Impact of the Deepening of Colonial Navigation Systems on Wetland Systems in India – case of Canoly Canal and Kottuli Wetlands, Calicut, Kerala
Anjana Bhagyanathan, Dr. A. K. Kasthurba, Prof. Deepak Dhayanithy
S-17 Water Management and Sustainable Ecosystem India Water Week 2013, New Delhi
Acknowledgement • For sharing their experience and expertise pertaining to Kozhikode, Canoly Canal and Urban Planning, we thank – Mr. C. K. Ramachandran • retd IAS officer, Kozhikode
– Dr. A. Achuthan • retd HOD, Civil Engineering, NIT Calicut
– Dr. Meera Bhagyanathan • MD, Kozhikode
– Prof. Seethalakshmi • School of Architecture and Planning, Chennai
Study Area
Wetlands • Kottuli wetlands – One of the largest eco-patches within city limits – Covers 87.04 hectares, rich in mangrove and associates, aquatic organisms and bird species – Identified by MoEF under National Wetland Conservation Programme (one of 115!)
• Perunthuruthi wetlands – Covers an area of 60 hectares in two parts – • Northern part called Mangala river (tidal influx from Korappuzha river) • Located further south, receiving tidal influx through Canoly Canal
Canal Development Proposal • Kerala Shipping and Inland Navigation department’s proposal to revive the West Coast Canal system includes – Deepening and widening of the Canoly Canal – NABARD assisted project to de-silt Canoly Canal and Kallayi river – Proposal to deepen canal and river funded by the River Management Fund – An aim to improve drainage in Kozhikode city
Objective of the Study • Impact on hydrodynamics of Kottuli wetlands by the proposed deepening of the Canoly Canal • Highlights the need for a similar study on the impact on Mangala river and Peruthuruthi wetlands
Topography • Canal oriented to direct inflow from 4 water bodies – Mangala river – Perunthuruthi wetlands – Kottuli wetlands – Kallayi river
• Elevation – Highest, Kunduparamba – Lowest, Kottuli
Hydrology • Surface water – Mangala river – Perunthuruthi wetlands – Kottuli wetlands – Kallayi river
• Ground water – Highest, Kunduparamba – Lowest, Kottuli
Impact sizing of the Canal deepening proposal • Canoly canal <> Wetlands <> Kallayipuzha <> Korappuzha • Basic effects of canal deepening – Increased ground and surface flow into the canal – Signature seasonal water pattern in wetland affected • 1,300 sq.km. of Kottuli and 1,080 sq.km. Perunthuruthi, assuming deepening by 2m • Water loss quantification is absent as of now!
Methodology, Analysis â&#x20AC;˘ Past, Present and Future of Kottuli Wetlands A. before Canoly Canal, 1848
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Methodology, Analysis â&#x20AC;˘ Past, Present and Future of Kottuli Wetlands A. before Canoly Canal, 1848 B. Present extent
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Methodology, Analysis â&#x20AC;˘ Past, Present and Future of Kottuli Wetlands A. before Canoly Canal, 1848 B. Present extent C. Projected extent with 2m deepening of Canal
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Recommendations • Interconnected nature of water bodies cannot be ignored • Canal deepening has larger impacts on flow dynamics • Watersheds approach to urban surface water management is crucial to iron out inconsistencies and unexpected outcomes • Key to develop a topographical base map as a common information set available to various urban planning exercises – water supply, sewerage, transport, water harvesting, irrigation and conservation efforts
Thank you!