Rivers Flashcards
Define precipitation
Rain or snow that falls onto the ground and sometimes condenses
Define condensation
Water which collects as droplets on a cold surface when humid air is in contact with it.
Define evaporation
The changing of a liquid into a gas.
Define interception
When rain water is intercepted by trees and plants.
Define evapotranspiration
The loss of moisture directly from rivers or lakes or from transpiration.
Define overland flow/ surface run-off
When the water can’t infiltrate into the ground and it flows down hill to the rivers or sea because it is saturated.
Define infiltration
The downward movement of water though tiny spaces in the soil.
Define throughflow
The movement of water sideways underground
Define percolation
The movement of water downwards though soil and rocks.
Define groundwater flow
This is the movement of water sideways through the soil.
Define water table
The level below which the ground is saturated with water.
Define source
The beginning of a stream or river
Define mouth
The end of a river where it empties into large body of water.
Define tributary
A river or stream that flows into another stream, river or lake.
Define confluence
When two rivers or streams meet and flow together.
Define watershed
The term given to the land that drains water into a particular stream or river.
Define attrition
When boulders and other materials are being transported along the bed and collide and break up into smaller pieces.
Define hydraulic action
When the sheer force of the river dislodges particles from the rivers bank and bed.
Define corrasion
When smaller material carried in suspension rubs against the banks of the river.
Define corrosion
When acids in the river dissolve rocks.
What is a v shaped valley?
V-shaped valleys are formed in the upper course where the river channel is narrow and fast flowing. The material is transported downstream by the river. This results in the distinctive v shape.
Define a waterfall
Occurs when a river meets a band of softer, less resistant rock after flowing over relatively hard rock.
Define an interlocking spur
Occurs because of the river taking the path of least resistance and looks like protruding hill sides that limit you from seeing further up or down the river.
What happens in traction? (River transport process)
Large boulders and rocks are rolled along the bed.
What happens in saltation? (River transport process)
Small pebbles and stones are bounced along the river bed.
What happens in suspension? (River transport process)
Fine light materials are carried along in the water.
What happens in solution? (River transport process)
Minerals are dissolved in the water and carried along in solution.
Define a meander
A twist or turn in a river.
What is a ox box lake?
When a meander is cut through due to the continual erosion and the neck of the meander gets smaller.
Define deposition
When the sea loses energy it drops the sand, rock particles and pebbles it has been carrying.
When is deposition likely to occur?
When:
Waves enter an area of shallow water
When there’s little wind
What’s a levee?
An embankment built to prevent the overflow of a river.
What is a floodplain?
An area of low lying ground adjacent to a river, formed mainly of river sediments and subject to flooding.
How is a delta formed?
Formed by deposited material sand and silt that have built up.
What is a drainage basin?
An area of land drained by a main river and it’s tributaries that can store rainwater within the river channel or lakes.
What’s a watershed?
The thing that divides one drainage basin from another.
Define inputs
Where water enters the system through precipitation
Define outputs
Where water is lost from the system to the sea or by evapotranspiration.
Define stores
Places where water is held, (soil lakes etc)
Fill in gaps:
As the ________ of the river increase so does the load it can carry and the rate at which it ________.
Velocity
Erodes
What happens in vertical erosion?
When the river erodes vertically and leads to steep sided, narrow valleys shaped like the letter “V”.
Define storm run off
Rain that falls on streets, parking areas sports fields etc.
What is the drainage density?
The total length of all the streams in the basins divided by the total area of the basin.
What is surface storage?
When water lies on uneven ground, like puddles
What else is the hydrological cycle known as?
The water cycle
What is the upper course of a river like?
It has a larger bed load, more roughness, turbulence and friction.
What is the lower part of a river like?
Has the greatest cross section
Define discharge
Amount of water flowing.
What does erosion involve?
The wearing away of rock and soil found along the river bed and banks.
What are the four main forms of river erosion?
Hydraulic action
Abrasion
Attrition
Solution
What are the four main river transport processes?
Solution
Suspension
Saltation
Traction
What do rivers need to transport material ?
Energy
