A confidential report by the Department of Atomic Energy (DAE) expressed concerns about possible calamities due to the proximity of the proposed Kalpsar dam and the Mithivirdi Nuclear Power Project (NPP),including flooding of the power plant in case an earthquake breaks the 65-km-long dam that will run across the northern edge of the Gulf of Khambat.
The DAEs site selection report was obtained by the Vadodara-based Paryavaran Suraksha Samiti through RTI. The outfit has attached it with a letter it sent to the Union Environment Ministrys nuclear projects division on Wednesday,alleging the reports observations had not been incorporated into the Nuclear Power Corporation of India Limiteds (NPCIL) environment impact assessment (EIA) for the proposed project.
The site selection report,dated June 28,2007,says,It is recommended that a detailed study be conducted to examine the effect of Kalpasar dam in the upstream of NPP site on the flooding of the proposed site due to breaking of dam in the event of an earthquake of very high magnitude as the Kalpasar dam is located over deep silted fault.
Kalpsar project authorities propose a dam of 65 km in length and top width of 35 m across Gulf of Khambat at a distance of 18 kms north of the Chhaya (Mithi Virdi) site. This will have following effects on the nuclear power llant – sedimentation and effect on intake and outfall of the plant,flooding due to dam break and aspects of reservoir induced seismicity, the report notes.
In another section,the report recommends a 300-km radius seismotectonic study should take into account reservoir-induced seismicity,a phenomenon in which large man-made water bodies cause earthquakes,such as at Koyna dam in Maharashtra,which caused a 6.3 magnitude earthquake in 1967.
(At least three other earthquakes of a magnitude above 6 have been caused by such water bodies worldwide,including in China (Xinfengjiang dam),Zambia (Kariba dam) and Greece (Kremasta dam).
P M Shah,chief engineer for the Mithivirdi project,told The Indian Express the EIA report did not incorporate Kalpsar because it was a study on how the project would affect the environment.
A detailed seismotectonic study covering a radius of 300 kms is being done by the National Geophysical Research Institute,Hyderabad,while oceanography studies are being done by the Goa-headquartered National Institute of Oceanography (NIO), Shah said.