About 40,700 hectares connected by canals: Colombo Metropolitan City, the first wetland city | Sunday Observer

About 40,700 hectares connected by canals: Colombo Metropolitan City, the first wetland city

18 February, 2018

It was a land wedged between two great rivers, the ‘rice bowl’ of the island nation providing sustenance not only to its kings but for a greater part of his subjects. Lying in the flood plains fed by the two rivers, it’s soil never lost its richness/riches. It was rich not only in an exchange of nutrients, but in purifying air and water, protecting the rest of the area from floods, fostering a myriad of life including that of human. Then came the invasion in the form of ‘reclamation’. First, by local lords to establish their kingdoms; next by foreign powers building their forts; last altogether creating modern business and administrative cities. The wetlands of western Sri Lanka have been violated since the time of Vijaya Bahu VI (Vira Alakeswara) instrumental in the establishment of the Kingdom of Kotte in the marshes of Kalu and Kelani, during the late 1300s. But, hope comes in the form of ‘restoration’ in vying for the Colombo Metropolitan City (CMC) to be recognized as the first Wetland City by/through the Ramsar Convention this year (2018).

When Red-Indian Chief ‘See-ahth’ (Seattle) delivered his speech, in the wake of the European established cities in the USA, he wouldn’t have foreseen that it would become a cliché among environment conservationists. Neither would King Vijaya Bahu VI, the inundation of the financial and administrative capitals of Sri Lanka during the monsoons of 2017.

Wetlands what are they?

It may be a strange phenomenon. However, many city dwellers, especially, high-rise dwellers are avert to the word ‘wetlands’. ‘Those smelly, boggy areas where everyone dumps waste, everything rots and disease is rampant’ is the common idea among many.

However, what are wetlands? “Wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres” defines the Ramsar Convention, the international agreement which provides the framework for action, nationally and internationally, in conserving wetlands and the wise use of its resources. Wetlands include a wide variety of inland habitats, coastal areas and human interventions.

What’s the importance of wetlands?

Clean or not, wetlands contribute greatly, towards the health and development of a city. Without wetlands, the water cycle, carbon cycle and nutrient cycle would be altered significantly. They are regarded the “nexus” between water, food and energy. The Colombo Metropolitan City (CMC) has a network of wetland areas of about 40,700 hectares, connected by canals.

Wetlands are the ‘lungs of the city,’ declares Herath Manthrithilake, Head of Sri Lanka Development Initiative of the International Water Management Institute (IWMI), speaking of the wetlands in the CMC.

They are a major filter of carbon dioxide, purify the air of pollutants through trapping and removal of the particulate matter and act as a natural ‘air conditioner’ reducing the air temperature through evaporative cooling, benefiting more than half of the city, they ensure urban food security. Around 90% of the wetlands in the CMC are actively involved in the food supply of the city. 

Moreover, they are a good source of plants and herbs used in traditional herbal medicine.

A crucial contribution of wetlands is the mitigation of floods. Wetlands working as a sponge absorb the runoff from storms preventing the flooding of the city. The wetlands in CMC could hold an equivalent of 27,000 Olympic Swimming Pools and contribute to the reduction of flooding by 39%, opines Dr. N.S. Wijayarathna, Deputy General Manager (Wetlands Management) of the Sri Lanka Land Reclamation and Development Cooperation (SLLR&DC). Though established for the purpose of reclamation, the hydrological aspects of the importance of wetlands had compelled them to conserve the same. “The wetlands absorb the stresses of the city as well as the stresses of its people,” commented Dr. Wijayarathna, “We are trying to conserve the leftover 20 square kilometers of wetlands in Colombo.”

How can wetlands be used wisely?

Development could go hand in hand with the wise use of wetlands. Conserving and managing wetlands are a much cheaper and natural alternative to waste water treatment, erecting flood buffers, mitigating flood damage and so on, says Lucy Emerton, Environment Economist of Environment Management Group, who has been conducting research in Sri Lanka for over 15 years. “The return of the investment in wetland management is ten to one, 10:1.” Research in Uganda had shown that while the government had to spend USD 4,000 per hectare per year, to provide the basic services for the people elsewhere, it only spent USD 400 per hectare per year to manage the wetlands which provided the same services. In calculating the economic value of the Maha Oya river estuary and Muthurajawela marshes they had found that each hectare of wetlands provides services equivalent to Rs. 874 million, per year. Wetlands could be used for recreational as well as educational purposes.

The wetland complex around the Parliament in Kotte and the Diyasaru Park, a wetland eco system created recently are examples. The rich biodiversity in the wetlands could be used to attract tourists, local as well as foreign.

The CMC wetlands are home to over 250 species of flora and 280 species of fauna, from which a significant percentage consists of threatened and/or endemic species.

The European Otter and the Fishing Cat are two such species sheltered within the confines of CMC wetlands. While the SLLR&DC along with the Metro Colombo Urban Development Project, plan to use the canal network to ease the transport problems in the city, through the Kimbulawela Model Farm and other farmer initiatives the government has taken steps to conserve the paddy land and support the traditional paddy farming techniques.