Flooding has been an issue that most areas prone to hurricanes experience. Mitigating the impacts of flooding is a challenge in itself; it does not help that erosion is another issue that needs to be addressed along with it.
Flooding is one of the major causes of soil erosion. With its strength and speed, the water sweeps away the top layer of the soil as it flows. However, that is not all. Sometimes water stays in one place and loosens up further soil layers, causing more soil runoff.
To understand what factors impact the extent of erosion and how flood planning can help reduce erosion, continue further in this article.
Before we begin to see how flooding and erosion are related, we must understand how floods occur. The most common cause of flooding is rainfall. This may be heavy rainfall over a short period or normal rainfall over an extended period.
This may make water bodies overflow, causing harm to the ecosystem around them. Storm surges are also a carrier of floods, but these are restricted to areas that experience storms.
On the other hand, erosion is the removal and movement of loose materials on the ground, which may include mud, sand, small vegetation, and debris.
Erosion is only caused by natural forces like the wind and water; without these two, erosion would cease to exist.
Why Does Flooding Cause Erosion?
Understanding the mechanisms of flooding and erosion already gives us an idea of how flooding may contribute to erosion. Floods carry large amounts of water, which also have a strong force.
When floods occur, water takes everything in its way with it, eroding the earth as it flows. It creates rills and gullies in the dirt.
Moreover, since floods are often caused by rainfall that is spread out over long periods, the water stays on the land for longer periods too. This loosens up the earth, causing the mud to lose structure, separate and mix with the water.
This further fuels the cycle of erosion. This makes erosion due to flooding a larger issue than erosion due to strong winds.
Factors That Affect Erosion During A Flood
The extent of erosion that takes place during a flood is dependent on several factors. Some of these include the volume and speed of the water, the duration of the flood, the type of soil, vegetation on the soil, and the region’s topography.
Volume Of Water – The amount of water that floods carry depends on the sources of the flood. If the flood has massive water, the impact would be more detrimental, and the erosion would be worse.
Speed Of Water – The water’s velocity determines the water’s force. The higher the speed, the more force the water will exert on the dirt on the ground, and more erosion will occur.
Duration Of Flood – Floods can go on for a few hours to a few days; depending on this, the erosion rate can vary. Longer floods will cause more erosion as they would erode the top layers of the earth, loosen up more dirt, erode that layer, and the cycle continues. However, shorter floods would only remove the top layer, depending on its force.
Vegetation – All kinds of vegetation aid in strengthening the soil against erosion. If an area has many trees and a flood occurs, the trees are likely to absorb the water, and the erosion rate would be considerably low. However, if vegetation is sparse, erosion rates would be much higher.
Type Of Soil – The soil type varies from region to region; some soils are more vulnerable to erosion than others. Soils with high clay content are the most stable ones and can deter erosion. However, other soils are more susceptible to runoff.
Topography – Erosion is higher in steep areas than on flat lands. This is because the steepness helps increase the speed and force of the water, causing more erosion. However, flat lands reduce the water’s speed and allow less dirt to be runoff.
How Can Flood Planning Impact Erosion?
Flood planning is a great way to reduce any impact caused by floods and related calamities. More state governments in areas that are prone to floods are beginning to adopt this.
Flood planning regarding soil erosion can reduce the impact of floods on soil quality and structure. The flood planning process may include the following:
- Risk Assessment – before any measures are taken to deal with the impact of flood, a thorough assessment of why floods occur, which areas they impact the most, and how badly the soil is eroded needs to be done.
- Response Plan – A response plan needs to be devised. It may not be implemented during active flooding but may be used during the months when flood risk is low.
- Soil Conservation – A massive campaign to conserve soil can be carried out, which includes planting cover crops, using conservation tillage techniques, and maintaining vegetation on slopes.
- Control Measures – Other measures to control erosion include adding erosion control blankets or wattles in more susceptible areas. Moreover, gravel or riprap may be added to stabilize the soil on slopes.
- Land Use Management – Preservation of land and restricting its use can often help the soil recover. For example, if agricultural land is allowed to rest for a few years, the soil may recover and be less prone to erosion. This also includes restricting land use for development and infrastructure and creating buffer zones.
- Community Education – Educating communities is a great way to achieve and retain the effects of any conservation measures. Deforestation is a huge reason for soil erosion; informing people to be wary of vegetation and engrossing them in tree plantation drives can effectively reduce soil erosion.
All natural issues are a byproduct of human activity. However, with the advent of technology and imminent action, most of the dangers to ecosystems can be monitored and controlled, much like erosion caused by flooding.