he Central Ground Water Board (CGWB) of the Ministry of Water Resources in its report “Dyanmic Ground Water Resources of India 2023”, has found that the national Capital is covered by diverse rock types of different geological ages from Pre-Cambrian to Recent. According to report, the national capital is among the States which are found
highest extractable of ground water.
The report mentioned as much as 89 percent of the Capital is occupied by alluvium and ground water is being tapped mostly through tube wells. “Yields of tube wells vary from 4 to 10 lps in older alluvial deposits and from 25 to 55 lps in newer alluvium. About 11 % of the State is occupied by quartzitic hard rock, where bore wells have yield of 0.6 to 5 lps. The ground water resources assessment has been carried out tehsil-wise,” the report said.
It further highlighted the Total Annual Ground Water Recharge of the State has been assessed as 0.38 bcm and Annual Extractable Ground Water Resources is 0.34 bcm. The Total Current Annual Ground Water Extraction is 0.34 bcm and Stage of Ground Water Extraction is 99.13 percent.
“Out of 34 assessment units (tehsils), 13 units (38.24 %) have been categorized as ‘Over-exploited’, 12 units (35.29 %) as ‘Critical’, 4 units (11.76 %) as ‘Semi-critical’, and 5 units (14.71 %) as ‘Safe’ categories of assessment units. Similarly, out of 1487.61 sq km recharge worthy area of the State, 617.25 sq km (41.49 %) area are under ‘Over-Exploited’, 306.4 sq km (20.6 %) under ‘Critical’, 233.73sq km (15.71 %) under ‘Semicritical’, 330.23 sq km (22.2 %) under ‘Safe’ categories. Out of total 344.49 mcm annual extractable ground water resources of the State, 122.11 mcm (35.45 %) are under ‘Over-exploited’, 102 mcm (29.61 %) under ‘Critical’, 46.94 mcm (13.63 %) under ‘Semi-critical’ and 73.44 mcm (21.32 %) are under ‘Safe’ categories,” it further stated.
As compared to 2022 assessment, the Total Annual Ground Water Recharge decreased from 0.41 bcm to 0.38 bcm and Annual Extractable Ground Water Resources decreased from 0.37 bcm to 0.34 bcm. The decrease in the total annual groundwater recharge can be attributed to a reduction in recharge from rainfall, resulting from lower precipitation during the current assessment year compared to the previous assessment year. There is decrease in the Annual Ground Water Extraction for the state from 0.36 bcm to 0.34 bcm and the Stage of Ground Water Extraction has increased from 98.16 % to 99.13 percent, said the report.
In the present assessment, the total annual groundwater recharge in the country has been assessed as 449.08 bcm. Keeping an allocation for natural discharge, the annual extractable ground water resource has been assessed as 407.21 bcm. The annual groundwater extraction (as in 2023) is 241.34 bcm. The average stage of groundwater extraction for the country as a whole works out to be about 59.26 %. Out of the total 6553 assessment units (Blocks/ Mandals/ Talukas) in the country, 736 units in various States/ UTs (11.23%) have been categorized as ‘Over-exploited’ indicating ground water extraction exceeding the annually replenishable ground water recharge.