Module 2 – (L6) Sustainable Watershed Approach Watershed Management Practices

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M odu le 2 – ( L6 ) Su st a in a ble W a t e r sh e d Appr oa ch M odu le 2 – ( L6 ) Su st a in a ble W a t e r sh e d Appr oa ch & W a t e r sh e d M a n a ge m e n t Pr a ct ice s

6 Soil Erosion & Conservation

1 1

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L6

Soil Er osion & Con se r va t ion

L6

L6 – Soil Er osion & Con se r va t ion



Topics Cove r e d



Topics Cove r e d



Soil erosion: causes, processes,

erosion factors, water erosion, types,

estimation of soil loss wind erosion

estimation of soil loss, wind erosion,

soil conservation practices



Keywords:

Soil erosion, Water erosion,

Wind erosion Soil conservation

2 2

(3)

I n t r odu ct ion t o Soil Er osion



Definition :

–

– soil erosion is the detachment, transport & deposition soil erosion is the detachment, transport & deposition of soil particle on land surface

of soil particle on land surface termed as loss of soiltermed as loss of soil of soil particle on land surface

of soil particle on land surface -- termed as loss of soil.termed as loss of soil. –

– measured as mass /unit area measured as mass /unit area -- tonne/ha or Kg/sq.mtonne/ha or Kg/sq.m



Soil loss is of interest primarily on

Soil loss is of interest primarily on--site effect of

site effect of



Soil loss is of interest primarily on

Soil loss is of interest primarily on site effect of

site effect of

erosion such as loss of crop productivity



Off site effect of erosion are siltation in ditches,



Off site effect of erosion are siltation in ditches,

streams , reservoirs



Sediment generated by erosion processes are

g

y

p

prime carrier of agricultural chemicals that

pollutes stream or lakes.

3 3

(4)

Soil Er osion Pr oble m

 Soil is the most precious gift of nature -Prime

resource-for food, fodder etc. -Soil mismanaged-less resource for food, fodder etc. Soil mismanaged less productivity.

 In India, more than 100 million hectares soil

degraded eroded unproductive degraded, eroded, unproductive

 About 17 tones/ha soil detached annually->20% of

this is transported by river to sea10% deposited in reservoir results 1 to 2% loss off storage capacity.

Soil erosion in a watershed

(5)

Soil Er osion Pr oble m …

I n dia ’s La n d

D e gr a da t ion : Source: state of environment report 2009 MoEF



 Soil erosion deteriorates soil quality & reduces Soil erosion deteriorates soil quality & reduces

productivity of natural , agricultural & forest ecosystem productivity of natural , agricultural & forest ecosystem

report 2009 MoEF

p y , g y



 Soil erosion deteriorates quality of water Soil erosion deteriorates quality of water



 Increased sedimentation causes reduction of carrying Increased sedimentation causes reduction of carrying

capacity of water bodies capacity of water bodies

5 5

(6)

Ca u se s of Soil Er osion



 H u m a n I n du ce d & N a t u r a l Ca u se sH u m a n I n du ce d & N a t u r a l Ca u se s



 Land use Land use -- Over grazing by cattle Deforestation Over grazing by cattle Deforestation 

 Land use Land use -- Over grazing by cattle, Deforestation, Over grazing by cattle, Deforestation,

arable land use, faulty farming, construction, mining arable land use, faulty farming, construction, mining etc.

etc.

l d d l



 Climatic conditions: precipitation & wind velocityClimatic conditions: precipitation & wind velocity



 Soil: soil characteristics Soil: soil characteristics -- texture, structure, water texture, structure, water

retention and transmission properties. retention and transmission properties. retention and transmission properties. retention and transmission properties.



 Hydrology: Hydrology: Infiltration, surface detention, overland Infiltration, surface detention, overland

flow velocity, and subsurface water flow. flow velocity, and subsurface water flow. L d f

L d f SlSl di di ll ll h d h d hh f f



 Land forms: Land forms: Slope gradient, slope length and shape of Slope gradient, slope length and shape of

slope slope

Soil erosion in a watershed

(7)

Type s of Soil Er osion



Geological erosion, Natural erosion &

Erosion from activities of human & animals

–

– Geological erosion:Geological erosion:--Soil forming and distribution Geological erosion:Geological erosion: Soil forming and distribution Soil forming and distribution Soil forming and distribution



