Syllabus
GS Paper 3
Disaster and disaster management.
Context
A glacial lake outburst flood (GLOF) in North Sikkim’s South Lhonak Lake washed away one of the biggest hydropower projects in India, the Teesta III dam at Chungthang.
Introduction
Dam is a structure built across a stream or river to hold water back. Dams can be used to store water, control flooding, and generate electricity. India has almost 6,000 large dams, the third highest number in the world after China and the USA.
- Top Indian States with large dams – Maharashtra > Madhya Pradesh > Gujarat > Chhattisgarh > Karnataka
- Top Indian States with large dams more than 100 years old – Madhya Pradesh > Maharashtra > Gujarat > Rajasthan > Telangana
Challenges faced by dams in India:
- Ageing Infrastructure:
- India, home to over 6,000 dams and ranking third globally in terms of large dams, confronts a critical issue of ageing infrastructure.
- Approximately 80% of these dams are over 25 years old, with 234 of them surpassing the century mark.
- Ensuring their safety is paramount, especially since more than 1,000 dams are poised to reach 50 years or older by 2025.
- Sediment Accumulation and Siltation:
- Dams in India face the ongoing problem of sediment accumulation, which diminishes reservoir capacity over time, directly impacting the dams’ life expectancy.
- Siltation, the accumulation of silt and debris behind the reservoir, also results in reduced storage capacity.
- Structural Vulnerabilities:
- 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.
- Flood Susceptibility:
- India experiences concentrated rainfall during specific periods, as opposed to distributed rainfall, which exposes dams to a heightened risk of flooding.
- Downstream areas are particularly vulnerable to flood disasters, and flooding has been a factor in 44% of dam failures in India.
- Seismic Hazard:
- Several Himalayan dam systems, including the Tehri Dam, are located in active seismic areas due to the constant geological changes and tectonic movements within the Himalayan mountain system, posing a significant seismic threat to these structures.
Top Dam Failures Globally:
- Banqiao dam failure (1975) in China resulted in collapse of 60 other downstream dams and killed more than 80,000 people.
- Machchhu Dam failure (1979) in Morbi, Gujarat claimed over 2,000 lives.
- Collapse of the two dams in Libya’s eastern port city of Derna killed nearly 11,300 people.
Steps taken for dam safety:
- Dam Safety Act, 2021 provides for proper surveillance, inspection, operation and maintenance of specified dams.
- Dam Rehabilitation and Improvement Project (DRIP) with external funding for improving dam safety and operational performances.
Dam Safety Act (DSA), 2021:
- It is legislation aimed at overseeing, inspecting, operating, and maintaining specified dams to prevent dam-related disasters and establish an institutional framework to ensure their safe functioning.
- It primarily applies to dams taller than 15 meters or those with heights between 10 meters and 15 meters, subject to specific design and structural conditions.
- Importance:
- This act is notable for introducing two categories of offenses related to dam safety and prioritizing regular risk assessments, showcasing India’s proactive approach to safeguard its extensive dam infrastructure, some of which have stood for decades, if not centuries.
- National Bodies:
- National Committee on Dam Safety (NCDS): Chaired by the National Water Commissioner, this body is responsible for formulating policies and recommending regulations pertaining to dam safety standards.
- National Dam Safety Authority: This authority implements the policies established by the National Committee, provides technical support to State Dam Safety Organizations (SDSOs), and resolves disputes between SDSOs of states or between an SDSO and any dam owner in that state.
- Dam Safety Unit: Dam owners are now obligated to establish a dedicated Dam Safety Unit, prepare Emergency Action Plans, and conduct Comprehensive Safety Evaluations at regular intervals.
- Head of Dam Safety: The Chairman of the Central Water Commission (CWC) assumes leadership in coordinating national dam safety protocols.
- State Responsibilities:
- State Committee on Dam Safety: States must establish this body to oversee the surveillance, inspection, and monitoring of dam operations and maintenance within their jurisdiction.
- State Dam Safety Organisation: A second state-level body tasked with ensuring dam safety.
- Provisions necessitate states to –
- Classify dams based on hazard risk.
- Conduct routine inspections.
- Develop emergency action plans.
- Institute emergency flood warning systems.
- Undertake safety reviews and periodic risk assessments.
- Document and report dam failure incidents.
- Non-Compliance: Failure to adhere to any provision of the Act carries penalties, including imprisonment and fines. If such non-compliance results in loss of lives or imminent danger thereof, the entity responsible may face imprisonment for up to two years.
Challenges in Dam Safety Act (DSA):
- Legislative Gaps Exemplified by Sikkim Incident:
- The incident in Sikkim highlights shortcomings in both the legislation and its enforcement. The DSA lacks provisions for risk-based decision-making and fails to encourage transparency.
- Reports indicate the absence of early warning systems, risk assessments, and preventive measures, as mandated by the Act.
- Transparency Deficiency:
- A robust DSA should facilitate easy access to information for various stakeholders, but India’s framework falls short in this regard. Dam safety, being a matter of public interest, should involve the public in its proceedings.
- However, currently, there is a lack of transparency, with no information being made readily available to the public.
- Government Influence in Oversight Bodies:
- Transparency is further hindered by the composition of national and state bodies, which primarily consist of government employees and engineers who have been involved in the construction of these projects. This situation compromises objective decision-making and oversight.
- Pattern of Neglect in Dam Safety:
- The recurring frequency and scale of dam-related disasters indicate a consistent pattern of neglect in ensuring dam safety.
- Other Challenges in Dam Safety:
- Ensuring dam safety involves multiple facets, including:
- Design and construction of dams adhering to safety margins.
- Maintenance and operation according to established guidelines.
- Real-time data recording in an accessible format.
- Effective forecasting of hazardous events.
- Implementation of comprehensive emergency plans, among other critical aspects.
Way forward:
- Scientists engaged in the study of Himalayan glacier lakes have raised concerns about these events.
- Periodic reviews are expected to result in the production of new inundation maps and the formulation of updated rule curves that determine dam reservoir capacities, all contributing to the safety of downstream areas.
- It is recommended to conduct reviews of spillway capacity and other relevant metrics approximately every five years to ensure ongoing safety and effectiveness.
Source: The Hindu
Practice Question
Analyze the reasons for the recurring occurrences of dam failures in India and emphasize the key measures outlined in the Dam Safety Act of 2021 aimed at addressing these issues. (Answer in 250 words)