JAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002
moisture status and subsequent development of vegetation
cover. An objective assessment of such an impact enables
implementing authorities to effect midcourse correction, if
required. Reported hereunder are two such case studies wherein
spaceborne multi-spectral and multi-temporal measurements
have been used for assessment of the impact of interventions
aimed at preventing/reducing soil loss.
2.1 Test Sites
Two test sites — (i) Adarsha micro-watershed in Kothapally
village, Shankarpally mandal (an administrative unit) of Ranga
Reddy district, Andhra Pradesh lying between geo-coordinates
17° 21° to 17°24’N and 78° 5° to 78° 8'E, and (ii) Lalatora
micro watershed, Lalatora village, Vidisha district of Madhya
Pradesh, central India (Fig.1) representing predominantly black
soil region were selected to realize the objective of the study.
Fig 1. Location map of the test sites
2.2 Database
The Indian Remote Sensing Satellite (IRS-1B, 1C and-1D)
Linear Imaging Self-scanning Sensor (LISS-IIIII) and
Panchromatic sensor (PAN) data were used for ' deriving
information on various natural resources and for generation of
intervention plans for sustainable development of land and
water resources — (Table-1). In addition, Survey of India
topographic maps at 1:50,000 scale, and published soil and
other resources maps, and reports were also utilised as
collateral information.
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Table - 1 The details of remote sensing data used
S. | Satellite/sensor Path/row | Date of pass
No Nos.
1 IRS-1B LISS-II | 26-56 25-11-1996
2 IRS-1D LISS-III | 99-60 29-11-1999
3 IRS-1D PAN 99-60 01-12-1999
4 IRS 1C LISS-III | 97-55 16-02-1997
5 IRS-1D LISS-III | 97-55 02-02-2001
6 IRS 1C WiFS 97-56 01-02-2000
7 IRS 1C WiFS 103-58 02-03-2000
8 IRS 1D WiFS 98-55 28-09-2001
9 IRS 1D WiFS 104-57 19-09-2001
10 | IRS P3 WiFS 98-55 06-10-2001
11 | IRS P3 WiFS 104-57 12-10-2000
2.3 Approach
Information on agricultural land use/land cover and soil erosion
status was generated through computer-assisted digital analysis
of multi-temporal IRS-1C LISS-II/LISS-III data of 1996/1997
and 2000/2001 using Gaussian maximum likelihood per-pixel
classifier. Since vegetation condition is the reflection of soils
and hydrological conditions that are altered in the event of
implementation of suggested interventions, the Normalized
Difference Vegetation Index (NDVI), which is an indicator of
vegetation condition and vigor was also generated from the
spectral measurements in red and near IR region of the
spectrum.
2.4 Results and Discussion
The NDVI has been used as a surrogate measure of terrain
transformation in terms of changes in ground water table and
soil moisture status, and its effect on vegetation cover as a
consequence of the adoption of soil and water conservation
measures. A close look at Figure-2 depicting the NDVI images
of Adarsha micro-watershed for the years 1996 and 2000
reveals a considerable increase in vegetation cover during this
period. The changes in the vegetation cover could be seen in the
NDVI images as light and dark grey colours representing
moderately dense and dense vegetation cover, respectively.
The spatial extent of moderately dense vegetation cover that
‘was 129ha in 1996 had risen to 152 ha by 2000. There is,
however, no perceptible change in the dense vegetation cover.
Being rich in water dispersible clays, soils of Lalatora micro-
watershed are more susceptible to soil erosion by water as
compared to soils of Adarsha micro watershed. The results of
Lalatora micro watershed indicate an increase in the crop land
to the tune of 269 ha i. e. 3,402, ha in 1997 versus 3672 ha in
2001, during four years period. Contrastingly, there has been
an attendant shrinkage in fallow lands. The fact is supported by
an increase in area under vegetation cover during this period as
indicated by NDVI. There has been an increase in the area