Long time processLong time process –

– Human and animal:Human and animal:--Tillage, removal of plants and Tillage, removal of plants and other vegetation

other vegetation accelerated erosion accelerated erosion other vegetation

other vegetation accelerated erosion accelerated erosion –

– Stream bank erosionStream bank erosion –

– Landslide, Volcanic eruption, floodingLandslide, Volcanic eruption, floodingLandslide, Volcanic eruption, floodingLandslide, Volcanic eruption, flooding –

– Water and wind:Water and wind: major factors of soil erosionmajor factors of soil erosion

(8)

Agents of Soil Erosion

Soil Er osion Pr oce sse s

Wind Water

Gravity (mass movement)

Water forms

Eg. Landslide

Glaciers Ba se d on Re f: G. D a s ( 2 0 0 0 ) :

H ydr ology & Soil Con se r va t ion En gg. Pr e n t ice H a ll of I n dia , N e w D e lh i

Rainfall

Reservoirs And Oceans Runoff

Surface

runoff Subsurface

runoff

Pipe erosion

Sheet/Interrill

runoff

Rill i

Gully

i Stream bank erosion erosion erosion

(9)

Soil Er osion Pa r a m e t e r s



Soil erosion – function of:

– Erosivity – depends on rainfall

– Erodibility – property of soil

– Topography – property of land

– Management – contributed by man

Erodibility:

Detachability & transportability

Topography:

Slope, length, relation to other

land

(10)

W a t e r Er osion



Detachment & transport of soil particles from

land mass by water including rain runoff

land mass by water including rain, runoff,

melted snow



Depends on: soil nature & capacity of water



Depends on: soil nature & capacity of water

to transport



More on sloppy land



More on sloppy land



More velocity



more transport



Water erosion



accelerated by agriculture,



Water erosion



accelerated by agriculture,

grazing and construction activities

(11)

Fa ct or s a ffe ct in g Er osion by



Climate



Precipitation, temperature, wind, humidity

and solar radiation



Soil



size, type of soil, soil texture, structure, organic

matter



Vegetation



interception of rainfall

interception of rainfall--reduce surface

reduce surface

sealing & runoff decrease surface velocity

sealing & runoff, decrease surface velocity,

improvement of aggregation, increased biological

activity and aeration, transpiration, physical holding



Topography



degree of slope, shape and length of

(12)

Type s of W a t e r Er osion



 W a t e r Er osion Type s:W a t e r Er osion Type s: Interrill (raindrop and sheet), rill, Interrill (raindrop and sheet), rill,

gully & stream channel erosion gully & stream channel erosion gully & stream channel erosion gully & stream channel erosion



 Ra in dr op e r osionRa in dr op e r osion (splash erosion) (splash erosion) Soil detachment & Soil detachment &

transport

transport -- from impact of raindrops directly on soil from impact of raindrops directly on soil particles or on thin water surfaces

particles or on thin water surfaces particles or on thin water surfaces particles or on thin water surfaces



 On bare soilOn bare soil  about 200 t/ha soil is splashed into the air about 200 t/ha soil is splashed into the air

by heavy rains by heavy rains



 Relationship Relationship -- erosion, rainfall momentum & energy erosion, rainfall momentum & energy -- by by

raindrop mass, size, shape, velocity & direction raindrop mass, size, shape, velocity & direction Relationship: Rainfall intensity & energy

Relationship: Rainfall intensity & energy (F(F tt t l t l 1981)1981)



 Relationship: Rainfall intensity & energy Relationship: Rainfall intensity & energy (Foster et al., 1981)(Foster et al., 1981)



(13)

Sh e e t Er osion /

Sh e e t Er osion / I n t e r r ill

I n t e r r ill Er osion

Er osion



 Sh e e t e r osion :Sh e e t e r osion : Uniform removal of soil in thin layers Uniform removal of soil in thin layers

from sloping land resulting from overland flow

from sloping land resulting from overland flow -- Idealized Idealized

form of sheet erosion rarely occurs form of sheet erosion rarely occurs



 Splash & sheet erosionSplash & sheet erosion sometimes sometimes combinedcombined & known as & known as Interrill erosion

Interrill erosion Interrill erosion Interrill erosion



 Function of soil properties, rainfall and land slopeFunction of soil properties, rainfall and land slope

Watson and Laften(1986) formula Watson and Laften(1986) formula(( ))

where, D

where, D_ii-- interrill erosion rate in kg/minterrill erosion rate in kg/m22_--s_s 4

