JAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002
ESTIMATION OF SOIL LOSS AND LAND USE ADJUSTMENT PLANING THROUGH
INTEGRATED USE OF REMOTE SENSING AND GIS-A CASE STUDY IN A PART OF
GANJAM DISTRICT ORISSA.
Jiten Malakar^*, Pradip Dutta?.
“Soil Conservation Research Divisiion, R.G.Baruah Road, Guwahati-5, India.
"Directorate of Soil Conservation, Assam, R.G.Baruah Road, Guwahati —5, India
KEY WORDS: IRS, Land cover, DEM, Sustainable, GIS, Software, Modelling, Estimation
ABSTRACT:
The study area a part of Ganjam District, with an extent of about 700 Sq. km lies North South Part of Orissa. Through visual
interpretation of remotely sensed data IRS-1C LISS III (1: 50,000 Scale) supplemented with intensified field checks land use/ land
Cover and physiography-soil map are prepared. Then using SOI topographical maps a contour map is prepared by on screen
digitization. Then DEM is generated through interpolation of contour and slope in percentage and degree is also generated first by
running dfdx and dfdy filter and using necessary commands under ILWIS software. And, by classifying DEM in different classes an
elevation zone map is also generated. Accordingly soil loss has quantitatively been estimated under GIS environment using the
universal soil loss equitation formula and categorized into five erosion classes (EQ — E4). Land capability class map is then generated
by integrating capability class of soil, topography and soil erosion class map using the suitable operational commands. The land use
adjustment map has ultimately been generated by integrating present land use map and land capability map which contains
information essential for making decisions on future land use planning, adjustment needs, Conservation needs and possible
resettlement etc.
INTRODUCTION
The study area lies between 84°30’E to 84°45°E longitude and
19°30’N to 19°45°N latitude covered by SOI topographical map
no.74 A/18 on 1:50000 scale with an extent of 700 sq. km
bounded on the north by Phulbani and Puri district, on the south
by Srikakulam district of the State of Andhra Pradesh, on the
west by Koraput district and on the east by Puri district and the
Bay of Bengal. The area mostly comes under hard rock terrain
with a narrow strip of alluvial formation along the River
Roshikulya. Physiography of the district is divisible into the
eastern plains and the western tablelands rising to the height of
above 1400m msl towards the center and south. Since the hills
of the districts are close to the sea, the rivers flowing from the
hills are not very large so they are subjected to sudden floods.
The climate is semi arid with mild to severe summer and mild
cold winter. The average annual rainfall of the district figures at
1295.6mm. More than half of the yearly rainfall received
during June, July, August and September. On and average there
are 65 rainy days in a year. The period from March to May is
one of the continuous increases of temperature, and June is the
hottest month with mean daily maximum temperature at 32.2°C
and mean daily minimum temperature at 16.9°C and mean daily
maximum at 27.5°C. Relative humidity is as high as about 75%
throughout the year. The soil moisture regime is ustic. The
natural vegetation mostly is of tropical moist and dry deciduous
forest. A large number of medicinal plants are also available in
the hilly forest.
Agriculture is the main stay of the people. Their another
occupation is also rearing of cattle and buffaloes for supply of
milk. They graze their cattle in the slopes due to which the soil
is directly exposed and eroded to a great extent. The hills for
the most part are moderate to severely eroded. Here, using the
Universal Soil Loss Equitation (USLE) with an ultimate aim to
prepare a land use adjustment plan to conserve Soil resource for
sustainable development of the area through integration of land
capability and present land use/land cover map under GIS
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environment are studied. Accordingly slope map in percentage
and degrees, elevation zone map, physiography-soil map are
prepared where land use / land cover map generated through
visual interpretation of remotely sensed data are being used as
major input. After being integrated the land capability class
map and soil loss map ultimately the land use adjustment map
has been generated which contains information essential for
making decisions on future land use planning, adjustment
needs, conservation needs and possible resettlement etc.
METHODOLOGY
Land use land cover map
Pre field interpretation was done with the help of IRS-1C LISS
III FCC dt.11™ Oct’ 96, 15" May' 97 and 5" June’ 98,
(1:50,000 scale) and verified in the field. Relationship of image
interpretation units with that of ground features were
established and legends are then finalized which comprises of
dense scrub, gullied land, kharif and rabi crop, land with scrub,
open scrub, plantation and rabi crop land.
Preparation of the base map, contour map, DEM, drainage
map etc.
The base map is prepared using SOI toposhets and satellite
imagery depicting permanent features such as road, rivers,
canals, habitations, major drainage lines etc. A contour map is
prepared by on screen digitization of SOI toposheets. Digital
elevation model (DEM) is generated through interpolation of
contour map. Slope in percentage is generated by running dfdx
and dfdy filter using the command,
Slope = ((Hyp (dx, dy)/23.5))X 100.