Groundwater is the water beneath earth’s surface that constitutes about 99% of all liquid freshwater. Overexploitation has thrown Pakistan among others at the verge of severe groundwater crisis, threatening food security, health and economy. This crisis can be prevented by implementing environment-friendly policies with proper involvement of Pakistan’s citizenry.
By Jamshed Arslan, PhD
What is groundwater?
Groundwater is the water beneath earth’s surface. It constitutes 1.69% of earth’s total water[1] and about 99% of all liquid freshwater.[2] Groundwater mainly comes from precipitation (rain, snow, ice) that soaks into the soil. The permeability and porosity of soil determines its ability to hold water.[1] Since the top soil acts as a filter, groundwater is free of disease-causing pathogens, and chances of its contamination by animal and human waste are generally low. Groundwater typically has weak turbidity, almost no oxygen, and constant temperature and chemical composition, although circulating groundwater shows variation in composition with a possibility of pollutants.[3]
Services offered by groundwater
Groundwater is a renewable fresh water resource that your wells draw from underground. In fact, about half of the world population needs groundwater for their drinking and other basic daily needs. Groundwater provides moisture needed for vegetation. Other uses of groundwater are in livestock, food processing, and manufacturing and other industries.[1][3]
According to the United Nations World Water Development Report 2022, groundwater offers the following major services:[2]
- Provisioning services, such as human water use.
- Regulatory in situ services, such as regulating quality and quantity of groundwater-bearing sediments called aquifers.
- Supporting services, like supporting groundwater-related ecosystems and environmental features.
- Cultural services, such as leisure activities, religion, tradition and values associated with certain sites.
Global exploitation of groundwater
The largest use of groundwater is agriculture. China, India, USA and Pakistan hold the largest areas under irrigation. China uses 54% of its groundwater abstraction for irrigation. India is the largest groundwater user that uses 89% of groundwater abstraction for irrigation. India’s groundwater withdrawal has distinctively increased since 1950 as compared to rest of the world (Figure 1). The USA, Pakistan and Iran also heavily rely on groundwater for irrigation. These five countries (China, India, USA, Pakistan and Iran) account for approximately 70% of the unsustainable water footprint (Figure 2).[2]
The area equipped for irrigation in South Asia has tripled since 1950. India’s annual groundwater extraction is 230 billion m3 (bm3), followed by Pakistan (60 bm3) and Bangladesh (30 bm3). These three countries irrigate over 40% of the groundwater-fed cropland of the world, since they use 85% of their groundwater for agricultural purposes, compared to just 40% in the rest of the globe.[4]
Groundwater can be near earth’s surface or it can be as deep as 30,000 feet.[5] Whenever discharge exceeds recharge, especially with extensive abstraction, groundwater stores start depleting. With groundwater shortage, less water flows into the seas, lakes and rivers after evaporation of surface water. This means that groundwater shortage affects fish, wildlife and almost everything in a particular region.[1]
Figure 1. Groundwater withdrawal between 1950–2020 (Credit: UNESCO)[2]
Figure 2. Estimated groundwater withdrawal and the percentage for irrigation (Credit: UNESCO)[2]
Case study: Pakistan
Pakistan occupies 4.6% of global groundwater-irrigated area and consumes about 9% of global groundwater, making Pakistan the third-largest user of groundwater.[4]
Evidence and consequence of shrinking groundwater
The groundwater level in over 50% of the irrigated area in Punjab, Pakistan’s largest province by population, has dropped below 6 meters, resulting in deteriorated water quality, increased soil salinization, drying up of wells, higher pumping costs and reduction of water in lakes and streams.[4]
Reasons #1: Ever-increasing demand for ever-increasing population
Pakistan’s economy relies heavily on agriculture as it employs 44% of total labor force and contributes about 20% to the gross national product. Country’s ever-escalating population requires expansion of irrigated area and the consequent diminishing of surface water supply. Over 80% of Pakistan’s population depends on agriculture to earn their living and two-thirds of rural population depends on groundwater for livelihood and food security. Most of Pakistan is arid or semi-arid. Evapotranspiration – total water loss to the atmosphere from a land surface – is high but rainfall and surface water supplies are unreliable. Surface water can irrigate 27% of the area, but remaining 73% depends on groundwater. So, irrigation becomes crucial; in fact, irrigated agriculture produces about 90% of grains in Pakistan.[4]
Reason #2: Short-sighted policies and less respect for law
Governments over the years have exacerbated the problem by subsidizing energy and pumps for using groundwater for agriculture. Pakistan’s extensive groundwater use started in 1960s when government subsidized tubewells for irrigation. The private tubewells jumped from 30,000 in 1960 to more than 1.2 million in 2018. In Punjab, over three million farmers are benefiting from tubewells. Punjab uses over 90% of the groundwater abstraction. There are 1.2 million private tubewells that extract groundwater, out of which 85% are in Punjab, 6.4% in Sindh, 3.8% in Khyber-Pakhtunkhwa and 4.8% are in Baluchistan.[4]
Other reasons for poor management and overexploitation of groundwater include a culture of less respect for the law, almost complete lack of political will and a dearth of needed information and institutional arrangements.[4]
How to reverse overexploitation?
At government level, it is crucial to integrate various government departments, knowledge institutions and other stakeholders for proper water resource management. Waste must be properly disposed of, and dumping of chemicals into the ground must be banned. Finding alternative sources of water, instead of withdrawing too much from the ground, is important to ensure that the aquifers have enough time to be replenished. In other words, groundwater withdrawal must never exceed renewal.[1][3][6]
The International Groundwater Resource Assessment Centre has launched a mobile groundwater monitoring app[7] with which governments can involve citizenry to monitor the groundwater resource. People must be educated to prefer using native plants and grass varieties that are adapted to the region’s landscape and climate; the reason being that such varieties usually require less watering or fertilizers. In addition, we must reduce, reuse and recycle the stuff in our lives in order to preserve our most valuable hidden resource known as groundwater.