its gully erosion wdg

1. SWE 112 SOIL AND WATER CONSERVATION OF
ENGINEERING (1+1)
GULLY EROSION
ANGEL A
2020048013
COURSE TEACHER
Ms. M. Limna Jasika Banu,
AP ( Agrl. Engg. )

2. GULLY EROSION
 Gully erosion is the removal of soil by running water with the formation of
channels that can not smoothed out completely by normal cultivation.
It is the advanced stage of rill erosion, much as rill erosion is advanced stage
of sheet erosion.
 Rills are small in size and can be destroyed by tillage operations.
If rills are not destroyed, the rills become larger in size and shape due to
prolonged occurrence of flow through them and cannot be removed by tillage
operations and these are called gullies.

3. GULLY EROSION
 Gullies unless stopped or controlled in the rill stage will get deepened and
widened.
High intensity of flow of the run off increase the gully dimensions.
Cattle paths, cart tracks, dead furrow, tillage furrow, or other depressions
down a slope favour concentration of water.
Large gullies and their network are called as ravines.
The rate of gully erosion mainly depends on the run off characteristics of the
watershed, namely watershed area, soil characteristics.

4. GULLY EROSION

5. Causes of gully erosion
• Gully erosion may occur as a result in continuous and heavy
rainfall
• The greater the intensity and duration of a rainfall, the higher
and erosion potential.
• The impact of raindrops on the soil surface can break down soil
sediments and disperse the sediment to down streams.
• It caused by mining activities.
• It is also caused by farming and uncontrolled grazing practices,it
breaks up soil and softens the overall structure.

6. STAGES OF GULLY DEVELOPMENT
• FOUR STAGES OF GULLY DEVELOPMENT ARE GENERALLY
RECOGNISED.
• STAGE 1 : FORMATION STAGE
• STAGE 2 : DEVELOPMENT STAGE
• STAGE 3 : HEALING STAGE
• STAGE 4 : STABILIZATION STAGE

7. STAGE 1
• FORMATION STAGE
 Initiation of gully erosion
 Channel erosion
 Deepening of gully bed
 Depends on top soil & other
factors
 This stage proceeds slowly if top
soil is resistant

8. STAGE 2
• DEVELOPMENT STAGE
 Major formation of the gully and erosion
takes place
 Upstream movement of the gully head
 Enlargement of gully in width and depth
 Gully banks are eroded to maximum and width becomes
maximum
 Gully cuts to C-horizon and parent material is removed
rapidly

9. STAGE 3
• HEALING STAGE
 Local vegetation starts growing in the gully
and get stabilized
 No significant erosion in any form from gully
section
 Healing process starts

10. STAGE 4
• STABILIZATION STAGE
 Last stage of gully development
 Gully gets fully stabilised
 Gully reaches a stable gradient
 Sufficient vegetation cover develops over the
gully surface to anchor the soil and permit
development of new top soil
 No further development of gully unless healing
process is disturbed

11. CLASSIFICATION OF GULLY
• BASED ON THE
 Shape of the gully( U shape , V shape )
 State of the gully (nature )
 Dimension of the gully ( depth, width and side
slopes)

12. BASED ON SHAPE
• BASED ON THE SHAPE OF THEIR CROSS SECTIO OF THE
GULLY
 U SHAPED
 V SHAPED

13. BASED ON SHAPE
• U SHAPED • V SHAPED
Found in alluvial plain where
surface and sub-surface soil
are easily erodible
Runoff flow undermines and
gully banks collapse
Formation of vertical side
walls in U shape
Where sub-soil are tough to resist
the rapid cutting of soil by runoff
flow
Resistance to erosion increases
with depth
Common in hilly regions
accompanied with steep slope

14. BASED ON STATE
• ACTIVE AND INACTIVE STAGE
 Active gullies ate those which continued to enlarge and they will be
recognized by the presence of loose soils.
 Inactive gullies are that which does not enlarge further and is
covered with vegetation on the side slopes.

15. BASED ON DIMENSION

16. Small Gully :
• Can easily be crossed by farm implements
• Removed by ploughing and smoothing operations
• By stabilizing the vegetation
Medium Gully :
• Cannot be easily crossed by farm implements
• Can be controlled by terracing and ploughing
• operations
• Sides are stabilised by creating vegetation on them
Large Gully :
• Cannot be reclaimed
• Tree planting is done as an effective method

17. STREAM BANK EROSION
• Serious hazard in drainage lines and river courses in India and other
countries.
• In India, it is serious in the Himalayan region Indo Gangetic Plains, The
Brahmaputra Valley, and in the Plateau region, especially in the black soil
areas.
• Natural process that occurs when the forces exerted by flowing water
exceed the resisting forces of bank materials and vegetation.

18. STREAM BANK EROSION

19. CAUSES
• When a stream is straightened or widened, stream bank erosion
increases.
• Damaging or removing streamside vegetation to the point where
it no longer provides for bank stability can cause a dramatic
increase in bank erosion.
• Heavy rainfall – soil can be eroded by heavy and excessive rainfall.
• Housing near bank causes the river bank erosion.

20. • USDA, SCS, Agriculture Handbook No. 61 (1954). A Manual on Conservation of
Soil and Water, Handbook for Agricultural Workers. USDA, Washington, D.C.
208 p.
• LINK ADDRESS
• http://ecoursesonline.iasri.res.in/mod/page/view.php?id=2103
• https://www.sciencedirect.com/topics/agricultural-and-biological-
sciences/gully-
erosion#:~:text=Gully%20erosion%20(Fig.,dependent%20on%20the%20rock
%20type.
Reference