Relevance: GS-3: Conservation, environmental pollution and degradation, environmental impact assessment; Disaster and disaster management

Key Phrases: Signs of ageing of dams, dams safety in India, Environment Impact Assessment, Dam Safety Act 2021, Central Water Commission(CWC), Dam Rehabilitation and Improvement Project

Context:

• India has 4,407 large dams, the third highest number in the world after China and the USA, according to the United Nations report on dam safety.
• Report says that over 1115 large dams will be about 50 years old by 2025, 4,250 in 2050 and 64 large dams will be more than 150-years-old in 2050.
• This makes it necessary for India to conduct a cost-benefit analysis and timely safety reviews of its ageing dams.

Background

• A dam is a barrier that stops or restricts the flow of surface water or underground streams.
• Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability
• However, faulty operations of reservoirs may sometimes result in flooding downstream regions.
• The dam, in a seismically active area, shows significant structural flaws and its management is a contentious issue between Kerala and Tamil Nadu.

Dams: Signs of Ageing

• According to the UN Report, at 50 years, a large concrete dam would most probably begin to express signs of ageing. These include -
  • Increasing cases of dam failures
  • Progressively increasing costs of dam repair and maintenance,
  • Increasing reservoir sedimentation, and
  • Loss of a dam’s functionality and effectiveness

Dam Safety in India

• Dam safety can be delineated into two elements based on the stage in a dam’s life-cycle in which they are pertinent viz.:
  • Pre-construction: includes various impact assessments, and design and engineering standards. These components determine what is the optimal location and design.
  • Post-construction: includes regulations, standards and best practices in dam operations and management. It includes Standard Operating Procedures (SOPs) for day-to-day O&M, SOPs for handling exceptional events and surveillance and monitoring.
  • During-construction elements of safety related to faithful implementation of an approved design.

Institutional Arrangements in India

• Under the 7th Schedule of the Constitution, water and water storage is a state subject. Therefore legislating dam safety is the responsibility of state governments.
• The Central Government can enact legislation governing dams in three scenarios -
  1. If a project affects multiple states or international treaties.
  2. If two or more states pass a resolution requiring such a law e.g. Andhra Pradesh and West Bengal passed resolutions requiring a law on dam safety - Dam Safety Bill 2019.
  3. It can legislate on matters related to the protection of the environment under the Environment Protection Act, 1986 as dams and dam failures can have a significant impact on the environment.
• The guidelines under Disaster Management Act, 2005 mandate the State authorities to give an intimation to the adjacent States immediately after a decision is taken to release water from the reservoirs/dams.
• The Dam Safety Act 2021 very comprehensively provides for surveillance, inspection, operation and maintenance of the dams for prevention of dam failure related disasters and to provide for institutional mechanisms to ensure their safe functioning and for matters connected therewith or incidental thereto.
• At the national level, the CWC provides technical expertise and guidance on all matters related to dams. It is tasked with research into dam safety, developing standards for dam design and operations, and it is involved in the process of granting environmental clearance to dam construction projects.
• CWC has issued guidelines for:
  • Dam Safety Procedures
  • Safety Inspection of Dams
  • Development and Implementation of Emergency Action Plan (EAP) for Dams
  • Standardized Data Book Format, Sample Checklist and Proforma for Periodical Inspection of Dams.
• These guidelines are not legally binding on all dams, but rather only applicable to projects which require environmental clearance from the Ministry of Environment and Forests (MoEF) under the EPA, 1986, or dams which are part of central schemes e.g. dams under DRIP.

Way Forward

• Data on flooding caused due to faulty operations of reservoirs is not maintained centrally. It makes it very difficult to analyze the safety of dams and develop a standard procedure throughout India.
• The rising frequency and severity of flooding and other extreme environmental events can overwhelm a dam’s design limits and accelerate a dam’s ageing process.
• A risk-based approach is necessary for making sound decisions on dam safety. Dam failure analysis is fundamental to a risk-based approach to dam safety.
• Some of the technological and institutional foundations for building a robust risk-based decision-making system for this sector are already in place. A few changes in policy, and leveraging already built resources e.g. WRIS, and MoEF environmental clearance portal can enable India to build a better, safer dam sector.

Sources:  PIB   NIPFP-Org

Mains Question:

Q. A risk-based approach is necessary for making sound decisions on dam safety. Discuss in the light of recent dam failures in India. [150 Words].