Managing new rainfall normal needs better storage & drainage
Kerala’s was undoubtedly a man-made tragedy—the inability to store and drain water efficiently and the assault on the Western Ghats ecology over the years, among other factors, had devastating consequences. This was compounded by the fact that Kerala received over 2,500 mm of rainfall this year—the second highest rainfall in nearly a century—of which more than a third fell over just 20 days. But, with climate change, extreme and erratic monsoon is becoming the new normal for India. A Down to Earth report points out how, over the past few years, flood-drought cycles are becoming both more common and pronounced in the country. This year, 86 districts in the country are facing >40% rainfall deificit—50 are experiencing a 40-50% deficit, 23 face a 51-60% deficit, 10 a 61-70% deficit and three face a >70% deficit, with Dhemaji in Assam reeling under 88% less rainfall. Of these 86 districts, 10 have also seen floods this year—Dhemaji faced flooding on August 31, when China released water from the upper reaches of the river Siang, claiming extreme rainfall in its side. A look at rainfall statistics across the nation confirms an extreme/erratic rains duopoly. While the country saw a 6% deficiency over the long period average, over 20% of the 718 districts in the country were flooded and nearly 40% are facing droughts with deficits of over 20%. What’s worse, many states have some districts flooded and some districts experiencing drought.
With extreme weather events, including flood-drought cycles, set to become routine—the global community continues to fail at making the requisite efforts to mitigate climate change effects—India must adopt resilience and adaptation strategies. No longer can it afford to have a storage capacity of just 253 billion cubic metres (bcm)—against 2,600 bcm of rainfall received in even a bad year and a usage demand of 1,110 bcm. The country has just 91 large reservoirs, storing just 158 bcm. New reservoirs must be built and at the right places. Sunita Narain of the Centre for Science and Environment, writing in the Business Standard in August, had proposed that a network of connected water storage structures be built to drain off excess water in case of floods and act as storehouses for droughts. In her latest article in that newspaper, she puts Kerala’s “decimation” of its drainage systems, including forests, hills, flood plains, paddy fields, ponds, etc, that could have helped store the excess water or recharge ground water levels, under the spotlight. While the Kerala government had planned an ambitious rain-water harvesting programme—the Kerala Municipal Building Rules, in fact, made rain water harvesting mandatory—this has not really taken off; Narain says in her article that the state would need to enforce this strictly as it rebuilds itself. Others, flooded or facing droughts or reeling under both, must take a cue from Kerala’s tragedy and focus on developing optimal storage and drainage capacity.