Abstract

Supply of sustainable water is a priority for urbanization of the country. Managed aquifer recharge (MAR) is recommended to enhance the groundwater resources, but finding the favorable site for MAR is quite challenging, particularly, in urbanized karst terrains because of highly heterogeneous and anisotropic properties of carbonate aquifers. The expansion along Naya Raipur is posing a severe threat to its groundwater resources by altering the hydrological framework in the area. In this work, we characterize the unsaturated zone for finding potential pathways for MAR in karst terrain of central India by using hydro-geophysical techniques. Sub-surface geophysical investigations including electrical sounding and profiling, captured the shallow surface of the area to the depth of around 40 m. The Wenner–Schlumberger and gradient methods could decipher strong lateral and vertical anomalies. The low resistivity in the unsaturated zone, as compared to the high resistivity of limestone bedrock is the main path for infiltration. The low resistivity anomalies in the 2D inverted sections might be water filled conduits or solution channels with uncertain geometry. Hydrogeological heterogeneity based on geophysical data helped to locate the favourable zones for construction of MAR structures. The Chokra Nala in the Telibandha area of Raipur is the favorable zone along which MAR could be more effective in replenishing the groundwater. The Telibandha lake area with the indication of the presence of hidden mafic dyke later intruding the limestone after its deposition, was also inferred from the geophysical data.

Highlights

1. 1.

   Characterizing the unsaturated zone for finding potential pathways for MAR in karst terrain using hydro-geophysical techniques.

2. 2.

   Establishing MAR along the solution channels, conduits and fracture network.

3. 3.

   3D fracture system in limestone from 2D ERT profiles.

4. 4.

   Mapping hydrogeological heterogeneity based on geophysical data.

中文翻译：

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喀斯特地貌的电成像，用于受控的含水层补给：来自印度中部赖布尔的案例研究

摘要

可持续供水是该国城市化的优先事项。建议使用管理性含水层补给（MAR）来增加地下水资源，但是要找到适合MAR的地点是非常具有挑战性的，特别是在城市化喀斯特地形中，因为碳酸盐含水层具有高度的非均质性和各向异性。纳雅赖布尔（Naya Raipur）沿岸的扩张通过改变该地区的水文框架，对其地下水资源构成了严重威胁。在这项工作中，我们使用水文地球物理技术来表征非饱和带，以寻找印度中部喀斯特地形中MAR的潜在途径。包括电测深和剖面分析在内的地下地球物理调查，捕获了该区域的浅表层，深度约为40 m。Wenner-Schlumberger和梯度方法可以破译强的横向和垂直异常。与石灰岩基岩的高电阻率相比，非饱和区的低电阻率是渗透的主要途径。二维倒置段中的低电阻率异常可能是注水的导管或几何形状不确定的溶液通道。基于地球物理数据的水文地质非均质性有助于找到有利于MAR结构建造的区域。赖布尔Telibandha地区的Chokra Nala是MAR沿其补充地下水更有效的有利区域。还从地球物理数据中推断出特里班达湖区，这表明存在暗伏性铁磁性堤坝，随后在沉积后侵入了石灰岩。

强调

1. 1。

   利用水文地球物理技术表征非饱和带，以寻找喀斯特地形中MAR的潜在途径。

2. 2。

   沿着溶液通道，导管和裂缝网络建立MAR。

3. 3。

   根据2D ERT轮廓，石灰岩中的3D断裂系统。

4. 4。

   根据地球物理数据绘制水文地质异质性图。