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

Thalangama Wetland Watch

Wetland Watch


Removing water hyacinths

April/May, 2024

At least twice each week, water hyacinths are removed from the lake to keep their growth under control.

Repairing the railing of the main bridge

  • On May, 1st, a three-wheeler, driving artistically, crashed into the railing of the main bridge. The collision severely damaged one end pillars which resulted in the collapse of three of the horizontal handrails. We fixed this as good as we could the next day.

  • This was the second time. The photos show one of our previous support structures (with white paint) and the new ones (not yet painted) as well as the repaired concrete pillar.

  • All work like this (repairing benches, dust bins, the bus stop roof, etc.) is - like our cleaning – self-funded by community members.

Cleaning again the Pothuarawa Road

March, 2024

With the assistance of about 15 community members as well as staff and interns of the International Water Management Institute, the Wetland Watch cleaned again the most polluted 150 m of the Pothuarawa Road in the center of the Thalangama Environmental Protection Area. This stretch has paddy fields on both sides of the road and is a favorite place of illegal dumping of waste bags. The same stretch we cleaned with different groups of volunteers also, e.g. in Oct 2022, Sept 2021, June 2018, and Dec 2016.

On 11 March 2024, the Thalangama Wetland Watch received an Award from the Battaramulla Community for 7 years of dedicated community service.

This was followed by an interview published in the Sunday Morning on 24 March 2024.

World Wetlands Day

February, 2024

The Thalangama Wetland Watch was honoured by the visit of Dr. (Mrs.) Ismahane Elouafi, Executive Managing Director of CGIAR, the world’s largest global agricultural innovation network, of which the International Water Management Institute (IWMI) with HQ in Colombo is part. What Dr. Elouafi had to say can be found here.

Three weeks later, Mrs. Temina Lalani-Shariff, CGIAR Regional Director, South Asia and Southeast Asia and the Pacific, and her CGIAR colleague Mrs. Sonal Dsouza, came to the lake while visiting IWMI, and took active part in the removal of water hyacinths.

Our eighth year of operations has started!

January, 2024

The Wetland Watch celebrated its birthday in December 2023. Seven years of daily cleaning activities in and around the Thalangama and Averihena lakes! We are very grateful to all private sponsors who help us financing our casual staff.

The 7th year ended unfortunately with bad news. Someone dumped during daytime 131 bottles of the insecticide Profenophos (500 g/l EC) in the Thalangama Lake. The bottles were not empty and only a few closed with a lid. Profenophos is highly toxic to fish, and moderately toxic to birds and bees. Although we retrieved and removed all bottles within a few hours, the dumping place still smelled of the chemical a week later.

Better news followed when students of the Kelaniya University tennis team supported the removal of water hyacinths from the Thalangama lake. Many thanks!

Removing invasive plants from the Averihena lake

December, 2023

Removing invasive plants from the Averihena lake with the help of over 30 volunteers, mostly from the Colombo International School, Environmental Society (2 Dec 2023). The plants were washed out from the Thalangama lake and got stuck in the Averihena lake. Without joint efforts to remove these, the small lake will soon disappear. Thanks a lot, CIS!

Free organic fertilizer and no demand?

October, 2023

Where are the farmers? Tons of organic fertilizer in the form of Salvinia are ready to collect. After the lake got nearly completely covered by this species, we pushed manually a significant volume of the invasive plant out of the Thalangama lake which created space on the lake for the rain and current to move on its own even more salvinia towards the Averihena lake where it can be easily harvested.

Without large parts of the free floating salvinia plant, the lake shows again its water.

So much rain!

September, 2023

The good side of the endless rain these weeks was that there are only a few folks having parties at the lake and leave their trash behind.

The bad side is that the inflowing streams and channels seem to carry all waste of the community, and we had to clean our mesh barriers every day to avoid that trash will accumulate and break or pass them with the next water wave. For that situation we have fallback barriers further down in form of bamboo strainers.

New wetland field guide out

August, 2023

The Field Ornithological Group of Sri Lanka (FOGSL) launched this August a new Field Guide on the Flora and Fauna of Colombo’s wetlands. The guide has its roots in the biodiversity hotspot of the Thalangama wetlands and includes a nice acknowledgement of our work to preserve the area.

Owner of dumped waste identified

May, 2023

We could again identify the source of some unresponsible waste dumping. There was enough information in the waste bags to locate its owner. He sincerely apologized. As it is common, he had paid a private ‘service provider’ to take care of his waste, and will now confront that person “with our best regards”.

Rejected donations

April, 2023

What the vast majority of lake visitors approves and enjoys, can remain unsupported by others. A sad example were two donations this month by external parties. The Melting Point (www.facebook.com/meltingpointproject) donated with funding by a private sector company six new metal trash bins to replace the broken ones we are operating around the lake. This initiative was supported by the Irrigation Department. The Wetland Watch pledged to empty the bins twice daily as we are also doing so far. Moreover, a private person donated some concrete slaps for benches at the lake where the slap was broken or lost. Surprisingly, both donations were vehemently rejected by a few farmers who are known for their general resistance to change. And maybe related, one bench and bin were forcefully destroyed over night (see photos).

A note: The Wetland Watch is emptying its current bins for two years. They are located at the dirtiest spots where folks meet during day or night. Our initial fear that they attract additional (household) waste was only confirmed on a few occasions, while the daily benefits of the bins for lake visitors, educational purposes, and to ease our trash collection are by far larger and significant.

Identifying the "bad" guys

January, 2023

We hear often the question if our works makes a difference, if we observe a change in behavior, and less trash (dumping) than when we started?

