Faculty Publications

Water scarcity has become a major problem especially in arid and semi-arid regions due to insufficient rainfall throughout the globe. This has led in serious search for groundwater resources. Kanavi Halla Sub Basin (KHSB) of Ghataprabha River basin drained by Ghataprabha River, Belagavi District of Karnataka state in India has been considered for present study. Electrical resistivity survey was carried out at selected sites using Schlumberger method with four electrode configuration. A total of 22 Vertical Electrical Sounding (VES) were conducted throughout KHSB and representative of different litho units were considered. Data obtained were then interpreted using curve matching technique with IPI2Win software. The interpreted graphs show three to six layers. The various interpreted curve types are of AAK-type, HA-type, A-type, KH-type, HAA-type, KQH-type, AK-type, K-type, HQH-type, H-type and AKQH-type. From the results it shows that the maximum number of curves are associated with A type which refers to hard rock terrain, whereas curve associated with H type indicates water potential site. The expected subsurface strata are interpreted on the basis of observed bore well drilling data. Borewell log reveals soil formation followed by moderately weathered formation, weathered jointed formation, jointed formation, hard formation from top to bottom. Further deep, the formation is devoid of joints and fractures. Therefore, the weathered, jointed formation may be interpreted as water bearing zone. 2-D geo-electric section has been drawn using IPI2WIN over eight selected trends to understand the geometry of the aquifer formed. The investigation was meant to characterize the aquifer in KHSB along with the risk assessment for contaminants through seepage in terms of protective capacity with the help of Dar-Zarrouk (D-Z) parameters such as longitudinal unit conductance (S), longitudinal resitivity (?1), transverse unit resistance (T), transverse resistivity (?t), Electrical anisotropy(?) and root mean square resistivity (?m). These were evaluated to know the aquifer conditions in order to demarcate the freshwater bearing zones. South eastern part of KHSB might be contaminated and 30% of the area is weak to poor capacity protective zone for contaminants. The work adequately highlights the practical use of geophysical techniques, combination of geo-electrical modelling, D-Z parameters, borehole log in the groundwater resource assessment process. This technique is highly recommended for the area with similar geological setup. © 2020, Geological Society of India.

Electrical resistivity method and RS & GIS techniques are very much useful in identification of potential aquifer zones for exploitation, management and recharge of groundwater. Vertical Electrical Soundings are conducted at 35 locations in Gurpur watershed using Schlumberger array. The thematic layers like porosity, transmissivity and hydraulic conductivity are prepared using electrical resistivity data. Total of 13 thematic layers are used for vector integration and identification of Groundwater Potential Zones (GWPZ). The numerical weights and ranks are assigned to the themes based on their relationship with groundwater. The findings shows that the depth to bedrock varies from 9.1 to 44.4 m and most of the mid land and low land region shows moderate to high depths of about 25–44 m. The GWPZ are classified into five classes namely, Very Good (?21.02 km2), Good (?231.35 km2), Moderate (?420.76 km2), Poor (?185.05 km2) and Very Poor (?19.56 km2). The Good and Moderate categories cover ?75% of total area. © 2019 Informa UK Limited, trading as Taylor & Francis Group.

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