This Presentation deals with the Soil erosion calculation based on Universal Soil Loss Equation.

1. Internal Guide:
Dr. PRADEEP. P. LODHA
Associate Professor & Head
Civil Engineering Dept.,
G.E.C - Valsad
External Guide:
Dr.INDRA PRAKASH,
Faculty
BISAG
Gandhinagar
1
STUDY OF SOIL EROSION FOR
VISHWAMITRI RIVER WATERSHED
USING REMOTE SENSING AND
GEOGRAPHIC INFORMATION SYSTEM
By
VISHVAM H. PANCHOLI
(130280712013)

2. Contents
 Importance of Watershed management
 Introduction to Remote Sensing and Geographic Information
System
 Objective of present study
 Introduction to study area
 Estimation of Soil Erosion using Universal Soil Loss
Equation(USLE)
 Calculation of R,K,L,S,C,P factor
 References & Useful links
2

3.  IMPORTANCE OF WATERSHED MANAGEMENT
1) WM is used to Conservation, Development and optimal utilization of land
and water resources for benefit to people.
2) Land Development (Agriculture, Forest etc.)
3) Development of Water Harvesting Structures
i). Check Dam
ii). Recharge well
iii). Recharge bore stone pitching
4) Nursery Rising
i). Timber
ii). Fuel Wood
iii). Horticultural Species.
5) Drinking water Facilities
6) Controlling Degradation of land (such as Erosion Control)
3

4.  Remote Sensing(RS) is used for
1). Image Interpretation
2). Analysis of images into various Fields
like Agriculture, soil, water.
 Geo Informatics System(GIS) is a
tool for
1). Capture,
2). Storage,
3). Retrieval and Manipulation,
4). Display and querying data
5). Decision making.
4
 INTRODUCTION TO RS AND GIS

5.  OBJECTIVE & METHODOLOGY OF
PRESENT STUDY
 OBJECTIVE:
1. To calculate annual Soil Erosion using Universal
Soil Loss Equation (USLE).
5
 METHODOLOGY:
1. Preparation of Thematic maps (Land use/Land
cover, Soil, Slope) using ArcGIS Software.
2. Estimation of Soil Erosion using Universal Soil
Loss Equation (USLE) which is following as
A=R*K*LS*C*P.

6. 6
 The Vishwamitri River originates
from the hills of Pavagadh in
Gujarat.
 It flows west through the Vadodara
city and empties into the Gulf of
Khambat of Gujarat State.
 Vishwamitri River Watershed is
located between 22 00’ and 22 45’
of North Latitude and 73 00’ and 73
45’ of East Longitude in
Panchmahal and Vadodara, in
Gujarat State.
CONT.
 INTRODUCTION TO STUDY AREA

7. 7
Annual rainfall varies from 850
to 1000 mm. Most of rainfall is
received during the mid-June to
early October.
The total area of the Vishwamitri
watershed is 1185 km2 .
 INTRODUCTION TO STUDY AREA (CONT.)

8.  THEMATIC MAPS
8

9.  THEMATIC MAPS
9

10. LAND USE MAP WITH CLASSIFICATION
10
Sr.no
Land use type Area in
sq.km
1 Agriculture 931.14
2 Built up 121.81
3 Forest 3.33
4 Waste land 51.51
5 Water bodies 36.68
6 Others 40.52
1185.0

11. SOIL MAP WITH CLASSIFICATION
11
Sr.no soil type
Area in
sq.km
1 Very fine sand 126.3
2 Fine sand 826.0
3 Fine loamy 177.1
4 Coarse loamy 55.7
1185.0

12. SLOPE MAP WITH CLASSIFICATION
12
Sr.no
Slope
range
Area in
Sq.km
1 0 - 1 % 1178.5
2 1 - 3 % 2.0
3 3 - 5 % 0.3
4 5 - 10 % 1.9
5 10 - 15 % 0.5
6 15 - 35 % 1.8
1185.0

13. INTRODUCTION TO SOIL EROSION
13

14.  Soil Erosion is the washing or blowing away by (Water or Wind)
removal of Top Layer of Soil. It is a Natural Process Generally It Is Not
Visually Identify.
14
Small particle
Detachment Transportation
Deposition

15.  UNIVERSAL SOIL LOSS EQUATION (USLE):
 The Universal Soil Loss Equation (USLE) an empirical model for predicting
the annual soil loss caused by rainfall was developed by Wischmeier and
Smith (1965).
 The Universal Soil Loss Equation (USLE) widely applied at watershed scale
to predicts the long-term annual rate of erosion on a field slope based
on rainfall pattern, soil type, topography, crop system and management
practices (Williams and Berndt,1972,1977).
 The Universal Soil Loss Equation is defined as,
A=R*K*LS*C*P
Where,
A= Annual computed Soil Loss (ton/ha/year)
R=Rainfall Erosivity factor
K=Soil Erodibility factor
LS= Slope-length factor
C= Crop management factor
P= Supporting Practice management factor
15

16.  METHODOLOGY :
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 All Five factors (i.e. R,K,LS,C and P) of USLE Equation are calculated as per
above methodology.

