FIVE YEARS after the 2005 Mumbai deluge, an expert panel of the National Disaster Management Authority (NDMA) came up with the first ever detailed national guidelines on management of urban flooding. The document made a distinction between flooding and urban flooding, describing the latter as a separate phenomenon which needs to be dealt with by an urban flooding unit under the Ministry of Urban Development (MoUD).
However, the dedicated unit is yet to be set up. This despite the fact that the Ministry of Home Affairs had in July 2012 issued orders designating the MoUD as the nodal ministry for urban flooding. An MoUD spokesperson confirmed that no such unit exists in the ministry.
Terming the Mumbai floods as an “eye-opener”, which showed that the cause of urban flooding is different and needs a separate strategy, the report stated: “The NDMA has for the first time decided to address urban flooding as a separate disaster, delinking it from floods.”
The NDMA panel held that unlike rural flooding, with urbanisation, natural catchments develop and the increase in impervious surfaces results in higher run-off of rainwater during heavy rainfall, which increases the flood-peaks from 1.8 to 8 times and flood-volumes by up to six times.
It noted that flooding in urban centres is made worse by inadequate stormwater drains and largescale encroachments along natural waterways, and stressed on the need for improved forecasting and urban planning strategies. For this, it held that a dedicated cell under the MoUD, headed by a joint secretary level officer, must coordinate all urban flood disaster management and mitigation efforts at the national level. This pattern is to be replicated at the state level where the nodal agency would be the state-level urban development department.
Shashidhar Reddy, former NDMA vice-chairman who headed the expert panel, said that since the MoUD has a major role to play in urban infrastructure, it can coordinate and integrate efforts to ameliorate the impact of floods. “The nodal ministry for flooding has always been the Ministry of Water Resources/ Central Water Commission which has focused solely on riverine flooding in rural areas. Despite the home ministry notification, the MoUD or state urban development departments are still not the nodal ministry in practice. For instance, in Chennai, it should have been at the forefront in flood management, which wasn’t the case,” said Reddy.
The report also stated that cities like Chennai and Pune have reported urban heat island effects, which results in localised rainfall of high intensity. This is caused by clouds induced due to higher temperatures in urban areas as compared to its surrounding regions owing to the lack of vegetation, moisture absorbing soils and increase in built surfaces. It cited international case studies by the National Aeronautics and Space Administration (NASA) which had observed increased rainfall intensities over urban areas due to this phenomenon.
Reddy pointed out that flood management is not only about rescue and rehabilitation but also about prevention, preparedness and mitigation which can be coordinated by the MoUD alone. “In our report, we had recommended that due to the localised nature of heavy flooding, cities need to have rain gauges every 4 sq km to transmit data in real time. Had Chennai had these, Doppler radars, and an institutional mechanism for more immediate-term, localised forecasts, it would have had three to six hours lead time for warning people, evacuating them, diverting traffic and rushing rescue teams,” he said. He added that considering the fact that by 2050, a majority of the 1.6 billion project population will be in urban areas, the country can no longer ignore its fragile urban ecosystem that constantly disregards land use classification.
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