Six years ago, trash was everywhere around and, in the lake, transforming some places into local dumps. It took us months to clean this up. Since then, the amount of fresh waste is decreasing. This includes what we collect from our bins which we empty twice a day. In fact, our bins help to raise awareness. Initially, we feared that the bins will be misused for waste from home, but this remained so far limited. On the other hand, two bins were stolen. Given our daily presence at the lake, we enjoy public support, although sometimes it needs a gentle push or reminder. The challenge comes from those who do not know that our area is conscious about trash and the environment, like those who pass the area after sunset and dump somewhere in the bush or lake large bags of unsorted waste, diapers, construction waste etc. In all these cases we are looking for evidence in the dumped bags to identify the waste source.

This January, for example, twice several large rice bags full of trash were dumped on the same road during nighttime. However, the waste contained enough evidence to trace its owner. The person was contacted and promised to follow up with those who dumped it, and that it will never happen again. The photos show the rice bags we found on the first day, and the evidence (receipts, expired vehicle registrations, ATM slips, utility bills, etc.) carefully extracted from the dumped bags during the second event

Thalangama Wetland Watch celebrates 6 years of daily action

December, 2022

Cleaning Pothuarawa Road

  • Six years ago, on Christmas eve, the Wetland Watch started with a 12-hours clean up of a very dirty stretch where the Pothuarawa Road has on both sides paddy fields (see under 2016 in our activity log). At that time, we were just two folks, and we removed waste dumped over years. Since 2017, we clean that stretch of the road which is cutting through the center of the Thalangama Environmental Protection area all few months.
  • This Christmas eve, 2022, we returned to the same location with a team of eight volunteers, mostly IWMI interns, with the objective to clean the road but also to give special attention to the water pond the road is passing. Here, the team tried to retrieve rice bags and other plastic bags from the water which required us to climb through a ‘jungle’ of trees to reach them. But the volunteers were marvelous and cleaned more than any team before at this difficult and highly polluted spot.

Since late 2016, we are supporting as volunteers about 40 hectare of our natural environment in the southern half of the Thalangama Environmental Protection area, including the Thalangama and Averihena lakes.

Our most visible work is the daily collection of trash along 2 km around the lakes, and control of water hyacinths in the Thalangama wewa. The cleaning is extended by another kilometer once a week and covers - depending on our capacity – also stretches along the Hokandara Road, Pothuarawa Road, and Udawatta Road.

Please see our regular activity updates on this webpage for more information about our work and how you could help.

Students joining hands to clean roads

October, 2022

On 29 October, about 12 students from the Colombo International School (CIS), Environmental Society, one CIS teacher, two students and three teachers from the Overseas School Colombo (OSC), and several supporters of the Thalangama Wetland Watch cleaned over two hours sections along the Pothuarawa, Udawatta, and Hokandara Roads within the Thalangama Environmental Protection Area.

The joint effort resulted in 7.5 cubic meters of removed inorganic trash, which was sorted into different categories of recyclables (glass, PE, other hard plastic, aluminium, and other metals, carton boxes, and remaining waste). The same afternoon, half of the separated bags were collected by the Kaduwela Municipal Council for its recycling centre. The remaining bags will have to wait till the coming week.

We like to express our gratitude to all involved students and other participants for their hard work.

Which brewery has the lion’s share among the beer cans we are collecting?
Guess 😁

August, 2022

Among the 314 aluminum cans collected in the week 21-27 August 2022 in the Thalangama lake area, 91% were produced at the Lion brewery, 7% by Heineken and 2% by others.

Of the 488 beer cans collected over two weeks (14-27 August) every second one (51%) was Lion Strong, followed by Lion Stout (15%) and Carlsberg (12%). Carlsberg is produced at the Lion Brewery under license.

High season of Water Hyacinth removal.

April, 2022

This time of the year, water hyacinths (Eichhornia crassipes) or Japan Jabara (in Sinhala) are appearing all over the lake. Water hyacinth is a noxious aquatic weed, multiplying at a fast speed. To keep the plant under control, the Thalangama Wetland Watch is removing every other day 3-4 boats of the plant from the lake. Farmers and the army collect the biomass from the roadside for composting. Other useful products based on Japan Jabara are described here .

The army and private farmers also collect the salvina plant (Salvinia molesta) from the lake to produce organic fertilizer through composting.

431 and counting.

March, 2022

In March 2022, overnight dumping of vehicle tires started also in the Thalangama lake, in addition to the Averihena one where we are struggling with this activity since long. As the timing, total number of tires, and dumping sites are otherwise always the same, we are sure it is always the same company.

As of 24 March, we retrieved 431 vehicle tires from both lakes, plus 26 from other locations in the Thalangama Environmental Protection Area. Like in the past, we handed all tires over to Rivoga (Pvt) Limited.  Rivoga is specialised in rubber pyrolysis, which converts the tires into a useful liquid fuel.  Our efforts continue to identify the company which is responsible for the dumping that it starts working directly with Rivoga.

Other noteworthy activities aside our normal street and lake cleaning routine were the identification and visit of two other larger polluters, who are leaving bags of trash in the area. One was a kitchen on wheels and the other a household which misused our dust bin for a house cleaning. Both parties promised that it will not happen again.

Finally, the CEA visited us for a walk around the lake to better understand its most recent environmental challenges.

Road cleaning.

January, 2022

Like every 1-2 months, we cleaned those sections of the Pothuarawa and Udawatta roads which are within the Thalangama Environmental protection Area. The photos from the Udawatta Road show Before and After our interventions. Also new signboards have been installed to visualize that the community cares about its environment. A CCTV camera (host) is still needed.

The tires are back.

December, 2021

During two nights in Nov and Dec 2021, again about 80 tires were dumped in the Averihena lake and the channel to the Thalangama lake. We retrieved all and handed most of them over to Rivoga Ltd which is recycling rubber into energy. The new dumping brings the total up to 365 tires, likely from the same source, while we also retrieved from other parts of the wetlands in total 12 tires over the last year, which were dumped by other individuals. Our CCTV cameras are helping us to close in on just a few vehicles which might be involved in these illegal activities.

