Canal Restoration in Kochi, India

In Kochi, India, canals have been used for transportation, fishing, and flood control for generations. Over time, these canals have severely degraded, polluting waters and increasing flood risks. According to a survey of over 300 households on the canalside, 44% experienced flooding during heavy rainfall and 39% experienced tidal flooding. This is expected to worsen as climate change leads to more extreme monsoons and sea-level rise.

To address these challenges, bechtel.org (the social impact arm of engineering company Bechtel) collaborated with ICLEI-Local Governments for Sustainability, South Asia, and Swiss Re to design a pilot canal restoration project using nature-based and hybrid infrastructure along 2 km+ of the Pandarachirathodu Canal.

Our report analyzes the socio-economic and environmental impacts of three potential intervention scenarios:

1. a new grey-green hybrid solution called integrated wetland technology (IWT), which treats wastewater and prevents floods,
2. IWT combined with nature-based interventions such as floating wetlands and mangroves, as well as the removal of culverts to further restore the canal, and
3. all of the above, integrating a biodiversity park to support ecotourism and create jobs for the community.

Our assessment found all three scenarios to be investment worthy, with the highest net benefit produced by scenarios 2 and 3 (INR 325-331 million): the combination of IWT with a form of NBI. However, the highest benefit-to-cost ratio (BCR) was Scenario 1, the baseline intervention of hybrid IWT. Here, for every INR 1 invested can result in INR 9.78 net benefits for society, the economy, and the environment.