India’s Old Dams
12th Jan, 2022
The Comptroller and Auditor General of India (CAG) has recently released a report, which states that Gandhi Sagar Dam on Chambal River in Madhya Pradesh is in need of immediate repair.
India’s dams are old and aging and there is an urgent need to assess their safety to prevent dam failure-related disasters. This brief aims to analyze the situation of dams in India and how their grim situation can have a serious threat to the country.
- About 55% of the world's dams are in just four Asian countries, including India.
- India has the third-biggest number of large dams in the world, after the US and China.
- Of its 5,745 large dams, around 80% are more than 25 years old.
- Over 225 large dams are more than a century old but fully functional.
- Older dams in the country pose serious threats. In this backdrop, the Government introduced the Dam Safety Act, 2021.
Dam Safety Act, 2021
- The Dam Safety Act, 2021 deals with engineering, construction, operations, surveillance, maintenance and safety of dams in the country.
- The essential elements of the Act are
- National Committee on Dam Safety: an overarching National Committee on Dam Safety to be headed by the Chairman, Central Water Commission, to evolve dam safety policies and recommend necessary regulations for the purpose;
- National Dam Safety Authority as the regulatory body to implement the policies, guidelines and standards evolved by the Committee.
- State Committee on Dam Safety to ensure proper surveillance, inspection, operation and maintenance of all dams in the state for their safe functioning
- State Dam Safety Organisation to carry out routine inspections, classify dams as per vulnerability and hazard classification and maintain records.
What are the points highlighted in the CAG Report?
- Gandhi Sagar Dam on Chambal River in Madhya Pradesh is one of the five water reservoirs of national importance.
- The dam was constructed in 1960 to provide drinking water to several districts of Rajasthan and generate 115 megawatts of electricity.
- Absence of regular checks, non-functional instruments and choked drains are the major problems plaguing the dam for years.
- It has been breached several times in recent years, causing flooding in downstream areas.
- Three districts in the state — Sheopur, Morena and Bhind, with an approximate collective population of 4.35 million (as per the 2011 Census) — lie downstream the dam.
- Gandhi Sagar was put in Category II of the dam inspection report.
Category I & II
- Category I: Dams with major deficiencies, which may lead to complete failure / partial failure and need attention at once, fall under Category I.
- Category II: Those with minor to medium deficiencies, which are rectifiable but need immediate attention fall under Category II.
- The state dam safety organisation (SDSO), the department responsible for its maintenance, did not comply with recommendations by the Central Water Commission (CWC) and Dam Safety Inspection Pane (DSIP) on remedial measures.
What are dams?
- Dam is defined as a barrier built across a stream, river or estuary to confine and check the flow of water for uses such as human consumption, irrigation, flood control and electric power generation.
- Lately, dams are considered more as hydropower generators while mitigation of flood, facilitation of irrigation and supply of drinking water, are considered only as additional benefits.
- A dam could be a central structure in a multipurpose scheme designed to conserve water resources on a regional basis.
What are the pros & cons of Dams?
- Multiple benefits: Dams are critical infrastructure, constructed with large investments which provide multipurpose benefits such as irrigation, power generation, flood moderation and supply of water for drinking and industrial purposes.
- Fulfillment of water demands: The primary functions of dams are - water supply, irrigation, flood control, hydropower, and recreation.
- Essential for the agricultural sector: Dams supply the wealth of water to the parched fields of millions of farmers.
- Meeting water demand of urban and rural areas: They meet the domestic, municipal and industrial water needs of urban and rural areas.
- Hydropower generation: They form the backbone of India’s Power Grid Management since they generate cheap and eco-friendly hydro power across the country.
- Sustainment of flora and fauna: Dams sustain the growth of flora and fauna in many of the degraded forests.
- Controlling depletion of water: Dams offer a viable solution for checking unsustainable depletion of groundwater, which may be inching towards tripping point under the tremendous pressure created due to the growing population.
- Expensive affair: Building a dam is very expensive and the government needs to ensure that strict guidelines are followed and a very high standard is maintained.
- Chances of flooding: People residing in villages and towns in the nearby area, where there are chances of flooding, have to be relocated.
- Loss of land and livelihood: They lose their businesses and farm lands.
- Forced removal: Sometimes people are removed forcibly to set up hydro-power plants and it poses a serious ethical concern.
- Geological damage: The building of large dams can cause serious changes to the earth’s surface and lead to geological damage.
- Acceleration of ageing process: Climate change would accelerate the dam ageing process.
- Siltation of reservoirs is a serious issue, though in most cases the extent of siltation continues to remain unknown.
What are the major problems?
- Absence of regular checks
- non-functional instruments
- choked drains
Why are Indian dams more vulnerable to deterioration?
- Earthen-built structure: India's dams are more vulnerable to deterioration because a large proportion of them are earthen--built by compacting successive layers of earth, and not concrete--and are hence more prone to ageing.
- Concentrated rainfall: Secondly, the country gets concentrated rainfall every year for a designated time period as opposed to distributed rainfall, which contributes to the dams' vulnerability.
- Siltation: Siltation leads to a reduction in the storage capacity of the dams.
- Siltation refers to the accumulation of silt and debris behind the reservoir.
- Flood disasters in downstream areas: The downstream areas are often exposed to flood disasters even without a dam breach, in which water creates an opening in a dam due to rapid erosion of a section of the embankment.
Flooding causes around 44% of dam failures in India, while the remaining were caused by other factors, including inadequate spillway capacity, piping and poor workmanship, etc., according to the Central Water Commission.
Why are older dams a threat?
Ageing dams could be associated with a number of deleterious and long-term consequences:
- Safety risks: Older dams pose greater safety risks, cost higher in terms of maintenance and have declining functionality due to sedimentation.
- Loss of life and property: Unsafe dams are a hazard and dam break may cause disasters, leading to huge loss of life and property.
- Impact on Food Security: When soil replaces the water in reservoirs, supply gets choked. Consequently, the cropped area may begin receiving less and less water as time progresses. As a result, the net sown water area either shrinks in size or depends on rains and groundwater (which ultimately gets over-exploited).
- Impact on Farmers’ Income: Since water is a crucial factor for crop yield and credit, crop insurance, and investment, crop yield may get affected severely, and could disrupt the farmer’s income.
- Increased Flooding: The flawed siltation rates reinforce the argument that the designed flood cushion within several reservoirs across many river basins may have already depleted substantially, due to which floods have become more frequent downstream of dams.
What measures are required?
- Effective analysis: There is a need to conduct a cost-benefit analysis of ageing dams, and also to conduct timely safety reviews in order to ensure their operational and ecological safety, as well as the safety of those who inhabit the areas downstream.
- Structural assessment: For India, 2025 is set to be a big year as more than 1,000 dams would turn roughly 50 years or older. Therefore, an assessment of the structure should be carried out, and, if needed, the dam should be decommissioned, states the study.
What about Decommissioning of dams?
- Decommissioning is the process of dam removal or demolition and letting the river flow its natural course.
- It is often undertaken when a dam suffers from structural flaws, its maintenance costs are mounting, concerns public safety or poses ecological risks.
- In India, the concept has not caught on as decommissioning of dams is considered a rather sacrilegious act.
Dams are a critical infrastructure constructed with large investment for multi-purpose uses such as irrigation, power generation, flood moderation and supply of water for drinking and industrial purposes. An unsafe dam constitutes a hazard to human life, ecology and public and private assets including crops, houses, buildings, canals and roads. The safety of the dam is a matter of great concern. Therefore, the country needs a complete re-look when it comes to dam management.