IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002
GEO-SPATIAL DATABASE FOR PRIORITIZATION AND EVALUATION OF
CONSERVATION STRATEGIES FOR LANDSCAPE MANAGEMENT IN A RIVER
BASIN
G.P. Obi Reddy", A.K. Maji", G.R. Chary*, C.V. Srinivas’, P. Tiwary® and K.S. Gajbhiye®
“National Bureau of Soil Survey & Land Use Planning, Amaravati Road, Nagpur-440 010, India
"Sr. Scientific Officer, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102, India.
E-mail: obireddy @nbsslup.mah.nic.in
KEYWORDS: Geo-spatial database, GIS, Landscape, Morphometry, Prioritization, River basin
ABSTRACT:
In the present study, an attempt has been made to assess the status of soil erosion for prioritization and evaluation of conservation
measures using basin morphometry and Universal Soil Loss Equation (USLE) parameters in GIS. The quantitative morphometric
parameters were computed at sub basin level and ranks were assigned in prioritization of sub basins based on erosional
characteristics of linear, areal and shape parameters. The quantification of rainfall erosivity (R), topographic factor (LS) and soil
erodibility (K) factor were used as inputs in GIS to estimate quantitative potential soil erosion. The area under moderately severe,
severe, very severe and extremely severe potential soil erosion occupied 7.62, 8.21, 5.33 and 24.86 per cent of the total area. The
actual soil erosion was estimated considering cover (C) and management (P) factors besides R, LS and K factors in GIS. The area
under moderately severe, severe, very severe and extremely severe was noticed nearly 4.01, 6.97, 6.15 and 16.74 per cent of the total
area. The sub basins were ranked based on the comparative analysis of quantitative morphometric, estimated potential and actual soi!
loss parameters. In the processes of evaluation of conservation measures the estimated potential soil erosion, slope, soil depth, soil
texture, land use/land cover layers were assigned weightages and scores for their classes in the multi-criteria overlay analysis in GIS.
The prioritization of sub basins and erosion susceptibility zone mapping will be of immense help in evaluation of site-specific
appropriate conservation measures for optimal utilization of available land and water resources to minimize soil erosion and improve
water availability on sustainable basis.
INTRODUCTION treatment. The quantitative analysis of drainage pattern is an
important aspect of characterization of river basins (Strahler,
Soil and water are the two basic resources of the country which 1964). Remote sensing and GIS techniques are being
must be carefully conserved and judiciously utilized to sustain effectively used in recent times as a tools in determining the
the ever increasing human and livestock population (Sharda, quantitative description of river basins (Biswas et al., 1999).
2002). India ranks high among the developing countries in The data sets in the core of GIS provides an excellent means of
respect of both extent and severity of land degradation (Yadav, storing, retrieving, manipulating and analysing geo-referenced
1996). The nature and extent of degraded lands of the country information (Burrough, 1986). Geo-spatial database on
were projected by various agencies from time to time (National drainage, slope, landforms, soils, land use/land cover and
Commission on Agriculture, 1976; Bhumbla and Khare, 1984: management practices is a pre-requisite for integrated analysis
Govt. of India, 1994). In India extent of soil degradation under in GIS to prioritize and evaluate the conservation strategies for
different degradation types was estimated nearly 187.7 million landscape management. In the present study, an attempt has
hectares (Sehgal and Abrol, 1994). Methods of qualitative been made to prioritize sub basins of Vena basin, Nagpur
assessment of soil erosion stressed the need to asses the district, Maharashtra based on the morphometric, estimated
combined effects of terrain attributes to identify and demarcate potential and actual soil loss parameters using USLE for
those zones that are relatively under various types of erosion evaluation of appropriate soil conservation measures.
and need priority conservation measures (Sharma et al, 1985;
Gawande, 1989). The Universal Soil Loss Equation (USLE) is MATERIALS AND METHODS
the empirical equation for the estimation of soil loss depending
on the existing conditions of slope, slope length, rainfall The methodology followed in this study is shown in figure
erosivity, soil erodibility, cover conditions and management l.The morphometric and slope parameters of the area were
factors of the given terrain (Wischmeier and Smith, 1978). The analyzed based on the drainage and contour information. The
river basin has been divided into 19 sub basins and quantitative
morphometric parameters at sub basin level have been
computed. The FCC of IRS-ID, LISS-III data of November,
1999 and March, 2000 were used for analysis of land use/land
cover based on the Maximum Likelihood Classification (MLC)
algorithm (Anderson, 1976). Visual interpretation techniques
have been followed in the analysis and generation of landforms
map based on the tone, texture, shape, drainage pattern, color
and differential erosion characteristics of the satellite imagery.
The geo-spatial database on landforms, soils and land use/land
cover properties from remotely sensed data and conventional
surveys have been generated in GIS. The USLE parameters
advent of remote sensing technology has paved the way to
gather information about the earth's resources more accurately
than conventional methods (Colwel, 1978; Karale et al., 1988).
Analysis of satellite data for drainage, lithology, landforms,
soils and land use/land cover aspects in conjunction with
collateral data, facilitate effective evaluation of status of soil
erosion.
River basin is the geo-hydrological unit drained to a common
point and it is considered as a appropriate physical unit for soil
loss estimation and prioritization of units for ridge to valley
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