17.  In present study, calculation
of Soil Erosion using USLE
based on Sub watershed
level.
 Vishwamitri river watershed
has four sub watersheds
(SW1, SW2, SW3, SW4)
given above in Figure with
area.
17

18.  RAINFALL EROSIVITY (R) FACTOR:
 The R factor was determined using formula given below (Chaudhry and
Nayak, 2003).
Ra=79+0.363*Xa
Where, Ra = Annual R factor,
Xa= Average Annual Rainfall in mm.
 In present study, Rainfall data for 5 rainguage stations are available for
estimating the R factor, such as Halol, Wadala Tank, Vadodara,
Waghodia, Pilol.
18
Station name Rainfall in mm R factor
(Ra=79+0.363*Xa)
Halol 1062.55 464.71
Wadala Tank 677.18 324.82
Vadodara 1020.48 449.43
Waghodia 867.70 393.97
Pilol 869.28 394.55
Table 1: Calculated R- factor

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 The average Calculated R-Factor is given below in Table-2.
Sr. No Sub watershed Calculated R-factor
1 SW1 627.12
2 SW2 920.85
3 SW3 974.92
4 SW4 449.43
Table 2: Calculated average R- factor

20.  SOIL ERODIBILITY (K) FACTOR:
 Soil Erodibility factor represents the soil susceptibility to detachment and
transport of soil particles under an amount of runoff for specific rainfall.
 In the Vishwamitri river watershed consist of soil texture classes namely
1) Course loamy
2) Fine & very fine sand
3) Fine loamy sand.
 Based upon several studies , organic matter content for vishwamitri river
watershed is considered as 2%.
 K values for different soil textures has defined by the stewert et.al (1975) in
Table-3.
20

21. 21
Sr.no Sub watershed
Code
K-factor
1 SW1 0.26
2 SW2 0.25
3 SW3 0.28
4 SW4 0.26
 As per the stewert et.al chart is value of K- factor is taken. The Calculated
Average K-Factor is given below in Table-4.
Table 3: K- factor value (stewart et.al) Table 4: Calculated average
K- factor

22.  SLOPE LENGTH & STEEPNESS (LS) FACTOR
 The slope length and slope steepness can be used in a single index,
which expresses the ratio of soil loss as defined by Wischmeier
(1978).
LS = (X/22.1) m (0.065 + 0.045 S + 0.0065 S)2
here, X = slope length (m or km); S = slope gradient (%)
 Slope value was derived from Digital Elevation Model (DEM) of
vishwamitri river watershed. The values of X and S were derived from
DEM.
 To calculate the slope length (X) value, Flow Accumulation was
derived from the DEM after conducting Fill and Flow Direction
processes by using Arc Hydro tool in ArcGIS 9.3.
22

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 The value of m varies from 0.2 –0.5 depending of the slope (Wischmeier
and Smith1978).
 Using Raster calculator plot the below equation for LS factor map.
LS=
(("Fac"*25/22.1)^0.2)*(0.065+0.045*"Slope"+0.0065*("Slope"*"Slope"))
Sr.no Sub watershed Code LS factor
1 SW1 3.43
2 SW2 3.41
3 SW3 0.12
4 SW4 0.29
Table 5- Calculated LS factor

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Procedure for LS factor
procedure

25.  CROP MANAGEMENT (C) FACTOR
 The crop management factor is
used to reflect the effect of
cropping and management
purpose on erosion rates.
 It is considered the second
major factor (after topography)
controlling soil erosion.
 The C factor is calculated
depending upon different land
use types as per below Table
(Wischmeier and Smith 1978).
25
Land use Sub Land use C-factor
Agriculture
Current Fallow 0.6
Kharif + Rabi (Double cropped) 0.6
Kharif Crop 0.5
Plantations 0.5
Buit up
Commercial 0.2
Industrial 0.2
Towns/cities (Urban) 0.2
Villages (Rural) 0.2
Forest Scrub Forest 0.02
Others
Prosophis and Quarry 0.15
Waste land
Land with Scrub 0.95
Land without Scrub 0.8
Water bodies Canal, Lakes, Rivers 0
Table 6: Values of C- factor

