The document discusses a soil erosion estimation project using GIS modeling in the Potohar region of Pakistan. It presents the Universal Soil Loss Equation (USLE) model which estimates long-term average annual soil loss based on rainfall patterns, soil type, topography, crop systems, and management practices. Factors like rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), vegetation and management (C), and support practices (P) are calculated within a GIS to estimate soil loss across the study area. Maps are created to spatially analyze the various USLE factors and the final soil erosion estimation.

1. PMAS ARID AGRICULTURE UNIVERSITY RAWALPINDI
Spatial Data Analysis
RSG – 511
Presentation
Group Members
Kashaf Bukhari (20-Arid-1333)
Nouman Ejaz (20-Arid-1328)
Muhammad Umair (20-Arid-1323)

2. PROJECT NAME
SOIL EROSION ESTIMATION USING GIS MODEL

3. SOIL EROSION ESTIMATION
• Introduction
• Soil erosion is caused by detachment and removal of soil particles from land surface. It is a natural
physical phenomenon, which has helped in shaping the present form of earth’s surface. With the advent
of modern civilization, the pressure on land increased, which lead to its overexploitation, and
subsequently, its degradation.
• Soil erosion is the removal of soils by water and/or wind. Erosion is slight from soil well covered by
dense grasses or forest, but is enormous from steep, poorly covered soil that are exposed to heavy
rainfall or strong winds. Well-aggregated soils resist erosion but pulverized silts and very fine sands are
the most easily eroded. The land area of our Country has been widely affected by water and wind
erosion.

4. STUDY AREA
POTOHAR REGION
• In fact, Potohar is a region in the Punjab which comprises four districts:
• Rawalpindi,
• Attock,
• Chakwal
• Attock.
• Islamabad, the country’s capital, also lies in the Potohar region.

5. MODEL OF EROSION
Universal Soil Loss Equation (USLE):
• Universal soil loss equation or USLE was developed by Wishmeyer and Smith in 1950s. USLE estimates
the long-term average annual rate of erosion on a field slope based on rainfall pattern soil type
topography crop system and management practices.
• The Universal Soil Loss Equation (USLE) by Wischmeier and Smith (1978) is a simplified model and was
found to be used most commonly throughout the literature because of its simplicity.
• Universal Soil Loss Equation (USLE) is used to predict longtime average soil losses in runoff from
watershed areas.

6. FORMULA
The Universal Soil Loss Equation is as follows:
A = R * K * L * S * C * P
Where,
• A is the average annual soil loss (tons/ha/year)
• R stands for rainfall erosivity (joules/(ha/year), (t-m/ha) (mm/h) per year)
• K is the soil irritability factor (tons/ha)/erosivity factor (R), t/joules, t/ha-year
• LS is the topographic factor c is (dimensionless)
• the cropping management factors (dimensionless)
• P is the practice support factor

7. GRAPHICAL REPRESENTATION

8. HOW TO CALCULATE
TOPOGRAPHIC FACTOR (LS)
• Topographic factors LS consist of slope length L and slope steepness S
• Data Required:
• DEM (12.5 meter)
• Shapefile of Area of Study
• Formula:
The slope length is calculated by the following equation
L = [(FA * cell size) / 22.13]m (Moore and Wilson 1992) where FA stands for the flow accumulation and m ranges from
0.2 to 0.6
This formula was developed by Moore and Wilson in 1992 whereas slope stiffness can be calculated by the another
formula
S = [(Sin β * 0.01745/0.09)]ⁿ
To Calculate Total LS Factor we
use the Formula
LS = LS / 100

9. MAP LAYOUT

10. HOW TO CALCULATE VEGETATION AND
MANAGEMENT FACTOR (C)
• It is used to determine the relative effectiveness of soil and crop management system in preventing the
soil loss
• Data Required:
• LULC data (10 Meter)
• Shapefile of Area of Study

11. MAP LAYOUT