A community based initiative in Sri Lanka to keep our natural environment clean

Thalangama Wetland Watch

General News



Tree planting along the banks of the lake

April/May, 2024

  • In May, the Wildlife and Environment Conservation Club of OBA (Old Boys' Association), D. S. Senanayake College, Colombo 7, returned to the Thalangama lake for stage 3 of their tree planting program here. The whole started in 2017 with 100 trees, of which those which did not make it were replaced over time, like on May 12. Emphasis was on two species with broad medical use (Magul Karanda (Pongamia pinnata ) and Madan (Syzygium cumini). Water hyacinths removed by us from the lake were used as mulch and start fertilizer for the young trees.

  • The OBA has carried out many tree plantation programs e.g. in the Kalawewa area and flood plains in Manampitiya, Polonnaruwa district, aside other conservation work.

  • In late January, we were grateful to the Leo club of the Sri Lanka Institute of Information Technology (SLIIT) which planted at the Averihena lake a larger number of Kumbuk trees (Terminalia arjuna) of which most survived despite missing watering during longer dry spells at that time.

The lake remains a popular filming and photo location

The pristine surroundings of the lake continue to attract film makers, be it for movies, tele drama or commercials. There is no week without some shooting. While most productions fear the rains, others can’t get enough (see photos).

Photo shootings for weddings and anniversaries is equally in high demand. There is hardly a day without, while birders are most common in the early hours on weekends and holidays.

Who is shooting at our monkeys?

March, 2024

  • A recent post on our Instagram site made the rounds through social media. It described that three purple-faced langurs near the Thalangama Lake were shot at, and two animals had succumbed to injuries. The Thalangama lake area is protected as it offers a unique biodiversity and is home to some very endangered animals, like the purple-faced langur, which is protected by law, and anybody who harms it, can be arrested without a warrant by the Police.

  • With people encroaching into the langur’s habitat and cutting tall trees, the monkeys have no choice than to jump across roofs which can cause damage and upset owners. However, there is no reason to kill them, and certainly it should be unacceptable for Buddhists.

  • Read more in the Daily Mirror from 19 March 2024.

Who takes responsibility of the Averihena lake?

January-February, 2024

The Averihena lake has an important function for paddy field irrigation and to absorb flood water coming from the Thalangama lake, which since 2018 should drain towards the Kelani River, and not be released over the so-called “shoe bridge” into the paddy fields to eventually flood the parliament. However, the lake is increasingly overgrown with vegetation. When paddy fields were flooded at the wrong time, farmers protested, and multiple organizations discussed at the lake the water levels recorded by the automatic measuring stations. If any organization considered clearing the water passage along the dam towards the Kelani River remained unanswered.

Green Painters club adopted the Thalangama lake

December, 2023

Members across all ages of the Green Painters club became a familiar picture this month at the Thalangama lake. to capture its unique environment on canvas.

A rare misty morning in late November

November, 2023

And a beautiful sunset as it is often seen


September, 2023

Thanks to an initiative of the compass party, the railing of the small bridge at the lake entrance was repaired on both sides and repainted. The party also beautified the street corner of Lake Road with flowers and a wooden bench.

Inter-institutional lake management

August, 2023

On 25th of August, different authorities responsible for the Thalangama and Averihena tanks (Central Environment Authority, Irrigation Department, Kaduwela Municipal Council, Grama Niladhari, Environmental Police, etc.) met at both lakes to discuss lake management challenges related to the lake boundaries, eutrophication, invasive plant species and environmental health. We are looking forward to any follow-up!

Did we miss something?

May, 2023

No, this signboard was only temporarily used for a TV drama shooting at the lake.

Bus service now passing the lake

Every morning and evening a bus service is now operating along the Thalangama lake, driving in the morning from Athurugiriya to Pettah, and in the evening back.

Highway News

April, 2023

The Sunday Times from 9 April 2023, page 14, reports that the CEA’s Environmental Council has suggested that it is appropriate to select an alternative route for the proposed highway that does not cross the Thalangama Environmental Protection Area. The draft Cabinet paper also seeks approval to suspend land acquisition for the proposed highway. There are also five ongoing court cases against this route.


Water-proof photography

March, 2023

The Thalangama lake remains a very popular attraction for wedding and wildlife photography. For the perfect shot, some photographers don’t mind getting wet.

While most wildlife photographers are interested in birds, also sightings of the fishing cat were repeatedly reported in February/March. The picture here shows a rare photo of a water monitor consuming a freshwater turtle.

