GROUND WATER EXTRACTION - ENVIRONMENT
News: Level of groundwater extraction lowest in 18 years, finds study
What is in the news?
● Groundwater extraction in India saw an 18-year decline, according to an assessment by the Central Ground Water Board (CGWB) made public on November 9.
● The assessment was carried out jointly by the Central Ground Water Board (CGWB) and States/UTs.
Key takeaways from the assessment:
● Assessment indicates increase in ground water recharge.
● Analysis indicates improvement in ground water conditions in 909 assessment units in the country compared with 2017 assessment data.
● Total annual ground water recharge for the entire country is 437.60 billion cubic meters (BCM).
● Annual ground water extraction for the entire country is 239.16 BCM.
● Out of total 7089 assessment units, 1006 units categorized as ‘Over-exploited’.
● Such joint exercises between CGWB & States/UTs were carried out earlier in 1980, 1995, 2004, 2009, 2011, 2013, 2017 and 2020.
● The 2022 assessment suggests that groundwater extraction is the lowest since 2004, when it was 231 bcm.
● The groundwater recharge levels don’t reflect the water that can be actually extracted, called the “extractable groundwater resources”. In 2020, for instance, the “extractable groundwater resources” amounted to 397.62 bcm, which is less than the recharge that year.
State wise report:
● Major increase is noticed in the States of Bihar, Telangana, Andhra Pradesh, Tamil Nadu, Arunachal Pradesh, Odisha and Gujarat.
Reasons:
● Increasing in recharge from canal seepage.
● Return flow of irrigation water.
● Recharges from water bodies/tanks & water conservation structures.
● North western part of the country including parts of Punjab, Haryana, Delhi and Western Uttar Pradesh where even though the replenishable resources are abundant, there have been indiscriminate withdrawals of ground water leading to over-exploitation.
● The western part of the country, particularly in parts of Rajasthan and Gujarat, where due to arid climate, groundwater recharge itself is limited, leading to stress on the resource.
● The southern part of peninsular India including parts of Karnataka, Tamil Nadu, Telangana and Andhra Pradesh, where due to inherent characteristics of crystalline aquifers, the ground water availability is low.
Ground water usage:
● About 87% of total annual groundwater extraction i.e. 208.49 bcm is for irrigation use. Only 30.69 bcm is for domestic and industrial use, which is about 13% of the total extraction.
● The decrease in annual groundwater extraction for irrigation, domestic and industrial uses is broadly in line with the similar decline in previous assessments.
● These variations are attributed mainly to refinement of parameters, refinement in well census data and changing groundwater regime.
● Ground water extraction during COVID 19 times:
● In the years 2020 and 2021, due to the outbreak of Covid-19 throughout the country, the field activities of CGWB including monitoring of water levels have been severely affected.
Importance of groundwater:
● Ground water has steadily emerged as the backbone of India’s agriculture and drinking water security.
● Contribution of groundwater is nearly 62% in irrigation, 85% in rural water supply and 50% in urban water supply.
● Ground water is an annually replenishable resource but its availability is non-uniform in space and time.
● Ground water available in the zone of water level fluctuation is replenished annually with rainfall being the dominant contributor.
SOURCES OF GROUNDWATER:
Rainfall:
● The main source of replenishable groundwater resources is recharge from rainfall, which contributes to nearly 61 % of the total annual groundwater recharge.
● India receives about 119 cm. of rain annually on average, with high spatial variation.
● A major part of the country receives rainfall mainly during SW Monsoon season, spread over the months of June to September, except in Tamil Nadu, where the major contribution is from NE monsoon during the period October– December.
● There are also States such as Jammu and Kashmir, Himachal Pradesh and Uttarakhand which receive significant rainfall in all seasons.
Causes of groundwater depletion in India:
1. Green revolution:
● While the expansion in groundwater-based irrigation helped meet the rising food demands of a large population of India, it has resulted in several environmental implications.
2. Groundwater pumping for irrigation:
● It remains the primary driver of groundwater depletion, which can further affect food and water security in India under climate change.
3. Pumping groundwater from aquifers:
● Water flows freely through the saturated rocks known as aquifers. There are large and small aquifers, and they are the underground water reserves that absorb water and hold it, enabling us to pump it for use.
4. Climate change:
● The activities that lead to groundwater depletion come mostly from humans, but a portion of it also comes from changes in our climate and can speed up the process.
5. Law Regulation:
● Vacuum in laws and regulations encourages the exhaustion of groundwater in India with impunity.
