The book incorporates the results of detailed Study of GIS Based Modelling and Impact Analysis of Rain-Water Harvesting on the Underground Water Characteristics of Lucknow, Uttar Pradesh. The APHA standards were followed for the analysis of the water samples related to the study of chemical parameters. An initial setup with limited database that has been used for the preparation of zones for rainwater harvesting (RWH) in context to the utilization in the land use/ land cover practices in the Lucknow region. ArcGIS 9.2 platform has been used to build the RWH model framework comprising three components viz, Data input, Data processing, and Model outputs. In the RWH model six available data layers were used as input viz. Land use, Drainage line, Digital Elevation Model (DEM), Slope, Contour, and Canal. The data inputs are in the order of priority. Finally, the study based on depletion of ground water shows that the area is under hydrological Stress where pressure on ground water has increased and as such the excessive withdrawal has depleted the aquifers leading to significant decline of water table in different parts of the city due to increasing urbanization and other practices.