Green tribunal asks for redefinition of floodplains

NGT directs Delhi govt to demarcate Yamuna floodplains with one-in-100-year risk probability, expanding protected area, amid concerns of last year's flooding.

The National Green Tribunal (NGT) has asked the Delhi government to demarcate Yamuna floodplains keeping one-in-100-year risk probability in its calculations, according to documents seen by HT, a direction that can significantly expand the area that could be made out of bounds for settlements and construction work.

The Yamuna’s inundated floodplains during the floods in Delhi last July. (Sunil Ghosh/HT)

Current efforts to demarcate Yamuna floodplains take into account a one-in-25-year flooding risk. A one-in-25-year floodplain includes and refers to land along a river that has a one-in-25, or 4%, chance of flooding every year. Therefore, a one-in-100-year demarcation will include floodplains that have even a 1% risk of flooding each year.

While these numbers may seem minuscule, last year’s flooding is an apt example on why floodplain protections must be strong. In July, swathes of the city were inundated in the worst flooding seen in 45 years, with knee-deep waters reaching bungalows in Civil Lines, the iconic Salimgarh underpass archway, the Kashmere Gate bus station and the intersection to the Yamuna Bank Metro station.

The river rose to an unprecedented 208.66m on July 13, sending water as far inland as the Supreme Court, a stone’s throw from the Pragati Maidan area where the government held the G20 Summit just months later.

The floodplains are officially demarcated as Zone O of the Yamuna and in a submission to the National Green Tribunal in January, the government said that taking a one-in-25-year probability would bring 9,700 hectare of land into the floodplain category. These lands include spots on which 94 unauthorised colonies are settled at present.

The new direction will inevitably widen the extent of the floodplains. The tribunal, while stating that this will record the river’s deepest flow inland, also asked the government for details of a standard operating procedure (SOP) it was following for the demarcation of the floodplain land and gave it three weeks to submit a fresh report.

NGT had in October, taken suo motu cognisance of a media report, when it formed a joint committee headed by the Delhi chief secretary to identify, demarcate and notify floodplains of the Yamuna as per the River Ganga (Rejuvenation, Protection and Management) Authorities Order, 2016. It said the delineation of Yamuna was required to prevent illegal developments in the floodplains.

Referring to the 2016 order, NGT said it had clearly defined floodplains to be “an area of the river Ganga or its tributaries which comes under water on either side of it due to floods corresponding to its greatest flow or with a flood of frequency once-in-hundred years.”

“The response which has been placed on record reflects that in terms of the above order the authorities intend to define the floodplain zone by taking 1:25 years as the criteria whereas the Rejuvenation Order, 2016 defines the floodplain as stated above. Therefore, with the river Yamuna being a tributary of Ganga, the flood plain corresponding to its greatest flow or with a flood frequency once in 100 years, is required to be demarcated,” said a bench headed by NGT chairperson justice Prakash Shrivastava in an order dated March 21.

In the latest submission made by the government on March 19, detailing progress of the demarcation, the environment department of the Delhi government informed the tribunal that the process of demarcation was nearing completion with major government departments and bodies like the Delhi Development Authority (DDA), the Irrigation and Flood Control (I&FC) department and the forest department having already provided details of land under them on the floodplains in a KML file format to prepare maps virtually.

Referring to the latest report, the order sought clarity on the process being followed by the government for demarcation, stating based on the submission made, nothing had been done yet to protect the floodplain zone.

“Nothing has been placed on record to show what criteria or SOP has been adopted for demarcation of flood plain, or the contour intervals taken for demarcation of flood plain or the contour mapping which is done for that purpose. Therefore, prima facie it appears that no effective step till now has been taken... though an earlier order of the Tribunal was passed in the year 2015,” said the order, giving authorities — both the Delhi government and the Central Pollution Control Board (CPCB) — three weeks for a fresh action-taken report.

Bhim Singh Rawat, a Yamuna activist and member of the South Asia Network on Dams, Rivers and People (SANDRP), said the directions from NGT are welcomed and will allow more areas to be counted as floodplain zones.

“The criteria for floodplains has become more stringent and this will allow more land along the river to be counted as a floodplain, as compared to earlier. This will also mean if demarcated properly, more encroachments are likely to be removed,” said Rawat, adding that despite multiple orders of NGT, there was no transparency on Yamuna’s floodplain area.

“Boards have also been placed in some parts along the river, stating this was a floodplain area, but they are not maintained properly and are suffering from wear and tear. Until we carry out a proper demarcation, such boards have no meaning,” he added.