Adyar River originates from Adanur Tank near Guduvancheri village and also surplus course from Chembarambakkam Lake in Kanchipurum District, which flows in the southern parts of Chennai. The river runs about 42 kilometers west to east and meets the Bay of Bengal in Adyar. Adyar estuary, the point at which the river meets the Bay of Bengal lies between Santhome beach in the north and Elliots Beach in the south. The estuary region from Thiru-vi-ka Bridge to the river mouth and the creek region from Santhome Causeway to river mouth spread over an area of about 300 acres.

Project Area – Adyar Estuary and Creek (300 acres)
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NEED FOR RESTORATION

Poor water quality in the river Adyar is the primary cause of degradation of the Adyar estuary and creek. The main cause for the degradation of water in the riverine and estuarine ecosystem of Adyar includes the following:

  • Untreated waste water discharged into the river and the estuary from the drains within Chennai Metropolitan Area
  • Discharge of partially treated industrial effluents from Pammal region beyond the CMA into the river.
  • Non-point pollution from slums not covered by the sewerage and open defecation along the banks and disposal of solid waste.
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OBJECTIVE OF RESTORATION

In order to address ecological issues and to implement long term measures as the holistic solution to restore the ecology of the Adyar estuary, a Master Plan and Detailed Project Report for Ecological Restoration of Adyar Creek and Estuary was prepared and restoration activities is being carried out.

The objective of eco-restoration of Adyar estuary and creek is to achieve and maintain best feasible water quality in its riverine and estuarine stretches and thus provide an opportunity to bring back the natural (endemic) life forms that interact with abiotic elements and create a healthy ecosystem. Improving and maintaining water quality to a level that can support a balanced population of phytoplankton, zooplankton and nektons is the real way forward towards the stated objective.

PROPOSED INTERVENTIONS

The following interventions were proposed under the Eco-Restoration of Adyar Creek & Estuary (Phase-II) – 300 acres:

IMPROVING WATER CARRYING AND HOLDING CAPACITY

A onetime cleanup by removing debris, plastics and sludge in the creek region and river mouth of project area to improve the flood carrying capacity of the channel and to improve the dilution by increasing the volume of water held in the estuary and creek, specifically during the low tides. It broadens the channel to 400m for tidal exchange.

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MEASURES FOR ENHANCED TIDAL EXCHANGE

Enhanced tidal exchange along with the control of organic pollution has been identified as an important aspect of the eco-restoration. This necessitates opening of the mouth of Adyar estuary throughout the year. Sustained opening of the mouth will also facilitate the re-colonization of the endemic aquatic fauna. The pattern of littoral drift along the coast is the primary cause for the formation of the sand bar at the mouth of the Adyar estuary causing complete/partial blockage. The sediment deposit at the Adyar river mouth due to the northward littoral drift, especially during the months of May to August being the primary reason for closure of Mouth. The solution to opening of the mouth lies in control of sediment in the sea water current flow crossing the river mouth and/or following a maintenance scheme that removes the sediments as those gets built up during the months of high littoral drift towards north.

HABITAT RESTORATION

The floral and faunal restoration is the other two major elements towards achieving the objective. The improvement in water quality allows the natural process of regeneration of flora and fauna. However, the following activities are taken up to improve the habitat;

  • Removal of Prosopis juliflora from the islands and edges with the gradual replacement by native species
  • Plantation of Mangroves in the low-level island and along the banks
  • Regeneration of mudflat vegetation.
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SHORELINE PROTECTION AND STABILIZATION

Bioengineering solution provides long-term benefits to the shoreline and water quality, stabilizes the bank and shoreline while improving fish and wildlife habitat. This method works well in combination with structural methods; the combination is described as a biotechnical installation. Bioengineering alone is generally not applied on steep slopes and usually requires some shaping of a slope as part of the installation.

CONTINUOUS MONITORING OF PROJECT AREA

An estuary is a sensitive ecosystem and needs constant monitoring of the project area during the eco restoration process as well as post-restoration, to improve people’s interactions with the estuary and the river, so that it does not become the neglected backyard that it is today. The existing access into the estuary is extremely poor and hidden from the public and this has been the major reason why the open spaces of the estuary have been misused. A pathway is designed for continuous monitoring of the project area.

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PROGRESS OF RESTORATION ACTIVITIES

The restoration activities of phase-II are nearing completion.

EARTHWORK EXCAVATION

a. Excavation at Creek: A total volume of 2,15,072 Cu.m, of sludge and debris has been excavated and disposed off at identified places. A sizable quantity of excavated earth was used for profiling of bunds in the creek area.


Before ExcavationAfter Excavation

HABITAT RESTORATION

a. Site Clearing in Islands: A Total of 1,34,106 Sq.m of Prosopis juliflora has been uprooted.

b. Bund Development:Bund stabilization has been carried out to a length of 2.2 kilometers from Foreshore Estate bus stand to behind Chettinad Palace. To prevent soil erosion and to facilitate plantation along the slope, 7000 sq.m of bio-engineering has been undertaken on the bunds along Santhome High Road on the Quibble Cemetery side up to CIBA complex. About 11,500 numbers of riverine species have been planted on the bunds.


Bund Stabilization behind Chettinad Palace Bund Development

c. Mangrove Plantation in Islands: Mangrove plantation has been completed in four Islands and in the mudflats for a total area of 1,07,430 sq.m. 57,137 numbers of mangrove species, viz., Avicennia marina, Exocearia agallocha, Acanthus illicifolious, Ceriops decandra, Brugeria cylindrica, Rhizhophora mucronata, Rhizhophora apiculata have been planted in the islands, mud flats and bunds of Adyar estuary.


Before Plantation - Islands Mangrove Plantation in Islands

INFRASTRUCTURE DEVELOPMENT WORKS

a. Compound Wall: Compound wall with grill over the masonry has been completed to a length of 512 meters with a height of 1.8m above plinth level all along the creek area covering Foreshore Estate Loop Road and Santhome High Road up to Quibble Cemetery. In order to avoid cutting of large trees, the compound wall was constructed around the trees in the creek area.


Before - Santhome High Road Compound Wall - Santhome High Road

Main Gate at Loop RoadWicket Gate at Loop Road Signal

b. Barbed Wire Fencing: Barbed wire fencing has been completed to a length of 1422m along Quibble Island Cemetery to Chettinad Palace.


Barbed Wire Fencing - Quibble Island Cemetery Barbed Wire Fencing behind Leela Palace

c. Solar Lighting: Installation of solar lights is being carried out within the creek area.

d. Seating: Six numbers of granite stone seating have been fixed. 10cm thick granite stone, dressed to required sizes was used.

e. Security Huts: Four Security huts for security guards to secure the plantations have been created within the creek area.


Security Hut with Seating near Loop Road Security Hut near Quibble Island Cemetery