4

K

K_ii--interrill erodibility of soil in kginterrill erodibility of soil in kg--s/ms/m44 _and_{and ii--rainfall}_rainfall

intensity in m/s intensity in m/s

S

S_ff--slope factor=1.05 slope factor=1.05 -- 0.85exp(0.85exp(--4sin4sinθθ); ); θθ--slope in degreesslope in degrees

S

(14)

Rill e r osion



 Detachment and transport of soil particles by Detachment and transport of soil particles by concentrated flow of water; Predominant form of concentrated flow of water; Predominant form of

erosion; Depends on hydraulic shear of water flowing erosion; Depends on hydraulic shear of water flowing

e os o ; epe ds o yd au c s ea o a e o g

in the rill, rill erodibility and critical shear in the rill, rill erodibility and critical shear

 Critical shear: shear below which soil detachment is negligibleCritical shear: shear below which soil detachment is negligible

 Rill detachment rate (Dr)Rill detachment rate (Dr) erosion rate occurring erosion rate occurring

 Rill detachment rate (Dr)Rill detachment rate (Dr)--erosion rate occurring erosion rate occurring beneath submerged area of the rill

beneath submerged area of the rill

Dr-Rill detachment rate in kg/m2-s

Kτ Rill erodibility resulting from shear in s/m  _Q  Kτ-Rill erodibility resulting from shear in s/m

τc-critical shear below which no erosion occurs in Pa

Qs-rate of sediment flow in kg/m-s

Tc-sediment transport capacity of rill in kg/m-s





_

where, ρ-Density of water in kg/m3; g-acceleration due to gravity in m/s2 r-hydraulic radius of rill in m; s-hydraulic gradient of rill flow

(15)

Gu lly e r osion

Advanced form of rill erosion

Advanced form of rill erosion ––forms larger channels than rills forms larger channels than rills –

– Fou r st a ge sFou r st a ge sou s a ge sou s a ge s

–

– Formation stageFormation stage –

– Development stageDevelopment stage –

– Healing stageHealing stage –

– Stabilization stageStabilization stage



 Gullies may be smallGullies may be small 1m or less1m or less

Gully & rill erosion in a watershed



 Gullies may be smallGullies may be small--1m or less1m or less



 MediumMedium--1m to 5m1m to 5m



 LargeLarge--more than 5mgg more than 5m

–

– St r e a m ch a n n e l Er osion :St r e a m ch a n n e l Er osion : Removal of soil for stream Removal of soil for stream banks or soil movement in channel

banks or soil movement in channel

(16)

Measurement of Soil Loss

Measurement of Soil Loss –

– Water Erosion

Water Erosion



Measurement from runoff plots

Size varies from 1/250 to 1/125 Hectare Size varies from 1/250 to 1/125 Hectare –

– Size varies from 1/250 to 1/125 HectareSize varies from 1/250 to 1/125 Hectare –

– Runoff measured by FlumeRunoff measured by Flume



Measurement from streams



Measurement from streams

–

– Silt observation Posts (SOP)Silt observation Posts (SOP) –

– Suspension, saltation and surface creep (bed load)Suspension, saltation and surface creep (bed load) –

– Both separately measured and addedBoth separately measured and added –

– Soil Sampler: Soil Sampler: S = p* q*86400/1000S = p* q*86400/1000

(17)

Est im a t ion of Soil Loss



Universal soil loss equation (USLE)

(th

h i

t )

(R j

Vi

Si

h

2000)

(th

h i

t )

(R j

Vi

Si

h

2000)

(through experiments) (Raj Vir Singh, 2000)

P

– AA--Average annual loss: in ton/ha/yearAverage annual loss: in ton/ha/year –

– RR--Rainfall & runoff erosivity index for locationRainfall & runoff erosivity index for location

P

R Rainfall & runoff erosivity index for locationRainfall & runoff erosivity index for location –

– KK--Soil erodibility factorSoil erodibility factor –

– LL--slope length factorslope length factor –

– S S –– slope steepness factorslope steepness factor –

– CC--cover management factorcover management factor P

P titi ti ti ff tt –

(18)

Rainfall and Runoff

Rainfall and Runoff Erosivity

Erosivity Index (EI)

Index (EI)



₃₀



/

100

30 KE

I

EI





EI

EI--by multiplying kinetic energy of storm to

by multiplying kinetic energy of storm to

maximum 30 min. intensity for that storm

y



KE

KE--kinetic energy of storm

kinetic energy of storm



II

₃₀₃₀₃₀₃₀

=Maximum 30 minutes rainfall intensity

y

of storm



KE=210.3 + 89 log I

KE=210.3 + 89 log I -- in ton/ha

in ton/ha--cm

cm



(19)