The green boats house is gone

January, 2023

The green boats ‘house’ was over 20 years a landmark at the Thalangama lake with several boats secured at the wooden piers at its sides. As the boats were, however, often misused, potentially resulting in tragedies, they were eventually removed and parked elsewhere.

According to local sources, the unauthorized shed was erected in 2003 and served as a storage place for those who took care of the lake (Mr. P. J. Bandara G.) till 2011, and was then abandoned and locked. While its roofed porch provided protection against rain, the wooden floor and metal railing required increasingly repair to avoid accidents. As the boats house was setup on the lake it falls legally under the responsibility of the Irrigation Department which ordered now its removal.

For lake visitors who require a boat for environmental or research purposes, the Wetland Watch will continue to offer its boats at the same location.

News on the elevated Highway

The “China Habour Engineering Company Ltd (CHEC)” initially selected for the construction of the proposed four-lane elevated highway from New Kelani Bridge to Athurugiriya (section II through the Thalangama Environmental Protection Area) has notified Highways Minister Bandula Gunawardena that it wishes to swiftly implement the project. www.sundaytimes.lk

Already earlier, the company expressed concerns that it was not keen on only going ahead with Section I as it would not be economically viable without section I. (www.themorning.lk). The highway construction was launched in 2021 but has been in the limelight since its proposal by the Government, as environmentalists as well as residents are vehemently opposed to it, alleging that it will pose severe damage to the remaining green patches of Colombo’s wetland in Thalangama and Averihena. www.hirunews.lk

The annual diya kepeema (water-cutting) ceremony took place at the Thalangama lake

December, 2022

On 18 December, the traditional diya kepeema (water-cutting) ceremony took place at the Thalangama lake. The actual “cutting of water” is done under a canopy so that no outsider can see it.

The ceremony varies from place to place. See also http://kataragama.org or watch www.youtube.com with more information in the text below the video.

Highway costs and cost recovery

October, 2022

The discussion around the elevated highway, passing among others the Thalangama Wetlands, continues:

Elevated highway EIA report: Resettlement costs alone will be a staggering Rs. 38bn

Charges and controversy over multibillion-dollar elevated highway from New Kelani Bridge to Athurugiriya

Latest on the Elevated Highway across the Thalangama Environmental Protection Area:

September, 2022

Automated water level gauge
A second solar-powered measuring device of the water level has been installed in the area (see last month news). This reader has been placed near the water outflow towards the Averihena tank.

Fishing, fishing, fishing.

June to August, 2022

Over the last months, the Thalangama lake saw a steep increase in daily small-scale fishing activities which was not the case over the last 5 or more years and might reflect the increase in food prices.

A new data recording station (15 Aug 2022).

To develop an integrated flood control and water management information system, the Center for Urban Water (CUrW), set up under the Metro Colombo Urban Development Project (MCUDP), installed an automated (solar-powered) monitoring system of the lake water level at the drift (‘shoe bridge’) of the Averihena lake. CUrW currently operate 50 weather stations and 6 water level stations in the larger Colombo area. Information about the project can be found at pub.curwsl.org. All data are freely available to the public in real time. The CUrW is partnering with different Sri Lankan universities.

Following the World Bank supported improved drainage of the Thalangama and Averihena lakes towards the Kelani river (see Recent Construction Work), a massive water level increase at the ‘shoe bridge’ should however be very seldom.

Capturing natural beauty.

March, 2022

The Thalangama lake has always been an ideal place for taking wedding photos and for filming television series or commercials. The Wetland Watch is happy to support renowned photographers like Manoj and Athula Mendis in their creative work of art within the serenity of the lake. At least for once, our boat is not carrying water hyacinths or trash, and hidden in both picture is one of our assistants who is behind the boat in the water to position the boat where and how ever needed.

Photo source: https://www.facebook.com/TwoBrothers1950/

Highway update, Fishing cats and World Wetland Day.

February, 2022

Highway update

The planned elevated highway between the New Kelani Bridge and Athurugiriya which would cross within the Thalangama Environmental Protection Area paddy fields and the Averihena lake was till end of March put on hold till the Government provides the Environmental [and Social] Impact Assessment and shows an alternative site for the construction. The Court of Appeal issued notices on respondents returnable for March 30, which was later extended to mid-May 2022.

Read more here:

Fishing cats

The fishing cat and its two cubs received significant attention by photographers. Thanks to all who came for maintaining distance that this endangered species remains undisturbed.

World Wetlands Day - 2 February 2022

The Wetlands Day was celebrated in the Thalangama area with a call to reconsider the so far envisioned route of the planned elevated highway. See these two articles:

Article - 1: https://ceylontoday.lk
Article - 2: https://ceylontoday.lk

The Thalangama Wetland Watch received media attention, too, although for us every day is a wetland day (see Wetland Watch in the News).

