I NDI AN SCHOOL OF MI NES Soil Erosion Hazard Evaluation By - - PowerPoint PPT Presentation

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I NDI AN SCHOOL OF MI NES Soil Erosion Hazard Evaluation By - - PowerPoint PPT Presentation

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I NDI AN SCHOOL OF MI NES Soil Erosion Hazard Evaluation By Integrating Revised Universal Soil Loss Equation (RUSLE) Revised Universal Soil Loss Equation (RUSLE) With GIS Techniques Dr. Dheeraj Kumar Dr. Dheeraj Kumar Dr. Dheeraj Kumar Dr.

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I NDI AN SCHOOL OF MI NES

Soil Erosion Hazard Evaluation By Integrating Revised Universal Soil Loss Equation (RUSLE) Revised Universal Soil Loss Equation (RUSLE) With GIS Techniques

  • Dr. Dheeraj Kumar
  • Dr. Dheeraj Kumar

Kuldeep Pathak

  • Dr. Dheeraj Kumar
  • Dr. Dheeraj Kumar

B.Tech B.Tech, M.Tech, Ph.D.(IIT KGP) , M.Tech, Ph.D.(IIT KGP) Head, Mine Surveying Section Head, Mine Surveying Section dheeraj@dkumar.org dheeraj@dkumar.org

Kuldeep Pathak

M.Tech (ISM Dhanbad) Survey Executive, Hindustan Zinc Ltd., India

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SLIDE 2
  • Quantitative

Assessment

  • f

soil

erosion

is

cumbersome and costly activity. cumbersome and costly activity.

  • The

advent

  • f

new techniques

for erosion assessment and recent developments in Remote assessment and recent developments in Remote

Sensing and Geographic Information Systems (GIS) has promoted a prominent growth in the number

and variety of GIS based models.

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SLIDE 3

Study area

  • The study area is located in Nainital district of

Uttrakhand in outer Himalayan region foothill zone, Uttrakhand in outer Himalayan region foothill zone,

lies between 29°19'48

to 29°24'0 N latitude and

79°26'24 to 79°34'12 E longitude.

  • The land is highly to moderately populated, with fragile
  • The land is highly to moderately populated, with fragile

soils and steep slopes that are highly prone to soil

erosion during the monsoon season.

  • The area is suffering with declining soil fertility due to

high erosion and nutrient leaching through run-off.

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RESEARCH OBJECTIVE

  • To generate a spatial erosion map with Revised

Universal Soil Loss Equation (RUSLE) method Universal Soil Loss Equation (RUSLE) method and GIS techniques.

  • To develop a numerical model for soil erosion
  • To develop a numerical model for soil erosion

hazard assessment to compute a soil erosion hazard index.

  • To assist erosion management strategies for

efficient management of present and future erosion disaster. disaster.

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SLIDE 6

METHODOLOGY

  • To choose most appropriate Soil Erosion Estimation

Method. Method.

  • Data acquisition and preparation.
  • Hazard

assessment

by

proper

decision making technique.

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SLIDE 7

METHODOLOGY METHODOLOGY

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SLIDE 8

SOIL EROSION ESTIMATION METHOD

  • Universal Soil Loss Equation/Revised Universal Soil

Loss Equation (USLE/RUSLE) Loss Equation (USLE/RUSLE)

  • Limburg Soil Erosion Model (LISEM)
  • European Soil Erosion Model (EUROSEM)
  • Soil and Water Assessment Tool (SWAT)
  • Others
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The Revised Universal Soil Loss Equation The Revised Universal Soil Loss Equation

The equation is the function of five input factors which are in raster format and soil erosion can be estimated within each

pixel. pixel. A= ( R * K * LS * C * P ) A= ( R * K * LS * C * P ) where:

  • A is the computed spatial average of soil loss over a period
  • R factor is a measure of rainfall-based erosivity
  • K factor is a measure of inherent soil surface erodibility
  • LS factor is a measure of slope length and steepness
  • LS factor is a measure of slope length and steepness
  • C factor is a measure of soil surface protective cover
  • P factor is a measure of soil conservation or management
  • P factor is a measure of soil conservation or management

practices

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DATA ACQUISITION AND PREPARATION

  • Satellite image , Landsat TM (Oct 24, 2011)
  • DEM Digital Elevation Model, ASTER GLOBAL

DEM (Geo-referenced Tagged Image File Format)

downloaded from USGS website downloaded from USGS website

  • Soil attribute data
  • Monthly

rain

fall

data from Indian meteorological department.

