IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
  
STUDY AREA 
The area selected for study is a part of Samastipur district of 
Bihar occupying 86° 05’ to 86° 20° E longitude and 25° 40° to 
25° 55’ N latitude. The study area is a part of Indo Gangetic 
plain and is situated in the North of river Ganga.The area is 
monotonously flat, the only diversities seen on the surface is 
due to the action of rivers Gandak and Burhi Gandak. The 
major constraints of the area are severe flooding and lack of 
drainage network due to relatively flat terrain, clay and silty 
soil. Thus, water spreads over the adjoining river area and 
remains stagnant throughout the year. The water tolerant 
capacity of surface and subsurface soil became saturated 
resulting waterlogging in the area. The most important 
characteristic feature of this region is formation of saucer 
shaped black swamp landscape called “Tal”. 
MATERIALS USED 
Satellite Data: 
Landsat TM — Kharif Season 
Date of Pass — 27.10.1996 
Path/Row — 140/42a 
IRS IC LISS III — Rabi Season 
Date of Pass — 04.03.1997 
Path/Row — 105/53 
Ancillary Data 
a) Survey of India toposheets — No. 72K/1, K2, K5, K6 On 
1:50,000 scales. 
b) Watershed Atlas — Prepared by All India Soil Survey and 
Land use Planning on 1:1,00,000 scale 
c) Village Boundary Maps — From Population Census 1991 
Since cloud free IRS data was not available for September 
October hence Landsat TM data was used instead. 
METHODOLOGY 
Two-season satellite data available on CCT were loaded and 
sub scene within which the study area falls were extracted. A 
standard FCC was prepared by passing IR, Red and green to 
Red, Green and Blue ranges respectively. Linear Contrast 
stretch was performed on the data for optimum utilization of the 
gray scales. The two sets of data were georeferenced to a 
common base on 1:50,000 scale with a geographic co-ordinate 
system and polyconic projection by selecting suitable Ground 
Control Points both on image and reference map. The RMS 
error was well within the limit (1/2 a pixel). The image was 
resample to 23.5m pixel size. Image classification was done 
using MLC. Waterlogged areas were easily identified by its 
low reflectance value (DN value) and black-brown appearance 
on satellite data. However, waterlogged covered with 
vegetation showed deep brown-red color on standard False 
Color Composite (FCC). Similar was the case with salt 
affected land. The high reflectance of salt affected lands marks 
a clear-cut separation with other categories of wastelands. Salt 
affected lands were seen as white and bluish white tone with 
fine texture. These were randomly distributed and were found 
in patches along the streams. Scrublands were identified by 
greenish blue tone and were in plenty in the study area. 
Complete geographic database viz. administrative boundaries, 
Cultural features like rail and road networks, drainage and 
major settlements were generated using Arc/Info GIS software. 
Since the village and watershed, boundaries were of concern in 
the present study hence watershed boundaries and village 
boundaries were marked as per the watershed atlas and village 
census map respectively. Finally, the wasteland map was 
intersected with villages and watersheds to get detailed village 
and watershed wise area statistics. (Table-1 and Table-2). 
RESULTS AND DISCUSSION 
Since the prime objective of the present study was to delineate 
and map the wastelands, which were compiled after the landuse 
land cover classification. Among the eight Landuse classes 
three were wastelands namely waterlogged, scrubland and Salt 
affected land. The statistics pertaining to these classes is given 
in Table 1. Table 2 and 3 show Village wise and Watershed 
wise distribution of wastelands respectively. 
Wastelands were extracted from the landuse/landcover map of 
the area and statistics of each class was generated upto village 
level for proper reclamation. Brief discussions of the 
wasteland classes mapped under the two interpretation 
techniques in the study area are given below. 
Waterlogged land 
The digital analysis showed an area of 6006 hectares, which is 
nearly 18.20 % of the total study area. The results of 
waterlogged area is mainly due to lack of drainage facilities 
because of flat surface. In some of the waterlogged area, water 
mud exists and area covered with weeds. 
Waterlogged'weeds 
These are those categories of land, which is permanently or 
periodically inundated by water and is characterized by 
vegetation which includes grasses and reeds. These appear as 
dark colored patches on the FCC. These patches have been 
found in close vicinity with rivers and cultivated fields. 
However the statistics for these two categories have been have 
been collectively calculated. 
Scrub Land 
Scrublands were scattered in the entire area in small patches. 
The digital analysis showed area of 3256.94 hectares, which is 
9.88% of the total study area. 
Salt Affected Land 
The digital analysis showed an area of 435.74 hectares, which 
is about 11.32% of the total study area. The existence of salt- 
affected land can be attributed to poor drainage facilities in the 
area, which in turn, causes waterlogging and salt affected lands. 
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