‘We have found some flaws': Why IISER scientists are red-flagging RFD

Indian Express

26-05-2025

On Monday, as monsoon arrived early in Pune, IISER was among the areas to be lashed by heavy rains. Dr Argha Banerjee, associate professor and deputy chair, Earth and Climate Science, at IISER, says hundreds of papers have been written all over the world that climate change is going to change the precipitation patterns and increase extreme events. 'It is the kind of situation that initiatives, such as the Riverfront Development (RFD), should be designed for,' he says.
A few weeks ago, Banerjee, Radhika Mulay and Tresa Mary Thomas, who are with the Earth and Climate Science department and the Center for Water Research at IISER Pune, released a paper, titled 'A brief review of the Hydrology and Hydraulics report for the Mula-Mutha Riverfront Development Project'. It summarises that climate change effects were not considered, flood levels were underestimated and world-class scientific expertise present in city institutes must be utilised.
Among the warnings from the report is that 'while the precise increase in the flood levels and flood frequency at the scale of the city are challenging to predict, it is imperative to consider significantly higher design floods … and ensure the city's flood resilience. The RFD report fails to address these critical concerns, and may not prepare the city for the unexpectedly high flood levels due to climate change. This can be remedied by extensive consultation with the world-class experts in climate and hydrology in institutes like IMD, IITM, IISER Pune, etc. that are present in the city'.
'Since we have a general interest in water and the RFD was going on right in front of us, we decided to have a look at the Detailed Project Report of the RFD: Annexure 2 – Hydrology and Hydraulics. We looked at the report from the basic science perspective. We did not run any of their simulations or redo the calculations. We just checked the basic science of it and from that perspective, already, we have found some flaws that we have highlighted in our report,' says Mulay.
One of the main factors pointed out is that 'there is very little data analysis'. 'Though Pune is home to the IMD and there are a few stations in the region, it is still a very complex terrain. The IMD data is not always good enough as precipitation varies a lot over a short distance. This tells us that we have to be careful and that care is missing in case of the RFD. We have pointed this out. We don't really have a solution but we can say that the data that exists was not looked into carefully,' says Banerjee.
The report emphasises that the RFD design team did not use their own estimates and, instead, relied on the estimates from the Irrigation Department, Pune. 'A recent Maharashtra Engineering Research Institute report came up with significantly higher flood discharge estimates than those suggested by the Irrigation Department. The extreme monsoonal rain can lead to floods, when the river levels and the storage in dams are already high. This was not considered in the RFD estimates of flood levels. It may be prudent to consider the combined effects of the average monsoon discharge and the discharge due to the extreme rainfall. In addition, a strong gradient in the rainfall from the Western Ghats to Pune, together with the sparse network of hydrometeorological stations in this catchment, makes all the above flood estimates inherently uncertain,' says the report.
The report also states that the RFD plans to replace 240 hectares of greenery, 'largely with concrete without any serious evaluation of the carbon footprint associated with the infrastructure development'. 'It is unclear if the damage to the ecosystem during the construction phase has been assessed. Additionally, the Environmental Impact Assessment report should be independently reviewed by scientists and experts in the city working in the relevant fields,' it states.