Updated: June 19, 2021 9:24:18 am
Frequent thundershowers and two strong cyclones— Tauktae and Yaas — brought significant rainfall during the summer. Thus, even before the southwest monsoon covers the entire country, the 130 major reservoirs monitored by the Central Water Commission have already stored 27% of their total capacity. This is well over the average storage for this time of the year — 21% averaged for the last 10 years.
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As of June 17, the collective stock in the 130 reservoirs was 47.63 billion cubic metres (BCM), or 27% of the total live storage capacity of 174.23 BCM. In June last year, they had stocked 55.11 BCM.
Of the 130 reservoirs, 49 have more water than they had stored in June 2020. A majority of these reservoirs are located in seven states — Jharkhand, Tripura, Andhra Pradesh, Telangana, Kerala, Karnataka and Tamil Nadu.
Of the reservoirs with less storage than in June 2020, many are in the larger states of Maharashtra, Uttar Pradesh, Madhya Pradesh and Odisha, besides Punjab, Himachal Pradesh, Chhattisgarh and Uttarakhand. This year, two large dams — Hariharjhore in Odisha and Ujjani in Maharashtra — have reached dead stock. This time last year, Hariharjhore had stocked 59% of its capacity.
Stocks are above normal in the basins of the Ganga, Narmada, Tapi, rivers of Kutch, Krishna, Mahanadi and Cauvery. The river basins of Mahi and Indus have normal and deficient reserves, respectively.
Region by region
In eight reservoirs in the Northern region (Himachal Pradesh, Punjab, Rajasthan), the available stock on June 17 was 3.82 BCM, or 20% of their total live storage capacity. This is below the storage of 2020 (38%) and also the 10-year average (32%).
In the 20 reservoirs in the Eastern region (Jharkhand, Odisha, West Bengal, Tripura, Nagaland), the available water stock is 4.59 BCM, or 23% of their total live storage capacity. Last year, these reservoirs had stored 28%. The 10-year average stock is 21%.
The Western region comprising Gujarat and Maharashtra has 42 major reservoirs. At 9.95 BCM, these are currently at 28% of their total live capacity. In June 2020, they were at 36% of capacity; the 10-year average is 19%.
In the 23 reservoirs of Central India (UP, Uttarakhand, MP, Chhattisgarh), the current storage is 12.73 BCM, or 28% of their total live capacity. This is below last year’s storage (37%) as well as the 10-year average here (24%).
The Southern region of Andhra Pradesh, Telangana, Karnataka, Kerala and Tamil Nadu has 37 reservoirs, in which the available stock is 16.55 BCM, or 30% of capacity. This is higher than the sticks of 2020 (24%) and also the 10-year average (17%).
Weather & storage
The summer of 2021 saw unusually cool day temperatures over most regions. This could have led to below-average evaporation from surface water stocks across the core heat zones, where heatwaves and high day temperatures are common during March-June.
The cooler summer was also due to frequent thunderstorms that brought rainfall spells at many places between March and May.
During the second and third weeks of May, Cyclones Tauktae and Yaas caused widespread rainfall over two-thirds of the country between them — Kerala, Tamil Nadu, Karnataka, Andhra Pradesh, Telangana, Goa, Maharashtra, Gujarat, Odisha, West Bengal, Jharkhand, Uttar Pradesh, Delhi, Bihar and some parts of the Northeast.
The all-India weekly rainfall during May 12-19 and May 20-26 was, respectively, 127% and 94% above the Long Period Average.
All these factors contributed to the stocking of at least 80% of their June normal capacity in 110 of the 130 reservoirs.
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