Table of Contents
How does gradient affect the velocity of the water?
Gradient looks at how far the water drops over the distance the water actually flows. The gradient influences the velocity of the stream. The steeper the gradient, the higher will be the velocity if all other factors are held constant.
Why does the velocity of the river increase downstream when the gradient is decreasing?
Velocity increases as more water is added to rivers via tributary rivers. This means that less of the water is in contact with the bed of the river and the mouth so there is less energy used to overcome friction. Hence rivers flow progressively faster on their journey downstream.
How does the gradient of the river affect its flow?
The flow of the river is dependent upon the position along the stream in terms of the gradient. Near the top of a high gradient, the flow will be less than that near the bottom. Likewise, the steeper the river’s gradient, the faster the flow of water (due to the pull of water down the gradient by gravity).
Why does river velocity increase downstream?
This is because a river tends to become deeper, wider and have a higher discharge the further downstream it moves. As a result relatively less water is in contact with the wetted perimeter, so friction on the river water from the bed and banks of the channel is reduced downstream and it consequently flows faster.
Why does gradient affect velocity?
When a river flows down a steep slope, the gravitational force that pulls the water downward is stronger than it would be on water flowing down a gentle slope, resulting in the river having a greater level of velocity.
Does river velocity increase or decrease downstream?
Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Analysis of some of the large number of velocity measurements made at stream-gaging stations demonstrates that mean velocity generally tends to increase downstream.
Why does a river flow faster in the middle?
Water flowing through a wide, deep river channel encounters less resistance than water flowing in a narrow, shallow channel, since a smaller proportion of the total water molecules will be slowed by the river’s edges. The center of the river experiences the greatest velocity.
Why does the gradient of a river change?
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.
What does gradient of a river mean?
Stream gradient is the grade measured by the ratio of drop in elevation of a stream per unit horizontal distance, usually expressed as meters per kilometer or feet per mile.
Does river velocity decrease downstream?
Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Near the streambed, shear in the vertical profile of velocity (rate of decrease of velocity with depth) tends to decrease downstream.
What affects river 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.
Why does the velocity of a river increase?
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. Additionally, less water is in contact with the river bed, which results in less energy needed overcome friction.
Why does velocity of flow decrease in the downstream direction?
Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Analysis of some of the large number of velocity measure- ments made at stream-gaging stations demonstrates that mean velocity generally tends to increase downstream.
How does a river change its course downstream?
Near the source, a river flows over steep slopes with uneven surfaces. It often flows over a series of waterfalls and rapids. 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.
What happens to the slope of a river as it flows?
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.