Celebrating 5 years and over 1000 cubic meters of collected waste.

October/November, 2021

  • The Thalangama Wetland Watch started in late 2016 as a voluntary (non-profit) community initiative, and can now look back on 5 years of daily activities, across the CEA designated Thalangama Environmental Protection Area with a focus on the Thalangama and Avarihena lakes.
  • Activities include the removal of invasive water plants and all types of non-biodegradable waste from the area including 4 km of surrounding streets, of which about 2 km are cleaned twice daily, 365 days a year.
  • All collected waste is sorted to facilitate recycling in the Kaduwela Recycling Center or Rivoga (Pvt) Limited for tires and rubber slippers. The cleaning activities are accompanied by awareness creation on the value of wetlands and good waste management.
  • After 5 years, we passed the 1000 cubic meter threshold of collected rubbish; not counting organic waste (which we let rot), removed construction waste, dead animals (see below), or the so far 277 (!) vehicle tires which were dumped over just ten nights during the last 15 months in the Averihena lake and the canal connecting it with the Thalangama lake.
  • We like to express our gratitude to our nature-loving community members who enable us through their regular donations to pay our casual labour force who do the really hard, always dirty, and often also dangerous work.

Sorting the weekly collection

Collected waste, 8-14 Nov 2021

What we normally do not report are our efforts to remove or bury road kill and other (dumped) dead animals (see photos), as well as the not easy task to find a home for abandoned cats and dogs.

Cleaning activities on land and water.

September, 2021

We removed about 50 boat loads of water hyacinths from the lake, as well as young Wel Atha trees. Due to the fertilizer shortage all water hyacinths were within a few days removed by farmers for composting.

We also cleaned the upper and lower ends (see red circles on the map) of the Thalangama Environmental Protection area, and the central stretch along the Pothuarawa Road, in addition to our daily cleaning area (blue circle).

We can also report that our dust bins are well used and only occasionally (see photo) we find there more waste than we had in mind.


August, 2021

In August, we continued during the Covid-19 lockdown our daily cleaning activities around the lake and the removal of plants from the lake. We also engaged in some modest landscaping activities:

    • We recovered and restored a lost concrete bench, and removed from the lake a well-preserved bench-top which we placed back on its legs. There are still more bench-tops missing.
    • We installed more of our green dustbins.
    • We ‘found’ in a lake corner a ‘secret garden’ with a stairway into an overgrown public well (bathing place) and an oral history of about 90 years (see Lake History). Unfortunately, some neighbors had used the place and pond over the years as rubbish dump, especially for broken window screens. The garden has now been cleaned, some of the vegetation trimmed, and fenced. We are also removing mud from the pond. As the garden is a ‘refuge’ for various animals, we do not want to clear more vegetation than necessary for entering the pond.

Cleaning along the Pothuarawa Road.

July, 2021

On 18 July, about 15 volunteers cleaned the part of the Pothuarawa Road which cuts through the center of the protected Thalangama wetland area. Along this stretch of the road, paddy fields are on both sides and a hot spot for illegal waste dumping. The waste was sorted at the road site and the same day collected by the Kaduwela waste management service. Many thanks to all involved!

Reducing the vegetation cover

Our work to reduce the vegetation cover on the main lake worked out (see previous update). With the help of strong rains and wind, the size of our created ‘lake within a lake’ has tripled. The grass and salvinia plants were washed towards the Averihena lake and Kelani river. However, what might save the Thalangama lake from eutrophication was not appreciated by those who harvest lotus leaves and flowers in the Averihena lake and see the incoming salvinia as strong competitor for their lotus plants. Fortunately, there is now an unexpected ‘run’ on salvinia (see News from the Lake, July 2021).

A growing lake within a lake.

March/May, 2021

In previous years, the monsoon rains were able to wash parts of the floating salvinia and grass vegetation on the Thalangama lake over the spillway at the main bridge direction Averihena lake and ultimately the Kelani river and ocean. This year the vegetation cover on the lake is too vast and interwoven with too many lotus leaves for this to happen. While the covered lake might look picturesque, the dynamic of dying and growing biomass takes its toll on the lake’s oxygen levels (eutrophication) which are rather low (DO around 3 mg/l). Water movement is limited, fish swim close to the surface or die. Of about 60 released Tilapia (by a private breeder) at least half were dead the next morning. The Thalangama Wetland Watch is continuously removing water hyacinths, salvinia and grass from the lake, cutting water and wind passages through areas which are at danger of a permanent grass cover, and started in May creating a ‘lake within the lake’ as the panorama picture shows. The removal of the plants growing above and below the water surface was done manually and continues as far as tank depth allows (i.e. our team can walk in the lake). We also cut grass islands into smaller units which the heavy rains on 3rd June were able to wash off the lake in direction of the smaller Averihena tank and Kelani river.

Tire problems – Tire solutions.

January/February, 2021

  • As a follow-up to the Dec 2020 update, we regret to report that also this year the dumping of car tires continued. Between 22 October 2020 and 20 Feb 2021, we retrieved 207 tires from a stretch of just 300 meters, in and near the Averihena lake. We hope the community-sponsored cctv camera will soon give us an identification.
  • The good news is that first a private farm and then also the company Rivoga (Pvt) Limited kindly agreed to take care of all tires for environmentally friendly reuse. Rivoga is specialized in transforming rubber through pyrolysis into liquid fuel.
  • Our target is to connect the firm dumping the tires with Rivoga.

Celebrating 4 years of community service.

