: Even as the Capital Region Development Authority clarified that floodplains in the Krishna River will be demarcated before taking up the construction of new capital Amaravati, there are suggestions that the government should take into account once in 1,000 years flood flow for identifying the floodplain area.
Allaying the concerns raised by petitioner E.A.S. Sarma, former IAS officer and social activist in the National Green Tribunal that the capital construction in the ecologically sensitive area was against the guidelines of Ministry of Environment and Forests, CRDA submitted that it would take 100 years flood flow into account and demarcate the zones.
The next hearing of the case is scheduled for July 7. The State government, which was also made respondent by the petitioner along with Union Ministry of Environment and Forests, is yet to submit its affidavit.
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Meanwhile, T. Hanumantha Rao, retired Engineer-in-Chief , UN (OPS) consultant, said that while there was nothing seriously wrong in government’s intention to demarcate Krishna floodplain for a flood occurring once in 100 years and construct the capital outside the flood zone, it should consider the thousand-year recurring flood for greater safety.
The magnitude of 1,000-year recurring flood would be much more than that of the 100-year recurring flood. For instance, a flood occurring once in 1,000 years at Pulichintala located at about 70 km upstream of the capital on the same river, is 20.4 lakh cusecs. Its 100-year recurring flood is about 16 lakh cusecs. Accordingly, spillways of irrigation projects are designed with different capacities for minor, medium and major irrigation projects. For major irrigation projects like Srisailam, Nagarjuanasagar and Pulichintala, 1,000 years frequency flood would be taken into account.
Similarly, he said greater caution was called for the proposed world-class city like Amaravati unlike for small and big towns.
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“Govt. will stick
to the code”
However, government sources said that the code for irrigation projects for water storage was different from that of civil structures in cities. “We don’t superimpose irrigation norms for the building structures in cities. The government would strictly adhere to the civil structures code and other precautions related to seismic activity, fire safety, and flood threat.”
In the 2009 Srisailam floods, the maximum flood discharge was more than the ‘Possible Maximum Flood’ of the Krishna itself and it would be taken into account for providing flood protection to the new capital City,” they explained.
Global warming implications witnessed in the recent times such as rainfall of 950 mm on a single day in Mumbai, Srisailam floods of 24 lakh cusecs against maximum of 8 lakh cusecs in 2009, Chennai floods and rains in 2015, should make one to take into account the Possible Maximum Flood for which there was no frequency and could occur at any time. The PMF can be much more than the 1,000 year flood. So for Amaravati too, PMF should be calculated and evacuation plans be kept ready to reduce hardships of people in the event of an eventuality, Mr. Hanumantha Rao said.
One should not
lose sight of global warming implications,
says expert