Vinayak Chatterjee’s Infravisioning video series analyses and explains developments in India’s infrastructure sector to the BQ Prime audience.
Edited excerpts of the video:
How safe are India’s dams? Has this question ever occurred to you? Not really. Most people don’t think about dams other than visiting tourist places with dams and reservoirs, but it’s an important question for us to spend some time over.
India is reprioritising hydropower to meet its green energy targets, but at the same time the magazine Nature Geoscience has published a rather frightening report that more than 650 hydropower projects planned or under construction in the Himalayan region are at reasonable risk of hazards which are related to global warming and climate change. These hazards include landslides, rock avalanches, debris flow and lake outburst floods, all of which could increase the glacial melt and destabilisation of the entire ecosystem around such dams related to hydropower projects. Are these just imaginary, or theoretical scenarios. Not really.
As recently as February 2021, an area of Chamoli district in Uttarakhand was devastated and 140 lives lost when a Himalayan glacier broke off and caused a high-velocity surge of water sweeping away one dam in its path and damaging another. Replying to questions in parliament, Jan Shakti Minister Gajendra Singh recently told the Rajya Sabha that since 1979, there were 42 instances of dam failures, the latest being the Annamayya reservoir of Kadapa district of Andhra Pradesh that led to the death of at least 20 people in November 2021. There have been other notable dam failures in India. These include the Kaddam in 1957, Panshet in 1961, Khadakwasla 1961, Chikole in 1962 and Nanak Sagar Sarovar in 1967. So, these are not imaginary threats. In fact, the biggest disaster in recent history was on Aug. 11,1979. After a week of extraordinary monsoon rains in Gujarat, the two-mile long Machhu Dam disintegrated. The water released from the dams’ massive reservoirs rushed to the heavily populated downstream area, devastating the industrial city of Morbi and its surrounding agricultural villages, bridges gave away, factories crumbled, and thousands of houses collapsed.
While no firm figures have been formally established on the disaster’s final death count, estimates have run as high as 25,000. Despite the enormous scale of the devastation, few people today remember this terrible event. The book ‘No One Has a Tongue to Speak’ by Tom Wooten and Utpal Sandesara debunked the official claim that the dam failure was an act of god and pointed to structural and communication failures that enhanced the disaster.
Do you know how many dams India has? Well, India has the third highest number of dams in the world at 5,745. Following China with 23,842 and the U.S. with 9,261. Think of that. The dams are also located across the length and breadth of the country. The point of concern really is not the 5,000-plus dams, but the fact that 80% of the dams are more than 25 years old. There have been many huge associated risks. Adding to the stress is the 293 dams: 6% are more than 100 years old, and 18% are 50 to 100 years old. We not only have a vast number of dams across the country, but a large proportion of them are pretty old.
The long-term safety of a dam depends on the extent of degradation of its materials, weakening of the foundations and seismological threats. The physical rehabilitation of dams involves two clear streams of activity. The first is de-siltation to restore the original reservoir capacity, the second is safety encompassing structural safety, hydrologic safety and operational safety.
With all this background, and the big Morbi dam disaster. The Dam Safety Organisation or DSO was established in the Central Water Commission in May 1979 to convince the states about dam safety because maintenance is a state subject. The first major programme initiated was the Dam Safety Assurance and Rehabilitation Project implemented with support from the World Bank from 1991 to 1999 at a cost of Rs 423 crore, in the four states of Madhya Pradesh. Orrisa, Rajasthan and Tamil Nadu. The second World Bank-funded project, code named DRIP from April 2012 to March 2021, had a much larger budget outlay of around Rs 3,500 crore. A legislation followed and the matter was given due seriousness by the government. The Dam Safety Bill 2019 was passed by the Lok Sabha on Aug. 02, 2019. This legislation provides for surveillance, inspection, operation and maintenance of specified dams by the establishment of a national committee on dam safety. The National Dam Safety Authority, state committee on dam safety and the state-run dam safety organisations are now part of all the organisations involved in this activity. The bill was opposed by several states on the ground that encroached on the sovereignty of states, to manage their own dams with water being constitutionally a state subject. The central government’s counterpoint was that interstate river basins covered 92% of the hinterland related to dams, and therefore the interstate nature of dam hinterlands makes the centre competent to enact such a law.
Finally, the Rajya Sabha passed the bill on Dec. 02, 2021. So, India has a parliament-passed Dam Safety Bill. This new act and associated rehabilitation programmes thus ushered in a new era of professional management of India’s dams and safety issues.