Bad start.

January, 2022

The new year started tragically for a young man who drowned in the Thalangama Lake after celebrating with friends. A bad start also happened to a three-wheeler. In this case, fortunately, injuries were minor although the shock was severe and several police officers got wet.

Highway update
At the increasingly overgrown Averihena lake, new wooden posts were erected by surveyors to mark the corridor of the elevated highway. The latest newspaper article on the planned highway can be found here: www.dailymirror.lk,

Currently, a team from the Kelaniya university is performing an Environmental Impact Assessment (EIA) for the CEA and RDA along the stretch of the planned highway which cuts across the Averihena lake and related paddy fields.

Tires again
Between Nov 2021 and early January 2022, again over 80 tires were illegally dumped in the Averihena lake, bringing the total up to 365 tires at always the same two spots. All have been retrieved for recycling (see: News on our work).

Started removing water hyacinths which were spreading again with heavy monsoon rains.

August, 2021

The heavy Monsoon rains over the last weeks supported our efforts to reduce the vegetation cover on the Thalangama lake which helps to increase water circulation and its quality. For the wind and rains to push the vegetation towards the circular outflow, we cut grass islands into smaller pieces and removed many boats full of deep rooting water lilies and “algae” to support the movement of the vegetation which mostly consists of Salvinia plants. At the same time, another team started removing water hyacinths which were spreading again at the southern end of the lake. The result of the action and the strong rain is that the outflow of the lake towards the Averihana tank is filled with Salvinia and floating grass. Hopefully, some farmers will harvest this biomass which can be composted to become a great organic fertilizer.

Update on the planned elevated highway.

June/July, 2021

The Central Environmental Authority (CEA) has amended the original gazette which declared in 2007 the Thalangama wetland as an Environmentally Protected Area (EPA) to allow the elevated highway to cross the land. Gazette 223/07 dated July 19 and issued by the Minister of Environment has now been published by the Department of Government Printing.

While the Government inaugurated on 7 June 2021 the construction work of the expressway from the new Kelani Bridge to Athurugiriya, the stretch over the protected Thalangama wetlands continues to receive media attention, e.g. by:

In Parliament, MP Dr. Harsha De Silva asked questions related to the finance of the highway.

A petition filed by the Center for Environmental Justice and two Thalangama residents seeking an interim injunction restraining the construction of the expressway will be heard on 17th September. www.colombopage.com

Organic fertilizer in demand.

Due to the Governmental shift to organic fertilizer, we got unexpected assistance in the removal of the salvina plant. Not only the plants we had harvested from the lake, but also fresh plants are now in high demand. The harvested crops are composted and the compost is used e.g. for vegetable farming.

Birder’s season.

March/May, 2021

The lake was over the last months very popular among photographers and birders, with particular interest in nesting birds till the small ones are ready to fledge. For photos see for example www.instagram.com/shard_xposures, www.instagram.com/asiri62, www.instagram.com/malakafonseka, or our page at www.instagram.com/wetlandwatch.

Silent protests around the highway impasse.

January/February, 2021

Our last entry of 2020 was on the proposed elevated highway, and now the first entry of 2021, too.

While according to the CEA chairman the project has been put on hold, parts of the Thalangama community organized a Wetland Day to express their sentiments. The event which attracted about 190 participants including many children was covered by the Daily Mirror, The Morning, and News First.

But also the residents of the alternative highway route which would imply the resettlement of 1,010 families expressed their strong concerns in a separate silent protest in front of the CEA, calling for the highway to better pass over the paddies and Averihena lake. More photos are here.

News on the Elevated Highway from the new Kelani Bridge to Athurugiriya.

December, 2020

The work on the planned 4-lane elevated highway, was paused in 2019 to decide on the best route around or through the Thalangama Environmental Protection Area (EPA) given that one options had significant social impacts and the other raised various environmental concerns (see www.dailynews.lk). This month the feasibility studies continued across the paddies and lake of the EPA. The Survey department started marking farm plots affected, and geo-engineers found bedrock to support the highway pillars at a depth of 6 m. According to the Daily Mirror, the impasse over the protected nature of the area might be solved by removing the protection status from that part of the EPA which will be affected by the highway (see www.dailymirror.lk). In the meantime, the community submitted a petition to His Excellency the President asking him to consider more options to protect this internationally recognized Ramsar wetland.

What do 27 tyres, 250 dead fish and 3000 eggs have in common?

