Remote Sensing and GIS Approach for Delineating and characterization of Groundwater Potential Zones in Hard Rock Terrain
D.M.D.O.K.Dissanayake
Department of Earth Resources Engineering,
University of Moratuwa, Sri Lanka
Abstract
For a long time, India had been dependent on monsoons to meet its fresh water requirements. However, over the years groundwater is being increasingly used for this purpose. This has resulted in reducing country's dependency on monsoon, but at the same time has led to depletion of groundwater level. In several areas of the country, such as Delhi, parts of Uttar and Uttaranchal Pradesh, Karnataka, Maharashtra and Tamil Nadu, groundwater levels are perilously low. Therefore, there is an urgent need to address the issue of management of water resources in these areas in a sustainable manner.
Integrated Remote Sensing and GIS can provide an appropriate platform for converging diverse data sets for analysis geared towards decision making in groundwater management. In this study, an integrated Remote Sensing and GIS based methodology was developed and tested for delineating and characterization of groundwater potential in hard rock terrain spreading over 2684km2 in the districts of Sirmur, Solan and Shimla of Himachal Pradesh.
In generation of hydrogeomorphological map, Index Overlay Method was used. This simple and straightforward method enables to combine multilayer thematic maps. The accuracy of this method is totally dependant on human judgment. Area covering highly dissected structural hills (3.2%) indicated very poor groundwater potential; moderate(33.92%) to lower dissected hills(52.24%) areas indicated moderate to low groundwater potential of total area while very high groundwater potential was indicated in river terraces, lower piedmont zones, sand bars, point bars, highly fractured areas, braided river and alluvial planes.
Water quality analysis indicated that most of the water quality parameters were within the permissible limit for human consumption. However, iron content was very high in few places and this may be due to reasons such as rusted iron casing of tube wells, and, or, contamination of groundwater with the presence of iron rich rock and soil. Hardness is comparatively high since this area is rich with limestone.
1. INTRODUCTION
Remote Sensing and GIS are playing a rapidly increasing role in the field of hydrology and water resources development. Remote Sensing provides multi-spectral, multi-temporal and multi-sensor data of the earth’s surface. One of the greatest advantages of using remote sensing data for hydrological investigations and monitoring is its ability to generate information in spatial and temporal domain, which is much crucial for successful analysis, prediction and validation (Saraf,1999).
However, the use of remote sensing technology involves large amount of spatial data management and requires an efficient system to handle such data. This is compensated by GIS technology which provides suitable alternatives for efficient management of large and complex databases.
Information from satellites is becoming more and more important in our life, including for research related to environment, urban planning, military strategy, navigation, etc. When we consider the environmental research, an important part of satellite information has relevance to water; being an element most essential for man, its phases and peculiarities, both spatially and temporally.
Water resources in India are unevenly distributed, both spatially and temporally. Idiosyncrasies of monsoon and diverse physiographic and geomorphological conditions give rise to unequal distribution of water. Over the years, increasing population, urbanization and expansion in agriculture has accentuated the situation. As a result of unplanned and using inappropriate and unscientific methods of exploitation of groundwater eventually leads to water stress conditions. Even now, some parts of the country are facing acute water crisis. Despite being a very important part of the nation’s growth, analysis of water resources has been fragmentary. Thus, as a part of filling the gap, this study focuses on development of remote sensing and GIS based analysis and methodology for groundwater prospecting in hard rock terrain.
In order to demonstrate the integrated remote sensing and GIS based methodology, an area which forms the Giri catchment, spreading over 2684km2 in the Districts of Sirmur, Solan and Shimla of the State of Himachal Pradesh was selected. The main objective of the study was to delineate groundwater potential zones and suitable sites for human consumption in the Giri catchment.
2. STUDY AREA
The study area lies between 300 25’ to 310 16’N latitude and 770 02’ to 770 44’E longitude and is spread over about 2632km
2 in the Districts of Sirmur, Solan and Shimla in the State of Himachal Pradesh, India. Its boundaries are the catchments of Sutlej river in the north-west, Tons and Yamuna in the north-east and Ghaggar in the south-west.