Unit 1- Rivers Flashcards
What and where is a river provided?
The source (upland)
Small river that later joins a larger river
Tributary
Rivers meet?
confluence
What is a tributary?
- Land around river
- Water (rain) flows/ is drained by that river
What is a watershed?
-Highest point of land surrounding river
- all water (gravity and rain) flows towards this river
4 types of fluival erosion
Hydraulic action
Abraision
Attrition
Solution
What is hydraulic action?
Rapid high energy water hits rock and is pushed inside gaps of rock
therefore erodes itt
What is abraision?
- Rocks hit other rocks
What is attrition?
-Rocks scrape along bed
What is solution?
Rocks (limestone) dissolve
x4
Transportation?
-Traction
-Saltation
-Solution
-Suspension
What is traction?
Large rocks roll across floor
What is saltation?
-Rocks bounce against other rocks
What is solution?
-dissolved materials flow with water
What is suspension?
- Small rocks held high in water and flow with water
What and when does depostion happen?
- Sediment discarded by water
- Water low energy / slow
How is a v-shaped valley formed?
- Weathering cuases top corners to erode
- Sediment falls into river
- cuases a v shape to form
How is a waterfall formed?
- Layer of hard rock above soft rock
- Soft rock eroded backwards —> plunge pool
- Hard rock above collapses
forms a backwards pathway
How is a gorge formed?
- Waterfall continuously created
- Backwards pathway
(land retreats/ slowly erroded backwards)
How is an Ox-Bow lake formed?
- Thalweg of water moves around hard rock/ erodes a slight bend
- Cuases slow water to move near hard rock and deposit material —-> slip of slope
- Larger bend made due to hyadralic action and abraision —–> meander
- Hard rock in corners eventually erode—–> straight river
- Water travels stright cutting off curve
- Curve cut of becomes and ox-bow lake
How is an inter-locking spur formed?
-Thalweg of water erodes sofdter rock
-Cuases curves/bends
Why are slip off slopes formed in meanders?
-Water is slower on inside bend
-Less energy
-Water deposites material
-Cuases more friction which furthers deposition
