This is the process by which
the surface of the Earth gets worn down. Erosion can be caused by natural
elements such as wind and glacial ice. But anyone who has ever seen a picture
of the Grand Canyon knows that nothing beats the slow steady movement of water
when it comes to changing the Earth.
the surface of the Earth gets worn down. Erosion can be caused by natural
elements such as wind and glacial ice. But anyone who has ever seen a picture
of the Grand Canyon knows that nothing beats the slow steady movement of water
when it comes to changing the Earth.
What is erosion?
How do physical processes change the
world?
world?
Erosion is the act in
which earth is worn away, often by water, wind,
or ice. A similar process, weathering, breaks down or dissolves rock,
weakening it or turning it into tiny fragments. No rock is hard enough to
resist the forces of weathering and erosion. Together, they shaped the
sharp peaks of the Himalaya Mountains in Asia and sculpted the spectacular forest
of rock towers of Bryce Canyon, in the U.S. state of Utah.
which earth is worn away, often by water, wind,
or ice. A similar process, weathering, breaks down or dissolves rock,
weakening it or turning it into tiny fragments. No rock is hard enough to
resist the forces of weathering and erosion. Together, they shaped the
sharp peaks of the Himalaya Mountains in Asia and sculpted the spectacular forest
of rock towers of Bryce Canyon, in the U.S. state of Utah.
The process of erosion moves bits of
rock or soil from one place to another. Most erosion is performed by
water, wind, or ice (usually in the form of a glacier). These forces carry
the rocks and soil from the places where they were weathered. If water is muddy,
it is a sign that erosion is taking place. The brown color indicates that bits
of rock and soil are suspended in the water and being transported from one
place to another. This transported material is called sediment.
rock or soil from one place to another. Most erosion is performed by
water, wind, or ice (usually in the form of a glacier). These forces carry
the rocks and soil from the places where they were weathered. If water is muddy,
it is a sign that erosion is taking place. The brown color indicates that bits
of rock and soil are suspended in the water and being transported from one
place to another. This transported material is called sediment.
When wind or water slows down, or
ice melts, sediment is deposited in a new location. As the sediment builds up,
it creates fertile land. River deltas are made almost entirely
of sediment. Delta sediment is eroded from the banks and bed of the river.
ice melts, sediment is deposited in a new location. As the sediment builds up,
it creates fertile land. River deltas are made almost entirely
of sediment. Delta sediment is eroded from the banks and bed of the river.
Water erosion
This refers to as is the
detachment and removal of soil material by water. The process may
be natural or accelerated by human activity. The rate of erosion may
be very slow to very rapid, depending on the soil, the local landscape, and
weather conditions. Water erosion wears away the earth’s
surface.
detachment and removal of soil material by water. The process may
be natural or accelerated by human activity. The rate of erosion may
be very slow to very rapid, depending on the soil, the local landscape, and
weather conditions. Water erosion wears away the earth’s
surface.
Water erosion is the detachment and removal
of soil material by water. The process may be natural or accelerated by human
activity. The rate of erosion may be very slow to very rapid, depending on the
soil, the local landscape, and weather conditions. Water erosion wears away the
earth’s surface. Sheet erosion is the more-or-less uniform removal of soil from
the surface. Rill and gully erosion occurs when concentrated runoff cuts
conspicuous channels into the soil. Deposition of the sediment removed by
erosion is likely in any area where the velocity of running water is
reduced—behind plants, litter, and rocks; in places where slop
of soil material by water. The process may be natural or accelerated by human
activity. The rate of erosion may be very slow to very rapid, depending on the
soil, the local landscape, and weather conditions. Water erosion wears away the
earth’s surface. Sheet erosion is the more-or-less uniform removal of soil from
the surface. Rill and gully erosion occurs when concentrated runoff cuts
conspicuous channels into the soil. Deposition of the sediment removed by
erosion is likely in any area where the velocity of running water is
reduced—behind plants, litter, and rocks; in places where slop
Why
is erosion a concern?
is erosion a concern?
