With a clutch of big hydroelectric power projects in the pipeline, the Kerala State Electricity Board (KSEB) has put together a comprehensive standard operating procedure (SoP) for undertaking the investigations necessary for their construction.
Technical hurdles faced in the development of some of its hydel projects and the spectre of geological accidents prompted it to adopt the SoP, according to the KSEB.
The ‘Guidelines for geological and geotechnical investigations of hydroelectric projects,’ a 38-page document, was found necessary against the backdrop of “adverse experiences in some of the projects undertaken by the KSEB like the Sengulam Augmentation Scheme and also in the light of the Joshimath disaster (January 2023) and various tunnel collapses,” the State-run power utility notes.
In approving the SoP, the KSEB director board observes that investigations and surveys play a crucial role in the planning, design, and construction of hydroelectric projects. The SoP covers general guidelines concerning topographical and geological investigations and mapping, surveys of river courses and reservoir sites, the various tests involved, and procedures for procuring the services of agencies such as the Geological Survey of India (GSI).
Importantly, the SoP deals extensively with the seismic aspects of hydroelectric projects and the related tests and studies. “The site specific seismic study for a river valley project requires an understanding of the seismic scenario with regard to the dam site, which includes geological setting of the area, tectonic features, and the history of earthquake occurrence in the region. The study enables evaluation of design ground motion based on identifiable seismic source zones and appropriate ground motion attenuation laws,” it notes.
Further, the SoP requires the use of geophysical techniques for all major projects and Pumped Storage Projects (PSP) of capacity 25 MW and above. “We already had guidelines for the construction of hydel projects. Now they have been compiled into an SoP. Today, modern technologies are available to us for conducting the necessary investigations,” Shanavas A., Chief Engineer (Civil-Investigation and Construction Central), told The Hindu.
After a long gap, the KSEB is now working on a number of big hydropower projects, including the 800 MW Idukki Golden Jubilee Extension Scheme, 300 MW Sabarigiri Phase II, 210 Pooyamkutty project, and the 240 MW Letchmi project.
