Rivers

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toc Introduction to rivers in a single paragraph. What are Rivers? (do this last)



=Terms about Rivers=


 * Gradient**: The angle at which the river flows downhill. All rivers start in the mountains and move downhill to the ocean, so therefore all rivers are going downhill.
 * Tributaries**: Are smaller rivers than join larger rivers.
 * Bank**: The side of river, on the wall.
 * Flow**: How fast the river is moving.
 * Mouth**: Where the river meets the ocean.
 * Whitewater**: Where the water is moving very fast it creates large waves of white water.

=Different Types of Rivers=

There are many different types of rivers in the world, but geologists classify them by their age:


 * Youthful River:** Not many smaller rivers joining it and it is very deep, with the walls going down sharply. This type of river flows very fast. Over time, it gets deeper and deeper. It has a steep gradient, which means it is going downhill fast. (Ebro River)


 * Mature River:** Has many smaller rivers feeding into it, and it not very steep, more level. It gives a lot of water to the ocean. Over time, it gets wider and wider. It flows much slower than a youthful river. (Mississipi River)


 * Old River:** This river runs very slowly, and is going downhill at a very slow pace. They are usually wide, and are prone to many floods. (Nile River)


 * Rejuvenated River:** When an earthquake happens and the tectonic plate is lifted up, the river starts to change.

=Floods=

Every flood is different, and the causes depend on the natural environment around the river. The main cause of flooding is too much rain, or too snow in the highlands. When the snow melts in spring, it flows down from the mountain and meets with the major rivers. If the snow was very heavy, the water level will rise dramatically in a short period of time. This will cause the water level to break over the river wall. If there is heavy vegetation around the river, the trees tend to drink up the extra water. However, when it is a wide open space, the results can be disastrous.

Flooding can cause millions of people to have to abandon their homes, and it causes millions of dollars in damage. Some countries have begun to do heavy construction projects to stop flooding. They are building large dams so they can control the amount of water that flows in the river. They are also planting forests along the river banks. This also helps the ecosystem stay strong.

Ironically, the floods leave a great amount of minerals in the soul after it leaves, making the land better for farming. That is why so many people have farms along rivers, because the soil is fertile and perfect for growing. It is a risk that humans take, but often many people pay for it with their lives. In 1936, a flood along the Yangze River in China caused the death of between 2,500,000 and 3,500,000 people.



=How Rivers are Formed=

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=Famous Rivers=

The Nile:

Mississipi:

Amazon:

Danube:

=Human Uses of Rivers=

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=Protecting Rivers=

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=Ecosystem=

Networks
A network is a balanced relationship that keeps life together and connected to every other living thing. There are two types of networks; Symbiotic and Trophic.

Symbiotic: A turtle that lives in the mississippi river collects lots of grime and dirt on its shell due to the muddy water. The small shrimp of the water clean the shell to pick out the healthy parts of the mud. The turtle gets a clean shell and avoids infection, and the shrimp get a free meal.

//Trophic//: Also know as food webs. The sun makes the plants and plankton. The plants and plankton are eaten by the shrimps and crawfish, and then the shrimps are eaten by the trout. The trout are then caught by the bears and the energy leave the river and goes into the forest.

Nested Systems
A Nested System is a system that shows how smaller systems are part and made of larger systems, but not connected. The systems that are closer have more impact to affect each other than systems that are farther away. For example, the plants in the river affect the type of fish, which affect the water, which affects the flow of water, which changes the lakes that connect to it.

Cycles
A cycle is an invisible order of events that creates the things nature needs to stay alive. Because Earth is on a tilt, its orbit creates changes in the temperature because of the distance from the sun (more energy hits the Earth in summer, less in winter). For example, in the winter everything freezes on the lake, which causes the fish to go into a dead sleep, and then in spring it happens again. The water itself is also a cycle. It flows down the river to the oceans, where it evaporates and becomes clouds and then rains back down and finds its way into the rivers.



Flows
A Flow is when life energy goes through an ecosystem and may or may not come back. For example, Salmon come from the ocean and move through the rivers to breed. Also, the sun sends rays of energy that flow through all life (producers, consumers, decomposers).

Development
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Dynamic Balance
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=See Also=

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=References=

http://www.bbc.co.uk/schools/gcsebitesize/geography/water_rivers/river_flooding_management_rev1.shtml http://en.wikipedia.org/wiki/List_of_deadliest_floods http://rachadathaicuisines.com/2010/11/06/flooding-in-thailand-has-far-reaching-impact/

=Links=

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