• Caused by the impact of falling rain drops.
• Factors determine rate of erosion : Climate, soil,
Topography & Plant cover.
• Impact of rainfall per unit area is determined by the no., &
size of drops, & velocity of the drops.
Forms of water erosion
• Uniform thin layer of removal of soil.
• Splash – primary cause.
• Detachment process – splash erosion & transportation of
detached particles – wash erosion.
Rill erosion: (Micro channel erosion)
• Advanced stage of sheet erosion.
• Removal of soil by runoff water forms shallow channel.
• Smoothened out by normal cultivation.
• If rill neglected, forms into large gullies.
• More in loose soil.
• Transition stage b/w sheet & gully.
• Advance & last stage of erosion.
• Cannot be smoothened out by normal cultivation.
• Principle: 1. Watershed area 2. Soil characteristics,
alignments, size & shape of gully & slope in gully bed.
• Main process : Water fall erosion & channel erosion.
Classification of gullies
1. Based on shape (c/s) : ‘U’ & ‘V’ shape
2. Based on state : Active & Inactive.
3. Based on dimension of the gully:
Type Symbol Specification Side slopes
Depth m Width m
Very small G1 ≤ 3.0 < 18.0 vary
Small G2 ≤ 3.0 ≥ 18.0 8 – 15%
Medium G3 3.0-9.0 ≥ 18.0 8 – 15%
Deep G4 > 9.0 vary Steep slope
Stages of gully development
• Stage 1: Formation stage
• Stage 2: Development stage
• Stage 3: Healing stage
• Stage 4: Stabilization stage
• Series of gully opening
• Interlocking pattern & drains into river.
• Soil conditions & texture
• Erratic rainfall
• Improper land use by grazing
• Faulty agril. Practices
• Heavy biotic inference
• Closure to grazing & biotic inference
• Adopt soil conservation measures
• Downward & outward movement of soil.
• Geologic factors
• Hydrological factors
• Seismic factors
• Increase vegetative covers
• Establishment of walls