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Water erosion Water wears a path as it travels down a slope.

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Presentation on theme: "Water erosion Water wears a path as it travels down a slope."— Presentation transcript:

1 Water erosion Water wears a path as it travels down a slope

2 Kind of water erosion Kind of water erosion Water erosion Rill erosionGully erosionSheet erosionStream erosion

3 Rill erosion Have you ever seen a scar or small channel on the side of a slope that was Have you ever seen a scar or small channel on the side of a slope that was left behind by running water? That is evidence of rill erosion left behind by running water? That is evidence of rill erosion An erosion process in which many small channels a few centimetres deep are formed; it occurs mainly on recently cultivated soils. See also rill. An erosion process in which many small channels a few centimetres deep are formed; it occurs mainly on recently cultivated soils. See also rill.

4 Rill erosion is the most common form of erosion. Rill erosion is the most common form of erosion. Its effects can be easily removed by tillage, it is the most often overlooked. It occurs when soil is removed by water from little streamlets that run through land with poor surface draining. Its effects can be easily removed by tillage, it is the most often overlooked. It occurs when soil is removed by water from little streamlets that run through land with poor surface draining.tillage Rills can often be found in between crop rows. Rills can often be found in between crop rows.

5 Rill Erosion picture

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7 Gully picture

8 Gully erosion It is a rill erosion channel becomes broader and deeper It is a rill erosion channel becomes broader and deeper Gullies are larger than rills and cannot be fixed by tillage. Gully erosion is an advanced stage of rill erosion, just as rills are often the result of sheet erosion Gullies are larger than rills and cannot be fixed by tillage. Gully erosion is an advanced stage of rill erosion, just as rills are often the result of sheet erosiontillagerill erosionsheet erosiontillagerill erosionsheet erosion

9 Question-1 What is Tillage? Tillage practices are used for wind erosion control by producing a rough, cloddy surface that maintains surface residue and conserves soil moisture. When used along with crop residues, also known as stubble mulch tillage, reduced tillage, or conservation tillage, it reduces wind velocity and traps eroding soil. Tillage practices are used for wind erosion control by producing a rough, cloddy surface that maintains surface residue and conserves soil moisture. When used along with crop residues, also known as stubble mulch tillage, reduced tillage, or conservation tillage, it reduces wind velocity and traps eroding soil.wind erosioncrop residuesmulchwind erosioncrop residuesmulch Tillage is also very effective in controlling rill and sheet erosion. The rough surface along with crop residues prevents rain water from carrying of soil particles and other organic matter.

10 Stream Erosion Some times water continues to flow along a depression it has created. It becomes a stream like the one shown Some times water continues to flow along a depression it has created. It becomes a stream like the one shown

11 Picture – Steam erosion It constantly picks up sediments from the bottom and sides of its channel. Water picks up and carries some of the lightweight sediments, while large, heavy particles just roll along the bottom of the stream channel. All of these difference-sized materials scrape against the bottom and sides of the cannel, where they continue to knock loose more sediments. Because of this a stream continually cuts a deeper and wider channel It constantly picks up sediments from the bottom and sides of its channel. Water picks up and carries some of the lightweight sediments, while large, heavy particles just roll along the bottom of the stream channel. All of these difference-sized materials scrape against the bottom and sides of the cannel, where they continue to knock loose more sediments. Because of this a stream continually cuts a deeper and wider channel

12 Stream picture

13 Sheet Erosion Sheet erosion is defined as the uniform removal of soil in thin layers from sloping land. Sheet erosion is defined as the uniform removal of soil in thin layers from sloping land. This, of course, is nearly impossible; in reality the loose soil merely runs off with the rain. This, of course, is nearly impossible; in reality the loose soil merely runs off with the rain. It is happens when rainwater flows into lower elevations, carrying sediments with it It is happens when rainwater flows into lower elevations, carrying sediments with it The water loses some of its energy of motion and it drains into the soil or slowly evaporates The water loses some of its energy of motion and it drains into the soil or slowly evaporates

14 Sheet Erosion picture

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16 Deposition Think about... Think about... As water moves throughout a river system, What do you suppose happens as it loses some of its energy of motion? As water moves throughout a river system, What do you suppose happens as it loses some of its energy of motion? The water can no longer carry some of its sediments, and they are deposited.

17 Deposition Some stream sediments aren’t carried very far at all before they are deposited. Some stream sediments aren’t carried very far at all before they are deposited. -Many sediments are deposited within the stream channel it self -Other stream sediments travel great distances before hey are deposited -Many sediments are deposited within the stream channel it self -Other stream sediments travel great distances before hey are deposited

18 Type of Deposition There is two types of Deposition There is two types of Deposition Alluvial fan: A triangular deposit of sediment that forms when water rushing down a slope loses its energy and abruptly slows at the bottom, depositing its sediment load. Delta: A triangular deposit of sediment that forms when a stream or a river slows as it empties into an ocean, gulf, or lake.


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