Safety ‘dam’ned in Telangana irrigation projects

And where the equipment does exist, it does not work as in the case of Nagarjunasagar, Sriram Sagar, Sripada Yellampalli projects, to name a few.

It is not just about seismic worries. Many of these dams also do not have operation and maintenance manuals, the list of which includes the likes of Nagarjunasagar, SRSP, Singur, Jurala, Lower and Upper Manair dams, Kaddem, and the closer to the city Osmansagar and Himayatsagar reservoirs.

With respect to instrumentation, many of the 174 dams do not have instruments to measure even water levels, seepages or leakages, or uplift and pore pressure measuring devices, which are among the instruments that the SDSO lists in its report in the section ‘Status of Instrumentation of Dam’. These include the popular with tourists Pakhal, Laknavaram, and Ramappa lakes, as well as the city’s Osmansagar and Himayatsagar reservoirs. Incidentally, many of the reservoirs formed by these dams are being sought to be developed as tourist destinations by the government.

It may be recalled that a 5.3 magnitude earthquake had struck just about 35 km from the Medigadda barrage on Godavari river on December 4. Though no impact on the Kaleshwaram barrages was reported after the December 4 quake, the Medigadda, Annaram, and Sundilla barrages of the Kaleshwaram project fall in the Godavari rift zone which, according to seismologists, falls in a moderate earthquake prone region. And with respect to Mallannasagar reservoir, the existence of the geological fault was first pointed out by the government of India’s National Geophysical Research Institute (NGRI), and this aspect was also noted by the Comptroller and Auditor General of India in its report on Kaleshwaram project.

Incidentally, according to the SDSO report, these three barrages also do not have instrumentation to measure seepage and leakages, two problems that were repeatedly witnessed at these barrages ever since they were inaugurated in June 2019, and were filled up soon. The report further notes that there are operation and maintenance manuals for these three barrages of the Kaleshwaram project.

A 94-page ‘2023-24 annual report’, prepared by the State Dam Safety Organization (SDSO) of the irrigation department, and submitted to the special chief secretary, revenue (disaster management) on January 18 this year, reads like a list of small and big disasters that could be waiting to strike the 174 specified dams - small, medium, and major – as required to be listed under the provisions of the Dam Safety Act of 2021.

Among the other issues mentioned in the report is that Nagarjunasagar dam has instrumentation to measure uplift and pore pressure monitoring but this equipment is not active. Same is the case with equipment related to crack and joint movement, and stress and strain measuring of the structure.

Finding place in the report in a long list of dams that have no instrumentation of any kind – at least from the ones evaluated by the SDSO for the 174 dams are three drinking water sources for Hyderabad city – Manjira, Osmansagar, and Himayatsagar.