Protecting People & Property: The World’s Largest Dam Rehabilitation Program

Throughout history, Indians have stored rainwater for the long dry season. They have stored it in large lake-like ‘tanks’ in the southern peninsula, in stepwells in Rajasthan, and in small underground storages in Gujarat.

Today, over 6,000 dams play this role. In addition, they irrigate the land, protect the people from floods, and meet India’s soaring demand for power.

Now, however, many of these dams are ageing. Erratic rainfall has also left them vulnerable, especially since they were built to deal with the precipitation patterns of an earlier era. What’s more, given the minimal investment in their maintenance, many of them are unable to perform to their full potential, while others have become substantial safety risks.  

India is one of the world’s first countries to undertake a large-scale dam rehabilitation program. Since 2012, with World Bank support, it has deployed the latest expertise and technology to upgrade 200 of its large dams in one of the largest such programs in the world.

Strengthening dams with new technology

Each dam faces different challenges. In Karnataka’s century-old Krishna Raja Sagara Dam, for instance, each of the 152 gates had to be lifted manually to allow the excess water to flow through. “This was extremely dangerous,” pointed out K.G Vijaykumar, the engineer in charge, “for when a flood came, water could not be released immediately.”

Although the authorities were reluctant at first to tamper with the dam’s iconic structure, they managed to replace the old iron gates with new stainless-steel ones, with the help of global experts. Now, computers operate all the dam’s 152 gates, and water is discharged in precisely the right volumes to prevent flooding downstream.

Uttarkhand’s Ichaari Dam, on the other hand, was frequently damaged by the large boulders that were carried down by the raging Tons River. But, given the remoteness of the region and the steep mountain terrain, it was difficult to bring in the large equipment needed to repair the damage.

“Logistics was an issue, accessibility was an issue. It was also difficult to ensure that the sharp drop in night temperatures did not alter the properties of the high-strength concrete as we were laying it down.” recalled Ankit Arya, assistant engineer in charge of the dam.

Once again, the authorities addressed these complex challenges with the help of global experts. A new, very-high-strength concrete was applied for the first time in the dam sector in India.

Long-standing challenges were also addressed with the latest technology. For instance, underwater drones  helped pinpoint cracks in the walls of Karnataka’s Krishna Raja Sagara Dam as well as a few others. And geomembranes were deployed as a one-time, long-term solution to control seepage from the walls of Tamil Nadu's Servalar Dam, reducing the problem by more than 90 percent.

Emphasizing safety

Strengthening a dam’s structure is just one aspect of dam safety. Keeping strict vigil on the dam’s condition is equally important.

The project thus brought in new equipment such as CCTV systems to spot weaknesses in hard-to-reach areas. “We now have proper instruments to do routine checks, especially in the monsoon season when we are on full alert,” said Ms. Supriya S., the chief engineer for dam safety in the Kerala government.

Decision making was also made quicker and more precise. As even small mistakes in handling large volumes of water can have catastrophic consequences downstream, new equipment was introduced to give dam managers instant access to all the dams’ data, enabling them  to take prompt and informed decisions.  Since this data can also be shared with other dams, managers who operate dams in a cascading sequence can now take coordinated decisions. “Data of 16 dams is now available in our control room,” added Ms. Supriya. “This was not so earlier.”

Preparing for emergencies

However, given the growing incidence of unusual weather events, both the dam authorities and local communities need to be prepared for emergencies, be it a flood, an earthquake, or a glacial lake outburst.

The project has thus enabled each dam under its ambit to develop an Emergency Action Plan, specifying who does what and when in an emergency.  These plans have been devised after extensive consultations with local administrations, disaster management authorities, the police and fire departments, and local communities, enabling a coordinated response to the challenge.

Mapping areas at risk

The mapping of areas at risk of flooding has shown how far-reaching the impacts of a breach can be. “Earlier, I thought if the dam fails, the impact will be felt some  30-40 kms downstream. After the exercise I realized how much larger the devastation could be, extending all the way down to Karnal in Haryana, over 150 kms away,” said Abhishek Kumar, assistant engineer at Uttarkhand’s Ichaari Dam.

Mapping has also helped dam authorities work out the safest evacuation routes. “Every day, we use one particular bridge to travel from Dakpatthar to Ichhari,” said Bhanu Prakash Joshi, assistant engineer at the Ichaari dam. “But we realized that this bridge would be submerged in a flood. So, we identified at least three alternative routes. Today, I am confident that we are prepared for any untoward incident and know what is to be done.”

Creating a new pool of dam professionals

Since dam management is a complex task, the project has also supported the creation of a new pool of dam professionals.  A new post graduate course in dam safety has been started at the Indian Institute of Technology (IIT) in Roorkee and the Indian Institute of Science (IISc) in Bengaluru.

The  program covers multiple aspects of dam management, from structural design to safety, as well as sedimentation, geological, seismic and environmental issues, in addition to the development of sustainable tourism.

“For the first time, academic institutions have been roped in to study the challenges, conduct research, and devise solutions for a dam’s long-term sustainability,” said Prof N. K. Goel from IIT Roorkee, India’s oldest engineering college founded almost a century ago to train engineers and surveyors for the construction of the Ganga Canal.

All told, better dam management and stronger safety measures will enable India’s dams to perform to their full potential, protecting people and property, ensuring better irrigation, helping recharge groundwater, and allowing for the more sustainable flow of water in the rivers.