Streams and Rivers

Streams and Rivers Definitions Tributary: A stream that runs into another stream or river River System: A river and all of its tributaries Watershed: includes all of the land that drains into the river Tributary: A stream that runs into another stream or river River System: A river and all of its tributaries Watershed: includes all of the land that drains into the river

Floodplain: a nearly flat area along a stream or river that is naturally subject to flooding.

Streams and Rivers Continued Oxbow: a bow-shaped bend in a river Oxbow Lake: a bow-shaped lake formed in a former channel of a river. Floodplain: a nearly flat area along a stream or river that is naturally subject to flooding. Oxbow: a bow-shaped bend in a river Oxbow Lake: a bow-shaped lake formed in a former channel of a river.

Deltas Delta: a nearly flat plain of alluvial deposit between diverging branches of the mouth of a river, often triangular Alluvial Deposit: clay, silt or gravel carried by rushing streams and deposited where the stream slows down 

Characteristics of Streams and Rivers Meander: to take a winding or indirect course Velocity: The distance that water travels in a given amount of time. Gradient: The slope of a stream (vertical distance/horizontal distance) Meander: to take a winding or indirect course Velocity: The distance that water travels in a given amount of time. A fast moving river can erode material more quickly and can carry larger particles Gradient: The slope of a stream- the steeper the slope, the faster the river, the more it can carry

Rivers with Many Meanders

Formation of a Cutoff and Oxbow Lake

Characteristics Continued Discharge: the volume of water that passes a certain point in a given amount of time Channel: The path through which the water flows. The size and shape effects the velocity- the more sources of friction the slower the river travels Discharge: the volume of water that passes a certain point in a given amount of time Channel: The path through which the water flows. The size and shape effects the velocity- shallow, winding streams with many boulders has a great deal of friction to slow it down (slowest river scenario)

Diagram

Water Velocity Streams flow fastest in the middle, just below the surface The surface is slower because air provides a little friction The bottom is slower because the ground provides friction The sides are slower because the edge/shore provides friction

From Above From Within X marks the area of highest velocity

ESRT (pg 6)

Most youthful river valleys are V-shaped V-Shaped Valleys Most youthful river valleys are V-shaped V-shaped valleys are found in regions where there is enough rain to erode the sides of the valley

The Yellowstone River Is an Example of a V-Shaped Valley

Visualizations How Sediment is Transported Meanderings

Erosion occurs on the outside of the bends where the water is moving the fastest Deposition occurs on the inside of the bends where the water is moving the slowest

Erosion by Wind When small, loose sediments like sand are available, erosion by wind is possible Arid regions are the most common places for wind erosion to take place

Ventifacts: wedge-shaped rocks formed by wind erosion, often pitted.

Sand dunes are hills of sand deposited by wind Found wherever there are strong winds and loose sand Have long, gentle slope on windward side Have shorter, steep slope on leeward side