Author(s): Tara Pillai; Swati Arya; Pranit Rai; Angelos Findikakis

Linked Author(s): Angelos N. Findikakis

Keywords: Canal restoration; Gray green infrastructure; Phytorid

Abstract: The combination of nature-based solutions and well-thought gray infrastructure improvements in inland waterways can contribute to several Sustainable Development Goals (SDGs). This includes but is not limited to- SDG 1 (No Poverty), SDG 3 (Good Health and Well-being), SDG 6 (Clean Water and Sanitation), SDG 8 (Decent Work and Economic Growth), SDG 11 (Sustainable Cities and Communities) and SDG 14 (Life Below Water). Several canals constructed in early 1500s served for centuries as routes of trade and transportation in the Fort Kochi area in the Indian state of Kerala. The canals were also used to irrigate the adjacent agricultural lands, which were highly fertile. During the last few decades, the condition of the canals has deteriorated due to the discharge of untreated wastewater, disposal of solid wastes, silt and debris accumulation. Encroachment by housing structures at its banks has further reduced the width of the canals. In addition, urbanization in the area has contributed to increased runoff draining in the canals, causing occasional flooding. A pilot project was undertaken to demonstrate methods for the environmental restoration of these canals and flood protection of vulnerable areas. The selection of the canal for the pilot project was based on several criteria that focused on flood protection, pollution and the daily usage of the canal for transportation. It also considered potential opportunities that the canal might be used for in the future, like ecotourism and fishing. Project feasibility in the form of community support also played a role in the selection process, which finally led to the selection of the Pandararchira Canal for the pilot project. The condition of the Pandarachira canal and the area it drains was assessed through several site visits, consultation with members of the community and local authorities. Further, a door-to-door survey of residents was also conducted using a specially developed detailed questionnaire. The objectives of the questionnaire were- (1) to help understand the socio-economic condition of the area, (2) to identify locations of monsoon and tidal flooding, and (3) to map current infrastructure, services & practices in solid waste and sanitation at household levels. Hydrologic modeling in combination with the responses to the survey was used to determine the extent and frequency of flooding in the area. A combination of green measures and gray infrastructure were proposed to mitigate the risk of flooding, improve water quality, and restore its biodiversity and allied environmental conditions. Some of those measures were the elimination of some choke points such as narrow bridges or insufficient culvert capacity under some road crossings, bar screens in front of culverts to intercept floating debris and trash, decentralized wastewater treatment plants using phytorid technology to eliminate wastewater dumping in the canal, planting mangroves in selected parts for erosion control, and phytorid floating beds for nutrient removal. In addition, the proposed pilot project includes the revival of the cultivation of Pokkali, an extremely nutritious heirloom rice variety, in selected areas adjacent to the canal, and the promotion of eco-tourism after the environmental restoration of the canal.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0764-cd

Year: 2023