The long profile of a river is a way of displaying the channel slope of a river along its entire course. … As more streams and tributaries join the river, roughness decreases, discharge and velocity increases and the erosive power of bed load will decrease.
What is the difference between a long profile and a cross profile?
The average flow velocity of a river increases along its long profile. This makes sense; along the profile, more potential energy is converted to kinetic energy, increasing the velocity. This is only the average velocity however; a cross-section of a river shows that the velocity varies from one side to the other.
Where does the long profile start?
The long profile starts at the source of the river. Water trickles from saturated land and merges to form a channel. The channel then flows downwards following a steep gradient. The steep channel gives the river more potential energy.
What are the 3 sections in the long profile of a river?
The long profile of the river can be split into three main sections, the upper course, the middle course and the lower course, as the above diagram shows. Upper Course – often flows through a steep sided valley with a narrow channel.
What are the features of a long profile?
The long profile of a river shows changes in the height (altitude) of the course of a river from its source to its mouth. A long profile is usually concave and the slope becomes more gentle towards the mouth of the river. Long profiles usually have irregularities such as waterfalls or lakes.
Which part of the long profile has the deepest channel?
The river channel is at its widest and deepest as it flows towards its mouth. Deposition is the main process in this part of the river, which creates large floodplains and deltas .
How does the long profile change downstream?
Long profiles As a river flows down steep slopes, the water performs vertical erosion . This form of erosion cuts down towards the river bed and carves out steep-sided V-shaped valleys. As the river flows towards the mouth, the gradient of the slope becomes less steep.
Are all valleys V shaped?
They all take the form of a “U” or “V.” Rivers and streams make most primary valley cuts, carving steep-walled sides and a narrow floor that from afar looks like the letter “V.” The gradient of the river—how quickly it drops—helps define the steepness of the sides and the width of the floor.
What does Waterfall mean in geography?
Definition: What is a waterfall? When a river flows over land that is two different levels or heights, the water flows from the highest level onto the lower level before continuing on its course. This is a waterfall.
What is the long and cross profile of a river?
The cross profile of a river shows how the width and depth of the river valley and channel change as you travel downstream. Near the source of a river there is more vertical erosion as the river flows downhill, using its energy to overcome friction (A).
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Where is the steepest gradient in the long profile of a river?
The steepest gradient in the long profile of a river is found in the upper course near to the source.
Why does a river's gradient decrease?
Gradient (the slope of the land) decreases as rivers flow because the river meanders across the land rather than erode into it and follow a straight path as it does in the source. This means it covers a decrease in height over a longer distance the further downstream you get.
What are the causes of river rejuvenation?
A river rejuvenates when there is an increase in gravitational potential energy. It causes the river to erode its bed vertically to achieve equilibrium with the slope of the landscape.
What is meant by river discharge?
‘River discharge’ is the volume of water flowing through a river channel; measured at any given point in cubic metres per second.
What is a mouth in geography?
The place where a river enters a lake, larger river, or the ocean is called its mouth. River mouths are places of much activity. As a river flows, it picks up sediment from the river bed, eroding banks, and debris on the water.
What are the 4 different types of erosion?
Rainfall produces four types of soil erosion: splash erosion, sheet erosion, rill erosion, and gully erosion.
What is geographical traction?
Definition: Traction is a method of transportation for large stones or boulders in a river. The stones are rolled along the river bottom by the water as they are too large to transport in the water.
Why does a river get deeper downstream?
As a river flows downstream, its velocity increases. The speed increases due to the fact that more water is added from tributaries along the course of the river. … The larger mass of water causes wider and deeper water channels in order to allow water in the river to flow more freely.
Why are river profiles concave?
Accordingly, as discharge increases with drainage area and through tributary inputs, and/or as median grain size declines, the slope should decrease, producing a concave- upwards river profile.
How does the discharge of a river change downstream?
Changes Downstream As one moves along a stream in the downstream direction: Discharge increases, as noted above, because water is added to the stream from tributary streams and groundwater. As discharge increases, the width, depth, and average velocity of the stream increase.
Where is a river fastest?
Toward the middle of a river, water tends to flow fastest; toward the margins of the river it tends to flow slowest. 2. In a meandering river, water will tend to flow fastest along the outside bend of a meander, and slowest on the inside bend.
What is the line of fastest flow in a river called?
In hydrological and fluvial landforms, the thalweg is a line drawn to join the lowest points along the entire length of a stream bed or valley in its downward slope, defining its deepest channel.
What is the Bradshaw model GCSE?
The Bradshaw Model is an idealized geographical model which suggests how a river’s characteristics vary between the upper course and lower course of a river. … Therefore, the model is often applied to compare natural rivers against ideal rivers that fit the model perfectly.
Why do waterfalls not run out of water?
It’s because it has a small catchment area. The water comes from wherever the river is fed from. It’s mainly rain but some come from springs in the ground.
What is a plunge pool in geography?
BSL Geography Glossary – Plunge Pool – definition A plunge pool is found at the bottom of a waterfall and is formed by erosion. As water drops over the waterfall then hits the ground beneath, it causes erosion, which forms a pool. This pool is known as a plunge pool.
What is the the start of a river called?
The place where a river begins is called its source. River sources are also called headwaters. Rivers often get their water from many tributaries, or smaller streams, that join together. The tributary that started the farthest distance from the river’s end would be considered the source, or headwaters.
What are river potholes?
Potholes form mainly in the upper course of the river, in high altitude where the river channel cuts directly into the bedrock. Potholes are the direct consequence of vertical erosion and processes of abrasion. … This turbulence forces water down on to the bedrock. Over time small depressions within the bedrock develop.
What is the largest valley in the world?
The largest valley in the world is the rift valley that runs along the Mid-Atlantic Ridge in the Atlantic Ocean. The Mid-Atlantic Ridge is a mountain…
What are potholes and plunge pools?
In Earth science, a pothole is a smooth, bowl-shaped or cylindrical hollow, generally deeper than wide, found carved into the rocky bed of a watercourse. … Although somewhat related to a pothole in origin, a plunge pool (or plunge basin or waterfall lake) is the deep depression in a stream bed at the base of a waterfall.
How do width and depth change along the long profile of a river?
Width and depth increases as more water is added from tributaries. Gradient (the slope of the land) decreases as rivers flow because the river meanders across the land rather than erode into it and follow a straight path as it does in the source.
What is a river profile definition?
river profile The slope of the long profile of a river, expressed as a graph of distance-from-source against height. It is generally concave-up, and this downstream reduction in gradient may be a consequence of the decreasing energy needed to transfer greater discharge and finer load.
