Urban Wetlands Breathe Life in to the City | Daily News
World Wetlands Day falls on February 2

Urban Wetlands Breathe Life in to the City

The urban wetlands make the city liveable.
The urban wetlands make the city liveable.

“The earth does not belong to man. Man belongs to the earth. Man has not woven the net of life: he is just a thread in it. Everything he does to this net he does to himself. What befalls the earth will befall the sons of the earth. We know this. All things are bound up in each other like the blood that binds the family.

“Continue to contaminate your bed, and you will one night suffocate in your own waste… When the buffalo are all slaughtered, the wild horses all tamed, the secret corners of the forest heavy with the scent of many men, and the view of the ripe hills blotted by the talking wires, where is the thicket? Gone. Where is the eagle? Gone. And what is it to say goodbye to the swift and the hunt? The end of living and the beginning of survival.”

– Extracts from the widely acclaimed letter by Native American Chief Seattle of the Duwamish Tribe to United States President Franklin Pierce in 1855, in response to an offer to purchase the Dwamish lands in the North East of the US, currently Washington State.

Waking up to the natural melodies coming from the chirps of the birds and to a picturesque landscape is a fortune that not many city dwellers around the world can boast of. However, this is what most of the residents in Sri Jayewardenepura Kotte, the administrative capital, and surrounding wetland areas still enjoy each morning, despite living in a highly urbanized setting. Of course, not all of them understand and appreciate that Nature’s gift.

The Salalihini Sandeshaya by Ven. Thotagamuwe Sri Rahula Thera, a historic piece of Sinhala literature, also depicts the beauty of these environs in a bird’s-eye view. This epic poem was written during the time of King Parakramabahu VI. The Kingdom of Kotte, which flourished in the 15th Century, was naturally protected by its wetlands.

“We are living in a very unique city, but we are not very conscious about the environment around us. From every breath we take to every rupee we earn, we are dependent on the environment surrounding us,” Dr. Chethika Gunasiri, an Environmental Scientist at the Sri Lanka Land Development Corporation (SLLDC), emphasized at the outset of her recent lecture titled ‘Living in the only wetland capital in the world’ at BMICH in Colombo. It was organised by the Wildlife and Nature Protection Society (WNPS) parallel to the World Wetlands Day which falls on February 2.

In her one-hour long thought-provoking speech, she underlined the major role played by urban wetlands to make the city liveable and resilient, and the challenges to their conservation.

When the cities are expanding, the urban wetlands are the first to be compromised. A study has found out that the wetlands in Colombo had shrunk by 40 percent from 1980s to 2014. We are losing the pristine wetlands at an annual rate of 1.2 percent. If this rate is continued, the consequences will be dire for all humans and animals in the city, including future generations.

Ramsar Wetland City

Environmental Scientist Dr. Chethika Gunasiri

The natural landscape of Colombo is a low lying area filled with marshes and it is crisscrossed with man-made canals and lakes. Today, even after decades of rapid development and degradation, there are about 36 interconnected wetland patches in this mosaic, which is called the Colombo Wetland Complex (CWC) or the Colombo catchment. They cover an area of about 19 square kilometres out of the 121.5 square kilometres of the Colombo Metropolitan Region. Noteworthy, it provides a 50 percent contribution to the country’s Gross Domestic Product (GDP) and has more than 2.3 million residents.

“If the Colombo catchment is divided into three areas, the downstream, which is closer to the West coast, has no wetlands. The middle area is a retention area and houses all big wetlands such as the Kolonnawa, Heen-Ela and Kotte wetlands, Parliament Lake, Diyasaru Park and Kimbulawala Walk Way. It stores 37 percent of rainwater coming to this hydrological area. Upper side of the catchment consists mainly of paddy fields. The water coming into this area is diverting to neighbouring catchments,” Dr. Gunasiri explained.

