GROUND WATER

Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock. It is stored in and moves slowly through geologic formations of soil, sand, and rocks called aquifers.

Reasons for Groundwater Depletion

• Green revolution: The advent of the Green Revolution during the 1960s and the use of HYV (High Yielding Variety) seeds and fertilizers led to the overuse of groundwater resources. Cheap electricity was also one of the main reasons.
• Frequent pumping: Frequent pumping of water from the ground without waiting for its replenishment leads to quick depletion.
• Limited storage: Limited storage facilities owing to the hard rock terrain, along with the added disadvantage of lack of rainfall, especially in central Indian states.

• Increasing population: With a rapid rise in population and its increasing demand for food, there is an expansion in the area of land under irrigation. This is leading to uncontrolled exploitation of groundwater in India.
• Water contamination: As in the case of pollution by landfills, septic tanks, leaky underground gas tanks, and from overuse of fertilizers and pesticides leading to damage and depletion of groundwater resources.
• Wrong policy: Subsidies on electricity and high MSP (Minimum Support Price) for water-intensive crops.
• Inadequate regulation: Inadequate regulation of groundwater encourages the exhaustion of groundwater resources without any penalty.
• Climate change: These include uneven rainfall and climate change that are hindering the process of groundwater recharge.
• Dependency on monsoon: India is mainly dependent on the Indian summer monsoon rainfall, and weaker summer monsoons can cause droughts. During such dry periods, water is extracted from the ground to meet various needs leading to a reduction in groundwater levels.
• Other: Deforestation, improper agricultural techniques, chemical effluents from businesses, and a lack of sanitation all contribute to groundwater contamination, rendering it useless.

Ground Water Contamination

1. Point sources:
   • Livestock wastes.
   • Leaky sewer lines.
   • Municipal landfills.
   • On-site septic systems.
   • Fly ash from coal-fired power plants.
   • Sludge disposal areas at petroleum refineries.
   • Underground injection wells (industrial waste).
   • Chemicals used at wood preservation facilities.
   • Leaky tanks or pipelines containing petroleum products.
   • Leaks or spills of industrial chemicals at manufacturing facilities.
2. Non-point (distributed) sources:
   • Fertilizers on agricultural land.
   • Pesticides on agricultural land and forests.
   • Contaminants in rain, snow, and dry atmospheric fallout.

Implications of Depletion of Ground Water

• Increased Costs: As the water table lowers, the water must be pumped farther to reach the surface, using more energy. In extreme cases, using such a well can be cost prohibitive.
• Land Subsidence: Land subsidence occurs when there is a loss of support below ground. This is most often caused by human activities, mainly from the overuse of groundwater, when the soil collapses, compacts, and drops.
• Water Quality Concerns: Excessive pumping in coastal areas can cause saltwater to move inland and upward, resulting in saltwater contamination of the water supply.

• Saltwater contamination can occur: Groundwater that is deep within the ground often intermingles with saltwater that we shouldn’t drink.
• Lowering of the Water Table: Excessive pumping can lower the groundwater table, and cause wells to no longer be able to reach groundwater.
• Reduction of water in streams and lakes: Groundwater and water in streams and lakes have interconnections. 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.
• Constraints in food supply: A huge part of Indian agriculture depends on irrigation from groundwater. If groundwater availability faces difficulties, then there will be hindrances in agricultural production leading to a shortage of food.
• 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.

Effect of Climate Change on Ground Water

• Affect quality: Climate change does not only affect groundwater quantity, but also its quality. Sea level rise may lead to salt water intrusion into coastal aquifers, affecting groundwater quality and contaminating drinking water sources.
• Variability in precipitation: Increased variability in precipitation and more extreme weather events caused by climate change can lead to longer periods of droughts and floods, which directly affects availability and dependency on groundwater.
• Optimistic assumption on drop in GW level: The most optimistic assumption suggests that an average drop in groundwater level by one meter would increase India’s total carbon emissions by over 1%, because the time of withdrawal of the same amount of water will increase fuel consumption.
• Realistic assumption: A more realistic assumption reflecting the area projected to be irrigated by groundwater suggests that the increase in carbon emission could be 4.8% for each meter drop in groundwater levels.

Way Forward

• Routine survey at regular intervals: There should be regular assessment of groundwater levels to ensure that adequate data is available for formulating policies and devising new techniques to find a solution to the problem.
• Assessment of land use pattern: Studies should be carried out to assess land use and the proportion of agricultural land falling under over-exploited units. This will help in determining a suitable crop pattern in water-stressed areas.
• Preventing groundwater pollution: Steps to minimize and control the dumping of industrial waste into surface water and underground aquifers should also be taken to prevent groundwater from getting polluted.
• Changes in farming methods: To improve the water table in those areas where it is being overused, on-farm water management techniques and improved irrigation methods should be adopted. Methods for artificial recharge of groundwater are also welcome.
• Conservation of waterbodies: Waterbodies maintain the groundwater level. There is a need to devise special programs for the upkeep, maintenance, and restoration of water bodies with sufficient budgetary allocation.
• Reforms in power supply subsidies for agriculture: The agricultural power-pricing structure needs to be revamped as the flat rate of electricity adversely affects the use of groundwater.
• Monitoring groundwater extraction: There should be a policy in place to monitor the excessive exploitation of groundwater resources to ensure long-term sustainability. Water meters could be installed to monitor overuse.