It’s been a particularly harsh monsoon this year. Flash floods and house collapses have claimed over 270 lives in India so far, hitting thousands across states in the South and West. Kerala, that saw once of the worst floods last year that took more than 400 lives, was again in the eye of the storm. Over the first half of August, the state recorded deaths of around 95 people — being either washed away or victims of landslides.
In neighbouring Karnataka, the toll is 54 with over 7 lakh people having to be evacuated after rivers burst their banks. Even the ancient town of Hampi, a World heritage site, was flooded. Maharashtra, which has been in the grip of the drought, saw massive flooding last month in Sangli and Kolhapur with 35 people losing their lives and the emergency evacuation of 50,000 people.
Mumbai too, which has its own flooding problem, has this season been paralysed on several occasions with 34 lives lost so far. Heavy rainfall and floods are natural calamities, though climate change is causing a strange spike in unpredictable cloudbursts. But are we doing enough in forewarning and flood control measures?
EARLY WARNING SYSTEM
The economic costs of heavy rains and flooding is very high. The National Disaster Management Authority, says on an average 75 lakh hectare of arable land is hit and 1,600 lives lost every year. Damage estimates annually vary from Rs 2,000 to Rs 20,000 crore.
While not much can be done to inhibit storms and cyclones, an early warning system and the construction of flood control measures can save lives and property. It is on flood warning that more needs to be done. The Central Water Commission was set up in 1958 for Yamuna river in Delhi, and it currently gathers forecasts for 173 stations, with an average of 6,000 forecasts issued annually. The forewarning is to tell people as to when the river is going to use its floodplain, to what extent and for how long.
Though the government claim that these forecasts achieve nearly 96 per cent accuracy, the truth is on the ground the system malfunctions; and the inability to arrange for quick evacuation defeats the purpose of alerts. For instance, a 2017 Comptroller and Auditor General report noted: “Nearly 60 per cent of the 375 telemetry stations set up between 1997 and 2016 are non-operational.”
Second it is not rainfall but the inability to drain away rain in time that causes death and destruction. The death of 30 people on 1-2 July night this year in Mumbai, was caused by a concrete wall that collapsed under the accumulated volume of water on hutments on a hillside because there were no water escape points.
FLOOD PREVENTION
On a larger scale, flooding of swollen rivers can be restrained by embankments as well as channelling excess water into dams, reservoirs and natural basins. Through these techniques, one can’t stop floods, but one can control and divert floodwater. Major embankment projects include those on rivers Kosi and Gandak (Bihar), Brahmaputra (Assam), and Godavari and Krishna (Andhra Pradesh). But obviously new, vulnerable water channels have come up, and the process of controlling and drainage has not kept pace.
A school of thought that needs to be given some weight feels that super dams and large reservoirs, far from controlling flooding, work to sink villages and farms in riverine areas. The South Asian Network for Dams, Rivers and People cite the example of the recent flooding of Sangli, Kolhapur and Satara. Though rainfall was heavy, the washing away of homes and crops was more a result of the release of large volumes of water from the three large dams — Koyna, Warna and Radhanagari – in the upper Krishna Basin.
In case of Mumbai and other cities, flooding is primarily a failure of urban planning. Through reckless construction, the natural run-off areas which allow water to percolate into the sub-soil have been destroyed, leading to water-logging. Other natural water dispersal areas like mudflats and wetlands have also been encroached. Specifically for Mumbai, the stormwater drainage system, designed in 1860 by the British, is still the city’s mainstay.
It consists of 2,000 km of open drains, 440 km of closed drains, and 186 outfalls. It has been upgraded and many parts of the old city like Byculla and Worli, don't flood anymore. However, in high tide when the sea washes back into the system, waist-high flooding in low-lying spots is not uncommon. Mumbai, and for that matter large river basins and high rainfall areas, need round-the-year planning to prevent and control flooding. Otherwise, it will be disaster management every monsoon.
270 liveslost in the country so far due to flash floods and house collapses during the monsoon season