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IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
and satellite imagery. Nal Sarovar and its environs fall in four 
1: 50 000 scale SOI maps (46 B/1, B/2, N/13, and N/14). Land 
use/cover map was prepared for the catchments of Nal Sarovar 
using May/November 1998 IRS 1C/D data on 1: 50 000 scale. 
Mapping was done using various elements of visual analysis 
such as tone, texture, shape, size and association corroborated 
with ground truth. 
4. RESULTS AND DISCUSSIONS 
4.1 Structural Components 
Interpretation and analysis of remote sensing data has helped in 
understanding the temporal behaviour of structural components 
of the Nal Sarovar wetland (Fig. 1, 3; Table 3). Total area of the 
Nal Sarovar wetland as estimated using satellite data is 17221 
ha. As per Forest Department, Gujarat, the area of Nal Sarovar 
bird Sanctuary is 12082 ha. 
    
  
    
  
Lisa 
FEE OPEN WATER 
PEN WATER SUBMERCRD Vey 
AY T" 
ses 
sas 
AQUATIC VERGET CTI 
EB MUD PLAT SALT PLAT 
Tod SALT WARTE 
BARREN LET 
VEGETATED rh 
MANS 
PET. AGRICULTURAL LAND 
CT mre 
   
P 
Fig. 2: Structural components of Nal Sarovar 
(Left May 1998, Right November 1998) 
Table 3: Structural components of Nal Sarovar in different 
Years (area in ha) 
Feature | Jan Dec Sep May Nov 
1985 1988 1992 1998 1998 
Open 8357 4077 11484 | 2847 8189 
Water 
Aq. 3659 5085 910 1586 515 
veg. 
Mud 4745 7462 4253 10801 6924 
flat 
  
  
  
  
  
  
  
  
  
  
  
  
Barren 461 597 574 556 383 
islets 
Veg. - - - 67 74 
islets* 
Grass* - - - 283 - 
Salt - - - 932 1032 
waste* 
Agri* - - 148 104 
  
  
  
  
  
  
  
  
Total 17221 17221 17221 17221 17221 
Data of 1985, 1988, and 1992 is of Landsat TM and IRS 1A 
LISS I where due to resolution these categories could not be 
delineated. Source: Satellite imagery of different years. 
  
À significant variation in the area under structural components 
viz. open water, aquatic vegetation (wetland vegetation) and 
mudflats has been observed. This variation appears to be caused 
by rainfall variation and withdrawal of water for irrigation by 
the farmers. A comparison of structural components deciphered 
from post-monsoon 1985, 1988, 1992 and 1998 satellite data 
has brought out that though there is a considerable variation in 
605 
the structural components over the years, nevertheless, 
variation in the total area is not significant. In 1985 cumulative 
total of open water, aquatic vegetation and mudflats was 16761 
ha while in 1988 and 1992 it was 16624 ha and 16647 ha 
respectively. On the imagery of November 1998 area under 
structural components including salt waste and agriculture land 
was 16864 ha. This proves the value of Nal Sarovar as a 
paradise for migratory and resident waterfowl and also no 
serious decline in their population. Rainfall during these years 
was normal and no significant impact was observed in terms of 
total area under structural components. 
4.2 Land use Pattern in the Catchment 
Total catchment area of the Nal Sarovar approximated from 
SOI topographical maps is 74117.98 ha. Fig. 4 depicts land 
cover pattern of the Nal Sarovar catchment and Table 4 gives 
the areal estimates of various land use classes present. 
Agriculture is the main land use in the catchment of Nal 
Sarovar occupying more than 80% area (60079.22 ha). Paddy, 
Jawar (Sorghum), bajra (Pennisetum typhoides) and cotton are 
the main kharif crops while wheat is the major rabi crop. 
Salt waste is the second largest land cover having an area of 
11727.87 ha (15.82%). These lands are characterised by high 
salt content. Due to run off during rainy season from the salt 
waste areas Nal Sarovar acquire its distinct ecological 
characteristic. 
Other land cover types in the catchment are mudflat (640 ha), 
grasslands (560 ha), Prosopis (441 ha), Tanks/ponds (506 ha) 
besides settlements. These cover types provide nesting, resting 
and roosting habitats for the avi-fauna. 
LEGEND 
TR 
    
  
EN WATER 
AQUATIC VEGETA 
MUD FIL.AT / SAI. T F 
SALT WASTE 
   
    
EN ISLET 
VEGETATED ISLET 
£0 GRASS LAND 
LN PROSOPIS 
AGRICULTURAL L.A 
POND / TANK 
Fig. 4: Land use map of Nal Sarovar 
Land use pattern surrounding a wetland exercise a profound 
effect on the health of wetland ecosystem. As has been brought 
out in the present study agriculture is the main land use in the 
vicinity of Nal Sarovar. Due to runoff during the rainy season a 
substantial amount of silt load rich in nutrients is brought into