Er odibilit y

Er odibilit y fa ct or ( K)

fa ct or ( K)



Soil erodibility factor K can be found by

regression equation by Foster et al(1981)

regression equation by Foster et.al(1981)









Where, M--particle size parameter (% silt+% very fine particle size parameter (% silt+% very fine



3



a--percent organic matter; bpercent organic matter; b--soil structure codesoil structure code

(very fine granular 1 fine granular 2 Medium or course granular 3 (very fine granular 1 fine granular 2 Medium or course granular 3 (very fine granular 1, fine granular 2, Medium or course granular 3, (very fine granular 1, fine granular 2, Medium or course granular 3,

blocks, platy or massive 4) blocks, platy or massive 4)

c

c--profile permeability class profile permeability class (rapid 1;moderate to rapid (rapid 1;moderate to rapid 2;moderate 3;slow to moderate 4;slow 5;very slow 6)

(20)

Slope Le n gt h Fa ct or ( L)

Where, L--slope length factor; I

slope length factor; I--slope length in m

slope length in m









22 m

m-- dimensionless exponent

dimensionless exponent



Where

θ

--field slope steepness=tan

field slope steepness=tan

--11

_(s/100)



s

s--field slope in %

field slope in %



(21)

Slope St e e pn e ss Fa ct or ( S)



Slope Length shorter than 4m

F

l

th l

th

4 d

9%



For slope length longer than 4m and s<9%

(22)

Cr op m a n a ge m e n t fa ct or ( C)



Combined effect of crop sequences,

productivity level, length of growing season,

p

y

,

g

,

p

y

,

g

,

tillage practices, residue management &

expected time distribution of erosive rain

t

ith

t t

l

ti

& h

t d t

t

ith

t t

l

ti

& h

t d t

storm with respect to planting & harvest date

Crop

Soil loss Value of C

Eg.

Hyderabad

(tn/ha)

Cultivated

5

1 Grass

0.59

0.12 Bajra

2 0 38

(23)

Con se r va t ion pr a ct ice fa ct or ( P)



Ratio of soil loss with a specific supporting

practice to the corresponding loss with up &

down cultivation

e g

Practice

P factor

e.g.

Practice

P factor

a) Up and down cultivation of

1.0 Kanpur

cultivation of Jowar

b) Contour)

cultivation of

(24)

W in d Er osion



Process of detachment transportation and

deposition of soil by action of wind



Depends on wind speed, soil, topographic

features and vegetative cover



arid region



Change in texture of soil



Change in texture of soil



In India: Mainly occur in Rajasthan, Gujarat

and parts of Punjab

(25)

M e ch a n ism of W in d Er osion



 Initiation of movement Initiation of movement ––due to turbulence and wind due to turbulence and wind

velocity velocity



 Transportation Transportation ––depends on particle size gradation wind depends on particle size gradation wind 

 Transportation Transportation ––depends on particle size, gradation, wind depends on particle size, gradation, wind

velocity and distance velocity and distance



 DepositionDeposition——occurs when gravitational force is greater occurs when gravitational force is greater

h f h ld l l

than forces holding soil particles in air than forces holding soil particles in air



 Types of soil movement by windTypes of soil movement by wind

–

– SaltationSaltation-- Fine particles lifted from surface and SaltationSaltation Fine particles lifted from surface and Fine particles lifted from surface and Fine particles lifted from surface and following specific path w.r.t wind and gravity following specific path w.r.t wind and gravity –

– SuspensionSuspension--floating of small particlesfloating of small particles –

– Surface creep Surface creep --rolling or sliding of large soil particles rolling or sliding of large soil particles along soil surface.

(26)

Est im a t ion of W in d Er osion



Average annual loss

)

(

I

K

C

L

V

f

E



 Where, EWhere, E--estimated average annual loss (tn/ha/year)estimated average annual loss (tn/ha/year)

)

 Where, EWhere, E estimated average annual loss (tn/ha/year)estimated average annual loss (tn/ha/year)

II-- soil erodibility index (ton/hasoil erodibility index (ton/ha--yr), Kyr), K--ridge roughness ridge roughness factor, C

factor, C--climate factor, Lclimate factor, L--unsheltered length of unsheltered length of eroding field (m) V

eroding field (m) V--vegetative cover factorvegetative cover factor eroding field (m), V

eroding field (m), V vegetative cover factorvegetative cover factor

II--Soil erodibility index (ton/haSoil erodibility index (ton/ha--yr)yr)

F

I



525 (

2

718 )



0 .

