Active River

Active River-2.0

by Restie Carullo

​What is a River System?

• ​When water hits the shower floor, the individual drops of water join together to form small streams. The small streams join together to form larger streams.

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The water in your shower is like the water in a river system.

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​A river is a stream that has many tributaries.

A tributary is a stream that flows into a larger stream.

Multiple Choice

A river system is a group of streams and rivers that drain an area of land.

• True

• False

​How do river system works?

​Watershed-is the land that is drained by a river system.

Many tributaries join together to form the rivers in a watershed. Watersheds are separated from each other by an area of higher ground called a divide.

Open Ended

Name three rivers that are tributaries to the Mississippi River.

​What is a stream channel?

​A stream forms as water wears away soil and rock to make a channel.

​A channel is the path that a stream follows. As more soil and rock are washed away the channel gets wider and deeper.

Multiple Choice

Why is the main channel of a river longer and wider than the channels of its tributaries?

• amount of water

• movement of water

• speed of water

​What causes stream erosion?

The amount of water that flows in a stream during a certain amount of time is called discharge. When the discharge of a stream gets bigger, the stream can carry more sediment.

Gradient can be used to measure how steep a stream is.

​stream with high gradient moves very fast compared to those streams with low gradient

Multiple Choice

How does the gradient of a stream affect how much erosion it causes?

• high gradient means more erosion

• low gradient means more erosion

​How does a stream carry sediment?

​Load-material carried in streams water that is affected by the movement of stream

1. ​Bed Load-large rocks that bounce along the bottom of the stream

2. ​Suspended Load-floating materials in the water (cloudy, muddy-look)

3. ​Dissolved Load-tiny sediments that are dissolved

Multiple Choice

A fast-moving steam can carry large rocks.

• True

• False

​How do scientists describe rivers?

PROCESS QUESTIONS:​

1. What are the features of a youthful river?

2. Why do mature rivers carry a lot of water?

3. What caused terraces to form in a rejuvenated river?

4. Very few tributaries flow into an old river. Do you think it will have a large or a small discharge?

​Youthful Rivers

​Youthful rivers are fast-flowing rivers with high gradients. Many of them flow over rapids and waterfalls. Youthful rivers make narrow, deep channels for the water to flow in.

Mature Rivers

​Mature rivers erode rock and soil to make wider channels. Many tributaries flow into a mature river, so mature rivers carry large amounts of water. The curves and bends are called meanders.

​Rejuvenated Rivers

​Rejuvenated rivers form where land has been raised up by plate tectonics. This gives a steep gradient. Therefore rejuvenated rivers flow fast and have deep channels. Step-like gradient called terraces may form along the sides of rejuvenated rivers.

​Old Rivers

​Old rivers have very low gradients. Instead of widening and deepening its channel, an old river deposits soil and rock along its channel. Since very few tributaries flow into an old river, the river does NOT quickly erode land. Old rivers have wide, flat floodplains and many meanders. In the picture, there's the formation of an oxbow lake.

​The End