Harit Setu: Blue-Green Infrastructure Strategies for Indian Metro Cities

Introduction: Re-engineering City Hydrology

Indian metropolitan regions face a dual crisis every monsoon: sudden urban flooding followed by acute groundwater depletion. Traditional concrete drains flush rainwater away as wastewater, starving the water table. The Harit Setu framework proposed by Ukiyo Habitat redefines urban drainage as linear ecological corridors—transforming flood zones into active public landscapes.

Harit Setu framework: integrating bioswales, rain gardens, and non-motorized transport along urban edges.

Key Pillars of Blue-Green Corridors

• Bioswales & Infiltration Trenches: Capturing run-off at source to naturally filter and recharge aquifers.
• Non-Motorized Transit (NMT) Paths: Shaded pedestrian and cycle lanes running along natural drainage paths.
• Native Wetland Flora: Phytoremediation using native plants like Typha and Vetiver grass to cleanse surface run-off.
• Micro-Climate Mitigation: Lowering ambient street temperatures by 2°C to 4°C during summer peaks.

Implementation Framework for Delhi NCR & Metro Regions

By retrofitting road rights-of-way and underutilized canal edges into Harit Setu corridors, cities reduce storm damage costs while adding high-quality recreational open spaces for dense neighborhoods.