This paper from the GIS Development site discusses the findings of a project titled " Natural Resource Management for Sustainable Utilisation of Water Resources in Siwane Sub-basin, Hazaribagh under NRDMS scheme of Department of Science & Technology, which was implemented by Bihar Council on Science & Technology, Patna with the main objective to map / explore the various natural resources i.e. surface water, groundwater, land and soil. The thematic and spatial data were analysed in the GRAM GIS environment for sustainable utlisation and management of groundwater. The study area was located in the upper reaches of Siwane sub-basin ( Latitude 240 0' - 240 10' and Longitude 850 15' - 850 30' ) .
For optimal utilisation and management of the limited groundwater reserves, to meet increasing demand for supplementary irrigation & domestic need and also for accelerating the existing recharge phenomenon in the watershed, detailed information for basement topography, aquifer geometry and fracture systems are essential. The approach adopted for deriving above information, was termed as " Digital Basement Topography modeling (DBTM). This helped in understanding groundwater storage & retrieval system for sustainable utilisation of groundwater in close relation with surface water. The overall objective of the study was to provide scientific database for sustainable utilisation & development of groundwater and surface water.
The study found that the present natural recharge estimation based on National Ground Water Estimate Committee of CGWB did not provide a realistic picture. There was need for site specific natural recharge estimation. Representative sites could be located on the basis of remotely sensed data. Measurement in each hydro-geomorphic unit was required to get better results. Geophysical electrical resistivity technique could be further refined for estimating the site specific aquifer porosity and yield estimation.
In present study, groundwater reserve was estimated on the basis of total average porosity. Estimation could further be improved if site specific porosity data could be incorporated in the calculation. Groundwater losses due to seepage in unconfined aquifer system of hard rock needed attention. There was a need for field level experimentation for knowing the relation between artificial recharge process and sub-surface basins derived from DBTM.
There was a need for developing dynamic groundwater model for predicting and forecasting the groundwater environment under changing intake and out take from the aquifer. For this purpose, huge databases on different parameters were required i.e. porosity, permeability, yield, rainfall, recharge, flow, seepage, withdrawal, aquifer geometry etc. DBTM could be used as one of important inputs to the Dynamic Groundwater Model.