December, 2020

The Wetland Watch started in late 2016, and can now look back at 4 years of hard work, strong community support and acknowledgement. A few highlights:

  • We are now 5 teams covering different parts of the Environmental Protection Area around the Thalangama and Avarihena lakes.
  • We are watching over the lake surface as well as about 4 km of surrounding streets, of which about 2 km are cleaned twice daily.
  • We are continuously seeking the dialog with lake visitors (especially those eating or drinking at the lake) to create awareness on the value of the wetland and the need to work together to protect it and keep it clean. In this way, we have an annual outreach to about 700 individuals, groups or families.
  • Although the lake area became very popular in 2020 as many other recreational sites were under Covid-19 lockdown, the amount of littering and household waste dumping in the night decreased.
  • Our current estimate is that we are collecting over the year about 110 cubic meter of waste; not counting biodegradable waste, construction waste, dead or live animals, or irregularly dumped materials, like those over 100 vehicle tires we ‘received’ during just five nights this year.
  • As before, we remain fully self-financed and nearly 100% of the collected waste is being sorted and handed over to the Kaduwela waste department for resource recovery and reuse. The exception are tires which Kaduwela does not accept.

Photo: C. Sivaneswaran

Tires remain a big challenge: Help needed

During only one night 42 used tires were dumped into the canal between the Thalangama and Averihena lakes. The was the third time within two months. The tires are beyond repair and all our efforts to find a solution/reuse/storage for them failed so far.

Assistance would be much appreciated. The CEA and Irrigation Departments have also be informed after in the night 29/30 Dec we received another batch of at least 35 used tires.

Supporting water flow and oxygen levels.

November, 2020

Large parts of the Thalangama lake are again covered by vegetation. Especially along the lake’s shore ‘carpets’ of salvinia and grass are getting denser and larger. The heavy rains were not able to cut into these carpets to move the plants towards the spill over in direction of the Averihena lake and ultimately the Kelani river and ocean. Decaying salvinia biomass, increased water turbidity and loss of water movement are depleting the lake’s already low oxygen level which is affecting fish. On the other hand, some birds love the grass islands and nest on them.

To make one of the larger carpets movable, and allow the water to flow, we separated it manually from the shore and cut it into a few units, creating what looks like a small “Dutch polder landscape” although our ‘land’ areas are still swimming.

Stopping the Dumping of Construction Waste.

October, 2020

Being located in a quickly urbanizing area, construction waste is a huge concern.

In the southern (marshy) part of the Thalangama lake area we observed the dumping of construction waste on an area of about one acre. The waste included plastics etc. which the wind could blow into the protected area and the lake.

After talking to the land owner, he reacted instantly and within a few hours we could hardly recognize the place. He also installed a barrier preventing trucks from entering.

It is good to see that some community members take environmental protection seriously. Many thanks.

Below are three more examples of what was dumped over the last few weeks directly at the lake, and where we actually saw the vehicles and could record the number plates (see photos):

  1. The driver of the white truck started dumping construction waste and was stopped by community members. He re-collected the material but ‘lost’ again parts on his departure. The driver was reported to the environmental police.
  2. Another truck unloaded a CEB pole at the road side into the bush (not the first one at that place!) telling us that they will remove it tomorrow morning when work starts again. Two week later we were still trying to figure out which ‘tomorrow’ the driver referred to.
  3. Another community member filmed a car driver dumping several tires in the bush. We removed the tires, identified and informed the car owner, and belief it will not happen again.

Donating Trash Bins and a new Roof.

September, 2020

We reinstalled a roof on the ‘bus stop’ at the main bridge to provide visitors with some shelter against rain, and installed three green barrel-based trash bins at hot spots of food, beverage and alcohol consumption. The bins are being monitored and emptied daily by our volunteers. They are for now an experiment as similar bins attracted in the past household waste in unmanageable dimensions.

We cleaned several drains along and under streets to prevent stagnant water and dengue.

School Children to Join Our Experienced Volunteers.

July, 2020

In July, we started inviting school children to join our experienced volunteers for Friday afternoon boat trips on the lake where they assist us in removing floating trash and water hyacinths from the water while learning about nature, biodiversity and the need to protect our environment.

Cleaning the Southern end of the Thalangama Wetland at Hokandara Road.

June, 2020

The Thalangama wetland end at Hokandara road remains an environmental eyesore. The photo shows Neil Burke separating organic from inorganic waste dumped near the bridge with the Thalangama lake in the background.

After serving the lake for 3.5 years, Neil Burke resigned for health reasons from his voluntary community service in July 2020. We are grateful for his dedicated service cleaning the streets every morning and evening during good and bad weather.

Our water hyacinth removal activities moved now into those back ends of the lake where the invasive plant continues to grow through seed and vegetative reproduction, till daughter plants are broken off by wind, rain or passing water buffaloes, starting their journey to conquer the lake. As the plant reproduces quickly, 10 initial plants can multiply to over 600 within 3 months. Lakes that are overrun by living and decaying water hyacinths get depleted of dissolved oxygen leading to fish death.

Water Hyacinths Control Continues.

May, 2020

Cleaning the lake area from litter continued throughout the curfew. In late May, we also started again the removal of invasive water hyacinths. Since a few years now, water hyacinths are under full control on the Thalangama lake.

In Times of Covid-19

March, 2020

The curfew in the Colombo area due to the Corona virus has also some positive aspects. The amount of trash we normally collect around the lake is now minimal. However, as households are unsure about the waste collection these days (it is working like always!), some dump especially their organic waste into the bush, unfortunately always packed in a variety of plastic bags. After checking with the Thalangama Police, our chief volunteer Neil continues collecting waste around our two lakes on a daily basis. He is keeping social distance and wearing our new shirts, donated by Mr Ravi Botejue from www.bernardsceylon.com.

