With declining recharge rates and sharply increasing extraction pace, the groundwater situation needs urgent attention and demands a change in irrigation and cropping methods.
Groundwater is the water that seeps through rocks and soil and is stored below the ground. The rocks in which ground water is stored are called aquifers. Aquifers are typically made up of gravel, sand, sandstone or limestone.
Question: What is the most extracted natural resource in the world? Answer: Groundwater!
Yes, planet earth gives us this invisible asset that sustains a range of human activities. Blinded by Western development model of perennial GDP growth humanity is busy plundering even this resource. And foolishly take its availability for granted without bothering to know how the groundwater reservoirs replenish themselves. It may be surprising for many people to know that India is the world’s largest user of groundwater, oblivious to the fact that since the 1980s the groundwater tables have been continuously dropping.
India annually extracts around 251 cubic kilometer groundwater which is 25% of the total global annual extraction and 26 times the water stored in the Bhakra Dam. In comparison, together China and the US extract just 112 cu km. Clearly, India’s water resource planning is very bad and farmers find it easy to use groundwater without much attention to which crops to grow. Ninety percent of the groundwater extracted is used for irrigation that covers 60 percent of the total irrigated area.
According to the 2016 Central Ground Water Board (CGWB) report, in the year ending January 2016 barely 3% well structures registered a rise in water level more than 4 metres, 35% showed lesser rise and 64% wells showed decline in water level. It is an alarming finding. The replenishment takes place through rainfall, back flows from irrigation and seepage from canals, other water bodies and conservation structures.
If the situation continues as it is, we are steadily inching towards catastrophe. Water, in any way, is going to be the reason for future troubles and conflicts in ways more than one. As climate change is altering the monsoon pattern, the stress on groundwater resources is likely to increase.
India’s groundwater use was just about 7 cubic kilometer in 1940; it went up to around 270 cubic kilometer at the millennium end. Since 1950, the total share of groundwater in irrigation has nearly doubled. The groundwater extraction rose sharply during the late 70s and 80s. People connect it with the Green Revolution during which two things happened: one, building of large dams by governments and two, small and marginal farmers bored wells everywhere. Thus, today livelihood of 26 crore farmers and agricultural laborers crucially revolves around groundwater.
In response to the drought of 1972, drilling technology and hand pumps were introduced in India. As a result, by now there are around 30 million groundwater structures in India that are replenished by around 3 million perennial springs in the country, but very little is done to preserve them.
The over-exploitation of groundwater has created a series of problems, particularly in the agriculture-intensive belts across India. The situation is becoming particularly acute in the Northwest, where the groundwater levels have plunged from 8m to 16m below ground. As the levels fall, rising pumping costs ultimately makes extraction uneconomical; small formers and labourers get directly impacted. The average farmer in Punjab, Rajasthan and Haryana faces the prospect of having no groundwater left for irrigation by 2025.
Groundwater scenario in Punjab – the champion of Green Revolution, shows a heavy deficit that would take up to 30 years only to restore to normal levels. In comparison, the poorer Odisha still has healthier groundwater tables, but there is talk of taking Green Revolution to the Eastern India that would make things worse.
Ground Water Availability
The map shows that ground water level has significantly reduced in the north- western region of the country. There are other pockets across the country where the water level is below more than 10 metres, when sophisticated equipment is needed for extraction.
As of April 2015, the annual water availability of the country in terms of natural runoff (flow) in the rivers was about 1,869 billion cubic meter (BCM)/year. However, the usable portion was estimated as 1,123 BCM/year because of the constraints of topography and uneven distribution of the resource in various river basins. Of this, the share of surface water was 690 BCM/year and groundwater was 433 BCM/year. Around 35 BCM of ground water is lost to natural discharge – as seepage to water bodies or oceans in coastal areas and as transpiration by plants whose roots extend up to the water table. So the net annual groundwater availability for the entire country was 398 BCM.
The overall contribution of rainfall to the country’s annual groundwater resource is 68% and the rest comes from other resources, such as canal seepage, return flow from irrigation, recharge from tanks, ponds and water conservation structures etc. Given the increasing population, India’s per capita annual availability of water reduced by 15% from 1,816 cubic metre in 2001 to 1,544 cubic metre in 2011.
Ground Water Development
Ground water development is a ratio of the annual ground water extraction to the net annual ground water availability. It indicates the quantity of ground water available for use. 0-70% is considered safe, 70-90% is semi-critical, 90-100% is critical, and over 100% is considered over-exploited. The table here gives the level of ground water development in different states over the past two decades.
In the states of Delhi, Haryana, Punjab and Rajasthan, the annual ground water consumption is more than annual ground water recharge. In the states of Himachal Pradesh, Tamil Nadu and Uttar Pradesh and the Union Territory of Puducherry, the level of ground water development is 70% or above. Over the years, usage of ground water has increased in areas where the resource was readily available. This has resulted in an increase in overall ground water development from 58% in 2004 to 62% in 2011, as illustrated in Figure 3.
Groundwater Use Pattern
As mentioned earlier, the availability of surface water (690 BCM/year) is greater than groundwater (433 BCM/year). However, groundwater, being available almost everywhere through bore wells, is easily accessible and thus, forms the largest share of agriculture and drinking water supply. Of the extracted groundwater around 89% is used in the irrigation sector, 9% is used for the domestic purposes and the remainder 2% goes into industrial use. Groundwater also fulfils 50% of urban water requirements and 85% of rural domestic water requirements.
