Wetland ecosystem services in the Kalu Oya basin, Sri Lanka

Context

This project focuses on wetland ecosystem modelling and economic valuation in the Kalu Oya and Mudun Ela basins in Sri Lanka. These areas are highly urbanised and prone to flooding due to rapid land use change, sea level rise and enhanced climate extremes. Wetlands provide essential local and global ecosystem services such as flood mitigation, carbon sequestration, and water quality improvement. The project is part of the Reversing Environmental Degradation in Africa and Asia (REDAA) programme, funded by the UK government, and aligns with efforts by JICA-ORI to assess flood mitigation strategies under changing climate and socioeconomic conditions.

What we are doing

The project, running from November 2023 to March 2025, aims to evaluate wetland ecosystem services using open-access tools such as Co$tingNature and WaterWorld. It will quantify these services, estimate their economic value, and model potential impacts of climate change and land use changes. Additionally, it will invest in long-term data collection infrastructure based on www.freestation.org open source designs and provide training on the tools used, ensuring that local stakeholders can continue using the findings beyond the project's duration. 

Expected Outcomes

The project will deliver a comprehensive assessment of wetland ecosystem services in the region, supporting more informed land-use planning and policy decisions. It will also enhance awareness and capacity among stakeholders regarding wetland conservation. A key output is an open-access Co$tingNature/local application tailored for the Kalu Oya and Mudun Ela basins, facilitating ongoing monitoring and management of wetland resources.

• We have built an instance of Co$tingNature/local for the basin, available here, including economic valuation

• We have carried out a range of analyses on baseline and scenario land use  for the basin

Example analyses

Outputs

• Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka: a literature review

• Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka: baseline ecosystem services modelled with Co$tingNature/local

• Climate and land use change impacts for the Kalu Oya/Mudun Ela basins, using Co$tingNature/local

• Total Economic Valuation of Wetland Ecosystems in the Kalu Oya and Mudun Ela Basins, Sri Lanka

• Live weather and flood level monitoring in the Kalu Oya

Partners

The project is led by the International Water Management Institute (IWMI) in collaboration with the Sri Lanka Land Development Corporation (SLLDC), King’s College London, and AmbioTEK, UK. It also involves the Japan International Cooperation Agency – Ogata Research Institute (JICA-ORI). Funding is provided by the UK’s Foreign, Commonwealth and Development Office (FCDO), managed by the International Institute for Environment and Development (IIED) as part of the Reversing Environmental Degradation in Africa and Asia (REDAA) programme.