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 (ρ1), transverse unit resistance (T), transverse resistivity (ρt), Electrical anisotropy(λ) and root mean square resistivity (ρm). 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.

中文翻译：

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卡纳塔克邦 Belagavi 区 Kanavi Halla 次盆地半干旱硬岩地形中使用综合方法划定地下水潜在区

由于全球降雨量不足，水资源短缺已成为一个主要问题，特别是在干旱和半干旱地区。这导致了对地下水资源的认真寻找。印度卡纳塔克邦 Belagavi 区 Ghataprabha 河流域的 Kanavi Halla 子流域 (KHSB) 已被考虑用于本研究。使用 Schlumberger 方法和四电极配置在选定地点进行电阻率调查。在整个 KHSB 中总共进行了 22 次垂直电测深 (VES)，并考虑了不同岩相单元的代表。然后使用曲线匹配技术和 IPI2Win 软件解释获得的数据。解释图显示三到六层。各种解释曲线类型有 AAK 型、HA 型、A 型、KH 型、HAA 型、KQH型、AK型、K型、HQH型、H型和AKQH型。从结果可以看出，最大数量的曲线与 A 型相关，指的是硬岩地形，而 H 型相关的曲线表示水势位置。预期的地下地层是根据观察到的钻孔数据解释的。Borewell 测井显示土壤形成，然后是中度风化地层、风化节理地层、节理地层、从上到下的硬地层。更深的地层没有节理和裂缝。因此，风化、节理的地层可以解释为含水层。使用 IPI2WIN 绘制了 8 个选定趋势的二维地电剖面，以了解形成的含水层的几何形状。该调查旨在借助 Dar-Zarrouk (DZ) 参数，如纵向单位电导率 (S)、纵向电阻率 (ρ1)、横向单位电阻 (T)、横向电阻率 (ρt)、电各向异性 (λ) 和均方根电阻率 (ρm)。对这些进行评估以了解含水层条件，以便划定淡水承载区。KHSB 东南部可能受到污染，30% 的区域是弱污染物保护区。这项工作充分突出了地球物理技术、地电模型组合、DZ 参数、钻孔测井在地下水资源评估过程中的实际应用。