The International Water Management Institute (IWMI), in partnership with Sri Lanka Land Development Corporation (SLLDC), Kings College London and AmbioTEK, UK, is conducting a project on wetland ecosystem modelling, and economic valuation in the Kalu Oya and Mudun Ela Basins in Sri Lanka. The focus of the project is to: 1) gain a better understanding of the current and future value of wetland ecosystem services; and 2) effectively communicate the value of the contributions made by wetland ecosystems to the people. Project Brief The 18-month project, which commenced in November 2023, is a contribution to the Reversing Environmental Degradation in Africa and Asia (REDAA) program funded by the UK government. The project supports ongoing work conducted by the Japan International Cooperation Agency – Ogata Research Institute (JICA-ORI) to assess the effectiveness of flood mitigation measures in urban areas, under changing climate and socioeconomic conditions. Peralanda Wewa, a wetland-based walking path in Wattala Divisional Secretariat within the Kalu Oya Basin in Sri Lanka (photo: Chaturangi Wickramaratne/IWMI). Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka IWMI • 2 Project Brief • Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka Background The project site (7.0215° N, 79.9625° E) is located within the Gampaha district of the Western Province (Figure 1) and covers an approximate area of 70 km². The catchments (Kalu Oya and Mudun Ela basins within the larger Kelani River Basin) are spread across five Divisional Secretariat Divisions, Wattala, Mahara, Kelaniya, Biyagama and Ja Ela, which cover nearly 140 Grama Niladhari Divisions. The catchments have high population densities, exceeding 6000 persons per km², and nearly twenty times higher than the country’s average population density. Both catchments are highly vulnerable to flooding due to land use changes caused by rapid urbanization. The remaining wetlands and vegetation patches in the catchment are vital for flood protection and provide a range of ecosystem services (Figure 2). Urban wetlands in Sri Lanka, provide a range of benefits including flood mitigation, thermal cooling, carbon sequestration, recreation/education, water quality improvement, agriculture, fisheries and others which contribute to the well-being of local communities. Project activities The project’s main aim is to evaluate the value of several ecosystem services provided by wetlands in the Kalu Oya and Mudun Ela basins. To this end, the project will conduct the following activities: • Evaluate and quantify a range of wetland ecosystem services using open-access tools: Co$tingNature and WaterWorld (https://www.policysupport.org). • Estimate the economic value of these ecosystem services using modelled results supplemented by local expertise and knowledge. • Investigate the variation in potential wetland ecosystem services under several scenarios related to climate change, in conjunction with potential future land development and restoration/conservation schemes. • Facilitate long-term data collection by investing in sensors upstream and downstream of wetlands to measure discharge, water storage and the flood attenuation role of the wetlands. • Conduct training on the Co$tingNature and WaterWorld tools for stakeholders engaged in wetland management in the basins and develop a bespoke application for the Kalu Oya and Mudun Ela basins that will be available open-access for use during and beyond the project. Figure 1. Location of Kalu Oya and Mudun Ela basins within the Gampaha District of Sri Lanka. IWMI • 3Project Brief • Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka Figure 2. A wetland-based walking path that provides recreational services to the local community, in Mahara Divisional Secretariat within the Kalu Oya Basin in Sri Lanka (photo: Chaturangi Wickramaratne/IWMI). Project outputs Title Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka Overall project impact Wetland ecosystem services provided wetlands in Kalu Oya and Mudun Ela basin are assessed and valued to inform effective decision-making related to land use planning in the region; increased capacity and awareness on wetland ecosystem services in peri-urban context Work Package 1 Review of existing models, research and expertise, and the integration of the work planned with the JICA-ORI program Work Package 2 Baseline biophysical assessment of ecosystem services Work Package 3 Impacts of climate change on ecosystem services Work Package 4 Valuation of ecosystem services Work Package 5 Dissemination, capacity building, training and legacy Partners International Water Management Institute (IWMI), Colombo, Sri Lanka Sri Lanka Land Development Corporation (SLLDC), Sri Lanka King’s College London, UK AmbioTEK Community Interest Company, UK Japan International Cooperation Agency (JICA) Ogata Research Institute (ORI), Japan Funder Foreign, Commonwealth and Development Office (FCDO) Project timeframe November 1, 2023 to March 31, 2025 IWMI • 4 Project Brief • Wetland ecosystem modelling and valuation in Kalu Oya Basin, Sri Lanka International Water Management Institute (IWMI) Headquarters 127 Sunil Mawatha, Pelawatte, Battaramulla, Sri Lanka Mailing address: P. O. Box 2075, Colombo, Sri Lanka Tel: +94 11 2880000 Fax: +94 11 2786854 Email: iwmi@cgiar.org www.iwmi.org The International Water Management Institute (IWMI) is an international, research-for-development organization that works with governments, civil society and the private sector to solve water problems in developing countries and scale up solutions. Through partnership, IWMI combines research on the sustainable use of water and land resources, knowledge services and products with capacity strengthening, dialogue and policy analysis to support implementation of water management solutions for agriculture, ecosystems, climate change and inclusive economic growth. Headquartered in Colombo, Sri Lanka, IWMI is a CGIAR Research Center with offices in 15 countries and a global network of scientists operating in more than 55 countries.IWMI is a CGIAR Research Center Published: June 2024 Source Some information in this brief was extracted from the following source: Weerakoon, D.; Piyadasa, R.; Serasinghe, P.; Herath, V.; Sakalasooriya, N.; Peiris, N.; Rathnasekera, S.; Pallethenne, T.; Dharmasoma, I.; Gunasiri, C.; Pindeiya, D.; Siripala, R.; Wijerathne, N.S. 2018. Consultancy services report on the preparation of wetland management strategy for the Kalu Oya and Mudun Ela Basins. Colombo, Sri Lanka: Sri Lanka Land Development Corporation (SLLDC). Unpublished. Acknowledgments Funding received from the Reversing Environmental Degradation in Africa and Asia (REDAA) program (www.redaa.org) is gratefully acknowledged. The REDAA program is funded by UK International Development from the Foreign, Commonwealth and Development Office (FCDO) and managed by the International Institute for Environment and Development (IIED). This study contributes to the CGIAR Initiative on NEXUS Gains (https://www.cgiar.org/initiative/28-nexus-gains-realizing-multiple-benefits- acrosswater-energy-food-forest-biodiversity-systems/). We would like to thank all funders who supported the initiative through their contributions to the CGIAR Trust Fund (https://www.cgiar.org/funders/). Disclaimer This publication has been created with care. Responsibility for opinions expressed and any possible errors lies with the authors and not the partner institutions involved. The boundaries and names shown and the designations used on maps do not imply official endorsement or acceptance by IWMI, CGIAR, our partner institutions and donors. Contacts Chaturangi Wickramaratne (IWMI Project Leader), Researcher-Freshwater Ecology - Sustainable Water Infrastructure and Ecosystems, International Water Management Institute (IWMI), Colombo, Sri Lanka (c.wickramaratne@cgiar.org) Mark Mulligan (Project Leader), Professor of Physical and Environmental Geography, King’s College London, UK (mark.mulligan@kcl.ac.uk) Priyanie Amerasinghe (Human and Environmental Health Specialist), Emeritus Scientist, IWMI, Colombo, Sri Lanka (p.amerasinghe@cgiar.org) Abandoned paddy fields in Gampaha District within the Kalu Oya Basin in Sri Lanka (photo: Chaturangi Wickramaratne/IWMI).