Understanding groundwater resources in Margajo Watershed, Koderma, Jharkhand - GWIS and GIS approach
Dr. Ashok Kumar and Lal Bihari Prasad
Remote Sensing Application Centre
IGSC- Planetarium, Patna - 800 001, India
Tele # +91-612-689001 (R ), +91-612-235264 (O)
Groundwater, which is widespread in occurrence though far from abundant in Jharkhand region, has gained recognition as a major asset to meet basic human needs for potable water and agriculture. In the present study area Agriculture needs during the rabi season can often not be met from surface water resources due to poor management practices. Thus low-yielding unconfined aquifers constitute the only viable source of supply. In entire watershed, groundwater occurs in secondary aquifers consisting primarily in weathered and fractured within the basement. But these aquifers provide low yields. Research priorities, therefore, include more efficient exploration methods, improved characterization of aquifers, better assessment of exploitability and safe yield, and enhancement of sustainable use through artificial recharge. This needs better understanding and management of resources. Ground Water Information System (GWIS) and Geographic Information tools which incorporate spatial and non-spatial details and its analysis provides better understanding and management of groundwater resources.
In the present study, different technique of groundwater exploration has been applied to derive the aquifer geomtery and hydro-geophysical parameters of the aquifer. The all available information has been used to develop the interactive GWIS. It has been also linked with drainage, landuse, socio-economic database prepared in GIS environment. This all exercise gives better understandability of groundwater in watershed perspective. GIS helps in analysing various spatial and non-spatial data related to groundwater whereas GWIS stores data, creates hydrographs, well logs, various chemical diagrams, cross section, fence diagrams, contour maps etc.
Groundwater, which is widespread in occurrence though far from abundant in Jharkhand. Growth in population, need to increase the acreage of agriculture and meet the demand of spreading industries, there is urgent need for advance planning and management of resources for its sustainable utilisation. Occurrence of groundwater depends on various parameters such as geology, geomorphology, recharge, aquifer geometry, porosity, specific yield, storage, yield etc. There is a need to create a modern, integrated, and comprehensive Ground Water Information System (GWIS). GWIS and GIS can be used for spatial and no-spatial data analysis, visualization, contouring, attribute tables, statistical analysis integration. This approach is best demonstrated with the United Nations Ground Water for Windows (GWW) package (Karanjack et. al., 1997). GWW is a relational ground water database, a suite of data processing, analysis, interpretation and presentation applications, and an information system.
The Maragajo watershed is located north-central fringe of Chotanagpur plateau of Jharkhand. It is located between latitude 240 15'-240 30' and longitude 85015' - 850 30'. The entire study area has areal extent of 150 sq. km. Watershed falls under the administrative jurisdiction of Hazaribagh district of Jharkhand. Geomorphologically, it is parts of undulating pediplain. The topographic height varies from 370 to 400 m from msl. The main river which flows in south-east direction and finally drains into Tilya dam. The drainage patterns are dendritic to sub dendritic and channels represent aggradational fluvial character. Geologically it is a part of Chotanagpur granite gneiss complex.
The methodology includes generation and collection of geo-hydrological data and vertical electrical sounding. Laboratory works include land-use mapping and hydro-geomorphic zonation using remote sensing technique, DTM based on topographic elevation and DBTM based on basement depth information derived from VES. Based on geo-hydrological data, hydro-geophysical properties of aquifer, hydro-geomorphic zonation and DBTM, groundwater developmental feasibility map has been prepared. Spatial details such as administrative boundaries, drainage, hydro-geomorphic zonation, land use, groundwater developmental feasibility map and non-spatial data such as demographic details are incorporated in GRAM++ (DST / IIT-B, 2000) GIS. For preparation of GWIS, GWW (Karanjac et al, 1997) software has been used. The GWIS facilitate analysis of geohydrological parameters such as Master Data, Chemistry, Pumping Test, Hydro-graphs, Mapping, Well Log, Cross Section, Fence Diagrams, Step Draw-down Test, Grain Size Curve, Abstraction etc.
The present information system has been developed using GRAM++ GIS and GWW. Database in GIS will facilitate the planner for knowing the various option available with different criteria. This will help in sustainable planning and management of groundwater in watershed perspective whereas GWIS will facilitate the technical expert to understand and analyse the groundwater. It has been described in following paragraphs
Geographic Information System (GIS)
For sustainable planning and management of groundwater besides geo-hydrological database depicting in time and space, its judicious utilization and management needs spatial and non-spatial database on other interacting natural resources. It is linked to entire eco-system of watershed. In the present study, primarily drainage system, surface water resources, land use and hydrogeomrphic information have been derived with the help of remotely sensed data. These maps give the spatial distribution. Further, groundwater need assessment and development also depends on the population and its distribution, industrial growth areas. These non-spatial details are also required to incorporated the database. Therefore GRAM++ GIS framework has been used to integrate the different non-spatial and non-spatial details for better assessment of need and working out possibility of utilization of groundwater and other viable alternative. The complexities of the data make a Geographic Information System (GIS) a valuable tool for use in the planning and management of groundwater because of its ability to create, store, analyze, and present relational data.