Ramachandran, Kausalya 
GIS FOR POINT-SOURCE POLLUTANT DISPERSAL ANALYSIS 
Kausalya Ramachandran* & LV. Muralikrishna** 
* Senior Scientist, Central Research Institute for Dryland Agriculture (ICAR), Hyderabad - 500059, India 
*** Professor & Head, Centre for Spatial Information Technology, Jawaharlal Nehru Technological University, 
Hyderabad - 500029, India 
kaushivs yahoo.com 
iyyanki Q yahoo.com 
Working Group WG VII / 2 
KEY WORDS: Chemical dispersion, GIS, Land use/Land cover, Monitoring, Multi-sensor, Remote sensing, Soil 
quality, Water quality. 
ABSTRACT 
Point-source pollution due to H-acid - a dye intermediate, leaching into subsurface from a factory storage facility in 
Bichhri in Rajasthan, India, led to groundwater and soil contamination since 1988. Satellite data, soil and groundwater 
sampling and their integration with resource maps of the region in ARC/INFO GIS, enabled the study of H-acid 
dispersion in soil and groundwater which had adverse impact on land use/land cover and the life of the residents. 
Application of GIS for overlay of maps of various themes, viz., land use/ land cover, hydro-geomorphology, 
groundwater potential, soil types, land capability and H-acid conc. in soil and groundwater, enabled the assessment of 
magnitude of H-acid contamination in the area. Significantly, H-acid conc. in soil extracts of surface and subsurface soil 
by far, exceeded the concentration level in ground water; H-acid conc. was 4000 - 7000 mg/kg in soil extract while it 
ranged between 2 - 50 mg/l in groundwater in 1998. 
GIS map-union using plots of H-acid conc. in groundwater with hydro-geomorphology of the region, indicated the 
magnitude of aquifer contamination. Areas with varying H-acid concentration levels were delineated; it was noted that 
over 3.1 Km? was contaminated with « 1 mg/l while 0.02 Km? was polluted with 500 mg/l. This analysis has facilitated 
in the estimation of cost of ameliorative measures necessary for cleanup. Fortunately, since 1998 the H-acid conc. has 
declined both in soil and groundwater owing to the passage of several hydrological cycles, as indicated by the gradual 
return of agricultural activity in the region. 
1. INTRODUCTION 
1.1 Location and natural resource base of study area 
Bichhri village, the focus of this study, is located at 24° 35 N and 73° 46 E, app. 16 Kms towards the Southeast of 
Udaipur city in the State of Rajasthan in India. The region lies in a transition belt between hot arid climate in west and 
sub-humid climate towards the east with a mean rainfall of 581 mm. Koppen's climate classification defines the area as 
BShw, i.e., warm semi-arid steppe type with mean annual temperature over 18°C. This typical climate is a result of its 
location near the Tropic of Cancer and the periphery of the Great Indian Thar Desert, which is moderated by the large 
water bodies located around Udaipur City, within the region. 
Geologically, the region belongs to the Archean Shield of the Deccan Plateau consisting of well-foliated, highly 
contorted and faulted Gneiss Basement Complex. The region belongs to Aravalli hill system and local geomorphology 
indicates denuded slopes and plain which is nearing peneplanation. The region forms a water-divide where the western 
streams drain into Sabarmati river which flows into the Arabian Sea and the eastern streams drain into east-flowing 
rivers flowing into the Bay of Bengal. The drainage density within the region varies from 0.5 to 0.7 Km/Km®. Five large 
earth-excavated tanks dot the Udaipur city, moderating the climatic rigour. 
Groundwater occur and circulate mainly through the weathered zones and weak planes like joints and fissures in 
Quartzite while in Phyllite and Schist, it occurs in fractured bedding. The water-table varies from 5 to 30 m below 
ground level and the yield from wells vary from 15 to 150 m/ day. Natural vegetation vary from deciduous to sub- 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1225