Ministry of Defense Road

January, 2020

  • With the opening of Sri Lanka’s new Army Headquarters in Akuregoda, 08.11.2019, the army also accepted responsibility for maintaining the Military of Defence road. In a significant effort, water bodies were dredged, trees planted, and unused land transformed into paddy fields.

    In the news:

  • The Thalangama Wetland Watch accompanied these activities in December and January by cleaning the road sides and water ways from trash, discussing with the officers that without addressing the waste problem, the beautification will not be sustainable.

Pollution at Ministry of Defence Road

Cleaning the water bodies

Another full boat to be emptied. No 6 on that Saturday in January 2020. All trash was brought to our sorting station and handed over (well sorted into PE, metal, glass, etc.) to the trucks of the Kaduwela Municipal Council

Cleaning land and streets around the water bodies

During the cleaning, we encouraged successfully local residents to join our activities. There is a significant willingness to support a clean environment; it only seems to need a lead or trigger. After handing over a clean lake, we discussed the need that they have to join hands to keep it the lake this way, and that the Thalangama Wetland Watch will be happy to assist e.g. with its boats


October/November, 2019

  • Different teams of Wetland Watch volunteers tried to address the “Salvinia” invasion in the Thalangama and Averihena lakes (see NEWS FROM THE LAKE). The challenge is that the Salvinia plant is very small, and difficult to harvest, even with many volunteers and nets. This is a very different situation than for Water Hyacinths which we continue to control successfully through manual harvesting.

  • The teams tried to create for example a passage through the ‘carpet’ of plants to facilitate its transport out of the area (see photos). The exercise was at least a good team building event and allowed brainstorming about options for mechanical and biological plant control (see also www.fao.org)

Another team, led by Neil, tried to support the flow over the spill-over (see video clip).

Youth engagement: Street cleaning along Battaramulla’s wetlands.

July/August, 2019

The Thalangama Wetland Watch supported the efforts of the Sri Indrajothi Vidyalaya School in Battaramulla, Sri Lanka, to carry out a street clean-up on July 24, 2019.

The event was co-facilitated with much enthusiasm by Chandra Athulathmudali from the Sri Lanka Association for Friendly Environmental Naturalists. About 25 students between 10 and 14 years old collected over 3 hours 126 glass bottles, 287 PE bottles and other plastic hardware, 197 beer cans and other metal items, and 5.5 cubic meters of other waste along the Ministry of Defence Road starting behind the bridge opposite Sri Lanka's Central Environmental Authority till the bus stop 700 m down the road.

This four-lane road without housing is developing into a dumping ground of waste bags. As every existing bag seems to attract more, the efforts of the students geared at the restoration of the natural environment.

Part of the program, which was also attended by some teachers included creating more awareness about waste separation, which is now mandatory in the country. The Wetland Watch team included the 700 meter stretch in its monthly cleaning program (see Feb/March 2019 news update).

Post-Vesak cleaning

June, 2019

After the Vesak festival in May, a particular type of ‘waste’ was added to our normal routine.

No easy job.

30 months plastic waste free!

April/May, 2019

  • Time flies. For 30 months now, our adopted lakes and paddy fields and the 3.8 km of streets surrounding them are plastic waste free! In fact, they are also free of any other type of waste due to our regular (means daily 50%, weekly 25%, monthly 25% of the roads) cleaning routine. As we are tracing and confronting larger polluters and always seeking a dialog with lake visitors from fishermen to picnickers, we also observe an increasing level of environmental awareness and cooperation, which helps our efforts.
  • We continued over the last two months the cleaning of the Military of Defense road (see previous update for a map) and the removal of water hyacinths from the Thalangama lake. Otherwise just routine work.

A new environmental menace is the burning of banners (from particular real estate companies). This leaves a large amount of metal wires behind. The banners are regularly delivered by a black Tata lorry with the number plate DAG 3657.

With volunteers from Sri Lanka, India, UK, Germany and Holland.

February/March, 2019

With volunteers from Sri Lanka, India, UK, Germany and Holland we cleaned over three days a 700 m stretch along both sides of the Ministry of Defense Road leading from CEA towards the new Army HQ. The cleaning included roadsides and the water bodies running parallel to the road. We did, however, not address the first 50m opposite Central Environmental Authority (CEA) till the first bridge as this needs a special effort by the Sri Lanka Land Reclamation & Development Corporation (SLLRDC) and local market traders.

Waste from one of the three days of collection, before sorting into resources

Another effort in February went into the creation of passages through the water plants in support of water movement also into cut-off areas of the lake (front of photo) where bird droppings are highest and water oxygen levels decreasing.

Removing Water Hyacinths.

January/February, 2019

These weeks we are harvesting again Water Hyacinths to keep the population of this invasive species under control. The harvested plants are used by farmers as a bio-fertilizer. We are supported by volunteers from Sri Lanka, Germany, India and the Netherlands to clean the lake area in those shallow parts where we find most of the plants, but also from plastics which entered the lake in areas we can not control from the street.

Thalangama Wetland Watch is now two years active!

November/December, 2018

Our work in numbers:

  • In total, we are monitoring about 3.8 km of roads and footpaths within the protection area, or 80 acres (33 ha) of paddy, woodlots and lake surface, and hope to expand this in 2019 also to Hokandara road.
  • Over 6 months in 2018, we harvested more than 260 boat loads of water hyacinths on the Thalangama lake and are since then regularly inspecting the lake surface to prevent a new hyacinth invasion.
  • 100% of the collected water hyacinths were taken over by farmers to fertilize their soils.
  • Since we started two years ago, we collect every day at least one full 90-liter bag of trash at the Thalangama lake, which accumulates till now to about 60-70 cubic meters of trash. In addition we collected since we started about 20 cubic meters of trash at the Averihena lake, and about 25-30 cubic meters of purposely dumped waste along the paddies and irrigation channels at the Pothuarawa and Udawatta roads.
  • Based on the analysis from selected weeks, a rough estimate is that over the last two years we removed from the 3.8 km we are monitoring :
      • 8400 beer cans and other metal pieces (on average about 80 per week)
      • 18400 plastic bottles and other hard plastic pieces (ca. 170 per week)
      • 15800 glass bottles (ca. 150 per week), and
      • 80 cubic meters of plastic sheets, paper and other waste (about 8.5 full 90-litre bags)
  • 100% of the collected waste is being sorted and handed over to the authorities for resource recovery and reuse.
  • Our daily efforts include educating lake visitors and identifying larger recurrent polluters to confront them (so far 8 individuals and companies).
  • We will continue working with volunteers and students, and are grateful to all community members who are supporting our self-funded efforts!

