Central Ground Water Board

Geography glossary

Also called: CGWB · Topic: Water Resources of India: Availability, Use and Conservation · NCERT: Beyond NCERT

Meaning

The Central Ground Water Board (CGWB) is India's main scientific agency for groundwater. It works under the Ministry of Jal Shakti. It measures how much groundwater India has, watches how fast it is used, maps aquifers (underground rock layers that hold water) and plans how to put water back into the ground together with the states.

It matters because India is the world's largest user of groundwater. Groundwater gives over 60% of irrigation and about 85% of rural drinking water. Most groundwater facts asked in the exam, such as "over-exploited block" and "stage of extraction", come from CGWB's work.

Explanation

What CGWB does: its main jobs

  • It assesses groundwater. With the states, it checks every block every year. This is called the Dynamic Ground Water Resource Assessment.
  • It maps aquifers. It runs the National Aquifer Mapping and Management Programme (NAQUIM), started in 2012.
  • It plans recharge. Recharge means refilling groundwater. CGWB and the States/UTs prepared the Master Plan for Artificial Recharge to Groundwater 2020.
  • It gives technical guidance. Its manual on artificial recharge structures says these structures need regular cleaning and repair.
  • Its maps are used by other schemes. PM-KUSUM does not allow new solar pumps in dark zones, which are areas CGWB has notified as having over-used groundwater.

How the yearly assessment works (cause → process → result)

  • Step 1: measure what comes in. Rain, rivers, canals and tanks recharge the aquifers. One recent assessment found annual recharge of 446.90 BCM (billion cubic metres).
  • Step 2: find what can be safely taken out. This is the extractable resource, put at 406.19 BCM.
  • Step 3: measure what is actually pumped out. Annual extraction was 245.64 BCM.
  • Step 4: work out the stage of extraction.
  • Stage of extraction = yearly extraction ÷ yearly extractable recharge × 100.

  • For India as a whole it was about 60% in 2024.

  • Result: each block gets a class.

Class Stage of extraction
Safe Up to 70%
Semi-critical 70–90%
Critical 90–100%
Over-exploited Above 100%
  • Why the national average can mislead: the 60% figure mixes safe blocks with over-exploited ones. In over-exploited blocks, more water is already pumped out than goes back in.

NAQUIM: mapping the aquifers

  • It maps the extent (how far the aquifers spread), the yield (how much water they give) and the quality of aquifers.
  • It maps at 1:50,000 scale and covers about 25 lakh sq km.
  • Purpose: to draw up groundwater management plans with the states.
  • Why the rock type matters:
  • The Indo-Gangetic-Brahmaputra plains have thick alluvial aquifers that give a lot of water.
  • About two-thirds of India lies on hard rock (basalt, granite-gneiss). Hard rock holds little water and runs dry quickly when pumped, as in the Deccan, Karnataka and Telangana.

Master Plan for Artificial Recharge 2020

  • It is a big-picture, national-level plan. It shows which recharge structures suit each type of land and what they would cost.
  • Target: about 1.42 crore rainwater harvesting and recharge structures, to catch about 185 BCM of monsoon rain.
  • Estimated cost: about ₹1.34 lakh crore.
  • Funding: there is no dedicated fund. The money comes through convergence (joining up existing schemes), mainly MGNREGS, PMKSY and state schemes.
  • Flexibility: the agencies that build the structures may change their location, size and type to suit local conditions.

Where it occurs

  • Coverage: all of India. Every block is assessed each year with the states.
  • Over-exploited areas it has flagged:
  • Over-exploited blocks cluster in Punjab, Haryana, Rajasthan and Delhi.

  • Punjab: the 2024 assessment put its stage of extraction at about 156%, with about three-quarters of its blocks over-exploited.

  • Contamination belts it watches:

  • Arsenic: Ganga-Brahmaputra plains (West Bengal, Bihar, Uttar Pradesh, Assam).
  • Fluoride: the dry hard-rock belt (Rajasthan, Maharashtra, Telangana's Nalgonda, Andhra Pradesh, Gujarat, Karnataka).
  • Uranium: parts of Punjab's Malwa.

  • Seawater seeping into coastal aquifers: Saurashtra and Tamil Nadu.

  • Rules on pumping: guidelines to control groundwater extraction were notified on 24 Sep 2020 and amended on 29 Mar 2023.

  • Who uses CGWB data: Atal Bhujal Yojana (7 states), Jal Shakti Abhiyan: Catch the Rain, PM-KUSUM's dark-zone rule and recharge-planning tools of the Ministry of Jal Shakti.

Don't confuse with

  • Central Water Commission (CWC): CWC deals mainly with surface water in rivers and reservoirs. Its 2019 reassessment put India's average yearly water availability at about 1,999 cubic km. CGWB deals with groundwater.
  • Punah Bharan app (BISAG-N): this recharge-planning app was made by BISAG-N with the National Water Mission. CGWB did not make it. CGWB prepared the Master Plan 2020.
  • Atal Bhujal Yojana: this is a scheme that works through community water budgets in 8,220 gram panchayats of 7 states, so it controls demand. CGWB is a scientific agency that assesses and maps groundwater.
  • CPCB: the Central Pollution Control Board checks surface water quality at 507 stations. CGWB looks at groundwater quantity and quality, such as arsenic and fluoride.

Prelims Hooks

  • Stage of extraction classes: safe (up to 70%), semi-critical (70–90%), critical (90–100%), over-exploited (above 100%).
  • NAQUIM: run by CGWB since 2012. It maps aquifers at 1:50,000 scale over about 25 lakh sq km.
  • Master Plan for Artificial Recharge 2020: prepared by CGWB with States/UTs. It plans about 1.42 crore structures to catch about 185 BCM of rain, at a cost of about ₹1.34 lakh crore. It has no dedicated fund.
  • Latest assessment figures: recharge 446.90 BCM, extractable 406.19 BCM, extraction 245.64 BCM. That is about 60% nationally.
  • Trap: "CGWB developed the Punah Bharan app" is FALSE. BISAG-N developed it.
  • Trap: "Low national stage of extraction means India has no groundwater stress" is FALSE. The average hides over-exploited blocks in Punjab (about 156%), Haryana, Rajasthan and Delhi.

Mains Points

  • CGWB measures depletion, but it cannot stop over-pumping on its own
  • Groundwater rights go with land ownership, so a landowner can still pump freely.
  • Free or subsidised farm power and a higher MSP for paddy and sugarcane push farmers to pump more.

  • 19 states have groundwater laws based on a 1970 model Bill (revised 2005), and these laws have no guidelines on how to put them into practice. Water is a State subject, so CGWB's assessments need strong state rules on pumping to have any effect.

  • Recharge plans fail after the map stage

  • CAG Report No. 9 of 2021 found that recommended recharge sites were not tracked to check whether they were built. It also found poor upkeep of recharge structures in Gujarat and Haryana.
  • Recharge structures lose infiltration capacity (how fast water can soak through into the ground) as silt builds up.

  • The Master Plan has no dedicated fund, so nobody clearly pays for cleaning the structures later.

  • The way forward (GS-III)

  • Use NAQUIM aquifer maps and block classes to choose where to recharge first, starting with over-exploited blocks.
  • Pair recharge with demand control (Atal Bhujal), crop diversification and power reform.
  • Link each suggested site to a geotagged record of what was built, and check it after every monsoon.

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