Loss
of topsoil changes the capacity of the soil to function and restricts its
ability to sustain future uses. Erosion removes or redistributes topsoil, the
layer of soil with the greatest amount of organic matter, biological activity,
and nutrients. The ability of a plant community to recover after topsoil is
lost is restricted. Erosion breaks down soil structure, exposing organic matter
within soil aggregates to decomposition and loss. Degraded soil structure
reduces the rate of water infiltration. Erosion of nutrient-rich topsoil can
cause a shift to less desirable plants, such as from grass to shrub species. In
this process, soil organic matter and nutrients eroded from one area contribute
to resource accumulation in another, such as the area around shrubs. Erosion of
shallow soils can decrease the thickness of the root zone and the amount of
air, water, and nutrients available to plants. The sediment removed by erosion
can bury plants and roads; accumulate in streams, rivers, and reservoirs; and
degrade water quality.
of topsoil changes the capacity of the soil to function and restricts its
ability to sustain future uses. Erosion removes or redistributes topsoil, the
layer of soil with the greatest amount of organic matter, biological activity,
and nutrients. The ability of a plant community to recover after topsoil is
lost is restricted. Erosion breaks down soil structure, exposing organic matter
within soil aggregates to decomposition and loss. Degraded soil structure
reduces the rate of water infiltration. Erosion of nutrient-rich topsoil can
cause a shift to less desirable plants, such as from grass to shrub species. In
this process, soil organic matter and nutrients eroded from one area contribute
to resource accumulation in another, such as the area around shrubs. Erosion of
shallow soils can decrease the thickness of the root zone and the amount of
air, water, and nutrients available to plants. The sediment removed by erosion
can bury plants and roads; accumulate in streams, rivers, and reservoirs; and
degrade water quality.
What
causes water erosion?
causes water erosion?
Erosion is caused by the impact of raindrops
on bare soil and by the power of running water on the soil surface. Natural
erosion rates depend on inherent soil properties, slope, and climate, which
together determine the ability of the site to support vegetation. Accelerated
erosion occurs when the plant
on bare soil and by the power of running water on the soil surface. Natural
erosion rates depend on inherent soil properties, slope, and climate, which
together determine the ability of the site to support vegetation. Accelerated
erosion occurs when the plant
What is wind erosion?
This is a serious
environmental problem attracting the attention of many across the globe. It is
a common phenomenon occurring mostly in flat, bare areas; dry, sandy soils; or
anywhere the soil is loose, dry and finely granulated.
environmental problem attracting the attention of many across the globe. It is
a common phenomenon occurring mostly in flat, bare areas; dry, sandy soils; or
anywhere the soil is loose, dry and finely granulated.
Wind erosion
is a natural process that moves soil from one location to another by wind
power. It can cause significant economic and environmental damage.
is a natural process that moves soil from one location to another by wind
power. It can cause significant economic and environmental damage.
Wind erosion
can be caused by a light wind that rolls soil particles along the surface
through to a strong wind that lifts a large volume of soil particles into the
air to create dust storms.
can be caused by a light wind that rolls soil particles along the surface
through to a strong wind that lifts a large volume of soil particles into the
air to create dust storms.
While wind
erosion is most common in deserts and coastal sand dunes and beaches, certain
land conditions will cause wind erosion in agricultural areas.
erosion is most common in deserts and coastal sand dunes and beaches, certain
land conditions will cause wind erosion in agricultural areas.
So, it is wind
that drives the erosion, but it’s mainly the landscape and condition of the
land which leads to the most damaging wind erosion.
that drives the erosion, but it’s mainly the landscape and condition of the
land which leads to the most damaging wind erosion.
Causes
Wind
erosion can be caused by activities that reduce ground cover below 50% and
remove trees and scrub that act as windbreaks, such as:
erosion can be caused by activities that reduce ground cover below 50% and
remove trees and scrub that act as windbreaks, such as:
·
land
clearing
land
clearing
·
over-grazing
by livestock
over-grazing
by livestock
·
cropping.
cropping.
These
activities leave the soil exposed to the wind.
activities leave the soil exposed to the wind.
Drought
causes greater wind erosion because:
causes greater wind erosion because:
·
less
rain means lower vegetation growth and it is vegetation that binds the soil in
place
less
rain means lower vegetation growth and it is vegetation that binds the soil in
place
·
less
moisture in the soil, makes it easier for soil particles to blow away.
less
moisture in the soil, makes it easier for soil particles to blow away.