Joint cleaning with IWMI’s Welfare Society.

Click to zoom

With strong support and engagement from the Welfare & Recreation Society of the International Water Management Institute (IWMI) about 25 volunteers cleaned on Dec 1st, the streets, irrigation canals and paddy fields around some of the most dirty stretches of the Pothuarawa and Udawatta Roads. On just less than 1000 meter of water ways and roads about 25 volunteers collected over 3 hours;

  • 280 beer cans and other metal pieces
  • 614 plastic bottles and other hard plastic
  • 526 glass bottles, and
  • ca. 3.0 cubic meter of other mixed waste (plastic sheets, etc.).

The collected waste was sorted and handed over to the waste management authority the same day.

Many different events and developments kept us busy the last weeks.

September/October, 2018

As an update to our August News on our ‘detective’ work, we can now confirm that we found at four different times the same names in those big black bags which are regularly dumped at the same place near the lake with always the same waste assortment. We also have phone numbers and hope we can soon locate this family to discuss environmental responsibility.

At nearly the same place near the lake, another polluter got busted early October. When the municipal waste cars do not come when expected, private waste contractors offer relief. In this case, one of the Cargills Food City stores in Battaramulla paid a private contractor to accept more than ten bags of food waste. The contractor then dumped his load of expired fruits and vegetables after sunset next to our lake. The load also included two bags full of Cargills cash register receipts, all from the same shop, allowing us to follow up. The store manager confronted the contractor and two days later (again over night) the waste was removed. We wonder where it might be now, and will soon visit the contractor to express our concerns. But thanks to Cargills for taking this issue serious! Such contractors should be blacklisted across all food stores.

IWMI affiliated students did again a great job by cleaning the Avarihena Lake area, Pottuarawa Road, Pelawatte Junction, and the irrigation channels between the Thalangama Lake and the Pottuarawa Road. The channel got recently desludged and with the mud a lot of trash surfaced.

We also started using our new inflatable kayak to reach trash along the shore from the water side.

With the tractor of the waste authorities broken down, the collected waste accumulated at our resource sorting station.

Some wildlife updates:

In the last two months we found two dead monitors, one at the Thalangama lake, the other in the Averihena lake. We buried both animals. As reported previously, we find all kind of dead animals (porcupines, monkeys, cats, rats, etc.) in dumped waste, usually packed in plastic bags. Taking care of their bodies is part of the job we accepted. On the other hand, we are happy when we see species we did not observe at the lake previously, like recently (4 Oct 2018, 21:30 pm) the Fishing Cat.

Photo of the Fishing Cat, by www.wwct.org

A glimpse at our daily detective work

August, 2018

We are not only sorting all waste we find but also trying to identify its source, i.e. the people who dumped it. For this all waste gets checked for any hints, like letters, pay slips, bills, etc. and we have a register of names, phone numbers, photos, number plates, etc. However, unless names appear again and again, or we have witnesses, we are very careful with approaching anyone. We also tried reporting offenders, but realized that our authorities are probably too busy to follow up. But we do it, and we ‘busted’ so far 6 offenders from private persons to companies. A current severe case, which makes us much headache, is described below:

On the Google map, you see four yellow circles which show where this particular polluter mostly dumps his/her waste all 5-6 days in two larger black waste bags. Dumping occurs in the late evening. We find then in the morning the bags in the water beyond the weir (sluice gate) or in the drain of the following side street. What we know from analyzing the waste:

It started about 5 weeks back. So we assume the person(s) moved within the last 2 months to our area, probably living along the Northern or Eastern part of Lake Road. It is a wealthy person or couple with maybe one child, able to shop with few exceptions very regularly at SPAR, with weekly stops at Pizza Hut, Red Orchid and Lavinia bakery. They have at least one larger beige dog (we found much dog hair), eating Pedigree dry food, probably living in-house as the waste always contains significant amounts of (big) dog poo, accompanied by local English language newspapers soaked in Ammoniac (heavy smell), dog urine? The other part of the waste is unsorted kitchen waste (organic rests, coconuts, dish wash bottles, mosquito sprays, dog shampoos, large sanitizer bottles, plastic bags, milk drinks,..…).

Analyzed waste..
With few exceptions, there are no cans, glass bottles or soft drink PE bottles, which implies that the family manages these separately.

We found similar bags recently in another location at the lake, with the same (urine soaked) newspaper, and this included a high society private wedding invitation. So we have a possible name now and know from third parties that these people moved recently into our area, although we do not have their address and 100% proof yet. Thus, before we contact anyone, we have more detective work to do…

Why is a wealthy and probably well-educated family which puts much efforts into ‘cleaning’ within its premises not able to manage its kitchen and dog waste? Or maybe it is their house help (domestic worker) who acts of his/her own accord?