November, 2020

  • In Oct/Nov, we removed 27 used tyres from the Averihena lake. They were dumped over night by a lorry on two separate occasions. We fear there will be more until we catch the lorry.

  • We heard in the News that Covid-19 is affecting fish sales. Here you see what happens to unsold fish (Night 29/30 November, Thalangama lake). At least some water monitors were happy.

  • Since early October, every evening at around 10 pm, plastic bags full with (mostly) eggshells are dumped into the irrigation channel at the small bridge. We do not mind the shells but the shopping bags.

Wildlife news.

October, 2020

Reports from the last weeks included these observations:

  • Four 5-6 feet large Kabaragoyas (water monitors) were spotted at one location where bags full of fish waste were dumped. We left the fish, but collected the plastic.
  • One water monitor was spotted high in the trees on the lake stealing eggs from the Openbill storks (see photos).
  • Two ‘dancing’ males rat snakes were seen, trying to decide who can follow a female snake (see photos).
  • A normally fearsome White-breasted Waterhen was seen jumping into the three-wheeler of a bread seller who sometimes stops at the lake to feed them.
  • After the heavy rains, many more dead snakes and frogs were found on the roads than ever before this year.

The construction at the bridge is now over and the sleuth gate machinery and its electrical connections have been installed and fenced. We are now waiting that the construction camps will close. The material storage areas are already getting cleaned.

Two sad months due to abandoned or killed pets

August/September, 2020

Six puppies were abandoned at the lake during the last two months. Four found a new home, one was killed by another dog, another one by a car before we could rescue them. Also with an abandoned cat we had no luck.

On 13 August, Ricky, our 6-year old, and most faithful Wetland Watch team member passed away. Ricky had joined us over nearly 5 years on the daily trash walks and even helped us to get bottles out of the lake. He died after an unlucky collision with a much stronger motorbike.

Stakeholder meeting on NAQDA proposal

June, 2020

In June 2020, the National Aquaculture Development Authority (NAQDA) proposed a plan for the removal of alien fish species from the lake and the development of coordinated fish/shrimp farming activities, with potential for commercialization. As commercial fish farming would undermine the status of the lake as an officially declared (23/Feb/2007) Environmental Protection Area (where only traditional fishing is allowed), most lake stakeholders did not support the plan. They also noted that for any proposals, all relevant authorities should be consulted as stated in the National Environmental Act #47 of 1980. NAQDA acknowledged the feedback and agreed to consider an alternative location.

A good fisherman is first of all an ecologist.

May, 2020

The two lakes are enjoying a popularity like never before!
While the Covid-19 curfew limited the movements of individuals and families, the Averihena and Thalangama lakes offered a safe haven for recreational evening and weekend walks which was appreciated by many more people than at any time over at least the last 5 years.

New floodgate soon in place.

March, 2020

  • The construction work at the bridge (see Recent construction work) is now well advanced. While neither weekends nor holidays could stop the work, the current Corona curfew finally gave the workers a break.

Stairs into the lake for those who like to swim

New Floodgate to release water before larger rain events
that the lake can absorb more storm water

Reinforcement of the drain connecting the Thalangama and Averihena lakes, to withstand the water
passing the floodgate (see the end of the two tubes on the right).
Photo taken from the bridge

The World Wetlands Day 2020

February, 2020

The World Wetlands Day 2020 was celebrated in Colombo on February 2 and 3. While a major clean-up of 20 wetlands of Colombo was coordinated by the Sri Lanka Land Development Corporation (SLLDC), high-ranking dignitaries met at the Thalangama lake for a tree planting ceremony. The Thalangama Wetland Watch contributed actively to both events.

Wetland Camp

January, 2020

A national wetland camp was held at the Averihena lake in the Thalangama Environmental Protection Area on 17th and 18th January 2020 with the participation of environmental pioneer students. Mr. S Amarasinghe, Chairman, CEA, Mrs. Kanthi de Silva, Deputy Director General EMA division and other officials participated in the event which accompanied the National program of the World Wetlands day.

Source: www.facebook.com


October/November, 2019

  • The Thalangama lake struggled with an invasion of Salvinia, covering at times more than 70 % of the lake’s surface.

  • Salvinia is a free-floating aquatic fern. The floating leaves have dense stiff hairs on the upper surface, whereas the submerged leaves function like a root and serves as nutrient absorbing organ.

After heavy rains, large parts of the Salvinia carpet moved towards the spillover in direction of the smaller Averihena lake. Directly behind the spillover, a “mountain” of Salvinia built up like foam.