26.  As per given value of C- factor by Wischmeier and Smith in
Table 6.The Average Calculated C-Factor for present study is
given below in Table-7.
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Table 7: Calculated Average C-factor
Sr.no Sub watershed code C-factor
1 SW1 0.30
2 SW2 0.31
3 SW3 0.34
4 SW4 0.31

27.  CONSERVATION PRACTICE (P) FACTOR:
 Conservation practice factor (P) in USLE expresses the
effect of conservation practices that reduce the amount
and rate of runoff, which reduces soil erosion.
 It includes different types of agricultural management
practices such as:
Strip cropping,
Contour farming, and
terracing etc.
27

28.  The value of P–factor ranges from 0 to 1, in which highest value is
assigned to areas with no conservation practices .
 Average P-factor is calculated as given in Table-9 .
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Table 8: P factor on different slope
gradient
Sr.no Slope percentage
(%)
P factor
1 0 - 1 % 0.6
2 1 - 3 % 0.6
3 3 - 5 % 0.5
4 5 - 10 % 0.5
5 10 - 15 % 0.7
6 15 - 35 % 1
Table 9: Calculated average P factor
Sr.no Sub watershed
code
P-factor
1 SW1 0.58
2 SW2 0.58
3 SW3 0.60
4 SW4 0.60

29.  SOIL EROSION CALCULATION
 A Quantitative assessment of vishwamitri river watershed is taken
place using USLE.
 All five parameters of Universal Soil Loss Equation (USLE) is
calculated for each four sub watershed.
 After calculation of all five parameters, annual soil erosion of
vishwamitri river watershed is 240.27 ton /ha/year.
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Sub
watershed
Code
R-
factor
K-factor
LS-
Factor
C-
factor
P-factor
Annual Soil
Erosion
SW1 627.12 0.26 3.43 0.3 0.58 97.31
SW2 920.85 0.25 3.14 0.31 0.58 129.97
SW3 974.92 0.28 0.12 0.34 0.6 6.68
SW4 449.43 0.26 0.29 0.31 0.6 6.30
Total Annual Soil
Erosion 240.27
Table 10:Annual Soil Erosion for different sub watershed

30. Sr.no Sub
watershed
Code
Annual Soil
Erosion
Class group Priority
1 SW1 97.31 Very Severe 2
2 SW2 129.97 Very Severe 1
3 SW3 6.68 Moderate 3
4 SW4 6.30 Moderate 4
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Table-11: Classes of soil erosion & prioritization Vishwamitri watershed
 The computed Annual Soil loss of study area is 240.27 ton
/ha/year.
 It is found that sub watershed coded as SW2 is in very
severe condition which needs to provide controlling
measures.

31. CONCLUSION:
 Soil erosion study is carried out for Vishwamitri
River watershed using Universal Soil Loss
Equation.
 The computed Annual Soil loss of study area is
240.27 ton /ha/year.
 After calculating all five parameters of USLE, it
is found that two sub watersheds coded as
SW1 & SW2 are subjected to very severe
condition which needs to provide controlling
measures.
 Remaining two sub watersheds coded as SW3
& SW4 are subjected to Moderate condition.31

32.  REFERENCES:
32
Agricultural Handbook Number 537, “Prediction Rainfall Erosion losses- A guide to conservation
Planning”, U.S.Department of Agriculture, Dec-1978
A.S.Ravikumar, H.B.Balakrishna, B.K.Anand, Watershed management and Impact of Environmental
changes on Water Resources-Page no-512-521.
Biswas et.al, 1999. Prioritization of Sub watershed based on Morphometric Analysis of Drainage Basin: A
remote sensing and GIS approach Journal of the Indian Society of Remote Sensing, (pg.155-166).
Chauhan Parul, Jadav Rita, P.P.Lodha. “Critical Watershed Analysis for Soil Conservation Management
using Swat model”. Hydraulics and Water Resources: National Conference on Hydraulics and Water
Resources (Hydro-2007), December21-22, 2007
Dr. Lodha, Pradeepkumar P. “ GIS Based Framework for Integrated Watershed Management with
Livelihood Linkages ”, January-2006.
Ghanshyam Das (2000): Hydrology & Soil Conservation Eng. Prentice Hall of India, New Delhi.
Handbook of Hydrology (1972), Soil Conservation Department, New Delhi.
Murthy JVS. Watershed Management In India,(pg.21-34).
Smith and Wischmer (1941), Interpretation of soil conservation data for field use. Agriculture Engineering
(page no .173-175)
USDA manual for Soil Conservation Service (1985), National Engineering Handbook, USA.

33.  http://www.omafra.gov.on.ca/english/engineer/facts/12-
053.html
 http://www.soilerosion.net/
 http://www.vishwamitririverproject.org/
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 USEFUL LINKS:

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