Other Natural Vulnerabilities in India: Analyzing Lesser-known Risks

India’s 7,500-kilometer coastline supports over 250 million people, but these coastal regions face vulnerabilities that often escape public attention. While floods and cyclones make headlines, subtler threats like salinity intrusion and freshwater scarcity silently undermine livelihoods and ecosystems. These interconnected challenges affect drinking water supplies, agricultural productivity, and coastal ecosystems across multiple states.

Understanding salinity intrusion in coastal aquifers 🔗

Salinity intrusion occurs when seawater infiltrates freshwater aquifers, making groundwater unusable for drinking and irrigation. This process isn’t uniform across India’s coastline. The eastern coast experiences more severe intrusion compared to the western coast, primarily due to lower elevation and varying hydrogeological conditions.

The Central Ground Water Board has documented extensive salinity problems across coastal states. In Gujarat, groundwater is saline even at shallow depths in areas close to the coast. Tidal ingress affects upper aquifers, and during pre-monsoon periods, lowered water tables create a reverse hydraulic gradient that pulls seawater inland.

Gujarat’s persistent challenge 🔗

The Saurashtra and Kutch regions of Gujarat face acute problems due to semi-arid conditions that limit natural groundwater recharge. According to government data, over 1,200 villages in these regions struggle with saline drinking water. The unconfined coastal aquifers in fractured basalt and alluvial terrain are poorly controlled, making them particularly vulnerable to saltwater invasion.

The Government of Gujarat appointed High Level Committees to examine salinity ingress problems and propose remedial measures. The state has designated certain coastal areas as dark zones to reduce groundwater over-exploitation and has implemented ground water recharge programs along with micro-irrigation systems in affected areas.

Tamil Nadu’s expanding intrusion zone 🔗

Tamil Nadu’s coastal regions, particularly around Chennai, showcase the severity of urban and industrial pressure on coastal aquifers. The freshwater-seawater interface in the Minjur area, north of Chennai, has moved dramatically inland from 3.5 kilometers in 1972 to approximately 15 kilometers at present.

Research from Anna University reveals that Chennai experiences seawater intrusion extending up to 14 kilometers inland. Areas including Tiruvanmiyur-Kovalam tract, Cuddalore coast, and districts like Ramanathapuram, Nagapattinam, Thanjavur, and Tiruvarur face significant salinity problems due to both anthropogenic activities and natural geological conditions.

The Thiruvallur district’s coastal region shows intensifying seawater intrusion due to excessive freshwater abstraction. Studies using electrical resistivity tomography and geochemical analysis have mapped saline plumes moving progressively inland, requiring urgent intervention.

Freshwater scarcity amplified by coastal dynamics 🔗

Coastal populations face a paradox: surrounded by water yet struggling to access freshwater. Several interconnected factors create this scarcity beyond simple salinity intrusion.

Tidal effects on groundwater availability 🔗

Tidal fluctuations directly impact shallow coastal aquifers. Studies along the Cuddalore coastal region in Tamil Nadu demonstrate that water table levels fluctuate in sync with tidal cycles, particularly during new moon and full moon periods. These fluctuations affect both the quantity and quality of accessible freshwater.

During high tides, seawater inundates low-lying marshy lands, mixing with groundwater in upper aquifers. This tidal ingress creates temporary salinity spikes that make wells unusable. In Gujarat’s coastal areas, the downward seepage from these inundated zones persistently increases groundwater salinity.

High water table challenges 🔗

Contrary to what might seem beneficial, a high water table in coastal areas often indicates proximity to saline groundwater rather than abundant freshwater. The shallow depth at which saline water occurs limits the viable extraction zone for potable water. During pre-monsoon seasons when freshwater demands peak, the water table drops, bringing the saltwater interface closer to the surface and rendering more wells unusable.

Extraction-driven depletion 🔗

India extracts approximately 240 cubic kilometers of groundwater annually, more than China and the United States combined. Coastal regions bear disproportionate pressure as urban centers, industries, and irrigation demands concentrate near shorelines.

Heavy pumping in Chennai and Cuddalore regions has caused salinity encroachment extending 10-15 kilometers inland in some areas. The aquifers, comprising sand with low natural recharge rates, cannot sustain this extraction intensity while maintaining a freshwater-saltwater equilibrium.

Effective mitigation strategies 🔗

Addressing coastal water vulnerabilities requires multi-pronged approaches combining traditional knowledge with modern technology.

