much water is in the reservoir. Dams & reservoirs help keep an even water flow and water supply all year long.
floodway = a prepared path for flood water to flow over, often to prevent damage to communities
Technology for controlling floods also has disadvantages. Levees do not make flood water disappear. Levees send extra water down the river. It may lessen flooding in some areas but increase flooding in other areas. Levees can fail. Levees can break causing a flood.
Flooding damages ecosystems. Sediment deposited during a flood enrich the soil for plants and animals. Controlling floods hurts plants & animals that depend on floods. • Examples: • The Nile River in Egypt once flooded every year. Its valley was very fertile. After the Aswan Dam opened in 1970, farmers began needing fertilizers to support their crops. • In Brazil, the Amazon River regularly floods the surrounding rainforest. Some plants and animals depend on flooding to complete their life cycles. News dams proposed for the Amazon’s future would cause great changes.
Another example: Everglades – River of Grass • Began as huge wetlands that covered much of Southern Florida. • The Everglades began to be managed for human needs. Levees, canals, and pumping stations were built. They control floods and provides the water supply for Florida’s population. • This has come with a price! • Water is used on farms and in cities. • The rivers carry dirt, fertilizers, and other unwanted chemicals. • Plant & animal populations in the Everglades have dropped. • The size of the Everglades has diminished. • Today, the government is restoring some of Florida’s wetlands. Canals are being filled and levees are being torn down. The goal is to restore its natural ecosystem.
Let’s Review! What is this? floodway
dam & reservoir
