As monsoon heads for lean run, spotlight is on reservoir levels

As intensity of the southwest monsoon shows signs of decline, water levels in 91-odd reservoirs located across the country would be one of the most critical elements that would be keenly watched.

A significant dip in the levels would not only harm the irrigation potential but could also have a telling impact on sowing of rabi crop, which is sown immediately after the kharif season.

Of particular importance would be the water levels in 45 out of the 91 reservoirs located in north, west and central parts of the country, as their current levels are either below last years' or just marginally above them (see chart). However, the current levels in all of them are more than the 10-year average.

If the southwest monsoon gets subdued from the July first week and temperature rises as is being predicted by state-run India Meteorological Department (IMD), then the levels could go down fast.

On June 26, water in the total 91 reservoirs across the country was at 43.26 billion cubic meters (BCM), which was 27 per cent of the total storage capacity in these reservoirs.

The storage was 111 per cent of last year and 146 per cent of last 10 years average. Thus, on both counts, water in most of the reservoir is at a comfortable position. The increase has been mainly due to strong performance of the southwest monsoon in June, despite a delayed entry. The rains were strong and much above their average in central, western and also northern India, which helped in filling up the reservoirs faster than expected. Better-than-normal rains from February-end to April also helped.

Till June 29, the southwest monsoon was 18 per cent more than normal across the country. Though, this had dipped from almost 27 per cent above normal a few days back, it is still on the higher side.

In northwest India, the rain so far has been 24 per cent above normal, while in central India, it has been 28 per cent above normal. In south peninsular India, the southwest monsoon was 22 per cent above normal, while it was just 3 per cent in excess in east and north-east India.

In the northern parts of the country, the six major reservoirs located in Himachal Pradesh, Punjab and Rajasthan had 7.76 BCM of water till June 26 as against an available capacity of 18.83 BCM.

During the same time last year, these reservoirs had water equivalent to 26 per cent of their total storage capacity, while the 10-year average has been 29 per cent of the capacity. In other words, water is at present more than all the parameters in these reservoirs. Water in northern reservoirs is also important, as these have irrigation potential and supply power to Delhi, much of Uttar Pradesh and Haryana. During the peak time, of the total 6,000 Mw of Delhi's power requirement, hydro-power contributes around 1,500 Mw.

In central India, that includes Madhya Pradesh, Chhattisgarh and also Uttar Pradesh, water levels in the 12 major reservoirs is at 12.67 BCM, which is 30 per cent of the total capacity of 42.30 BCM. Last year during the same period, this was 31 per cent of the total capacity, while the 10-year average is 14 per cent. Water in the 27-odd reservoirs of western India is at 5.91 BCM, which is 22 per cent of available capacity of 27.07 BCM. Last year, this was at 24 per cent, while the 10-year average is at 21 per cent.

Water in the 15 reservoirs of eastern India in Jharkhand, Odisha, West Bengal and Tripura is at 5.41 BCM, which is 29 per cent of 18.83 BCM.

IMD has said after a good start in June, the southwest monsoon might remain subdued over vast tracts of north, central and western India over the next 20 days.

However, private weather forecasting company, Skymet, disagreed and said the dry spell would be broken by strong cyclonic current over the Bay of Bengal.