It isn’t rainfall averages but reservoir levels and rain-fed sowing trends that give a true picture of the monsoon, says KJ Ramesh, Director-General, India Meteorological Department (IMD).
A meaningful assessment can be made from reservoir storage for irrigated crops and the sowing acreage of the rain-fed segment, Ramesh told BusinessLine.
“How the acreage rises from July 1 to the middle of August should give you an indicator of the health of the monsoon. That’s the sowing time for most of the kharif crops.”
One should not look beyond last year for the best example. With 97 per cent rainfall, the country produced its best-ever foodgrain output.
Ramesh pointed out that global weather models had last year predicted the possibility of a monsoon-friendly La Nina event taking place in the Equatorial Pacific. In reality, this didn’t happen until after the monsoon season.
As a result, India got less rain than forecast. But it was still a comfortable quantum, though deficient in the South, especially Kerala, South Karnataka and Rayalaseema.
This was only an aberration. The rain-deficient area amounted to 15-20 per cent of the geography, which has been the trend even during the best of monsoons.
Bad timing
What was unfortunate was that this had come on the back of a failed monsoon during the preceding year, leading to a major crisis in terms of availability of water for farmers and the general public in these areas.
Discussing last year’s monsoon, Ramesh said that the Central Water Commission (CWC) monitors water levels at 102 critical reservoirs.
By September 30, 2016, almost 94 per cent of them were full. These are major reservoirs for which irrigation ayacuts are built. These reservoirs were full even after meeting the irrigation needs for July, August and September. Normally, the water gets released from July. Only four to five per cent of this was required for the rest of the kharif season. Rabi crops also benefited from the generous storage.
“These reservoirs went a long way to ensure the bumper foodgrain output last year. Even in April 2017, storages are climatologically higher,” said Ramesh.
“The CWC plots a continuous moving 10-year average of reservoir storage. In April, this was above 10 years’ average. That’s a true measure of a strong monsoon on the ground,” he added.
Rain-fed crops
Another measure is the yield of rain-fed crops — oilseeds, cereals pulses. Yields were phenomenally high last year both for kharif and rabi. All this was possible with 97 per cent rainfall.
“So it depends on where the rain is happening, not purely on statistics ... if the rains happen in those river catchments that fill up critical reservoirs, then the percentage of rainfall doesn’t count for much.”
As for the ongoing onset phase of the 2017 monsoon, if the rain were to spread from the South up to the Konkan region, where it is expected to reach by June 8, it is good enough.
Only, it should not miss the Cauvery basin or any other major river basin. “It is not necessary that we have above-average rainfall here, since the normal itself is very high,” said Ramesh.
“Suffice to say that the true manifestation of the monsoon is on the ground. People tend to look at percentages and jump to conclusions. Instead, look at reservoir storage and rain-fed crop acreages.”