The Cooum’s strangulation over the past fifty years by government inaction and active connivance is recorded history.
Right from the seventies, when the deterioration of the main water way of Chennai city had caught the attention of its citizens, governments have leveraged the political significance with half measures . Why I say half measurers is because most of the causative problems like slums and encroachments have also blossomed under the government’s watchful patronage over the same period.
The Reclamation of polluted Cooum cannot be a time limited activity. It must be a permanent process in continuum. It must begin with a consensus between all political formations that the Cooum’s restoration to its original flood plains and catchment areas consisting of tanks etc is non negotiable and inviolable political territory. Legislation to this effect must be done forthwith in alignment with national environmental objectives. Only then can the real corrective implementation recommended by reputed institutions and technical studies be possible without fear or favour.
The encroachments including government and educational institutions must be removed. It is sad that while technical studies are based on return periods of 10,100 and 200 years. The significance is immediately overlooked when the study then accepts configurations as it exists with encroachments that have come up over the last few decades. Hard engineering solutions like concrete walls 10 mtrs high is offered as solutions. The government quietly condone past impounding of flood plains by vested interests. A strong retrieval of records will throw up sufficient data in the governments favour. But do they wish to reclaim the flood plains. Roads have been laid over the channel beds and approved buildings over wide drains in many instances within the city limits.
Ecological reason of the death of Cooum river.
Historically, the fate of the Chennai rivers changed, after the artificial Harbour was built in Chennai (Madras) in late 19th century.
The natural "Littoral drift" along the Indian east coast moves the sand in a south to north direction along the coastline. If any wall is built into the sea, this flow is affected. The Chennai harbour breakwater forms a long wall built into the sea from the land. This disrupts the northern movement of the littoral drift. So the sand which was to move further north of Chennai Port, started getting accumulated south of it.
Hence, when you see the satellite image of Chennai, you can find the width of the Sandy area of Chennai Beach being wide just beneath the Port (Anna/MGR memorials) and the width gradually reduces as we go south.. This has contributed to the land erosion in the areas north of Chennai port (Ennore etc.). The currents having lost its sand load south of the port replenishes its sediment carrying capacity, leading to the constant erosion just north of the port.
The cooum river's mouth, south of Chennai Port, gets filled up with sand affecting the tidal action and thereby flow of the river. You can find sand settlements increasing along the south side, of the Ennore port as well (which in turn has started blocking the flow of Ennore creek/Kosathalai aaru).
shortcomings of the Integrated Cooum River Eco - Restoration Plan
The government under the above plan, has done a fairly comprehensive study and recommended possible Solutions.
This present plan is a very capital intensive plan estimated at about Rs 1500 crores, with a component of 1200 crores to be spend in the first three years. The plan is based entirely on hard engineering interventionist methodology. The major components are slum relocation, dredging and embankment beautification. The evaluation has failed to consider globally proven and accepted bio-remediation technologies that can be executed at fraction of the cost.
Research over the past half of a century of natural bio remediation and hard engineering solutions have been carried out by reputed institutions. Most hard engineering solutions world over have been seen to last for not more than 25 years. Bioremediation solutions performance, on the other hand, get stronger over period of time and are self sustainable and cost much less.
While some of the changes regarding encroachment along the banks and reclaiming the flood plains are essential it also forms a part of the long term bioremediation process. Some work as usual has started on the relocation of slims (about 7 nos).
One major shortcoming is the acceptance of the present flow conditions of the Cooum as the performance objective. the non flow months is envisaged to be augmented with the discharges from STPs along the banks. This is a veiled admission of the fact that the Cooum will continue to be used for sewage flow. It is not only dangerous but recipe for disaster of the plan. It is a recorded fact that some of the major point pollution is from the non performing STPs discharging raw sewage into the Cooum. Hence this possibility of this happening should be completely eliminated.
When The PCB is insisting on industries to have zero discharge, why is the government STPs given such liberty to pollute public water ways. It must release only fully treated water to required specification into the Cooum which can sustain aquatic life. This alone will regenerate the dead Cooum into a living stream for Chennai. This is technologically feasible and should be non negotiable parameter if STPs are to be allowed.
The cosmetic recommendation of parks and walk ways must be de-prioritized to first enhance performance metrics and conserve resources. The objective focus on a clean Cooum must not be diluted It can definitely be taken up, but much later. The resources available must initially be used to improve the water quality to sustain aquatic life. Only this will set the stage for natural rejuvenation process to set in. Then and then alone will walk ways and parks be relevant for public use.
Bio-remediation the natural cost effective rejuvenation process
Technologies are available for bio remediation of both flowing and semi stagnant polluted water bodies like Cooum. In this technology of naturally multiplying microorganisms is a one time introduction into the soil. They biologically react with pollutants converting them to harmless by products and simultaneously release oxygen into the water body. This supports other species of flora and fauna to revive naturally . This renders the polluted water non toxic. Also aquatic life can regenerate and sustain further reduction of COD and BOD to levels that can bring back life back to the Cooum.
Secondary works after improving water quality.
The core reason for the death of the Cooum from a living water way into a sewage channel is the anthropogenic causes within the 17 kms of the urban stretch inside Chennai limits. the sheer apathy of the government which has allowed unabridged flow of effluents by private and commercial and public sources into the Cooum.
Ensuring strict compliance under existing PCB norms itself will eliminate 80% of the effluent discharge and achieve enhanced water quality without any additional financial outlays but within available budgets. But will the government have the political will and commitment to carry out these simple enforcements. The government can save millions in investments and leakage of funds by using appropriate technologies. But Will the government initiate a serious evaluation of bio-remedial technologies? Bioremediation systems is only fraction of the costs of hard engineering solutions and also fully sustainable. Can we avoid another round of splurge of public money is done.
The original river bed level enabled tidal action and assisted water exchange in the final reaches of the Cooum. But the river bed has risen due to sedimentation of dumping of solid waste. Absence of tidal exchange has caused stagnation over the last 1.5 kms of the Cooum. Dredging in phases to enable the tidal action and natural rain flow from the tanks should be a long term measure. This will increase natural flows to original levels. The cost of transporting dredged materials, a huge element of cost in the envisaged plan, can be totally eliminated. The dredged soil can be used in-situ through suitable design for embankments and appropriate usage. The proper management of Chembarambakkam over flow should enable better flow parameters to flush the Cooum also.
Both civil society’s non participation and lack of political will have taken a toll on the once beautiful river. It may be difficult but not impossible given the opportunity in restoring its lost glory. Can we look forward to someone taking up the cause for a clean Cooum
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