6. Industries:
● The release of hazardous chemicals, the release of sludge in rivers and lakes, and the dumping of sewage lead to the contamination of groundwater resources.
7. Over-population:
● The increase in population has put pressure on water resources. Thus, leading to higher extraction of groundwater.
EFFECTS OF GROUNDWATER EXTRACTION:
1. Pump water from deeper within the Earth:
● The more we extract groundwater right below the Earth’s surface, the further down we have to go in order to get more.
2. Saltwater contamination:
● Groundwater that is deep within the ground often intermingles with saltwater that we shouldn’t drink.
3. Large bodies of water will become shallower from groundwater depletion:
● A groundwater shortage keeps additional water from flowing into lakes, rivers and seas. This means that over time, less water will enter as the existing surface water continues to evaporate.
4. Constraints in food supply:
● If groundwater availability faces difficulties then there will be hindrances in agricultural production leading to a shortage of food.
5. Limitations to biodiversity and creation of sinkholes:
● Water table plays a major role in sustaining biodiversity. Often, sinkholes are created when the water table lowers.
● These sinkholes are dangerous for buildings and towers.
6. Reduction of water in streams and lakes:
● A substantial amount of the water flowing in rivers comes from seepage of groundwater into the streambed.
● Depletion of groundwater levels may reduce water flow in such streams.
Government Initiatives:
1. Jal Shakti Abhiyaan:
● It was launched in 2019 in 256 water-stressed districts to improve water availability including groundwater conditions.
2. Aquifer Mapping and Management Program:
● It was taken by the Central Ground Water board to delineate aquifer disposition and their characterization for area-specific groundwater plans.
3. Atal Bhujal Yojana:
● It is a 6000 crore scheme with assistance from the World Bank for the sustainable management of groundwater resources.
4. AMRUT (Atal Mission for Rejuvenation and Urban Transformation):
● It focuses on the development of basic urban infrastructures such as water supply, water sewage, stormwater drainage, green spaces, and non-motorized urban transport.
5. National Water Policy:
● It has been formulated which advocates rainwater harvesting and conservation of water and highlights the need for augmenting the availability of water through direct use of rainfall.
6. Micro irrigation:
● Encouraging farmers to adopt micro-irrigation techniques such as drip irrigation and micro-sprinklers.
7. The government has initiated schemes like the DRIP program, more drop per crop, Krishi Sinchai Yojana to ensure economical water use practices in agriculture.
Concerns associated:
1. Estimation of groundwater resources:
● There is a lack of data available for estimation of groundwater sources and even if they are available, they are indicative and not representative.
2. Crop pricing and water-intensive crops:
● Decisions such as cropping pattern and cropping intensity are taken independent of the groundwater availability in most areas.
● Minimum Support Price (MSP) is also available for water-intensive crops leading to widespread cultivation of such crops.
3. Energy subsidies:
● The challenge is to find a balance between the needs of farmers and the need to ensure the sustainable use of groundwater.
4. Inadequate regulation:
● Lack of proper regulations and their further implementation has been one of the major challenges in managing groundwater levels in India.
5. Lack of local management:
● There is a lack of local management of groundwater resources.
● Local communities have an important role to play in groundwater management and there is a need for devolution of power for local management of such resources.
Way forward:
1. Proper examination:
● The adequacy of groundwater monitoring networks for shallow and deep aquifers needs to be examined.
● Groundwater storage variability needs to be examined under changing climatic conditions.
2. Drip Irrigation:
● Drip irrigation systems deliver water directly to a plant’s roots, reducing the evaporation that happens with spray watering systems.
3. Drought-Tolerant Crops:
● Growing crops that are appropriate to the region’s climate is another way that farmers are getting more crop per drop.
4. Compost and Mulch:
● Compost, or decomposed organic matter used as fertilizer, has been found to improve soil structure, increasing its water-holding capacity.
5. Investment in R&D:
● More comprehensive research and additional funding can help with groundwater depletion.
Go back to basics:
Central Ground Water Board:
● It is a national apex organization with responsibility to carry out scientific surveys, exploration, monitoring of development, management and regulation of the country's vast groundwater resources for irrigation, drinking, domestic and industrial needs.
● It was established in 1954.
● It functions under the Ministry of Jal Shakti.
Mandate:
● To Develop and disseminate technologies, and monitor and implement national policies for the Scientific and Sustainable development and management of India’s Ground Water Resources, including their exploration, assessment, conservation, augmentation, protection from pollution and distribution, based on principles of economic and ecological efficiency and equity.
Vision:
● Sustainable Development and Management of Ground Water Resources of the Country.