To get the plants moving, volunteers tried in different ways to help (see LATEST NEWS ON OUR WORK).

The local construction company pushed the Salvinia further down the channel where it got stuck again, in particular at the entrance of the shallow Averihena lake.

Capacity Development.

July/August, 2019

The Ministry of Education visited the Thalangama lake several times in July to train teachers in water sampling and analysis.

Re-launch of the construction work

The largest impact on the lake will have the construction of a new flood gate near the circular overspill. See here for more details. Once the construction will be over, the area near the overspill will be set up in a family friendly way with stairs into the lake.

The construction work along the lake also brought us a new excellent road cover and vehicles driving with higher speed than ever before. Especially the biker community will be excited but hopefully not endanger other lake visitors, residents, livestock and themselves.

Rajagiriya – Athurugiriya Elevated Highway Project.

May, 2019

The Road Development Authority (RDA) and the Central Environmental Authority (CEA) continue discussing options for the proposed elevated highway which will in one or another way affect the Thalangama wetlands. The challenge is to balance social, economic and environmental impacts.

DailyNews.lk: Impasse over proposed route

See also: http://www.mohsl.gov.lk/

  • It is obvious from the two maps (shown in this update) that the elevated highway will pass the whole upper (paddy field) part of the protection area, independently of the two alternatives near the Averihena lake.
  • The Averihena lake is a reservoir and flood retention area between the Thalangama tank and the Kelani river (more..)
  • The Thalangama wetland area was declared an Environmental Protection Area by Gazette Notification No.: 1487/10 Dated: 2007.03.05.
  • Resources from CEA: Slide | Web
Thalangama Environmental Protected Area
Click to zoom

TV drama shooting at the Lake.

February, 2019

President calls Navy to help paddy farmers getting more water.

January, 2019

One year after the World Bank supported dredging of the Thalangama Lake ended, some farmers further away from the tank are not yet satisfied with the result. In contrast to the World Bank project which followed a broad stakeholder consultation and an environmental impact assessment, before the actual work started, the Navy responded with machinery within days of the call, supported by the Kaduwela Municipal Council. A large number of concerned citizens, including the Thalangama Wetland Watch discussed with the Irrigation Department the need to involve CEA to assist the Navy in a balanced approach which should not harm the internationally recognized flora and fauna of the Environmental Protection Area, and in particular the bird resting places. In a first meeting, the Irrigation Department expressed its interest to use the opportunity of the moment to restore the ancient lake size by dredging the marshland in the back part of the current lake which would however seriously affect wildlife and lake water quality (as the wetland is a natural wastewater treatment system) if not done with buffer zones and clear expert advice. A careful approach is supported by the fact that Colombo just received international accreditation as a “Wetland City” under the Ramsar Convention, with strong support by the President. In this regard, the community responded to the President with a letter.

Update: With regard to the expressed needs by farmers for more irrigation water, CEA, Irrigation Department, and Navy formally met in February to discuss the way forward. The Irrigation Department is currently (March 2019) performing a lake depth survey to prepare a work plan for CEA approval. Once approved, the Navy will return to the lake.

Signboard Explosion at the Thalangama Lake.

January, 2019

There are some signboards at the Thalangama lake with useful information on the environment and good practices for visitors.

Traditional Devil Dancing and Diya-Kepeema ritual.

December, 2018

Tree planting around the lake.

October, 2018

There were recently again much appreciated initiatives of tree planting around the lake. More trees will have multiple benefits aside replacing trees which died or were deliberately cut down.

However, different initiatives apply different techniques and also different levels of post-planting care as the photos show. In the worst cases, planted trees died straight away or where within a few weeks completely covered by climbing weeds. As a result, the planting success rate varies a lot and it would be good if the different initiatives could learn from each other.

Government officials in action.

July, 2018

The search of a knife which was used in a severe crime on the bottom of the Thalangama lake attracted many curiosity seekers, watching divers and police in action.

New signboards were installed by the Irrigation Department, with information about the Thalangama tank and on correct behavior to maintain human and environmental health.

The spillover nearly disappeared under heavy rains in May 2018.

May, 2018

Bad parking.

April & May, 2018

A lot of ‘bad parking’ (poor driving) in April and May 2018

World Bank published a brief.

April, 2018

URBAN WETLANDS MANAGEMENT IN COLOMBO: A new model for urban resilience

"In response to devastating floods, the government of Sri Lanka has prioritized urban wetlands management in the Sri Lankan capital Colombo as a key pillar of its climate and disaster resilience strategy."

More activities in the lake

March, 2018

Lake baptism on March, 25, 2018