The focus of the present study is on the downstream area where the river basin drains into the Bay of Bengal sea in close proximity to Buckingham Canal and Ennore Creek.
Rationale
The study area has been selected for its eco-sensitive nature where the scope for a ‘River city method’ of planning is huge as well as urgently needed to plan for sustainable urbanisation in the coming decade. Specifically, three major factors affecting the water quality of the coastal stretch need to be looked at from the perspective of the river-city nexus:
- Pollution (including fly ash pollution and thermal pollution)
- Groundwater deterioration (possible saltwater infiltration from the sea)
- Excessive cyclone-induced flooding (during NE monsoons)
Moreover, freshwater reservoirs along the stretch such as Poondi, Puzhal lake, and Sholavaram are critical to supplying water to expanding Chennai city. Ennore creek and Pulicat lagoon connected to the river constitute eco-sensitive areas of high interest for biodiversity conservation. Gummidipundi and the surrounding fringe villages are known as hubs of industrial activity. The selected stretch is shown in the enclosed map.
Strategy
- The goal would propose to document the dynamicity of the changes in the river Kosasthalaiyar basin. The case would propose interventions which will help to reduce the vulnerability of its residents to frequent floods. Annual disasters have destroyed property and livelihoods, which could be reduced.
- Designing plans to declog the sea-canal-river mouth from industrial fly ash and solid wastes.
- Plans for mangrove forestation or native vegetation to improve the livelihoods of the inhabitants and Improve the ecosystem with endemic marine species from the perspective of ‘Nature-based Solutions’ will be initiated.
- Innovative designs and interventions for climate-resilient flood management, along with integrated urban planning, can be widely replicated in other Indian cities.
- Creating a manual for green infrastructure design, with aims to enhance stakeholders’ involvement, including the participation of women, improving flood preparedness by raising community knowledge.
- Improve sustainable and responsible tourism plans to bring wider attention and stakeholder involvement.
Methods
The river connects the sea at Ennore creek sharing with the Buckingham Canal. Kosasthalaiyar river originates from the Panapakkam forest of Andhra Pradesh State and enters the urban area through the eastern slope of the hills in the Pallipattu block at an altitude of about 531 m. Nandiyar and Nagariyar are the tributaries of the Kosasthalaiyar river which are seasonal and non-perennial. The flood in the rivers are sporadic and it lasts generally for about 10 days in a year. The total length of the main river from its origin is about 155 km in which Poondi reservoir is located on the eastern river course. It is the major source of storage, irrigation and supplying drinking water to the nearest city. The steps towards revitalisation are defined as follows:
- Derive baseline datasets on the status of critical ecosystems connected to the river and the city as described in the study area
- Use survey information to derive the transformational means to achieve revitalisation -
- Provide land cover management plans related to lowering pollution, increasing catchment strength for freshwater, and riverscape rejuvenation by designing adequate blue-green spaces, and maintaining a balanced connection with the sea
- Indicate policy gaps which will impede the above revitalisation strategies and improve enablement measures
- Developing a network of social, administrative and scientific (Academic/research) stakeholders who will use the RCM to facilitate low-impact, sustainable development measures, considering the unique vernacular character of the monsoon-dependent river as well as preserving the Central Asian fly zone bird habitats.
