River and Stream Erosion

Complete Starter

Hydrologic Cycle

Water picks up energy as it flows downhill.

Water that does not soak into the ground or evaporate will runoff.

Runoff eventually empties into streams, lakes or oceans.

Water’s trip

Amount of rain that fallsAmount of vegetation on the land

Time span over which it fallsSlope (steepness) of land

What Affects Runoff?

Forms deep and wide channels carrying many sizes of sediment.

Stream Erosion

Classified by their agesAges can be identified by:1. Landforms2. Velocity (speed) of the

water3. Carrying ability (size of the

sediment it can transport)

How are Streams Classified?

Young or Youth Streams/River Fast flow Steep V-shape Large boulders are moved

Flow slower Starting to meander Does not carry boulders, large rocks bounce

on the bottom of streams

Mature Streams

meander

Old Streams Flow slowly through

wide, flat floodplains. Smallest sediments

◦ Suspended load – sediments are in the column of water

◦ Dissolved load – dissolved sediment

Features include: Oxbow lakes, large meanders

A stream that runs into another stream or river is called a tributary.

The running water carries bits of eroded rock called sediment. Larger tributaries carry this sediment until it reaches a main river. The main river carries the sediment to a lake or an ocean and deposits it there.

A river and all of its tributaries is called a river system.

Parts of a River System

The drainage basin, or watershed, of a river includes all the land that drains into the river either directly or through its tributaries. The high land that separates one drainage basin from another is called a divide.

Example: N. American Continental Divide.

Parts of a River System

Velocity The distance that water travels in a given

amount of time. The velocity of the water in a river is related to the amount of energy that the water has.

Factors: steepness of the slope, the amount of water shape of the path.

A fast-moving river erodes more quickly/carry larger particles

Characteristics of River Erosion

Faster erosion & carries more sediment

Characteristics of a RiverGradient Is the steepness of the slope of a stream

or river .. A river’s gradient varies along its course.

Discharge The discharge of a stream or river is the

amount, or volume, of water that passes a certain point in a given amount of time.

In many rivers, discharge increases downstream because tributaries continually add more water.

Characteristics of a River

Channel The path through which the water flows in

a stream or river. The size and shape of a channel affect

the velocity of water.

Characteristics of a River