Analysis of Soil Erosion: Effects of Gradient and Surface Cover

This assignment solution analyzes the factors influencing soil erosion, focusing on the impact of slope gradient and surface cover. The analysis begins by outlining the different types of erosion, emphasizing the role of splash erosion as the initiator. The solution presents experimental data demonstrating the relationship between slope gradient, surface cover, and sediment transport, highlighting how increased gradients and the absence of cover lead to higher erosion rates. The analysis further explores sediment concentration and soil loss across various slope gradients, comparing surfaces with and without strips and cover. The findings reveal that increased slope gradient correlates with increased sediment concentration and soil loss, while surface cover acts as a mitigating factor. Ultimately, the assignment underscores the importance of both vegetation/cover and slope gradient in determining the extent of erosion, with surface cover inversely proportional to erosion and gradient proportional to erosion.

SOIL EROSION
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Question 1
Erosion is enhanced by the speed of the moving water and by reducing the amount of exposed
surface, there is a reduction in the number of sediments transported downslope. Majorly, erosion
is of four types which are as a result of direct rainfall: sheet, rill, splash and gully erosions.
However, of the four processes, splash erosion is the initiator which is followed by sheet erosion
while rill and gully follow it consecutively. It has been noted that the most severe of the erosion
processes is the splash erosion which is caused by the raindrops falling on the bare surface. The
raindrops have the kinetic energy to dislodge the soil particles from the matrix and therefore
initiate the erosion process. Therefore a reduction in the amount of surface exposed to the rain
results to a decrease in the amount of erosion.
The experiment indicates that erosion for the slopes with gradients of 2%, 4%, 6%, 8% and 10%
is higher on surfaces without cover than on the same surfaces with cover. However, the same is
not true for the surfaces with slopes of 1%, 3%, 5%, 7% and 9%.The discrepancy has been
rectified by the line of best fit.However,comparison may be observed on a bar graph.
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no cover with cover

Question 2
Slope gradient, as well as the amount of cover provided, determine the number of sediments
transported by runoff. Therefore, it can be said that a 0% gradient does not result into any runoff
because the rainwater does not have enough energy to transport the soil downslope. An increase
in gradient is likely to lead to an increase in the amount of erosion and as it has been
demonstrated from the experiment, a 10% cover on the 2% gradient has the most predominant
cover to erosion.
The 2% gradient has prevented soil loss by approximately 46.66 % compared to the other slopes
which have slightly lower effects on the soil loss.
Question 3
According to the data obtained from the experiments, the slopes do have a profound effect on the
soil loss as well as the sediment concentration. However, it is important to note the type of
surfaces used in the experiment. In determining the sediment concentration, there is a
comparison on slopes with the strip and those with no strips. On the other hand, analyzing soil
loss involves surfaces with cover and those with no cover.
Increase in slope has the effect of increasing the sediment concentration on the no strip slopes.
This can be observed from the 3% gradient all the way to the 10% gradient. In this regard, the
10% gradient has the maximum sediment concentration with 30.365g/l. As with the strip slope,
the sediment concentration increases all the way to the 8% gradient but reduces the 9% before
increasing.

As with the no cover surfaces, there is an increase in soil loss with the 8% gradient having the
maximum soil loss with a loss of 918.032g/m2/ hour. As with the surfaces with cover, the
amount of soil loss increases from the 2% gradient with the maximum soil loss observed in the
7% gradient (1765.416 g/m2/hour).Therefore, an increase in gradient results to an increase in the
sediment concentration as well as the soil loss.
Question 4
There are primarily two factors that determine the amount of erosion on any surface: the amount
of vegetation/cover and the gradient of the slope. The gradient is proportional to the erosion
while the surface cover is inversely proportional to the erosion. As it can be observed from the
experiment, surfaces with cover and those with no cover have different rates of soil loss. In this
regard, those with cover have a reduced rate of erosion compared to those with no cover.