What are the differences between wind erosion
and water erosion?
Wind erosion is the result of material
movement by the wind. There are two main effects. First, wind causes small
particles to be lifted and therefore moved to another region. This is called
deflation. Second, these suspended particles may impact on solid objects
causing erosion by abrasion (ecological succession).
movement by the wind. There are two main effects. First, wind causes small
particles to be lifted and therefore moved to another region. This is called
deflation. Second, these suspended particles may impact on solid objects
causing erosion by abrasion (ecological succession).
Wind erosion
generally occurs in areas with little or no vegetation, often in areas where
there is insufficient rainfall to support vegetation. An example is the
formation of sand dunes, on a beach or in a desert. Windbreaks (such as big
trees and bushes) are often planted by farmers to reduce wind erosion.
generally occurs in areas with little or no vegetation, often in areas where
there is insufficient rainfall to support vegetation. An example is the
formation of sand dunes, on a beach or in a desert. Windbreaks (such as big
trees and bushes) are often planted by farmers to reduce wind erosion.
Water erosion
Nearly perfect
sphere in granite, Trégastel, Brittany.Splash erosion is the detachment and
airborne movement of small soil particles caused by the impact of raindrops on
soil.
sphere in granite, Trégastel, Brittany.Splash erosion is the detachment and
airborne movement of small soil particles caused by the impact of raindrops on
soil.
Sheet erosion
is the detachment of soil particles by raindrop impact and their removal
downslope by water flowing overland as a sheet instead of in definite channels
or rills. The impact of the raindrop breaks apart the soil aggregate. Particles
of clay, silt and sand fill the soil pores and reduce infiltration. After the
surface pores are filled with sand, silt or clay, overland surface flow of
water begins due to the lowering of infiltration rates. Once the rate of
falling rain is faster than infiltration, runoff takes place. There are two
stages of sheet erosion. The first is rain splash, in which soil particles are
knocked into the air by raindrop impact. In the second stage, the loose
particles are moved downslope by broad sheets of rapidly flowing water filled
with sediment known as sheetfloods. This stage of sheet erosion is generally
produced by cloudbursts, sheetfloods commonly travel short distances and last
only for a short time.
is the detachment of soil particles by raindrop impact and their removal
downslope by water flowing overland as a sheet instead of in definite channels
or rills. The impact of the raindrop breaks apart the soil aggregate. Particles
of clay, silt and sand fill the soil pores and reduce infiltration. After the
surface pores are filled with sand, silt or clay, overland surface flow of
water begins due to the lowering of infiltration rates. Once the rate of
falling rain is faster than infiltration, runoff takes place. There are two
stages of sheet erosion. The first is rain splash, in which soil particles are
knocked into the air by raindrop impact. In the second stage, the loose
particles are moved downslope by broad sheets of rapidly flowing water filled
with sediment known as sheetfloods. This stage of sheet erosion is generally
produced by cloudbursts, sheetfloods commonly travel short distances and last
only for a short time.
Rill erosion
refers to the development of small, ephemeral concentrated flow paths, which
function as both sediment source and sediment delivery systems for erosion on
hillslopes. Generally, where water erosion rates on disturbed upland areas are
greatest, rills are active. Flow depths in rills are typically on the order of
a few centimeters or less and slopes may be quite steep. These conditions
constitute a very different hydraulic environment than typically found in
channels of streams and rivers. Eroding rills evolve morphologically in time
and space. The rill bed surface changes as soil erodes, which in turn alters
the hydraulics of the flow. The hydraulics is the driving mechanism for the
erosion process, and therefore dynamically changing hydraulic patterns cause
continually changing erosional patterns in the rill. Thus, the process of rill
evolution involves a feedback loop between flow detachment, hydraulics, and bed
form. Flow velocity, depth, width, hydraulic roughness, local bed slope,
friction slope, and detachment rate are time and space variable functions of
the rill evolutionary process. Superimposed on these interactive processes, the
sediment load, or amount of sediment in the flow, has a large influence on soil
detachment rates in rills. As sediment load increases, the ability of the
flowing water to detach more sediment decreases.
