What is the issue?
- The recent Kerala floods have highlighted the dangers of excess water accumulation in dams.
- It is essential, in this context, to understand the role of dams in flood control.
Why are dams dangerous?
- Dams store millions of tonnes of fresh water in large reservoirs.
- However, this is only after submerging prime forests, villages, farms and livelihoods.
- The 4,700 large dams built since 1947 have cumulatively displaced 4.4 million people.
- This makes dams the single largest cause for displacement post-Partition.
- These dams take decades to come up, but only a fraction of their output is for the household sector.
- Over 85% of them are used in agriculture for producing cash crops such as sugarcane.
- Dams have displaced the poorest of India’s people in favour of richer farmers and urban residents.
- Notably, this often comes with little or no compensation.
- Worryingly, dams are far more hazardous than any other infrastructure project, except nuclear plants.
- Moreover, many dams in India are over a century old, and so have major defects.
- There is also a case for reservoir-induced seismicity (RIS) from the weight of the reservoir.
- This has resulted in earthquakes in various parts of the country.
How should dams be managed?
- The water level of a reservoir should be kept below a certain level before the onset of the monsoon season.
- This is an internationally accepted practice.
- This ensures that there is enough space to store the excess rainwater when the monsoon rains come.
- This also facilitates releasing water in a regulated manner.
- It thus prevents floods downstream when there is heavy inflow to the dams.
What is the concern?
- The roles of dams in irrigation and power generation are acknowledged.
- However, its role in flood control has always been underestimated.
- It is unfortunate that in both irrigation and hydel projects, flood control is completely ignored.
- Authorities always look to store the maximum amount of water in reservoirs during the monsoon season.
- It is then used for irrigation and generation of electricity during the summer months.
- Despite the extra quantity of electricity produced and area of land irrigated, excess storage is risky.
- It leads to loss of human lives, infrastructure and agricultural land, in times of heavy rains as in Kerala.
- The estimated loss to Kerala runs into thousands of crores and it will take years to rebuild the state.
What should be done?
- Dams - The meteorological department can predict rains or cyclones only a few days in advance.
- So keeping space in reservoirs is must, whether or not there are heavy rains.
- It is essential that at least 30% of the storage capacity of dams is kept free before the monsoon.
- This is crucial to ensure that the flood control purpose of dams is met.
- This allows discharge of water as well as increase of storage slowly as the monsoon progresses.
- There is also a task of critically reviewing every dam in the country.
- Decommissioning those that are at end-of-life, stopping building new ones and establishing sound safety protocols are essential.
- Policies - It is high time that government formulate water management policies for reservoirs.
- This should be in such a manner that dams are used to control floods, and not cause them.
- There is also a need to act on decentralised alternatives involving water recycling and reuse.
- Electricity - The over-dependence on hydel projects to produce electricity is another driving factor.
- So enhancing non-conventional sources for electricity generation is important in this context.
- Authority - Dam and water management is vested with the Public Works Department, Electricity Board, and Irrigation Department.
- But even in normal conditions there are contradictory opinions among these.
- This poses implementation hurdles to the decisions taken.
- So, the State Dam Security Authority, if competent, should be entrusted with the task of water management in reservoirs.
- It should also be empowered to take decisions in emergency situations.
Source: The Hindu
