10 years after deemed safe, UT groundwater extraction now at ‘semi-critical’ stage

According to the study, the total extraction of the ground water in UT is 3,793.76 ham/year. The net ground water availability in 2020 was 5,738 ham (hectare metre)/ year, while in 2022 it has was decreased to 4,684 ham/year.

Authorities blamed the increase of concretisation – roads, cycle tracks etc in the city, and insufficient rainfall for the decline in groundwater.

Currently, the major share of groundwater being extracted is for the domestic purpose, which is 2,625.72 units, while the pie of industrial use is 217.35 units. Extraction for irrigation use makes up 950.7 ham/year, according to the data. Increasing population in the city is also a key factor in the decline.

As far as the groundwater recharge is concerned, in the monsoon season, it is 772.06 ham/ year, while in the non-monsoon season, the refill is 313 ham/ year. Recharge from other sources make up only1,424.78 ham/ year during the monsoon season, while in the non-monsoon season, it is 2,695.13 ham/ year.
“Since, Chandigarh has been considered an urban unit, significant decrease in the natural recharge has been observed,” the report stated.

Present water scenario
There are 281 deep tube wells in the city for drinking and domestic use, and out of them, 277 are operational. As many as 23 tube wells are for commercial/ industrial use and they are permitted to withdraw 217.65 ham/year groundwater. For irrigation use, 30 tube wells are used and total draft of these wells are 5950.80 ham/year.

The urban water supply of the UT is 88.89 mld (million litre per day) which includes groundwater supply of 21.13 mgd and surface water supply through the canal of 67.76 mgd. The water supply losses are 26.66 mld (30 per cent of total water supply).

Deficit rainfall since 2012
Chandigarh has been seeing deficient rainfall since 2012. The normal rainfall for Chandigarh (UT) 1,078 mm, but it has great spatial variations, the authorities found.

The actual annual rainfall, from 2012 to 2021 of the UT, when analysed and compared to the normal rainfall, shows a constant declining trend: In 2012, the annual rainfall was seven per cent less than normal rainfall, and in 2021 it reduced to 24% less than the normal annual rains.

‘Tubewells to be sealed in next five years’
Chandigarh Municipal Commissioner Anindita Mitra told The Indian Express that keeping in the mind the situation of groundwater and for the project of water supply round the clock, overhead tanks would be disappearing over a period of time. “Also, since the entire 24*7 water supply project will draw water only from canals, 281 large tube wells will be sealed in the next 5 years. Once we stop tapping groundwater, automatically the groundwater table level will improve,” Mitra added.

She also underscored the plan to extend tertiary-treated water network across the city. “Once the maximum number of people shift to tertiary-treated water for watering of lawns, the pressure on drinking water will automatically subside,” the commissioner added.

Irrigation through tertiary-treated water
Chandigarh has a large number of open spaces, parks, gardens, and houses with big lawns, where water is required for irrigation. There are 1,800 parks in the city. In a recently-held meeting, it has been directed that for UT’s entire 1,800 parks, no drinking water shall be used for irrigation, and only the tertiary-treated water.

At present, 680 parks and green belts are irrigated through tertiary-treated water and after laying of some lines, all 1,800 parks will be irrigated through such water.

A high-level committee chaired by the UT adviser last week accorded administrative approval for strengthening tertiary-treated water supply system in the UT at an estimated cost of Rs 97.25 crore.