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Mysterious water flows: How does rain trigger four different types of soil erosion?
Soil erosion is the phenomenon in which the soil surface is removed and transported to another location by natural processes such as water flow and wind. This is a global environmental problem, especially in today's era of climate change, large-scale agriculture and booming urbanization, where soil erosion is increasing at an alarming rate. Especially in the rainy season, various forms of erosion begin to occur under the action of rainfall and surface runoff, ranging from minor splash erosion to severe gully erosion, which are specific forms of erosion caused by rain. This article will take a closer look at these different forms of erosion and the impacts behind them.
The relationship between rainwater and soil erosion
Rainfall creates four main types of soil erosion: splash erosion, sheet erosion, gully erosion, and furrow erosion.
First, splash erosion is the first stage in the soil erosion process. When raindrops hit the ground, they create small depressions and eject soil particles, a relatively mild form of erosion. As rainfall intensity increases, when the soil becomes saturated and cannot absorb any more water, surface runoff follows and begins to transport the newly loosened soil particles, a process known as sheet erosion.
Next comes gully erosion, which usually occurs in disturbed high areas when surface water flows often focus in specific small channels, forming gullies that carry soil. The most serious form of erosion is gully erosion, which often occurs rapidly after heavy rainfall, removing soil on a large scale, making the edges of shallow hills steeper.
Rainfall formation and erosion mechanism
In rainfall science, rainfall pattern and changes are a key factor affecting soil erosion. Especially in areas lacking vegetation cover for agricultural activities, high-intensity rainfall will greatly accelerate soil loss. This is because soil not protected by vegetation is most susceptible to erosion.
In addition, the intensity and duration of rainfall also affect the extent of erosion. For example, a sudden downpour will have very different effects on the soil than a long, drizzling shower. Heavy rains can quickly run off flows, causing dramatic soil erosion and long-term impacts on the land.
The role of water flow: river erosion
As rivers continue to flow, there is not only downward vertical erosion, but also upward extension of water flow.
As rivers flow steadily, the mechanisms of erosion are quite complex. This is a process of continuous deepening and widening, especially during flood periods, when the water flow accelerates and carries large amounts of sediment. In addition to the erosion caused by the water itself, these processes also involve friction between suspended particles and gravel, which is called traction.
Impacts of coastal erosion
Next, we look at coastal erosion, which is primarily caused by the action of tidal currents and waves. The strength and direction of waves, as well as changes in sea level, can affect the stability of the shore.
In this environment, scouring, impact and abrasion cause the elevation and shape of rocks or beaches to change continuously, further exacerbating the retreat of the coastline. This has far-reaching impacts on surrounding ecosystems and poses additional challenges in areas of rapid urbanization.
The impact of human activities
Human activities have increased the rate of soil erosion worldwide by 10 to 40 times.
In many areas, human factors such as over-cultivation and deforestation have destroyed the soil's protective layer, resulting in more erosion than would occur naturally. For example, intensive agricultural practices in the Appalachian Mountains have caused soil erosion rates to reach 100 times the natural rate. This not only leads to a decline in agricultural productivity, but also damages the ecosystem and causes problems such as desertification.
Conclusion
Rainfall and related erosion processes affect not only the shape of the land surface and the health of the soil, but also entire ecosystems and human life. In the face of increasingly severe environmental changes, how to evaluate and solve these soil erosion problems is a topic that society really needs to think about together?
