1. Introduction
Land, air and water may be regarded as a stock of natural resource assets, which provide a range of functions to meet the increasing human need for food, fodder and fuel wood combined with industrial activities. Recent research indicates that the human induced conversions and modifications of land cover have significance for the functioning of the earth system. Though landuse is mainly controlled by, various biophysical factors like soil, climate, relief and vegetation but the human activities are mainly responsible for the change of attributes of landuse modification and conversion. Continuous exploitation of natural resources beyond threshold limit of resilience of the ecosystem accelerates various geomorphic processes on the earth surface, thereby causing imbalance in natural ecosystem resulting in large-scale disaster in present day habitation. The impact of landuse in the prevailing surface and subsurface hydrologic conditions is remarkably high. Within a basin, the dynamics of hydrologic processes are governed partially by the temporal and spatial characteristics of inputs and outputs and the landuse conditions (Shih, 1996). Keeping these factors in view a full featured spatial information about the changeable landform features and related landuse (i.e. land-water-vegetation inter-relationship) on a natural unit basis is very essential for integrating the same with the related non-spatial data (e.g. demographic, socio-economic etc.) to obtain a real world feature.
The fullest utilization of the potential of the two technologies can be realized only when an integrated approach is adopted. Blending of the these two technologies has proved to be an efficient tool in groundwater studies (Gustafsson, 1993; Saraf and Jain, 1994; Saraf et al., 1994; Krishnamurthy and Sriniwas, 1995; Krishnamurthy et al., 1996; Saraf and Choudhury, 1997; Saraf and Choudhury, 1998 and Saraf et al, 1999). The present study demonstrates the capabilities of LISS-II and LISS-III (Linear Imaging self Scanning Sensor) in understanding the landuse-groundwater relationship and changes in landuse pattern. LISS-III provides higher spatial resolution 23.5m, which makes ground features more prominent in comparison with LISS-II having spatial resolution 36.5m.
The main objectives of the study were:
-
to develop an integrated remote sensing and GIS technique to establish and evaluate the relationship between landuse and groundwater hydrology,
- to identify factors influencing this relationship and their role in controlling the groundwater scenario of the study area,
- to evaluate the nature of changes in selected landuse categories,
- to have a quantitative assessment of groundwater recharge,
- to delineate the groundwater potential zones in the area,
- to suggest suitable sites for artificial
recharge to augment groundwater in the study area.
2. Study Area
The study area has been chosen as it represents a typical case of landuse impact on groundwater. The Dwarkeshwar watershed with a semi-elliptical shape occupies the northeastern part of Purulia district, but the major part of the Dwarkeshwar watershed is situated in a part of Bankura district of West Bengal state, India. The Dwarkeshwar watershed is bounded by longitudes 86°37’E and 87°28’E and latitudes 23°00’N and 23°32’N. The total area of the watershed is 2270 km2 and it is in between the Damodar basin (to the north) and Kangsabati basin (to the south).
The study area comprises of Precambrian crystallines and recently deposited alluvium connected by an intervening tract (GSI, 1997). In this area, monsoon groundwater recharge cannot meet the demands for groundwater throughout the year. Artificial recharge is necessary to improve the groundwater conditions in the area. In the past, very little thought had been given to utilize artificial recharge methods at suitable locations. The present work is an attempt in this direction.