Colombo was among the first 18 cities the Ramsar Secretariat officially accredited as wetland cities in 2018. Dr. Gunasiri, who was a team member that prepared the Colombo Wetland Management Strategy and the application for the Ramsar Wetland City Accreditation for the Colombo City, thanked all the stakeholders who contributed to that landmark achievement as a country.

“Colombo was the only capital city to get that title. Colombo City was re-branded and internationally recognized as a wetland city with this accreditation. Another 25 cities received this title in the last Conference of the Parties (COP) held in Geneva in November 2022. Altogether 43 cities have now been accredited as Ramsar Wetland Cities. These cities serve as examples and inspire deliberate actions for other cities toward sustainable urbanization,” she added.

The Ramsar Convention, signed in 1971 in the Iranian City of Ramsar, is the intergovernmental treaty that provides the framework for the conservation and wise use of wetlands and their resources. As of now, 172 countries are signatory to it, and Sri Lanka became a part of it in 1992.

Natural sponge

A wetland is an ecosystem that comes in between a terrestrial ecosystem and deep water aquatic ecosystem. It is an intermediary stage. The main component of a wetland is water, and this water can be in different forms. The Ramsar Convention defines wetlands as “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”.

“Wetlands usually have shallow water bodies, and because of that, they support a lot of biogeochemical cycles. That is the reason why wetlands are considered the most productive ecosystems in the world. Humans are strongly connected with them because they provide a lot of ecosystem benefits and services,” Dr. Gunasiri expounded.

Serving as flood retention areas is a known function of wetlands. “They act as natural sponges and protect the city from floods. The wetland soil, which is called hydric soil, has a high amount of clay and can absorb a lot of water. This is important as cities have a lot of impermeable surfaces,” she observed.

Her lecture underlined that Colombo wetlands save Rs 15 billion every year through flood control. Colombo is vulnerable to floods, and the devastative flood event in 2010, during which even the Parliament Complex went under water, was an eye opener for the authorities as well as the public on the importance of conserving the remaining wetland patches, which are also the only green patches in the city.

“This flood event transformed the way we looked at the Colombo Wetland Management. The Metro Colombo Urban Development Project, which primarily focused on hydrological solutions to the floods, started in 2012. The Wetland Management Division was established in the SLLDC in 2013. The Colombo Metropolitan Region Wetland Management Strategy, the first strategic document for the wise use of urban wetlands, came up (2013-2016), and wetland-based urban recreational and agriculture projects were actively started,” she recalled.

More benefits

“Wetlands are also considered as Nature’s kidneys. As same as kidneys purify the blood, the wetland plants (reeds and floating vegetation) and the soil, in a process called phytoremediation, absorb toxic materials from water and convert them to non-toxic materials through a chemical process, and purifies the water,” she elucidated, reminding that this function is of great importance as the water pollution is quite high in cities.

Touching on the financial aspect, she pointed out that the urban wetlands save Rs. 2 billion per year by cleaning polluted water.

Dr. Gunasiri drew the attention of the audience to the waste water problem in the Colombo Wetland Complex due to the mushrooming number of condominiums.

“The horizontal expansion of Colombo is over now as there is no more space. We have started expanding it vertically with high rise buildings and condominiums. It does both good and bad. Sri Lanka does not have a sophisticated waste water management system. When the condominiums increase in number, a lot of people settle down in a small space, and the amount of waste water they produce is high. Though many are not yet aware about it, this is one of the biggest problems that we are going to face in the future,” she noted.

Another important function of these ecosystems is that they cool the cities and help control temperature, thus making the cities more comfortable for humans and all other living beings. In that way, they also help save electricity used for air conditioning.

The Environmental Scientist pointed out that urban wetlands act as wildlife refuges, and because of that, they have high levels of biodiversity. Colombo wetlands are home to 277 animal species and 285 plant species, including many endemic and vulnerable species. For example, Colombo is the only city in the world where an urban fishing cat population is found.

