Section 13.1 Streams and Rivers

Important Definitions! ____________ – a stream and all its tributaries ________ – a smaller stream that empties into a larger stream ______ – a high point that separates river systems _________ – the land area drained by a river system River System Tributary Divide Watershed

Characteristics of Streams and Rivers 3 factors that determine a streams velocity: gradient discharge channel shape

Gradient how steep or flat a river is steeper the gradient, the faster the river will flow

Discharge the amount of water that passes by a certain point in a given amount of time varies depending on the time of year and the weather conditions

Channel Shape path that makes up a river velocity of a river depends on the depth of the channel and how winding it is

Stream Erosion and Deposition Section 13.2 Stream Erosion and Deposition

Stream Erosion and Deposition Velocity and discharge affect how much material a river can transport. When river velocity greatly decreases, sediment drops out of the water to form a delta or alluvial fan. Over time, sediments build up, forming a delta.

Stream Weathering and Erosion Deposition process by which the material is deposited

Erosion Pothole Deep circular basin developed when the river develops small whirlpools

Pothole

Transporting Material Load Downstream Eroded rock and soil By action of the river Suspension Muddy looking Clay, silt, and fine sand Between the water molecules Bed Load Rock transport

Stream Load/Suspension

Stream Competency vs. Capacity Total amount of sediment the stream can carry Competency Maximum size of particle the stream can carry

Stream Deposition Increase velocity more movement Decrease velocity more deposition Everything held by the water will be deposited

Delta Fine sediment River slows down to a body of water

13.3 River Valleys

Headward Expansion Land is worn away at the head of a river/stream

Canyon and V-Shaped Valleys

Progression

Base Level Level to which the stream can go down Set by the body of water the stream enters

Waterfalls Differential erosion Hard top Soft under-strata

Section 13.4 Floodplains and Floods

What is a flood? What is a floodplan? river or stream overflows its banks What is a floodplan? area along a river that is most susceptible to flooding

Flood Prevention Restoring natural plant life in areas along rivers Dams can help to control the amount of water moving downstream Artificial levees such as sandbags can be put into place as a temporary solution Maintain safe floodplains by not allowing people to develop the land in a floodplain