Artificial recharge structures 🔗

Artificial groundwater recharge represents a fundamental supply-side strategy to combat over-exploitation. The technique aims to augment groundwater storage by modifying natural surface water movement through engineered structures.

Percolation tanks and ponds: These structures capture and store rainwater, allowing it to slowly infiltrate into aquifers. Studies in Tamil Nadu’s Amaravathi aquifer system have identified locations where implementing percolation ponds could create an additional water resource of 198 million cubic meters annually.

Check dams and nala bunds: Small structures built across seasonal streams slow water flow and increase infiltration time. These are particularly effective in areas with fractured rock formations where surface water can reach deeper aquifers through natural fissures.

Injection wells: In Gujarat’s Central Mehsana area and Saurashtra coastal regions, injection wells pump treated surface water directly into deeper confined aquifers. This method creates a hydraulic barrier against seawater intrusion by maintaining freshwater pressure in the aquifer.

Managed aquifer recharge techniques 🔗

The most efficient mitigation approach according to research is increasing groundwater recharge through permeable pavements and strategically designed infiltration systems. These structures not only capture rainwater but also reduce surface runoff that would otherwise be lost to the sea.

Subsurface dykes represent another innovative solution. A successful experiment at Kalpakkam in Tamil Nadu used subsurface barriers to slow saltwater advance while allowing freshwater accumulation behind the barrier.

Sustainable water management practices 🔗

Controlled groundwater extraction: State governments must regulate borewell drilling through licensing systems that account for local aquifer capacity. Gujarat has designated certain overexploited coastal areas as dark zones where new extraction is prohibited.

Micro-irrigation adoption: Drip irrigation and sprinkler systems in Saurashtra have reduced groundwater extraction by approximately 30 percent while maintaining agricultural productivity. Expanding such systems across coastal agricultural zones can significantly reduce pressure on aquifers.

Rainwater harvesting mandates: The Jal Shakti Abhiyan’s “Catch the Rain” campaign promotes creating rain water harvesting structures across all blocks. When implemented comprehensively in coastal districts, these structures can substantially improve natural recharge rates.

Integrated monitoring systems 🔗

The Central Ground Water Board maintains long-term monitoring networks in vulnerable coastal districts to track seasonal and spatial salinity fluctuations. Technologies like electrical resistivity tomography and electromagnetic induction provide non-invasive methods to map subsurface salinity distribution, enabling targeted intervention planning.

The path forward 🔗

Coastal water vulnerabilities demand urgent attention because they affect drinking water security, agricultural sustainability, and ecosystem health simultaneously. The approximately 2,600 square kilometers already affected by seawater intrusion increased by 500 square kilometers between 2007 and 2017, indicating an accelerating problem.

Success requires coordination between central and state governments, implementation of scientifically planned recharge programs, strict regulation of groundwater extraction, and community participation in water conservation. States like Gujarat and Karnataka have initiated important measures including salt water exclusion dams and tidal regulators, but scaling these interventions across all vulnerable coastal areas remains essential.

Climate change will intensify these challenges through sea-level rise and altered rainfall patterns. Building resilience now through comprehensive artificial recharge programs, sustainable extraction practices, and ecosystem-based solutions like mangrove restoration will determine whether coastal communities can maintain water security in coming decades.

What do you think? How can your local community contribute to groundwater conservation efforts? Are there traditional water management practices in coastal areas that could complement modern technical solutions?

References

1. https://www.pib.gov.in/PressReleaseIframePage.aspx?PRID=1807855
2. https://testbook.com/ias-preparation/seawater-intrusion-in-the-coastal-aquifers-is-a-major-concern-in-india-what-are-the-causes-of-seawater-intrusion-and-the-remedial-measures-to-combat-this-hazard-upsc-mains-2025-gs-3-question
3. https://researchmatters.in/news/seawater-intrusion-threatens-drinking-water-source-along-indias-coast
4. https://link.springer.com/article/10.1007/s42452-020-03510-7
5. https://link.springer.com/article/10.1007/s13201-018-0654-5
6. https://www.climatescorecard.org/2023/09/india-has-16-of-the-global-population-but-only-4-of-total-water-resources-resulting-in-water-scarcity-in-many-regions/
7. https://www.apn-gcr.org/bulletin/article/artificial-recharge-initiatives-in-india-challenges-and-future-scope/