The Central Electricity Authority (CEA) has issued guidelines on the adoption of advanced methodologies during the investigation, tender and construction stages of hydropower projects to minimise geological uncertainties in long water conductor systems. The guidelines aim to address recurring geological challenges encountered during tunnel construction, such as groundwater ingress, fault and shear zones, rock bursting, squeezing ground and seismic hazards.
To improve geological assessment, the guidelines recommend advanced investigation techniques, including remote sensing, aerial electromagnetic surveys, active-passive seismic tomography, directional core drilling and geo-hydrological studies for tunnels with a vertical cover exceeding 300 metres. They also recommend that bid documents include geotechnical baseline reports, probabilistic geological risk modelling, risk-sharing provisions, and compensation schedules for extraordinary geological conditions. During construction, the guidelines call for the use of real-time ground prediction, site-specific rock mass classification, and advanced monitoring and stabilisation measures to improve safety and reduce geological risks. In addition, the CEA has proposed a separate budget head titled “Advanced Geo-technical Investigations for Water Conductor System,” with budgetary allocations for geological investigations linked to project capacity, capital cost and length of the water conductor system.