For small particles (clay and silt) considerably higer velocities are required for erosion than for transportation because these
finer particles have cohesion resulting from electrostatic attractions
. Think of how sticky wet mud is. … The faster the current, the heavier the particle that can be transported.
How does velocity influence deposition and erosion?
To erode particles larger than 0.5 millimetres, the minimum flow velocity rises again. … As the flow velocity increases,
only larger and larger particles will be deposited
. Particles between these two curves (either moving too slow or being too small to be eroded or deposited) will be transported in the stream.
Why Does Clay have a high erosion velocity but is only deposited when the speed of flow is very low?
Anything smaller or larger requires a higher water velocity to be eroded and entrained in the flow. The main reason for this is that small particles, and
especially the tiny grains of clay, have a strong tendency to stick together, and so are difficult to erode from the stream bed
How does velocity affect erosion in a river?
During low flow periods rivers will tend to carry only dissolved and suspended load, and when velocities pick up they will carry bedload as well. Finally, the capacity of a river tends
to increase with distance downstream as volumes
and velocities increase. At 10 cm per second [?] is eroded whilst would be deposited.
Is erosion influenced by velocity or discharge?
Stream Velocity
Depends on the Shape and Size of the Channel
Flowing water is a very important mechanism for both erosion and deposition. … The higher discharge also increases the cross-sectional area of the stream, so it fills up the channel.
What factors control a stream’s velocity?
The velocity of a river is determined by many factors, including the shape of its channel,
the gradient of the slope that the river moves along
, the volume of water that the river carries and the amount of friction caused by rough edges within the riverbed.
When discharge increases the flow velocity will increase?
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. The gradient of the stream, however, will decrease.
What are the factors that affect stream erosion?
Both natural and human- caused factors affect the amount of erosion a stream may experience. Natural factors include the gradient (or steepness) of the streambed since that affects the speed of the flow of water.
Rainfall and snowmelt
affect the amount of water in a stream as well as the speed of the flow.
What is the relationship between water velocity and the rate of erosion?
If the water velocity increases,
the rate of erosion increases
. If the water velocity remains constant, the rate of erosion decreases.
Where do stream channels experience the most erosion?
At a stream’s headwaters, often high in the mountains, gradients are steep. The stream moves fast and does lots of work eroding the stream bed.As a stream moves into lower areas, the gradient is not as steep. Now the stream does more work eroding the
edges of its banks
.
What are the 4 types of river erosion?
- Hydraulic action – This is the sheer power of the water as it smashes against the river banks. …
- Abrasion – When pebbles grind along the river bank and bed in a sand-papering effect.
- Attrition – When rocks that the river is carrying knock against each other.
What type of erosion makes a river wider?
Lateral erosion
makes a river wider. This occurs mostly in the middle and lower stages of a river.
What are the 4 types of erosion?
Rain, rivers, floods, lakes, and the ocean carry away bits of soil and sand and slowly wash away the sediment. Rainfall produces four types of soil erosion:
splash erosion, sheet erosion, rill erosion, and gully erosion
.
Which stream will flow the fastest?
If a stream is flowing along straight, the strongest, fastest flow will be in
the center of the stream well above the bottom of the bed or channel but below the surface
.
What is the minimum water velocity?
MINIMUM YOU CAN CONSIDER
0.75 TO 1.0 M/SEC
( FOR HVAC CONSIDER ONLY 25 % LOAD AT MAIN HEADER VELOCITY SHOULD NOT BE LESS THAN 0.5 M/SEC , FOR WQUIPMENT PIPING YOU CAN MAINTAIN 1 M/SEC AS MINIMUM VELOCITY)
What is the minimum velocity required for particles of 0.1 mm eroded?
On the other hand, a 0.01 mm silt particle only needs a velocity of 0.1 cm/s to remain in suspension, but requires
60 cm/s
to be eroded. In other words, a tiny silt grain requires a greater velocity to be eroded than a grain of sand that is 100 times larger!
