Context
- Traditionally, excess rainfall was seen as a sign of abundance, but in recent times, climate change has emerged as a major challenge that has influenced rainfall patterns.
- Rainfall has become erratic, short, and intense, leading to flooding, waterlogging, and widespread disruption.
- In 2025, the northeast monsoon arrived early in Tamil Nadu, posing challenges related to urban flooding, agricultural losses, and infrastructure management.
About Northeast Monsoon and Its Importance for India
- The Northeast Monsoon (October-December), also known as the retreating monsoon or winter monsoon, occurs when winds reverse direction after the southwest monsoon withdraws.
- These winds blow from land to sea, picking up moisture from the Bay of Bengal and bringing rainfall mainly to southeastern India, especially Tamil Nadu, Puducherry, coastal Andhra Pradesh, and parts of Kerala.
- Tamil Nadu receives nearly 48-50% of its annual rainfall during this season, making it the main rainy season for the state.
- The rainfall supports rabi crop cultivation, drinking water supply, groundwater recharge, and reservoir filling in southern India.
- It also helps maintain hydropower generation, livelihoods of farmers, and ecosystem balance in the rainfed regions.
What challenges does excess rainfall pose and what can be done to mitigate it?
| Challenges | Way Forward |
| 1. Urban flooding and infrastructure strain: In cities, widespread concretisation prevents rainwater absorption. This causes rapid surface runoff, overwhelming drainage networks and leading to flash floods, traffic disruptions, and property damage. Power cuts are often imposed as a safety measure during such events. | Develop sponge cities with permeable pavements, green roofs, and urban wetlands to enhance rainwater absorption. Upgrade stormwater drains, ensure regular desilting, and integrate urban flood management plans with real-time rainfall forecasting systems. |
| 2. Sewage overflow and water contamination: Excess rainfall can cause sewage systems to overflow, discharging untreated wastewater into streets and waterbodies. This leads to severe health hazards, water pollution, and the spread of infections. | Establish separate networks for sewage and stormwater, improve treatment capacity in wastewater plants, and promote nature-based solutions such as constructed wetlands for filtering runoff. |
| 3. Agricultural waterlogging and soil degradation: Prolonged rainfall leads to waterlogged soils, suffocating plant roots and washing away seeds and topsoil. This depletes soil nutrients and reduces fertility, threatening long-term productivity. | Promote raised-bed and contour farming, improve drainage channels in farmlands, and incentivise the use of climate-resilient and flood-tolerant crop varieties. Encourage soil health restoration through organic manure and mulching. |
| 4. Crop diseases and pest outbreaks: Excess moisture favours the spread of fungal diseases and pests, which destroy crops and lower yields, leading to financial stress for farmers. | Expand agro-advisory services with timely pest and disease alerts, strengthen crop insurance coverage, and promote integrated pest management (IPM) practices. |
| 5. Pollution of waterbodies: Heavy runoff washes fertilisers, pesticides, and agrochemical residues into rivers, reservoirs, and lakes, degrading water quality and harming aquatic ecosystems. | Adopt buffer zones and vegetative barriers along fields and waterbodies to trap sediments. Encourage judicious fertiliser use and promote organic and sustainable farming practices. |
| 6. Spread of vector-borne and zoonotic diseases: Stagnant water after heavy rainfall becomes a breeding ground for mosquitoes and pathogens, increasing the risk of malaria, dengue, and other infectious diseases. | Conduct regular drainage clearance and anti-larval operations, enhance public health surveillance, and ensure rapid medical response in vulnerable areas. |
| 7. Damage to infrastructure and building foundations: A persistently high water table weakens soil stability, damaging roads, foundations, and basements. Saturated soil can cause cracks, leaks, and even collapse of structures over time. | Use proper soil compaction, waterproofing, and foundation design standards in flood-prone regions. Introduce zoning regulations to restrict construction in low-lying or flood-risk areas. |
| 8. Economic and social losses: Flooding disrupts economic activity, damages property, and displaces people. It imposes heavy costs on recovery and rebuilding and takes a psychological toll on affected communities. | Implement comprehensive disaster risk reduction (DRR) plans, strengthen early warning and evacuation systems, and promote community-based resilience programs with livelihood diversification and post-disaster mental health support. |
Why is Tamil Nadu Particularly Vulnerable?
- Dual Monsoon Impact: Tamil Nadu and Kerala receive rain from different systems: the Southwest Monsoon (Kerala) and Northeast Monsoon (Tamil Nadu). When both occur simultaneously, it leads to heavy and overlapping rainfall, worsening flood risks.
- Mullaperiyar Dam Factor: The Mullaperiyar Dam, though located in Kerala, is operated by Tamil Nadu. Hence, heavy rainfall in Kerala’s catchment areas directly affects Tamil Nadu’s river systems.
- Simultaneous Inflows: During intense rains, Tamil Nadu must open the dam’s shutters to maintain safety. Released water flows towards both States; flooding Kerala’s Idukki and increasing inflow to Tamil Nadu’s Vaigai Dam, already filled by monsoon rains.
- On-Ground Situation: Currently, all 13 shutters of the Mullaperiyar Dam are open, releasing thousands of cusecs of water to manage inflow. As a result, farmlands and residential areas in Theni district have been submerged, even as the region continues to face heavy monsoon rain.
- Overall Concern: Tamil Nadu faces dual challenges: managing its own monsoon rainfall and inflows from Kerala. This calls for better inter-State coordination, real-time water management, and a shift from the “excess is good” mindset.
Conclusion
The early and intense northeast monsoon in Tamil Nadu, worsened by inflows from Kerala via the Mullaperiyar Dam, exposes the state to floods, agricultural losses, infrastructure damage, and health risks. Effective mitigation requires urban planning, resilient agriculture, inter-state water management, and a shift from the “excess rainfall is good” mindset.
| Ensure IAS Mains Question Q. Climate change has made monsoon rainfall increasingly erratic and intense, leading to floods, agricultural losses, and infrastructure damage in India. Critically examine the challenges posed by excess rainfall and discuss policy measures to enhance resilience and sustainable management of water resources. (250 words) |
| Ensure IAS Prelims Question Q. Consider the following statements about the northeast monsoon in India: 1. The northeast monsoon occurs between October and December and brings rainfall mainly to southeastern India. 2. Tamil Nadu receives nearly half of its annual rainfall during the northeast monsoon. 3. The southwest monsoon is the primary rainy season for Tamil Nadu. Which of the statements given above is/are correct? a) 1 and 2 only b) 2 and 3 only c) 1 and 3 only d) 1, 2 and 3 Answer: a) 1 and 2 only Explanation: Statement 1 is correct: The northeast monsoon occurs from October to December and affects southeastern India, including Tamil Nadu. Statement 2 is correct: Tamil Nadu receives around 48-50% of its annual rainfall during this period. Statement 3 is incorrect: The southwest monsoon primarily affects western and northern India; Tamil Nadu’s main rainy season is the northeast monsoon. |
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