Water reserves in southern India depleting faster in 2023

Context:

As per the latest findings, the Southern peninsular India remained the sixth driest in 123 years. The collective reservoir stocks have already fallen below 50 per cent in November 2023.

Water Stress in Southern Indian Peninsula

According to a recent report from the Central Water Commission (CWC), water levels in these states’ reservoirs are low compared to last year and compared to other regions of the country in 2023.

Current available water stocks in the dams:

The CWC monitors 42 reservoirs located in the southern states: Andhra Pradesh, Telangana, Karnataka, Kerala and Tamil Nadu. Their collective storage capacity is 53.334 Billion Cubic Metre (BCM).
There has been a sharp drop, observed over the past two months. In September 2023, the water stocks stood at 25.609 BCM (48 per cent of the total storage capacity), which then dropped to 24.575 BCM (46 per cent of the total storage capacity).

State	Reservoir stocks (% of total storage capacity)
Andhra Pradesh	-51
Karnataka	-38
Kerala	-16
Telangana	+33

Normal monsoon years: During normal monsoon years over the country, the available water reserves in southern India touch 91 per cent of the total storage capacity.
Low water availability: Even though the country as a whole recorded normal rainfall in 2023 (820mm, 94 per cent of the Long Period Average), the monsoon over the south peninsular was not appreciable.

Reasons for low water stocks:

Inter-seasonal rainfall variability: There was a vast inter-seasonal rainfall variability recorded during the southwest monsoon this year.
Normal rainfall in Initial months: Rainfall records by the India Meteorological Department (IMD) showed that the south peninsular India received normal or above rainfall only during the July 26-August 3 period during the four-month season.
Rainfall deficit in Later months: The season, thus, ended with seeing large-scale rainfall deficits – June (-45 per cent), July (45 per cent), August (-60 per cent) and September (49 per cent), which cumulatively ended with 8 per cent below normal, which was quantitatively 659mm.
Rainfall deficit: The rainfall recorded was 58.7mm against a normal of 148.2mm. Normally during October, most of southern India receives rainfall, contributed by the retreating southwest monsoon and the incoming northeast monsoon.
Cyclone Hamoon: According to IMD, cyclone Hamoon’s development in the Bay of Bengal during the onset phase of the northeast monsoon dampened the rainfall activity, particularly over Tamil Nadu and coastal Andhra Pradesh.
Collective Deficit: The collective rainfall deficiency in south peninsular India slipped to 60 per cent.

Deficit Rainfall in Peninsula India:

The recorded rainfall during October was

Andhra Pradesh and Yanam (-90 per cent)
Rayalaseema (-90 per cent)
Tamil Nadu, Karaikal and Puducherry (-43 per cent)
Kerala (1 per cent)

Regional Impact due to Water Crisis:

Shrinking Development: The shrinking of water reserves is not an encouraging development.
Irrigated Farming: The immediate impact could be felt on irrigated farming, particularly the high water-intensive paddy cultivation which is largely undertaken in Andhra Pradesh and Tamil Nadu.
Drinking Water Issue: Besides, during the unfolding months, the impact will spiral over to the availability of drinking water.
Declaration of Draught: While Karnataka has begun declaring drought-hit talukas, other states may soon follow suit.
Political Impact: With new state governments to be sworn in in Andhra Pradesh and Telangana, it would be a challenge to tackle the agri-crisis triggered by water shortage.