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

Thalangama Wetland Watch

Wetland Watch



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