Activities in July: With strong assistance

July, 2018

On 7 and 14 July, we cleaned with the assistance of more than ten students from Horizon Campus, Malabe, as well as some interns and staff from the International Water Management Institute (IWMI), the shoreline, slopes and streets around the Pelawatte lake (Diyawanna Gardens side) and plastic waste which had accumulated in the small tank next to Hemas Hospital (both at the Battaramulla - Pannipitiya Road). The students worked with much dedication, receiving instant appreciations by the local community. A Horizon core team returned on the second weekend to help us cleaning different sections of the Thalangama Environmental Protection Area, starting with the irrigation canals between the Thalangama lake and Pothuarawa Road, the road itself between the paddy fields, and a highly polluted stretch along the Udawatta Road.

Activities in June

June, 2018

The setup of more poles in the Thalangama lake
as resting place for birds.
Photo credit: Sam Vincent


The creation of corridors for free water flow where dense algae infestations
resulted in stagnant water zones.

The cleaning of trash hot spots along the paddy fields
at the Pothuarawa and Udawatha roads. For this
task we need help and ideas on how to prevent
the never-ending over-night trash
dumping at scale.


The installation of debris barriers (meshes) in road drains where
regularly trash is washed into the lake, taking care that
they do not hurt water monitors or prevent
them from passing the barrier.


Struggling with waste dumped at Udawatta Road.

The Water Hyacinth invasion has been successfully stopped

May, 2018

With the help of many volunteers and our staff (Neill and Ravi), we removed since February over many weekends from the lake more than 260 boat loads of hyacinths. For our progression see in particular the March 2018 update. Most of the collected plants have been taken over by farmers to fertilize their soils, the remaining plants we still have to remove from the lake shore.

The green/yellow color on the map shows the lake area where water hyacinths are now under control (status 4 June 2018). The blue spots are areas which still need some final touches. We will give from now on more attention to other invasive plants.

Working hand-in-hand with the Irrigation Department

Our water hyacinth campaign got support from the Irrigation Department. We also inspired some local farmers who are now harvesting water hyacinths on their own to decompose them on their fields.

The challenge of invasive plant species has also been recognized by the Government. Five weed harvesters have been purchased. However, there are too many tanks in Sri Lanka to wait for these machines in Thalangama.

Animals in the dumped trash around the lake

So far we found dead cats, rats, a monkey, a porcupine, a turtle, different types of fish, … you name it. If we can, we bury them and that is it. But what to do with living animals?.

How many hyacinths can a boat carry?

March, 2018

Removing the plants from the lake is the first job. The second job is to empty the boats, and the third the transport of the plants to their destination, here a neighboring tree plantation which receive about 20 cubic meters of fresh hyacinths which are an excellent fertilizer.

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Snapshots from 31 March 2018

The Thalangama Wetland Watch received strong support from the Rotaract Club
of Colombo in cleaning our wetlands from trash and water hyacinths.

Spontaneous community protest helped to prevent illegal dumping of
construction waste in our paddy fields.

Fighting Water Hyacinths.

February, 2018

February 2018 started with emphasis on the quickly spreading water hyacinths on the Thalangama lake. With active support from the CEA and its staff, and endorsed by the Irrigation Department, a group of local residents and interns from the International Water Management Institute (IWMI) started on 10th of February the removal, an activity that is labor-intensive and will continue over many of the coming weekends, depending on the availability of volunteers.

The water hyacinth is an invasive alien species and one of the worst aquatic weeds in the world, able to cover whole lakes within a few months. Native to Brazil and other South American countries, the plant was introduced in Sri Lanka in 1905 as an ornamental plant from Hong Kong. The recent dredging of the Thalangama lake brought many nutrients from the sediment back into the water which supports the growth of the weed. With increasing surface coverage, the plant can easily overtake the habitat of native plants, lower the oxygen levels in the water and kill fish. The Thalangama lake has already very low dissolved oxygen levels between 1 to 4 mg/l (compared with a minimum threshold of 3 mg/l) which does no longer support most species of fish. Please help us getting this weed under control.

17/18 February – 2nd weekend tackling water hyacinths.
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Collecting several truckloads of hyacinths for composting.
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On the third weekend, the impact of the work became visible. Several “islands” of water hyacinths are gone..

Fourth February weekend addressing Water hyacinths and Salvinia (watermoss)

Special attention to the Averihena Wewa, 14-21 January.

January, 2018

To support the flow of flood water from the Thalangama tank to the Averihena tank, and from there towards the Kelani river, the outflow of the Averihena tank currently undergoes rehabilitation work to improve bank protection towards the Athurugiriya Road. Our attention focused on the stretch from the lake to the Amaragoda Road (see map).

With kind support from lake neighbors and the local construction company, a boat and raft could be used. In total, 10 members of the local community, four IWMI staff/interns, and several members of the Wetland Watch core group supported the activities. The focus was on the lake itself, its outflow (canal) towards the Amaragoda Road, local tributaries, as well as the new road along the canal where large amounts of mud (mixed with trash) are deposited from canal dredging.

Cleaning the lake with kind support of participants.
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Cleaning the lake with kind support of participants.
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Between 14 and 21 January, about 95% of all visible waste was removed resulting in approximately 60 bags with cans, bottles, styrofoam (regifoam), buckets, plastic bags of all sizes, flip-flops, etc. Waste transport was supported by IWMI. One part of the waste was sorted into different recyclables straight away and handed over to the local waste management service, the rest will be sorted over the coming days.

Collected trash..

The trash cleaning along the outflow of the Averihena lake continues every week by local residents with increasing emphasis on tributaries from local settlements. Bamboo barriers are now planned to stop floating trash and simplify its collection.

Cleaning the less accessible parts of the lake..

December, 2017

Cleaning the less accessible parts of the lake with in-kind support of the small boat house.

…while struggling with the regular dumping of larger bags full with diapers in the road-side canal along the lower Udawatta Road, branching off Pothuarawa Road. Water-soaked diapers are extremely difficult to manage.

Celebrating one year of Wetland Watch..!

November, 2017

Working hand in hand with the authorities.