In addition, she explained that urban wetland habitats are important for food security as 87 percent of total wetlands provide food for the citizens in Colombo. Moreover, these wetlands add aesthetic beauty to the city, and have a recreational value. Dr. Gunasiri brought up in her lecture that the country can generate at least Rs. 1.6 billion per year from recreation and tourism in these wetlands.

She observed the jogging tracks and parks in these areas serve two purposes. Firstly, they help improve the health of the people, and secondly, they bring people closer to the wetlands, enabling them to understand and appreciate their value. She mentioned that it was also a strategy to stop further encroachment of these areas.


Garbage dumping, land filling and human encroachments have become common problems to the urban wetlands.

“With the construction of the Parliament Complex in Sri Jayewardenepura Kotte, a lot of developments and settlements started around this area, and a lot of marshes and paddy fields were cleared. In 1991, in order to protect that area from floods, 1,000 acres of marshes and active paddy fields around Parliament were acquired by the Government as flood retention areas. Those mainly included Kolonnawa, Kotte and Heen-Ela wetlands and Parliament upper retention area.

“Recently, the Government re-demarcated those wetlands, and at that point it could be seen that some boundaries were going in the middle of home gardens, and sometimes even living rooms. That much of encroachment has happened in the last three decades,” the environmental professional underscored.

The sensitive ecosystems of wetlands are heavily disturbed and destroyed due to garbage dumping. “Even in highly managed public places such as jogging tracks and wetland parks, littering has become an issue. In some countries, people do not throw their litter until they find a dustbin, but our people are not like that. I admit that in some places garbage bins are not properly kept, but sometimes, even the dustbin is there, but the litter is out of the dustbin,” she commented, adding that correcting such behaviours must happen from the school level.

She highlighted that alien invasive species pose a biological threat to Colombo wetlands. For example, she said that, the canal in Kolonnawa is covered with Water Hyacinth (‘Japan Jabara’), the canal in the Diyasaru Park is covered with Salvinia and most of the wetlands in Colombo are covered with Pond Apple or ‘Wel Atha’. Pond Apple has become a problem as it is making wetlands more terrestrial, negatively influencing functions of wetlands like water retention. Its removal has been difficult because the wildlife has adapted to it.

She also drew the attention of the audience that various Government agencies, such as the Urban Development Authority, Department of Wildlife and the SLLDC, own various parts of the CWC, and bringing them all to one table for decision making has become challenging.

Role of citizenry

Commenting on the issue of pollution of Beira Lake in the heart of Colombo, she said the major sewerage lines that discharge wastewater to the Lake have already been identified and stopped. “This issue has been there for many decades now, and it has to be addressed with multiple solutions. We often come across new proposals in that regard and pilot studies have been conducted for them, but the main constraint in going into the mass scale is that they are not economically viable. The recent floating wetlands project has made some positive impact. We have to be careful that any solution that we implement does not negatively affect the many offices, hotels and business places around it,” she added.

“After all, Colombo is our Capital City and we cannot stop development. Both development and Nature have to go hand in hand. To achieve this end, we have to think of using urban wetlands as nature-based solutions for the environmental problems in the city. A lot of countries are using similar concepts,” she said, commenting on the future management of Colombo wetlands.

Responding to a question by the audience on high profile interventions and political interventions that hamper the wetland protection, she admitted that they are a pressure to be reckoned with. “Because of the high land price, everybody wants to fill these lands and put them into commercial use. We too have to struggle at times to stop such activities. That is why public awareness is important. If the public can make a strong voice in opposition to such activities, that helps our task, because sometimes we cannot fight alone,” she stressed.

Every tiny urban wetland patch that remains is important, and we all, in our personal as well as professional capacities, have a role to play for their protection, was the take home message of her well-articulated and well-organised lecture.

 People come to the Beddagana Wetland Park for recreation.

Colombo is vulnerable to floods.

The Colombo Wetland Complex comprises many paddy fields.

The wetland ecosystems are polluted due to haphazard dumping. These pictures were taken recently in the stretch between the Beddagana Wetland Park and the newly opened Rampart Wetland Park in Ethul Kotte.

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