Since the Green Revolution in the 1960s, agriculture has been the lifeblood for millions of Indian farmers, and groundwater has played a critical role in irrigating water-hungry crops like rice to feed India’s ever-growing population. However, during the last three decades, India has faced acute and rapid depletion of groundwater reserves as a result of human-caused climate change and over-extraction. According to studies, water shortages can impact food supply, leading prices to skyrocket and inciting societal unrest. Groundwater, combined with soil moisture, surface waters such as lakes and rivers, and snow and ice, constitutes the majority of freshwater accessible on Earth.
In a new first-of-its-kind global analysis of freshwater availability, northern and eastern India were identified as significant zones of groundwater depletion, primarily due to overharvesting for irrigation, although eastern regions also encountered low rainfall, whereas the central and southern regions demonstrated consistency due to the water policy change and uncertain rainfall. The study predicts increased rainfall throughout India by 2100, despite rising temperatures and substantial greenhouse gas emissions. However, previous research indicates that the Indo-Gangetic Plains have seen increased droughts as a result of climate change, and new water management strategies are urgently needed to address India’s groundwater concerns.
Groundwater has been critical to raising food output and establishing food security in India. It is a vital supply of water for agricultural, household, and industrial purposes. Groundwater, a renewable source of water, has the unique distinction of being a very reliable and secure source of water supply. This, together with large-scale rural electrification in India and readily available loans through financial institutions, has played a role in the unrestrained exploitation of groundwater during the previous several decades.
Our globe is presently facing a major environmental crisis: the loss of one of our most important natural resources, groundwater. Groundwater overexploitation and extensive irrigation in key canal commands have caused considerable challenges for groundwater managers in India. Overexploitation and excessive irrigation have serious repercussions such as water table depletion, seawater incursion, aquifer dryness, groundwater contamination, water logging and salinity, and so on. It has been claimed that the water table is decreasing at a pace of 1-2 meters per year in various sections of the country.
At the same time, the water table increase in certain canal commands can reach 1 m/year. Another important concern is the deterioration of groundwater quality due to numerous factors. The recent discovery of elevated arsenic levels in West Bengal shallow aquifers has alarmed groundwater consumers. All of these challenges, taken combined, are predicted to diminish the freshwater supply for irrigation, residential, and industrial applications. If this trend continues, India would face a significant water issue shortly.
Issues in Tackling Groundwater Contamination and Pollution
The first stage in developing methods to avoid and recover groundwater quality deterioration is to collect trustworthy and reliable information via water quality monitoring (WQM) to determine the real origin, nature, and amount of pollution. Unfortunately, there are just a few monitoring sites in the nation that cover all of the important factors for water quality, therefore the data acquired are not conclusive on the water quality state. Second, WQM requires expensive and sophisticated technology that is difficult to run and maintain, as well as significant experience in data collection, analysis, and management. Because water technology in India is still in its early stages, the current data is likely to be less accurate. The current WQM approach is insufficient for analyzing the different sources of contamination. Data on water quality are seldom integrated with data on water supply, which is critical for estimating water availability for satisfying diverse social, economic, and environmental objectives. Finally, in the absence of stringent water quality testing standards, results can vary across agencies depending on sampling procedure, testing time, and testing instruments and procedure.
In India, artificial recharge solutions for seawater intrusion are available for various geo-hydrological conditions. Artificial recharging might shift the seawater-freshwater interface to the sea. Based on the dilution concept, these procedures can also be used to lower fluoride, arsenic, or salinity levels in aquifer fluids. However, considering the enormous aerial expanse of polluted aquifers, the difficulty is the availability of excellent water for recharging in dry and semi-arid regions. There are three forms of industrial pollution issues: pumping filthy water from the aquifer, treating this water to acceptable limits, and replacing the depleted aquifer with fresh water.
Groundwater quality monitoring in India is largely the responsibility of the Central Ground Water Board and state groundwater agencies, each of which has established its monitoring network. However, there are concerns about the adequacy of scientific evidence accessible from them:
- The monitoring station network is not thick enough.
- Water quality analysis eliminates crucial characteristics that aid in the detection of fertilizer and pesticide contamination, heavy metals, and other harmful effluents.
- The available scientific data, particularly on pollution, is the responsibility of civil society institutions, and there are few such institutions capable of carrying out such professionally hard, technologically complicated, and frequently politically sensitive responsibilities.
DANGERS OF CONTAMINATED GROUNDWATER
Drinking polluted groundwater can be hazardous to one’s health. Contamination from septic tank waste can cause diseases including hepatitis and dysentery. Toxins that have leached into well water sources may cause poisoning. Contaminated groundwater can potentially impact wildlife. Exposure to dirty water may potentially have long-term consequences, such as some forms of cancer.
POTENTIAL SOURCES OF GROUNDWATER CONTAMINATION
- Storage Tanks
They can be above or below ground and can hold gasoline, oil, chemicals, or other forms of liquids. Over 10 million storage tanks are expected to be underground in the United States, and the tanks can corrode, break, and leak over time. Serious pollution can result if the toxins seep out and into the groundwater.
- Septic Systems
On-site wastewater disposal systems are used by residences, offices, and other structures that are not linked to the city sewage system. Septic systems are designed to release human waste underground slowly and safely. A septic system that is not properly planned, situated, built, or maintained can leak bacteria, viruses, household chemicals, and other toxins into the groundwater, causing major difficulties.
- Uncontrolled Hazardous Waste
There are about 20,000 documented abandoned and unmanaged hazardous waste sites in the United States today, and the number is growing every year. If there are barrels or other containers with hazardous materials lying about, hazardous waste sites can lead to groundwater pollution. These toxins can ultimately find their way down through the soil and into the groundwater if there is a leak.
Landfills are locations where our rubbish is buried. Landfills are obliged to have a protective bottom layer to prevent pollutants from entering the water. However, if the layer is missing or damaged, toxins from the trash (vehicle battery acid, paint, home cleaners, and so on) might seep into the groundwater.
- Chemicals and Road Salts
Another cause of possible groundwater pollution is the extensive use of pesticides and road salts. Chemicals include weed killers and insecticides used on lawns and farm fields, as well as fertilizers used in homes and businesses. These chemicals can seep into the ground and subsequently into the water when it rains. In the winter, road salts are used to melt ice on roadways, preventing automobiles from sliding about. When the ice melts, the salt is swept off the roadways and ends up in the river.
- Atmospheric Contaminants
As groundwater is part of the hydrologic cycle, contaminants from other parts of the cycle, such as the atmosphere or bodies of surface water, can end up in our groundwater supplies.