a river system is made up of a main stream and tributaries – tributary: a stream that flows into a...
DESCRIPTION
A river system is made up of a main stream and tributaries – Tributary: a stream that flows into a lake or into a larger streamTRANSCRIPT
River Systems
Stream Erosion
Target #22- I can label the parts of a river
system on a diagram
draw diagram on board
Target #23- I can define all the parts of a river system
• A river system is made up of a main stream and tributaries–Tributary: a stream that flows into a lake or into a larger stream
Target #23 cont.
• The land from which water runs off into these streams is called a watershed–Watershed: the area of land that is drained by a river system• The ridges or elevated regions that separate watersheds are called divides
Target #23 cont.
• Channel: the relatively narrow depression that a stream follows as it flows downhill
Target #23 cont.
• Banks: the edges of a stream channel that are above water level• Bed: the part of the
stream channel that is below the water level• Mouth: where the
stream enters a larger body of water
Target #24- I can describe how stream load, stream discharge, and velocity affect
the erosion of a stream
• A stream transports soil, loose rock fragments, and dissolved minerals as it flows downhill–Stream Load:
the materials other than the water that are carried by a stream
Target #24 cont.
• Stream discharge: the volume of water moved by a stream in a given time period–The faster a stream flows, the higher its discharge and the greater the load the stream can carry
Target #24 cont.
• A stream’s velocity also affects how the stream cuts down and widens its channel– Swift streams
erode their channels more quickly than slow-moving streams do
Target #25- I can define the term “meander”
• As a river evolves, it may develop curves and bends–A river that is flat,
or nearly flat, has lots of beds & curves•Meander: one of the bends, twists, or curves in a low-gradient stream or river
Target #26- I can draw the process of oxbow lake formation
Target #27- I can explain the process of oxbow lake formation
• 1- When a river rounds a bend, the velocity of the water on the outside of the curve increases–The fast moving
water on the outside of a river bend erodes the outer bank of that bend
Target #27 cont.
• 2- As this process continues, the curve enlarges on one side, while further sediment deposition takes place on the opposite bank
Target #27 cont.
• 3- Meanders can become so curved that they almost form a loop separated by only a narrow neck of land
• 4- When the river cuts across the neck, the meander can become isolated from the river and an oxbow lake forms