Monitoring One of the Highest Arc Dams in Asia — Idukki Dam Case Study

Dams have been constructed through the many centuries to fulfil the needs of humankind as well as save them from many disasters. Dams not only provide water for society but also protects us from the river and marine floods, provides hydroelectric power, irrigation water, and a pleasant environment. As we see the old dams ageing and the new ones being constructed, dam monitoring becomes more significant than ever.

Various factors influence the healthy working of the structure, including hydrological, geotechnical, structural, and other power-related issues. Avoiding dam failure requires several dam monitoring instrumentations.

In this article, we look at the case study of Idukki Dam Monitoring, one of the highest arc dams in Asia, by Encardio-rite.

Idukki Dam — An Overview

Idukki Dam is a thin arc dam located across the Periyar River in a ravine between two granite hills known as Kuravan and Kurathi in Kerala, India. The concrete, double curvature parabolic dam is one of the highest arc dams in Asia with a height of 168.91m. Completed in 1973, the dam currents measure 365.85m at its top with 7.68m width at the top and 19.81m on the bottom.

Idukki Dam is owned by the Kerala State Electricity Board (KSEB) and constructed with two other dams at Cheruthoni and Kulamanu. The three dams create an artificial lake.

Together, they harness a major portion of the power potential of Periyar, the largest river in Kerala. They do so by creating a reservoir, diverting water through a conductor system consisting of a power tunnel and two underground pressure shafts to an underground powerhouse in Moolamattom.

The installed capacity of the powerhouse is estimated to be 780 MW with 6 units of Pelton-type turbines that have a power generation capacity of 130 MW each. The water of the Periyar river falls through a drop of about 669.2 m, producing power in the underground powerhouse.

Idukki Dam — Purpose of Monitoring

Encardio-rite was assigned the contract for Real-Time Early Warning Structure Health Monitoring & Data Interpretation (RESHMI). RESHMI plays an essential role in dam safety and risk management. It is a part of the Dam Rehabilitation and Improvement Project (DRIP). The essential purpose of RESHMI is as follows:

• Improve the reliability of the dam by looking after its safety and longevity.
• To identify any early signs of failure or potential danger to the dam and implement corrective measures without resulting in a complete shutdown or failure.
• Acquire data on the dam’s performance in the real world to improve future designs.
• Study the impact of any natural event on the dam’s structural integrity.
• To propose the maintenance of the dam in an effective & efficient manner.

| Also Read: Instrumentation & Structural Monitoring of Dams |

Encardio-rite’s Scope of Monitoring Work

Encardio-rite was entrusted with the following responsibilities during the monitoring of the Idukki Dam.

• Supply and Installation of Geotechnical, Geodetic, and Hydro-meteorological sensors.
• Monitoring the existing working sensors installed in the structure.
• Programming and authorizing data loggers with wireless data transmission and robotic total stations with in-house developed control boxes
• Providing seamless data storage and backup servers
• Setting up Drishti, Encardio-rite’s in-house data management software for real-time monitoring and prompt alerts.
• Lightning surge protection and earthing …[Continue reading]