Investigation of Lineaments for Identification of Deeper Aquifer Zones in Hard Rock Terrain: A Case Study of WRWB-2 Watershed from Nagpur District, Central India

Abstract

In current scenario, the groundwater resources are gaining much attention due to enhanced demand of rising population, urbanization, agricultural expansion, etc. The groundwater condition in hard rock terrain, specifically in Deccan trap basaltic region of Maharashtra state, is highly uncertain due to anisotropic aquifer system. In addition, high evaporation and run-off limits the natural recharge to the groundwater. Therefore, the unsustainable distribution of water from the dug wells and bore wells in basaltic region is common which altogether results in acute scarcity of drinking water in the event of drought. In order to mitigate this situation the state groundwater departments often resorts to tapping of deeper aquifers to meet the drinking water demand. However, it is found that the percentage of high yielding borewells is very low due to anisotropic hydrogeological condition of basaltic terrain, and also due to lack of primary porosity unlike sedimentary formations. In view of this it is pertinent to understand the role of lineaments and fractures on the yield of the borewells, as the lineaments i.e. weaker zones, plays vital role in groundwater movement. The current study focuses on the influence of lineaments on groundwater regime in hard rock areas by employing the remote sensing technique. For this study the WRWB-2 watershed of the district of Nagpur, Maharashtra, Central India has been investigated. The aim of the study is to understand the importance of lineament mapping in groundwater prospecting. The satellite image of the area was studied to decipher the geomorphological setup and lineament fabrics through visual interpretation. The study area is characterized by basaltic hard rock which forms the multiple aquifer system, wherein wide variations in yield of the borewells are expected. Under this situation the controlling factors such as geomorphological set-up and lineament fabrics have been analysed with respect to yield of the borewells. The overall study revealed that the yield of the borewells tapping deeper aquifers are highly influenced by presence of lineaments as out of the total 143 borewells, 30 are very high yielding with yield >4500 l/h, which is uncommon in Deccan trap terrains. The study demonstrates utility of lineament mapping in the hard rock regions mainly to target productive aquifer system. The decision maker, therefore, should use this technique for successful harnessing of potential groundwater pockets in hard rock areas to achieve the sustainable groundwater availability.