Wind Erosion Soil Transport Relationship
The amount of soil transported by wind erosion depends on the wind's ability to move particles and the characteristics of the particles themselves.
Based on established principles (simplified and represented by the options), the soil transport rate is primarily influenced by the excess wind energy available to move particles beyond the minimum required (threshold velocity). It is also affected by particle size.
Key Factors in Wind Transport
The relationship described in the correct option highlights two main factors:
- Wind Velocity Difference: The difference between the actual wind velocity ($V_{actual}$) and the threshold wind velocity ($V_{threshold}$) is crucial. The transport rate increases significantly as this difference grows. Specifically, it's proportional to the cube of this difference: $(V_{actual} - V_{threshold})^3$.
- Particle Diameter: The mean soil particle diameter ($d_{mean}$) also plays a role. Smaller particles are generally easier to transport. The relationship specified is proportional to the square root of the mean particle diameter: $\sqrt{d_{mean}}$.
Combining these, the amount of soil transported ($Q$) can be expressed proportionally as:
$Q \propto (V_{actual} - V_{threshold})^3 \times \sqrt{d_{mean}}$
This formula indicates that higher wind velocities exceeding the threshold significantly increase soil transport, and the influence of particle size follows a square root relationship.
Important Questions from Wind Erosion
- A $16 \text{ m}$ high wind break is constructed to protect soil from wind erosion due to wind velocity of $18$ $\text{m s}^{-1}$ at $15 \text{ m}$ height. The minimum wind velocity at $15 \text{ m}$ height capable of moving the soil fraction is $8 \text{ m s}^{-1}$. The angle of deviation of prevailing wind direction from the perpendicular to the wind break is $30^\circ$. The distance of full protection from the wind break in $\text{m}$ is
In wind erosion, the maximum portion of soil is transported by the process of ____________.
A windbreak, 15 m in height and 200 m in length, is established to protect the land from wind erosion in an arid area. The minimum wind velocity at the height of 15 m above the ground required to move the most erodible soil fraction is $9.6\ m\cdot s^{-1}$. If 5-year return period wind velocity at 15 m height is $16\ m\cdot s^{-1}$ and the wind direction deviates $20^\circ$ from the line perpendicular to the windbreak, the area protected by the windbreak in ha is ________________.
[round off to 2 decimal places]- In wind erosion process, the rate of soil movement (S) depends on wind speed (v), threshold limit of wind speed required to move the soil ($v_m$) and average soil particle size (d). This interrelationship is expressed as
- To protect a wheat field from wind erosion, windbreaks of $2.7$ m height are provided. The actual wind velocity at $15$ m height perpendicular to the wind barrier is $9$ m.s$^{-1}$ and the minimum wind velocity at $15$ m height required to move the most erodible soil fraction is $9.6$ m.s$^{-1}$. The distance of full protection from this windbreak is __________ m. (Rounded off to 2 decimal places)
