National

Groundwater reserves estimate to be updated soon

Survey samples a sliver of blocks in each State and counts how many blocks have critically low levels of water

The Union Water Ministry is finalising an updated estimate on the state of groundwater reserves in India.

The groundwater assessment, last done in 2013, is a survey that samples a sliver of blocks in each State and counts how many blocks have critically low levels of water and how many are well-stocked.

“We have received reports from most States and have passed it on to the Water Resources Ministry for approval. I expect that this will only be made public after the new government comes in,” a senior official from the Central Ground Water Board (CGWB) told The Hindu.

The person said “some States” showed a precipitous decline whereas some blocks showed an “improvement.”

An assessment from Punjab, the official said, pointed to “extreme” overexploitation of groundwater.

Break-up

In 2013, the CGWB assessed 6,584 units across the country and found 4,520 to be “safe,” 681 to be “semi-critical” 253 to be “critical” and 1,034 to be “overexploited.” About 96 blocks were “saline”.

In a CGWB report of April 2015, the agency noted that the water resource potential or annual water availability of the country in terms of natural runoff (flow) in rivers is about 1,869 Billion Cubic Meter (BCM)/year. However, the usable water resources of the country is about 1,123 BCM/year. This is due to geographical limitation and water being unequally distributed in various river basins, making it difficult to extract all the available 1,869 BCM/year. Out of the 1,123 BCM/year, the shares of surface water and groundwater are 690 BCM/year and 433 BCM/year respectively. Setting aside 35 BCM for natural discharge, the net annual ground water availability for the entire country is 398 BCM.

The overall contribution of rainfall to the country’s annual ground water resource is 68%.

The share of other resources, such as canal seepage, return flow from irrigation, recharge from tanks, ponds and water conservation structures taken together is 32%.

The national per capita annual availability of water has reduced from 1,816 cubic metres in 2001 to 1,544 cubic metres in 2011 — a reduction of 15%.

Cause of concern

That India’s groundwater has been depleting at a worrying rate since 1995, the CGWB has shown.

In 1995, only 3% of districts had overexploited their groundwater reserves whereas by 2011, that had increased to 15%.

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Printable version | Jul 1, 2020 9:09:59 AM | https://www.thehindu.com/news/national/groundwater-reserves-estimate-to-be-updated-soon/article27211009.ece

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