We are celebrating one year of Wetland Watch! Since Nov 2016, our two lakes are – as far as possible - ‘free of plastic and other waste’ and also more than 3 km of the surrounding environmental protection area are regularly monitored and cleaned. Especially in our core area along the two lakes, no new waste gets older than a day. We are proud as this was possible without any external funding, following the motto “If it is to be, it is up to me”.

We are removing - on average - one 90-liter bag of trash per day, generated by lake visitors who enjoy the serenity but unfortunately ‘forget’ their trash of which volume-wise half consists of recyclables (like beer cans, paper, glass and PE bottles). We counted more than 120 glass bottles over three weeks of collection just around the lake. There should be a cash refund also on smaller Arak bottles! In addition, there are every second week a few large bags of diverse waste materials from small industries, shops or households dumped deliberately in drains or the bush, usually after sunset. Also these materials are sorted to recover recyclable resources but also screened for anything which could lead to their source.

Recovered resources from one week of collection.

Looking back at our first year, we like to thank our main partner, the local authority in charge of waste collection, as well as all those who contribute to Neill’s allowance for his daily cleaning job, as well as the about 100 local residents and visitors who regularly express their appreciation for the work.

Looking forward, more educational efforts are needed, and for the sustainability of our work, we need more active members to share tasks and responsibilities. Our main collectors are already over 55 years old; younger volunteers are welcome!

Another success of tracing polluters.

October, 2017

Dumped and again removed waste.

October started with another success of tracing polluters. Just next to the main recreational spot at the Thalangama lake, a truckload of construction waste was dumped overnight (see photo). Fortunately, the pile contained clear evidence leading us to its source, and the responsible estate developer apologized and removed the pile within 24 hours.

Waste that can kill..

A different challenge was observed at Udawatta Road where a so far unknown hairdresser dumped several bags of saloon waste which did not only contain large piles of human hair, small cosmetic bottles etc., but also many razor blades. These blades are not only a threat to anyone removing the waste, but like plastic bags also to our roaming cows which are magically attracted by any waste pile.

Extending the drain cleaning on Parliament Road.

September, 2017

Drain cleaning area
(stretch between the two yellow pins)

On 9th and 10th September, the team extended its cleaning efforts along Parliament Road (see July 2017) to cover now 370 m of the main drain from Pelawatte junction beyond the Ministry of City Planning and Water Supply. This part of the drain is less suffering from indiscriminate dumping, but accumulates in particular plastics washed by storm water towards Parliament lake. Especially the plants in the drain function like a "bar screen" for floating plastics. Again, this was a ‘special action’ aside the routine monitoring and cleaning of the Thalangama lake area.

Lower drain section with "natural plastic screen"

Middle stretch at the ministry

Preventing waste to reach the Diyawanna lake.

July, 2017

With the growing waste problem interlinked with the outbreak of dengue fever in Sri Lanka, a team of volunteers (including several IWMI staff) supported by local community members, did a clean-up of the dirtiest 150m of the drain opposite IWMI-HQ, from Pelawatte junction towards the Ministry of City Planning and Water Supply. Several hours of cleaning was done on July 15 and on July 22, the vegetation was cut, several cubic meter of trash collected, sorted (PE, metal, glass, etc.) and handed over to the authorities. Residents in the locality expressed their sincere appreciation and praised it as a positive example. Cleaning is now being repeated every other weekend.

Udawatta Road, along the Thalangama Environmental Protection Area.

March, 2017

Along the early parts of Udawatta Road (starting from Pothuarawa Road direction Malabe), folks start dumping larger bags of trash on both sites of the road: On the left side of the road under some trees bordering the Thalangama paddy fields and on the right side of the road into the drain which supplies the paddy with irrigation water. As a result, water quality and flow decreased, plants took over, and residents complained about the increasing mosquito numbers. With support of the local waste management department supervised by the Environmental police, dumping place and drain were cleared over two days of hard work. Since then, about 350 m along both sides of the street without housing are cleaned by us once a week. The drain is now flowing again, signboards were erected, and local residents reported less mosquitos. However, the area remains difficult to monitor as parts of the road are hidden between trees and illegal dumping continues. As this is the most Northern part of the area we adopted for cleaning, it would be ideal if another team of residents living closer to the street could adopt this stretch along the Thalangama Environmental Protection Area.


December, 2016

Illegally dumped waste

As a special holiday action, several cubic meters of waste were collected on Christmas eve (24th December 2016) on just 140 meter of the Pothuarawa Road where it is crossing the Thalangama paddy fields between Battaramulla and Malabe. As there are no residential plots on both sides of the road, many folks used the area including its water bodies for illegal waste dumping of usually larger mixed waste bags, construction waste, old TVs, etc. The Wetland Watch team worked 12 hours on these 140 meters to collect the waste, sort it into recyclables and remove it. Passing cars supported the efforts by donating drinks and food. We also fenced parts of the road where most waste was dumped and installed a series of signboards against illegal dumping. Since this action in December, the road over the paddy fields is regularly serviced by us to prevent any new waste accumulation.

Collected waste

Half of the collected recyclables
mostly PE & glass bottles)

The beginning.

September to December, 2016

Weekly collection of trash around the Thalangama lake started in late 2016 as a family activity. Involving our children in the cleaning efforts gave opportunity to give them some fresh air, as well as for environmental education, from water pollution to plastic recycling, or on the sense of community service. And the amounts of collected waste over just a few hours were every time astonishing and a real achievement as the photos show.

Realizing that weekly efforts would not be sufficient to keep the area clean, our efforts became more serious in December when Mr. Neill Burke joined the initiative as full-time assistant, supported financially by about ten community members. At the same time, also the collaboration with the official waste collection operators intensified and the sorted waste gets since then regularly removed from our collection points.

Collected waste