Learning how does precipitation affect the rate of erosion is quite interesting and vital to get an idea about how the surface of the earth changes over time.
Erosion is a naturally occurring process carried on by removing and transporting rock, soil and many other materials.
When these materials move and change places, it changes the surface of the earth.
Many factors are at work here but precipitation has a major role to play, be it in the form of hail, snow, or sleet.
Nonetheless, it is vital to know the answer to, “How does precipitation influence the rate of erosion?”
Precipitation triggers erosion by making water move quickly, moving dirt around and causing landslides, all of which shape the earth’s surface.
How Does Precipitation Affect the Rate of Erosion?
Precipitation can have an impact on the rate of erosion in many different ways, including:
- Water-Based Erosion
- Glacial Erosion
- Mass Wasting
Water-Based Erosion
When talking about erosion, you just cannot ignore the role of water-based erosion.
Here are the different factors at play here:
Rainfall Induced Surface Erosion
When it rains, the drops can really mess with the ground and cause erosion.
When rain hits the ground, it moves dirt around with the water.
The thing is that when it rains hard and long, and the ground is steep and the soil is not great, erosion happens faster on the surface.
Sheet Erosion
So, basically, when it rains a lot, the water can create a thin layer on the ground and flow around. That is what we call sheet erosion.
This flow can totally break off and move dirt around on top, which can end up taking away the upper layer of soil.
When water flows it can make rills and gullies, which makes it even better at eroding stuff.
It is worth mentioning that sheet erosion happens a lot on slopes because the water moves faster and can break off dirt particles easier.
If sheet erosion keeps happening, it can mess up the soil, making it less fertile and causing land to degrade.
An Important Consideration
If you want to stop and fix sheet erosion, you have to take good care of your land.
Keep those plants growing, do not mess with the soil too much, and use soil conservation methods. Easy peasy, right?
River Erosion
Precipitation is a vital source of water for rivers and streams, which helps to shape their banks and beds through natural erosion processes.
Water flowing downstream has the power to shape the surrounding land through natural processes such as:
- Abrasion
- Hydraulic action
- Solution
Similarly, the rate of river erosion can be positively impacted by factors such as:
- Increased precipitation levels
- Higher stream velocity
- A larger and more diverse sediment load
With heavy rainfall, rivers have the potential to increase in velocity and cause erosion and sediment transport.
Fact: Reduced erosion rates and increased sediment deposition can occur during drought conditions due to reduced river discharge.
Precipitation and Glacial Erosion
When snow falls on mountain tops, it creates a beautiful and serene landscape.
As time passes, the snow compacts and forms a solid foundation, creating a winter wonderland for all to enjoy.
As the snow accumulates, it’s amazing to see how the lower layers transform into beautiful, dense, crystalline ice under the weight of the snow and ice.
This process is excitingly known as firnification!
With each snowfall and ice accumulation, we are one step closer to the formation of solid glacial ice.
The weight and movement of the glacier have a significant impact on shaping the landscape and creating unique features such as U-shaped valleys and moraines.
But, it is certainly an example of how precipitation in the form of snow plays a role in the formation of glaciers and erosion.
To understand it better, you must learn about the different processes involved in transporting bedrock.
For instance:
Glacial Plucking
When a glacier engulfs and carries away massive chunks of rock, this is known as glacial plucking.
Meltwater from precipitation helps fuel this process by seeping into crevices and fissures in the rock.
In the process of refreezing and expanding, water can exert a great deal of pressure, cracking and fracturing glacial ice and ripping out portions of the underlying bedrock.
It is possible for the glacier to pick up these chunks of bedrock from its initial site and carry them downstream as it advances downhill.
Cirques and tarns are two of the characteristic structures left behind after glacial plucking has eroded the landscape significantly.
Fact: Water from precipitation is essential for glacial plucking, which in turn helps shape the landscape over time as glaciers advance and retreat.
Abrasion
Glacial abrasion happens when boulders and debris at the glacier’s base scratch and grind the underlying bedrock as the glacier moves downwards.
Intense pressure from the glacier and the debris it brings causes the underlying rock to crack and crumble.
Many factors play a role in the degree of abrasion, including:
- Glacial velocity
- Ice thickness
- The quantity of debris embedded in the glacier
Similarly, rainfall is essential because it increases the glacier’s total mass and causes the formation of meltwater, speeding up the glacier’s movement and boosting its erosional force.
Fact: Glaciers have the power to sculpt the environment by grinding against the underlying bedrock, generating valleys and unique formations like roche moutonnée and glacial grooves.
Mass Wasting and Erosion
The process of soil, rock, and debris sliding downslope under the effect of gravity is called mass wasting.
On the other hand, the material is worn away and shifted about by forces of nature such as water, wind, ice, and gravity; this process is known as erosion.
Both actions dump sediment and reshape landscapes.
Soil Saturation
Precipitation can raise the soil’s water content and lower its internal friction, both of which weaken the soil.
On saturated soil, you are more likely to witness events like:
- Mudslides
- Landslides
- Debris
This happens because of the extra weight and loss of cohesiveness, making the soil more likely to move and slide downhill.
Even a slight increase in soil saturation in unstable locations or on steep slopes can cause devastating landslides.
Furthermore, the increased water content might encourage the growth of vegetation and contribute to the breakdown of organic materials in the soil.
Pore Water Pressure
When rainwater seeps into the ground, it has the potential to fill the voids between soil particles, raising the water pressure there.
If the pore water pressure in the soil gets too high, the soil particles may separate from one another, weakening the soil and making it more vulnerable to mass wasting.
Slope failures like landslides and mudslides can occur when soil particles shift due to the increased pore water pressure.
Small increases in pore water pressure can pose a substantial risk to human safety and infrastructure in places with steep slopes or unstable ground.
Fact: It is essential to keep an eye on and control pore water pressure to lessen precipitation's effect on mass wasting occurrences.
Weathering
Through weathering mechanisms, precipitation can also affect erosion rates.
By means of physical, chemical, and biological processes, weathering results in the fragmentation of rocks and soil into finer materials.
Water from precipitation facilitates chemical reactions, drives freeze-thaw cycles, and enables biological processes like plant root growth, all of which contribute to the weathering process.
Fact: Precipitation can play a role in mass wasting in an indirect way, making weathered materials more prone to erosion.
Vegetation and Root Systems
We all know that vegetation helps make the soil more stable, which in turn lowers the risks of erosion.
But, it can change with a change in the rate of precipitation.
For instance, heavy rain can lead to soil saturation or even cause the root to rot quickly.
This weakens the soil and increases the chances of erosion.
Rapid Snowmelt
A rush of water can destabilize slopes and contributes to mass wasting in colder places.
It is quite likely to be the case if snowmelt occurs quickly due to a fast increase in temperature or heavy rainfall.
Runoff from melting snow can erode the land’s surface and set off mass-wasting processes like avalanches and debris flows.
Alternatively, it can soak into the ground, raising soil saturation and pore water pressure.
Takeaway
How does precipitation affect the rate of erosion? Precipitation in any form can have a direct impact on erosion.
Water-based erosion is quite common and is directly related to the amount of rainfall in an area.
But, glacial erosion may also have an impact in certain regions.
Finally, precipitation can trigger mass wasting and again increase the rate of erosion.
