water management policies to control floods

 In the monsoon season, there is an increase in frequency of heavy rainfall. Global warming and lack of scientific flood management hold clues to the frequent floods witnessed in recent years.
The tragedy in Kerala has highlighted the dangers of excess water accumulation in dams. More than 20 dams released water that cascaded down the hills, leaving behind a trail of destruction.

Dams are used to control floods:-

The world over, dams are constructed mainly for the purposes of irrigation, power generation, and flood control. The role of dams in flood control has been underestimated.
It is an internationally accepted practice that the water level of a reservoir should be kept below a certain level before the onset of the monsoon season. This is to prevent floods downstream when there is heavy inflow to the dams.

Dams have caused floods as well:- Dams have also induced floods when water released from a dam reservoir is beyond the carrying capacity of channels downstream.
Authorities always look to store the maximum amount of water in reservoirs during the monsoon season, which is then used for irrigation and generation of electricity during the summer months.
In India, most of the flood-management systems are not supported by science.
Dam proponents are ignoring crucial decision-making data now available on patterns of rainfall, geology and climate change.
According to the India Water Portal, over 100 dams in India are over a century old, and more than 500 large dams which are 50-100 years old, many have major defects and need urgent repair.
Dams can trigger seismic events.
The reservoir-induced seismicity (RIS) from the weight of the reservoir has resulted in earthquakes in various parts of the country

Way forward:-

International Practice
The Colorado River in the US runs through seven states. They do very good reservoir system management. They look at weather forecasts to understand how much water to expect. They start releasing water, based on the predictions, even before something serious happens. India can follow this scientific approach
It is time for the government and the public to formulate water management policies for reservoirs in such a manner that dams are used to control floods.
It is important that at least 30% of the storage capacity of dams be kept free before the monsoon.

Non conventional sources:-
It is time to think of non-conventional sources for electricity generation such as solar, wind and tidal power, rather than over-dependence on hydel projects.
The practice of solar power generation in Kochi airport can be copied in similar large-scale projects by other government agencies.

administrarion

• The State government, the State Dam Security Authority and the National Water Commission should all be prepared to take bold decisions together on water management so that there are no devastating floods in the future.
• At present, the task of dam and water management is vested with the Public Works Department, the Electricity Board, and the Irrigation Department. Even in normal conditions, given contradictory opinions from various departments, it is difficult to implement decisions. Hence, the State Dam Security Authority, if competent, should be entrusted with the task of water management in reservoirs and with taking decisions in emergency situations etc.
• Regular desiltation of dams should be done
• India needs full-fledged flood management systems using scientific methods to understand when the time is right to open the gates.
• Decentralised alternatives involve water recycling and reuse.
• The immediate task is to critically review every dam in the country, decommission those that are at end-of-life, and establish sound safety protocols.

By: SONAM SHEORAN