Syllabus: GS- I & V: Urban Flooding

Why in News

Recurring waterlogging in Guwahati has raised concerns over lack of rainwater harvesting integration in flyover infrastructure.

More About the News

Guwahati’s flyovers were primarily designed to reduce traffic congestion, but they have failed to address the city’s chronic urban flooding problem. During heavy rainfall, water flows directly from flyovers onto roads, worsening water accumulation and creating safety hazards.

Key Issue: Lack of Integrated Urban Planning

• Flyovers act as impervious surfaces, increasing surface runoff.
• Absence of rainwater harvesting systems (RWH) leads to:
• Sudden discharge of water onto roads
• Increased waterlogging
• Damage to urban infrastructure (roads, footpaths)

What is Rainwater Harvesting (RWH)?

Definition: Collection, filtration, and storage of rainwater for reuse or groundwater recharge.

Urban relevance: Helps manage stormwater and reduce flooding.

Potential Benefits of Integrating RWH in Flyovers

• Flood Mitigation: Reduces rapid runoff and urban waterlogging
• Groundwater Recharge: Helps replenish shallow aquifers
• Water Conservation: Provides water for non-potable uses (cleaning, irrigation)
• Urban Safety: Prevents splashing hazards for vehicles and pedestrians

Global & National Best Practices

• Flyovers used as stormwater catchment systems in dense cities
• Example: Coimbatore (Avinashi Road Flyover)
• Equipped with downpipes, storage tanks, recharge pits
• Supports greenery through drip irrigation systems

Policy & Legal Framework

• National Green Tribunal (2015): Mandates rainwater harvesting in major infrastructure projects
• Urban planning guidelines: Encourage sustainable drainage systems
• Linked with national initiatives like:
• Atal Mission for Rejuvenation and Urban Transformation (AMRUT)
• Smart Cities Mission

Challenges in Guwahati

• Lack of long-term planning and foresight
• Focus on short-term solutions like drain cleaning
• Poor integration of infrastructure with environmental needs
• Recurring floods due to inadequate drainage and rapid urbanisation

Way Forward

• Retrofit existing flyovers with rainwater harvesting systems
• Adopt Sustainable Urban Drainage Systems (SUDS)
• Integrate climate-resilient urban planning
• Strengthen coordination between urban local bodies and planning agencies

Exam Hook

Key Takeaways

• Urban infrastructure must integrate environmental sustainability
• Flyovers can act as multi-functional assets (traffic + water management)

Prelims (MCQ)

Consider the following statements:

Rainwater harvesting reduces urban flooding by increasing groundwater recharge.
The National Green Tribunal has mandated rainwater harvesting in major infrastructure projects.
Flyovers cannot be used as rainwater catchment structures.

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)

One-line Wrap

Guwahati’s flyovers highlight how infrastructure without environmental integration can worsen urban problems instead of solving them.