Tamil Nadu to restore 'remaining' 700 hectares Pallikaranai marsh

CHENNAI: After decades of neglect and wanton degradation, the Pallikaranai marshland may see the light as the Tamil Nadu Forest Department has proposed to carry out comprehensive restoration and conservation of the ecologically sensitive swamp. Ironically, the department could only restore 698 hectares of the marshland as the remaining 5,500 hectares were lost due to rapid and unplanned urbanisation and dumping of garbage.

According to a department document, the restoration and conservation project will be taken up under Tamil Nadu - Sustainably Harnessing Ocean Resources and Blue Economy (TN - SHORE) with funding from the World Bank.

As a part of the work, the department will clear the Perumbakkam Channel of debris, solid waste and other impediments to allow flood water to enter the marshland which will improve water management in the marshland apart from enhancing soil stability. Also, the Veerangal Odai and Ottiyambakkam Channel that feed the marsh will also be cleared.

"Pallikaranai marsh drains an area of 250 sqkm of south Chennai encompassing 65 wetlands through two outlets such as Okkiyam Madavu and the Kovalam creek and drains into the Bay of Bengal. Though in the past the wetland had water all around the year, due to several impediments, part of it becomes dry during summer," the document said.

Presently, due to dryness and change in elevation profile due to obstructions, a few areas inside the marsh lack vegetation and water stagnation.

70 hectares under karuvelam infestation:

Besides clearing the feeding channels, the department will clear aquatic weeds and invasive species including water hyacinth and Prosopis juliflora (karuvelam). "If the water hyacinth is not controlled, it will cover the entire water spread area, affect water flow and block sunlight from reaching native aquatic plants which often die.

Shockingly, of the 698 hectares under the administrative control of the forest department, about 10 per cent of the area is encroached with invasive alien Prosopis juliflora. "It had environmental effects, aggravating and influencing invasions into various ecosystems that significantly weakened ecosystem services. It reduced palatable grasses of livestock," the department says.

The forest department will build bunds along the boundary of the marsh and form walk paths along the bund using natural hard granite. Native trees will be planted on either side of the walk paths. Also, three small bridges will be constructed across the waterways in the marsh to link the existing eco-park and the proposed Wetland Conservation Centre. Prior assessments will be conducted to minimize disruption to the natural habitat before the construction of the bridges, the department assures.

It may be noted that the Pallikaranai marshland restoration has four components — update of the Comprehensive Management Plan, protection and consolidation, eco-restoration and conservation, monitoring bird diversity, and eco-tourism and eco-development. However, the department has decided to take up protection and consolidation, and eco-restoration and conservation components as a priority basis, under which clearing of channels, removal of invasive plants and creation of bund fall under.

"The department will carry out activities of other components separately and the measures will be taken to remove garbage and arrest sewage entering the marshland," an official assured.

Despite the suggestions from the southern bench of the National Green Tribunal (NGT), the Chennai Corporation has refused to hand over 173.56 hectares of marshland, which is under its control. Of the 173.56 hectares, the Perungudi dumping yard is on 250 acres. Amid opposition from the public, the civic body has taken measures to create an eco-park on the dumping yard after the completion of the ongoing biomining project.

MARSH STATUS

1,247.54 ha -- Declared as Ramsar site

700.47 ha -- Under forest department

530.07 ha -- Reserved forest under dept

173.56 ha -- Under Greater Chennai Corporation

163.25 ha -- With TN Electronics Corporation

46.92 ha -- Under Railways

5.85 ha -- IT park

Et cetera -- Residential areas, educational institutions

Problems identified by forest dept:

~ Organic waste disposal and contamination with high levels of chloride and sulphate ~ Channels from settlements carrying wastewater

~ Institutional, commercial, and residential buildings, and dump yards inside marshland ~ Invasive species like water hyacinth, Prosopis juliflora ~ Changes in habitat topography resulting in total dryness of certain areas

Biodiversity profile:

Birds - 190 species

Mammals - 10 species

Reptiles - 21 species

Amphibians - 10 species

Fishes - 50 species

Molluscans - 9 species

Crustaceans - 5 species

Butterflies - 14 species

Plants - 164 species

Total - 459 species