Irrigation Through Groundwater
Major means of irrigation in the country are canals, tanks and wells, including tube-wells. Of all these sources, groundwater contributes the largest share. Wells – dug wells, shallow tube-wells and deep tube wells – provide about 62% of water for irrigation, followed by canals with around 25%.
Over the years, there has been a steady rise in the groundwater utilisation for irrigation while other sources remained stagnated in the volume terms. As can be seen from the image above, the tube-well share has increased exponentially. There is a clear correlation in rise in groundwater use with the onset of the Green Revolution that demanded intensive use of inputs like water and fertilizers to boost crop production. Incentives such as credit for irrigation equipment and subsidies for electricity supply have further worsened the situation. Low power tariffs have led to excessive and wasteful water usage, leading to a sharp fall in water tables.
Table here shows the number of states and districts affected by geogenic contaminants as on July 2014.
Ground water is considered contaminated when certain pollutants are present in excess of the limits prescribed for drinking water. The commonly observed contaminants include arsenic, fluoride, nitrate and iron, which are geogenic in nature. Geogenic contaminants are those that occur as a result of geological processes happening within the earth’s crust. Besides, there are other contaminants such as bacteria, phosphates and heavy metals resulting from human activities – from domestic sewage, agricultural practices and industrial effluents. The sources of contamination include pollution by landfills, septic tanks, leaky underground gas tanks, and from overuse of fertilizers and pesticides. It has been pointed out that nearly 60% of all districts in the country have issues related to either availability of ground water, or quality of ground water, or both.
Government studies have revealed high arsenic content in groundwater of 68 districts in 10 states – Haryana, Punjab, Uttar Pradesh, Bihar, Jharkhand, Chhattisgarh, West Bengal, Assam, Manipur and Karnataka.
Some Key Issues
There are some vital issues related to the groundwater usage; for instance
Estimation of Groundwater Resources
A clearer picture of the state of aquifers in India will be greatly useful in managing the groundwater resources of the country. The current assessment methodology relied on observation of just around 15000 wells and then extrapolating to guess the status of around 30 million groundwater structures; it is neither accurate nor representative. There is a need for more extensive information gathering and shift from development to management of water resources.
Agricultural Crop Pricing and Water Intensive Crops
Since the 80s, roughly 84% of the total addition to the net irrigated area has come through groundwater, agriculture sector being the prime driver. Decisions of cropping intensity and pattern are taken largely independent of the status of groundwater availability in most areas. Another factor was pin pointed by the High-Level Committee on restructuring of the Food Corporation of India in 2014, chaired by Mr. Shanta Kumar. It found that although Minimum Support Prices (MSPs) are currently announced for 23 crops, the effective price support is for wheat and rice. This creates highly skewed incentive structures in favour of wheat and paddy, which are water intensive crops and depend heavily on ground water for their growth. Additionally, Indian agriculture is highly water inefficient. The table here above the average amount of water (in cubic meters/tonne) needed to grow different crops in different countries. As can be seen, India irrigation system is highly wasteful; it uses almost twice the amount of water to grow crops as compared to China and United States.
The Committee also suggested that cropping pattern needed to be diversified by providing better price support for pulses and oilseeds. This would also incentivize the production of these food grains. For reducing dependence of agriculture on groundwater, other experts have suggested the use of demand management measures in agriculture. For example,
- Dry-season crop planning for specific areas depending upon the aquifer type, monsoonal rainfall and groundwater table level. This would include some shift towards higher-value and less-water consuming crops.
- Adoption of modern efficient irrigation technologies such as drip and sprinkler systems.
- Controlling groundwater extraction through regulatory measures such as restricting the depth of irrigation water wells, establishing and enforcing minimum spacing between irrigations.
Energy Subsidies and Groundwater Extraction
The practice of providing power subsidies for agriculture has played a major role in reckless use and over extraction of groundwater in India. Moreover, electricity supply is not metered and a flat tariff is charged depending on the horsepower of the pump. So some kind of regulation on the use of electricity is needed to avoid wastage of groundwater. Separate electric feeders for pumping ground water for agricultural use could address the issue.
The state of Gujarat solved this problem through its ‘Jyotigram’ scheme which was launched during 2003-2006 by investing 1450 crore rupees. It involved separation of agricultural electricity feeders from non-agricultural ones and establishing a tight regime for farm power rationing in the rural Gujarat. By 2006, the state had covered almost all of its 18,000 villages under the scheme of rationalized power supply. This led to two major benefits: (i) villages receive 24 hour three-phase power supply for domestic uses, in schools, hospitals, village industries, all subject to metered tariff, and (ii) tube-well owners receive eight hours/day of power of full voltage on a pre-announced schedule.
National River Linking Project
Government proposes to physically transfer 178 billion cubic meter water annual across river basins by building 12,500 km water canal network. The estimated cost of the proposal is massive: $120-billion. This is the largest such project in the world — aiming to expand irrigated agriculture by moving water from “water surplus” to “water deficit” basins. The first of the planned canals linking the Kaveri and Godavari rivers was completed on September 16, 2015.
Experts opine that merely transferring water would not solve the problem of falling water tables. It would need a simultaneous increase in the storage capacity to be effective. They also advise working on other plans to reduce stress on groundwater – such as promoting more efficient irrigation, growing less water-intensive crops in the dry season and moving away from water-intensive crops in areas where there is less water.
While government is paying a lot of attention to river cleaning (although nothing much has happened beyond sloganeering) it would be best if groundwater replenishment is coupled with this initiative. Further, MNREGA work can be directed towards strengthening the water bodies that play a crucial role in recharging groundwater reservoirs.
What is needed is action; the time for talk has already passed!