05

F

F--% of dry soil fraction greater than 0.84 mm% of dry soil fraction greater than 0.84 mm

(27)

Rou gh n e ss Fa ct or



A measure of effect of ridges made by tillage

implements on wind erosion



Ridge roughness in mm

h

2

16

0 h

h ridge height in mm; d

ridge height in mm; d ridge spacing in mm

ridge spacing in mm

d

h

K

_r



0 .

16 h

h--ridge height in mm; d

ridge height in mm; d--ridge spacing in mm

ridge spacing in mm

from K

_rr

, roughness factor K

(28)

Clim a t ic Fa ct or



Index of climatic

Index of climatic erosivity

erosivity--> depends on wind

> depends on wind

velocity and soil surface moisture

Mean wind velocity profile expression





_z

_d

u

*

Where, u_z-wind velocity at z height (L/T)

u*_{-friction velocity (L/T)= (}τ_0/ρ₎0.5

τ shear stress at boundary (F/L2₎



z-Height above a reference surfaceg

d-an effective surface roughness height z₀-a roughness parameter (h)

(29)

Un sh e lt e r e d Be lt & V e ge t a t ive Cove r Fa ct or



Unsheltered distance (L)

Unsheltered distance (L)--

Distance from a

sheltered edge of a field to end of unsheltered field



Vegetative Cover

Vegetative Cover--

Factor represented

Factor represented by relating

by relating

the land quantity and orientation of vegetative

the land, quantity and orientation of vegetative

material to its equivalent of small grain residue

b

aR

V





 VV--vegetative cover factor expressed as small grass equivalent vegetative cover factor expressed as small grass equivalent

b

aR

V



_w

in kg/ha; a, b

in kg/ha; a, b--crop constantscrop constants



 RR_w_w –– quantity of residual to be converted to small grain quantity of residual to be converted to small grain

(30)

Pr e ve n t in g Soil Er osion

Photo, A.K. Singh, 2002

 Pr e ve n t in g soil e r osion r e qu ir e s polit ica l, e con om ic &

t e ch n ica l ch a n ge s.

 Aspects of technical changes include:

 use of contour ploughing and wind breaks;

 leaving unploughed grass strips between ploughed land; g p g g p p g ;  making sure that there are always plants growing on the

soil, and that the soil is rich in humus (decaying plant and animal remains).

a a e a s)

 avoiding overgrazing and the over-use of crop lands;  allowing indigenous plants to grow along the river banks

en o ging biologi l di e it b pl nting e e l diffe ent

 encouraging biological diversity by planting several different

types of plants together;

(31)

Soil Con se r va t ion Pr a ct ice s

 Con se r va t ion m e a su r e s - reduce soil erosion by

both water & wind. both water & wind.

 Tilla ge a n d cr oppin g pr a ct ice s, as well a land

management practices, directly affect the overall soil erosion problem

erosion problem.

 Com bin a t ion of a ppr oa ch e s (Eg. contour plowing,

strip cropping, or terracing)

 Ot h e r m e a su r e s: Silt Fencing, Erosion Control

Blankets, Sediment Traps, Plastic Covering/Bank Stabilization Pipeline Sand Bagging Check Dams Stabilization, Pipeline Sand Bagging, Check Dams, Drain Inlets, Filter Berms & Silt Dikes

31 31

(32)

Soil Conservation Practices - Types

yp



Vegetative practices

Contouring – Contouring – Strip cropping

– Tillage operationsTillage operations – Mulching



Mechanical practices

p

– Terraces

– Bunds (graded & contour) – Check dams

– Vegetated outlets & watercourses

32 32

(33)

Ca se St u dy: I n dia n Sce n a r io

 Soil erosion prevalent –

almost 55% of total land almost 55% of total land

 Himalayan & lower Himalayan

regions highly affected h

 More than 25% reservoir

capacity lost

 Erosion rates in

India- Iso-erosion lines- annual

(34)

