Monsoon boosts South Indian dams, but rest of India is drying fast

Despite a good monsoon, levels of water in the country’s big river water reservoirs are substantially below where they were last year, and are also well below the average levels seen in the last ten years. The only exception was South India, which had seen extreme water stress last year.

On average, the quantity of river water stored in dams and reservoirs across India as of February 15 is 12% lower than what it was on the same day last year.

Compared to the average level seen over the last 10 years, this year’s storage levels are 9% lower.

The assessment is based on data from 91 of the top dams of the country. These dams account for 63% of the total river water storage capacity in India and are monitored by the ministry of water resources.


However, when it comes to monsoon and river water levels, the trends tend to show a lot of regional variations.

For example, last year had seen very poor monsoon in South India, which led to a sharp dip in water levels even as other parts of India did not see such a big impact.

However, this year, it is the opposite, with decent levels of summer rains helping South India emerge out of the duress seen last year.

Of course, while the rains did help fill some of the gap, they were not enough to fully compensate for the deep draw witnessed winter of 2017-18.

The result is that while South India — which accounts for 32% of India’s big dam capacity — showed good progress in terms of building up water levels from last year’s level, but these were still very much below the long-term, 10-year average.

At nearly 8 percentage points, the gap between the 10-year average and the current year actual is the highest in the Southern reservoirs.

Normally, South Indian reservoirs would have been 39% full as of now, but this year, they are only filled to the extent of 31%. This is better than last year, when they had only 24% of the water, but far from ideal for farmers in the region.

In fact, this year, four out of five regions in India are running a water deficit compared to the 10-year average, though the gaps are not as high as in the case of the South.

In Central India, the gap is 4.5 percentage points (see the chart above), while it is 3.7 percentage points in Western India, which includes Gujarat and Maharashtra.

The deficit in Central and Western India is despite a strong performance seen last year, when they were the best performing regions in terms of historical storage levels.

These three regions account for 77% of India’s total dam capacity.

The other region which is still running a deficit compared to the long-period average is the North, including Himachal Pradesh, Punjab and Haryana. But the shortfall was not as wide as in other areas.

Here, the storage level as of Feb 15 was 36.65% of total capacity compared to long-term average of 38%, implying a deficit of 1.35 percentage points.

The fifth zone, which has actually done very well this year, is Eastern India, which includes the hilly north eastern states.

Though it accounts for only 12% of the total capacity of India’s major dams, the region continued to do well this year as well.

The dams in East India are filled with water to an extent of 61% this year, compared to a long-term average of 55% for this time of the year. Last year was even better at 68%.

However, as a result of the major shortfalls seen in Western, Central and Southern parts of India, the overall figure for the country as a whole showed significant indications of water stress.

For India as a whole, the percentage of water in reservoirs as of Feb 15 was only 39.3%, well below the long-term average of 43.1% and last year’s level of 44.61%.