Pumped Storage Projects (PSPs) require a thorough understanding of subsurface conditions before initiating any construction, excavation, or infrastructure development. The primary goal is to collect essential geological, geophysical, hydrogeological, and geotechnical data to guide design, ensure safety, and minimize construction risks and costs. These investigations typically combine invasive methods (such as drilling and sampling) with non-invasive geophysical surveys. Among these, geophysical techniques are particularly valuable in areas with limited borehole data or where detailed subsurface imaging is necessary.

Advanced geophysical methods such as Electrical Resistivity Tomography (ERT), Seismic Refraction Tomography (SRT), Cross-Hole Tomography, and Multichannel Analysis of Surface Waves (MASW) are widely employed in PSP studies to develop a detailed understanding of subsurface conditions. ERT maps electrical resistivity variations to distinguish between different soil and rock types, assess moisture content, and identify potential contamination zones. SRT analyses seismic wave travel times to detect changes in subsurface stiffness and stratification. MASW focuses on shear wave velocity measurements, which are crucial for evaluating seismic hazards and soil stiffness. Cross-Hole Tomography provides high-resolution imaging between boreholes, enabling the detection of fractures, voids, and subsurface anomalies that may be missed by surface-based methods.

The process of Litho-Structural and Terrain Investigation (LTing) involves integrating these diverse datasets with borehole logs, core sample analyses, and geological interpretations. This integration includes inversion modelling and parameter correlation to create accurate 2D and 3D geotechnical models. These models support well-informed decisions on foundation design, slope stability, groundwater control, and construction planning. Ultimately, LTing enhances the precision and reliability of subsurface assessments, contributing to safer, more efficient, and cost-effective development of Pumped Storage Projects