refers to the development of small, ephemeral concentrated flow paths, which
function as both sediment source and sediment delivery systems for erosion on
hillslopes. Generally, where water erosion rates on disturbed upland areas are
greatest, rills are active. Flow depths in rills are typically on the order of
a few centimeters or less and slopes may be quite steep. These conditions
constitute a very different hydraulic environment than typically found in
channels of streams and rivers. Eroding rills evolve morphologically in time
and space. The rill bed surface changes as soil erodes, which in turn alters
the hydraulics of the flow. The hydraulics is the driving mechanism for the
erosion process, and therefore dynamically changing hydraulic patterns cause
continually changing erosional patterns in the rill. Thus, the process of rill
evolution involves a feedback loop between flow detachment, hydraulics, and bed
form. Flow velocity, depth, width, hydraulic roughness, local bed slope,
friction slope, and detachment rate are time and space variable functions of
the rill evolutionary process. Superimposed on these interactive processes, the
sediment load, or amount of sediment in the flow, has a large influence on soil
detachment rates in rills. As sediment load increases, the ability of the
flowing water to detach more sediment decreases.
Where precipitation
rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence
can often cause more erosion than the initial raindrop impact.
rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence
can often cause more erosion than the initial raindrop impact.
Gully erosion
results where water flows along a linear depression eroding a trench or gully.
This is particularly noticeable in the formation of hollow ways, where, prior
to being tarmacked, an old rural road has over many years become significantly
lower than the surrounding fields.
results where water flows along a linear depression eroding a trench or gully.
This is particularly noticeable in the formation of hollow ways, where, prior
to being tarmacked, an old rural road has over many years become significantly
lower than the surrounding fields.
Valley or
stream erosion occurs with continued water flow along a linear feature. The
erosion is both downward, deepening the valley, and headward, extending the
valley into the hillside. In the earliest stage of stream erosion, the erosive
activity is dominantly vertical, the valleys have a typical V cross-section and
the stream gradient is relatively steep. When some base level is reached, the
erosive activity switches to lateral erosion, which widens the valley floor and
creates a narrow floodplain. The stream gradient becomes nearly flat, and
lateral deposition of sediments becomes important as the stream meanders across
the valley floor. In all stages of stream erosion, by far the most erosion
occurs during times of flood, when more and faster-moving water is available to
carry a larger sediment load. In such processes, it is not the water alone that
erodes: suspended abrasive particles, pebbles and boulders can also act
erosively as they traverse a surface.
stream erosion occurs with continued water flow along a linear feature. The
erosion is both downward, deepening the valley, and headward, extending the
valley into the hillside. In the earliest stage of stream erosion, the erosive
activity is dominantly vertical, the valleys have a typical V cross-section and
the stream gradient is relatively steep. When some base level is reached, the
erosive activity switches to lateral erosion, which widens the valley floor and
creates a narrow floodplain. The stream gradient becomes nearly flat, and
lateral deposition of sediments becomes important as the stream meanders across
the valley floor. In all stages of stream erosion, by far the most erosion
occurs during times of flood, when more and faster-moving water is available to
carry a larger sediment load. In such processes, it is not the water alone that
erodes: suspended abrasive particles, pebbles and boulders can also act
erosively as they traverse a surface.
Wind erosion
occurred when pieces of the earth are worn away by the strong winds. It occurs
in dry bare areas when wind blows and moves the dirt around. Wind erosion
causes damage to the crops by removing the soil which crops needed from it.
Wind erosion can be prevented by soil tiling and by properly managing the
crops.
occurred when pieces of the earth are worn away by the strong winds. It occurs
in dry bare areas when wind blows and moves the dirt around. Wind erosion
causes damage to the crops by removing the soil which crops needed from it.
Wind erosion can be prevented by soil tiling and by properly managing the
crops.
Water erosion
is the process where the piece of earth is worn away by water. It occurs at
river banks or streams. Muddy water is the sign of water erosion. Water erosion
is the more powerful erosion than wind erosion.
is the process where the piece of earth is worn away by water. It occurs at
river banks or streams. Muddy water is the sign of water erosion. Water erosion
is the more powerful erosion than wind erosion.
Therefore, water erosion is more destructive
and more severe than wind erosion.
and more severe than wind erosion.
Water erosion is more severe because, it
causes serious problem to the soil which actually causes environmental problem.
causes serious problem to the soil which actually causes environmental problem.