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SLIDE 11

DATA ACQUISITION AND PREPARATION

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RAINFALL-RUNOFF EROSIVITY FACTOR (R)

  • Rainfall erosivity is a term that is used to describe the potential for soil to wash
  • ff disturbed, de-vegetated areas and into surface waters of the state during

storms.

  • Rainfall data collected from Indian Meteorological Department (IMD) were used
  • Rainfall data collected from Indian Meteorological Department (IMD) were used

for

calculating

R-factor

using the following relationship developed by Renard and Feimund (1994): Where R is the yearly rainfall erosivity factor (MJmmha-1 h-1 y-1), Pi is the monthly rainfall (mm), and P is the annual rainfall (mm). F is the modified Fourier rainfall (mm), and P is the annual rainfall (mm). F is the modified Fourier coefficient

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SOIL ERODIBILITY FACTOR (K)

  • Soil erodibility factor K represents both susceptibility
  • f soil to erosion and the rate of runoff, as measured
  • f soil to erosion and the rate of runoff, as measured

under the standard unit plot condition.

  • To generate individual factor map for K, the method
  • To generate individual factor map for K, the method

which was followed is shown in Eq. (William and Renard,1983): Where Sd, Si, Cl and C represent sand (%), silt (%), clay

(%) and carbon (%), respectively.

(%) and carbon (%), respectively.

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TEXTURE OF THE SOIL (SAMPLE TESTED)

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SLIDE 15

K-FACTOR MAP K-FACTOR MAP

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SLOPE LENGTH AND STEEPNESS FACTOR (LS)

  • L is the slope length factor, representing the effect
  • f slope length on erosion.
  • f slope length on erosion.
  • LS-factor is computed by means of ArcInfo ArcGIS

Spatial analyst extension using the DEM following Spatial analyst extension using the DEM following the equation as proposed by Moore and Burch (1986a, b) (1986a, b)

Pow(([flow accumulation] *

30)

/

22.13,

0.4) * Pow(Sin([slope] / 0.896), 1.3) Pow(Sin([slope] / 0.896), 1.3)

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SLIDE 17

FLOW ACCUMULATION FLOW ACCUMULATION

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SLOPE FACTOR MAP SLOPE FACTOR MAP

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LS FACTOR MAP LS FACTOR MAP

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COVER MANAGEMENT FACTOR (C)

  • The C-factor is used to determine the relative

effectiveness of soil management system in effectiveness of soil management system in

terms of preventing soil loss.

  • The Normalized Difference Vegetation Index

(NDVI), an indicator of the vegetation vigor and (NDVI), an indicator of the vegetation vigor and health is used to generate the C-factor value

image for the study area (Zhou et al., 2008; Kouli

et al., 2009). et al., 2009).

  • Command in raster calculator is:

(Exp(( - 2)[ndvi] / (1-[ndvi])

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SLIDE 21

COVER MANAGEMENT FACTOR MAP COVER MANAGEMENT FACTOR MAP

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CONSERVATION PRACTICE FACTOR (P) CONSERVATION PRACTICE FACTOR (P)

  • The support practice factor (P-factor) is the soil-loss

ratio with a specific

support

practice

to the

ratio with a specific

support

practice

to the corresponding soil loss with up and down slope

tillage (Renard et al., 1997).

  • In the present study the P-factor map was derived
  • In the present study the P-factor map was derived

from the land use/land cover and support factors.