An n u a l Soil Loss Est im a t e

An n u a l Soil Loss Est im a t e –

– I n dia n Sce n a r io

I n dia n Sce n a r io

Re gion La n d- Use Soil loss( t / k m2₎

North Himalayan forest region

Forest ~280

Punjab-Haryana alluvial plains Agriculture ~330

Upper-Gangetic-alluvial plains Agriculture/waste land ~1400-3300

Lower Gangetic alluvial plains Agriculture ~280-950

North-eastern forest region

Agriculture/shifting cultivation

~2750-4100

Gujarat alluvial plain Agriculture ~300-3300

Red soil region Agriculture ~250-350

Black soil region Agriculture 2370 11000 Black soil region Agriculture ~2370-11000

Lateritic soil Agriculture ~4000

Ref:

(35)

Re fe r e n ce s



 State of Environment of India 2009: report of Ministry of Environment State of Environment of India 2009: report of Ministry of Environment

and Forest ( source:

and Forest ( source: http://moef.nic.in/downloads/home/homehttp://moef.nic.in/downloads/home/home--SoE SoE--R

R 20092009 dfdf ))

Report

Report--2009.pdf2009.pdf ))



 Raj Vir Singh (2000), Watershed Planning and Management, Yash Raj Vir Singh (2000), Watershed Planning and Management, Yash

P bli hi H P bli hi H

Publishing House Publishing House



 http://www.geo.fuhttp://www.geo.fu--berlin.de/fb/e

berlin.de/fb/e--learning/geolearning/en/soil_erosion/types/index.html learning/geolearning/en/soil_erosion/types/index.html 

 http://iahs info/redbooks/a236/iahs 236 0531 pdfhttp://iahs info/redbooks/a236/iahs 236 0531 pdf 

 http://iahs.info/redbooks/a236/iahs_236_0531.pdfhttp://iahs.info/redbooks/a236/iahs_236_0531.pdf



 http://www.ias.ac.in/currsci/25jan2010/213.pdfhttp://www.ias.ac.in/currsci/25jan2010/213.pdf

 G D a s ( 2 0 0 0 ) : H ydr ology & Soil Con se r va t ion En gg Pr e n t ice H a ll of  G. D a s ( 2 0 0 0 ) : , H ydr ology & Soil Con se r va t ion En gg., Pr e n t ice H a ll of

(36)

Tu t or ia ls - Qu e st ion !.?.



I llu st r a t e t h e possible soil con se r va t ion

m e a su r e s w it h in t h e pe r spe ct ive of

su st a in a ble w a t e r sh e d m a n a ge m e n t

pr a ct ice s.



 Identify the components soil erosionIdentify the components soil erosion



 Scientific interventionsScientific interventions

Identif the p oblems Identif the p oblems



 Identify the problems Identify the problems



 Identify vegetative & mechanical measures. Identify vegetative & mechanical measures.



 Importance of soil conservation.Importance of soil conservation. 

 Importance of soil conservation.Importance of soil conservation.

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Se lf Eva lu a t ion - Qu e st ion s!.

Q



What are the causes and consequences of

soil erosion?

soil erosion?.



What is wind erosion & under what

conditions does it occur?

conditions does it occur?.



Enumerate measures adopted for control of

soil erosion caused by wind.

(38)

Assign m e n t - Qu e st ion s?.

g

Q



Differentiate between geologic & accelerated

erosion of soil

erosion of soil.



Illustrate soil erosion processes.



What are the important factors affecting soil

at a e t e

po ta t acto s a ect g so

erosion by water?.



What are different types of water erosion?.

Di

h

t

Discuss each type.

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Un solve d Pr oble m !.



For your Watershed area, study the soil

erosion problems?.



Identify the problems.



Find out the ways to control soil erosion

bl

problems.

–

– Carry out surveyCarry out survey –

– Consider traditional practices to control erosionConsider traditional practices to control erosionConsider traditional practices to control erosionConsider traditional practices to control erosion –

– Suggest scientific methods for soil conservationSuggest scientific methods for soil conservation

(40)

Dr. T. I. Eldho Dr. T. I. Eldho

Professor, Professor,

Department of Civil Engineering, Department of Civil Engineering, pp gg gg

Indian Institute of Technology Bombay, Indian Institute of Technology Bombay, Mumbai, India, 400 076.

Mumbai, India, 400 076.

Email:

Email: eldho@iitb.ac.ineldho@iitb.ac.in

40 40 Email:

Email: eldho@iitb.ac.ineldho@iitb.ac.in

Phone: (022)

Phone: (022) –– 25767339; Fax: 2576730225767339; Fax: 25767302

http://www.