An Integrated Geochemical and Geospatial Approach for Assessing the Potential Ground Water Recharge Zones in Mahi -Narmada Inter Stream Doab Area, Gujarat, India

摘要

Mahi-Narmada inter-stream region (Doab) in Gujarat is a unique landscape bounded by rivers Mahi and Narmada in the north and south respectively followed by the physiographic truncation by the eastern highlands comprising mainly the Deccan flood basalts and abruptly ending along the western margin due to the Cambay gulf. These distinct hydro-geological boundaries have controlled the ground water regime in the region. The region being part of the Golden Quadrilateral has witnessed highest industrial growth in India. Use of groundwater for irrigation, industrial development and urban expansion have stressed the aquifers and even the surface water bodies are also over utilized; thus adversely affecting the quality and quantum of the water resource of the region. A study was carried out to understand the gravity of the problem stated and also to propose a strategy of monitoring and management of the water resource of the region. The pre- and post-monsoon groundwater sampling of 2002 was carried out and corresponding physical and chemical data generated has established that the groundwater in the study area has unusually high concentration of major, minor and trace elements. A multi-parametric dataset comprising satellite data and other conventional maps including Survey of India (SoI) topographic maps (1:50,000 scale), drainage density, landforms, slope, soil and land use maps, etc. were integrated into Geographic Information System (GIS) environment to generate various thematic maps such as; recharge and discharge zone maps, groundwater quality maps finally culminating into water resource management scheme for the region. The maps so generated have been very close to the field conditions, the study has thus helped in the development of ground water monitoring and managing strategy. The study indicates that periodic monitoring of the groundwater resource with the help of GIS will help in proper management of groundwater resource by identifying the zones/areas of recharge that shall be required to be protected from being converted into built up areas. Moreover, such area also needs to be protected for being used for extensive cultivation as this can leads to contamination of groundwater resource by use of insecticide, pesticides and other chemicals. The study puts emphasis on conjunctive use of surface and groundwater by applying proper management practices so that there is effective use of water.