  • the

P factor

was assigned according

to the conservation practice in the area which ranges from conservation practice in the area which ranges from 0.0 to 1.0, with the highest value assigned to areas

with no conservation practices.

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CONSERVATION PRACTICE FACTOR MAP

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EROSION ESTIMATION MAP

  • The erosion estimation map is prepared by RUSLE equation by multiplying each component map

in raster calculator tool of ArcGIS. in raster calculator tool of ArcGIS.

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HAZARD ASSESSMENT HAZARD ASSESSMENT

  • Approach

to

decomposition-analysis-aggregation

was used for the initial, ill-defined evaluation criteria. was used for the initial, ill-defined evaluation criteria.

  • Analytical

hierarchy process (AHP)

(Saaty,1977)

approach was used for standardization of different approach was used for standardization of different

criteria.

  • The relevant criteria for soil erosion by water are soil

erodibility, slope, soil depth, rainfall, elevation, erodibility, slope, soil depth, rainfall, elevation, vegetation, population density and the presence of existing soil erosion.

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STANDARDIZATION STANDARDIZATION

  • In

this study the AHP

utilizing expert judgment was used to determine the was used to determine the degree of hazard.

  • First,

a

decision-maker makes

a comparison

makes

a comparison between

each element under evaluation. Later, these are converted

to

these are converted

to

quantitative values using a scale designed by

Saaty

(1977):

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SLIDE 27

Standardized weighted maps of selected factors

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SLIDE 28

E

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COMPUTATION OF HAZARD INDEX COMPUTATION OF HAZARD INDEX

Pair-wise comparison matrix for standardized factor maps: Using these values from table the final model for Hazard index can be stated as : Hxy= (8.09108)S1 + (6.373)S2 + (4.52682)S3 + (10)S4 + (1.42785)S5 + (5.9577)S6 + (2.53019)S7 + Hxy= (8.09108)S1 + (6.373)S2 + (4.52682)S3 + (10)S4 + (1.42785)S5 + (5.9577)S6 + (2.53019)S7 + (1.029235)S8

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RESULT AND DISCUSSION

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SLIDE 31

STATISTICS OF GRADED SOIL EROSION HAZARD

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SLIDE 32

SOIL EROSION HAZARD MAP

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SLIDE 33

Soil erosion hazard with soil erosion rate

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Hazard class Rate of Soil erosion Management strategies

SOIL EROSION MANAGEMENT STRATEGIES

Hazard class Rate of Soil erosion Management strategies Very low to low (0-181) Low (=244 t/h/year) These areas should be protected strictly with very less human activities and Lumbering. Moderate Low (=244 t/h/year) Should be protected from vegetation degradation and removal and made stabilize with proper plantation. Moderate (181-214) removal and made stabilize with proper plantation. Moderate (244-754 t/h/year) Lumbering, human activities, vegetation degradation should be stopped .Stabilization through plantation.

High to very high (>214)

Low (=244 t/h/year) Proper land use planning is needed as conservation tillage, suitable cropping pattern as there is probability that the rate

  • f erosion will increase.

Moderate (244-754 t/h/year) Environment impact assessment must be performed and Moderate (244-754 t/h/year) Environment impact assessment must be performed and crop rotation practice should be done with soil management program.

High (=754 t/h/year) On emergency basis priority should be given to control and

protect areas from erosion. Conservation tillage and other protect areas from erosion. Conservation tillage and other engineering structures (contour banding, contour hedgerows) should be properly implemented.

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CONCLUSION

  • 1. Soil erosion hazard map along with annual soil loss map can be

effectively used to formulate appropriate management effectively used to formulate appropriate management strategies for protection and conservation of soil erosion.

  • 2. By appropriate adjustment of some local influence factors, the
  • 2. By appropriate adjustment of some local influence factors, the

model could be applied to other regions. Hence, hazard index is considered useful for spatial planning for policy maker and considered useful for spatial planning for policy maker and planning authorities, particularly to soil scientists and conservationists.

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