How do monsoons affect Tamil Nadu, Pg12.

Key Highlights:

• Tamil Nadu received 33% excess rainfall last year, and similar patterns are expected this year.
• Climate change is causing short, intense bursts of rainfall instead of evenly distributed showers, overwhelming urban drainage and rural irrigation systems.
• The Mullaperiyar Dam issue between Kerala and Tamil Nadu has resurfaced, as synchronized rainfall increases the risk of flooding in both States.
• Heavy rain impacts urban infrastructure, agriculture, and public health, while also triggering inter-State water management conflicts.

Detailed Insights:

• Urban Challenges:
  • In cities, rainwater cannot seep into the ground due to concretized surfaces, causing flash floods, road damage, and drainage overflows.
  • Excessive water pressure weakens power infrastructure, resulting in electricity disruptions and wastewater contamination.
• Agricultural Impact:
  • Excess moisture damages crops by causing root rot, fungal infections, and soil nutrient loss, reducing long-term fertility.
  • Flooding disrupts transport and storage networks, increasing agricultural losses.
• Public Health Risks:
  • Stagnant water creates breeding grounds for mosquitoes, leading to diseases such as dengue, malaria, and Japanese encephalitis.
  • Flood-related displacement and property loss worsen mental health issues and anxiety among affected communities.
• Inter-State Dimension – Mullaperiyar Dam:
  • The dam, located in Kerala but operated by Tamil Nadu, creates a direct hydrological link between Kerala’s rainfall and Tamil Nadu’s river systems.
  • Heavy rains in Kerala’s Idukki district fill the reservoir quickly, forcing Tamil Nadu to release water, flooding Kerala’s low-lying areas and simultaneously raising levels in Vaigai Dam in Tamil Nadu.
  • The dual rainfall inflow from both the southwest and northeast monsoons exacerbates management challenges, leading to safety and flood risks on both sides.

Scientific/Technical Concepts Involved:

• Northeast Monsoon: Seasonal wind system occurring from October to December, vital for Tamil Nadu’s rainfall.
• Urban Heat Island Effect: Increases local convection, enhancing rainfall intensity over cities.
• Hydrological Linkage: The dependency between rainfall patterns, river basins, and dam management in adjacent states.