ejustice 1.1 - COLOMBO’S DISAPPEARING WETLANDS

COLOMBO’S DISAPPEARING WETLANDS

Indika Rajapaksha (B. Sc)Environmental Officer

Colombo is a city built on and around wetlands. Over 500 years ago the ancient Kingdom of Kotte flourished in Sri Jayawardenepura Kotte and centred on a fortress surrounded by lakes and marshes known as Diyawanna Oya and Kolonnawa Oya. Whilst much has changed in the intervening years, today the home of the Sri Lankan parliament and administrative centre for the country can still be found situated on a reclaimed island on a lake in the suburb of Sri Jayewardenepura Kotte at the centre of the Colombo Metro Region (CMR).

Today wetlands cover approximately 20 km2 across the CMR .However, the extent of the wetlands only tells part of the story. Since the days of the Kingdom of Kotte wetlands within the CMR have been progressively degraded, infilled and lost. Much of this damage is considered irreversible. Some estimates suggest that wetlands comprising the Kolonnawa Marsh have been reduced in area by as much as 65% since the 1980s. Similarly, as much as 60% of paddy lands across the wetlands of CMR may have been converted to non‐wetland use over a similar time period.

The wetlands provide effective protection from flooding. During intensive rainfall events, the wetlands are able to store several tens of millions cubic meters of water (up to 68 Mm3 for the 100 year return period flood or the equivalent of more than 27,000 Olympic sized swimming pools). The wetlands can reduce extreme air temperatures and make the city more livable. Due to evaporative cooling, the wetlands can reduce air temperatures, the effect of which can extend into areas up to 100m away from the wetlands’ physical boundaries.

This means that over 65 km2, or more than 50% of urban Colombo, benefits from this natural air conditioning. The wetland soils are mitigating global climate change. Estimates suggest that the wetland soils contain approximately 1.43 million metric tons of carbon; the equivalent of almost 90% of the annual carbon emissions from CMR.

The wetlands are protecting the health of citizens. Four out of five of the wetland areas in Colombo buffer the negative impacts of airborne pollutants on air quality. Through the trapping and removal of particulate matter the wetlands are reducing the incidence of cardiopulmonary and respiratory diseases, coughing, bronchitis, and lung cancer, as well as premature deaths from these diseases resulting from elevated concentrations of ambient particulate matter.

The Colombo Metropolitan Region losses 1.2% of wetlands per year (World Bank,2018) The city of Colombo has been declared as a wetland city by the International Ramsar Convention Secretariat. The Wildlife Department, together with the cooperation of all relevant parties had made an application to the Ramsar Convention Secretariat to obtain the international wetlands certification for the Colombo city.

Highlighting the importance of making use of the urban wetlands amidst urbanization and focusing on protecting its biodiversity, it was decided at the Ramsar Secretariat Stakeholders Conference in 2015 to name such cities as international wetland cities.

Accordingly, 18 wetland cities were chosen from China, South Korea, France, Madagascar, Sri Lanka and several other cities to be named as wetland cities by the Ramsar Secretariat.

This provides a unique opportunity to protect the existing wetlands in the Colombo Metropolitan Region. A national wetland policy has been formulated by the Central Environment Authority in 2006. National Wetland Day which falls on 02nd of February is celebrated annually. However actual effort put towards conserving the existing wetland is minimum. Many unauthorized fillings are happening overnight. It is high time for individuals, civil society and citizens of Colombo to raise their voice against illegal filling, garbage dumping, and industrial effluent dumping to wetlands. Otherwise this title Colombo has gained as a wetland city would be just a title.[END]