Restoring irrigation systems for enhanced climate resilience, food and nutrition security, and rural livelihoods in Sri Lanka

Background

Sri Lanka’s Tank Cascade System (TCS) is an ancient irrigation system, unique to the country’s dry zone. An ecosystem in itself, the TCS consists of an intricate network of small to very large ‘tanks’ positioned along a gradient and connected through a series of canals. Within the system, paddy fields and dense forests coexist. The system’s vital role in food and nutrition security, rural livelihoods and local culture led to its designation as a Despite the TCS’s significance, the system has been deteriorating, and its sustainability is threatened by widespread tank neglect, rapid land use changes, and biodiversity loss, the impacts of which are exacerbated by the effects of climate change.[ii] Further, since 2019 Sri Lanka’s multiple crises—the political, economic and fuel crises, as well as the COVID-19 pandemic and rising cost of food—have pushed many households in the cascade landscape into food insecurity.[iii] To advance adaptation and resilience in the agriculture and water sectors, Sri Lanka’s NDC commits to restoring small tank cascades and individual tanks through 2030.

Activities

The project “Healthy Landscapes: Managing Agricultural Landscapes in Socio-ecologically Sensitive Areas to Promote Food Security, Well-being and Ecosystem Health” (short name: Healthy Landscapes Project) focuses on the rehabilitation and sustainable management of the TCS. Aligning with national priorities for climate resilience in the agriculture and water sectors outlined in Sri Lanka’s NDC and in partnership with local governments and communities, the project has restored five water tanks and 500 hectares of forests and micro-land uses.[iv],[v] At the same time, 300 farmers were trained in sustainable land management (SLM) practices such as the preparation of soil bunds, use of drip irrigation, and application of organic fertilizer (e.g., manure and compost). The project also partnered with two local women’s farming organisations to strengthen the livelihoods of 120 women farmers by supporting them with maize cultivation, ensuring they benefit from the growing demand for this crop. Finally, by organizing a workshop on smart agriculture for participants from both academia—including students, lecturers, and researchers—and government, the project highlighted emerging opportunities for local youth, encouraging them to stay in the cascade landscape, as opposed to moving to urban areas to pursue better livelihoods.

Impact

The Healthy Landscape Project’s restoration efforts improved the TCS’s ability to capture and store rainwater, enhancing local communities’ resilience to increasing rainfall variability and extreme weather events, including floods and droughts, in the dry zone. In fact, well water levels were maintained in surrounding villages during the prolonged drought of 2023-2024.[vi] Farmers trained in SLM practices applied their knowledge across 1,000 hectares of agricultural land minimizing soil erosion and water loss in their fields while improving soil fertility and helping to sustain crop productivity even under changing climate conditions. Additionally, SLM guidelines and policy recommendations for cascade landscape management developed under the project will be incorporated into national policy during the upcoming review, with 150 policymakers and implementers already sensitised on how to put these guidelines into practice. Finally, by cultivating 120 acres of maize, the 120 women farmers supported by the project collectively earned 25 million LKR (USD 82,000). This success clearly demonstrates the powerful impact of addressing gender disparities in access to and control over resources (such as land, water, and high-quality seeds), as well as skills training—Overall, the project contributed to safeguarding the TSC to benefit both current and future generations of cascade landscape communities.[viii]

Sources

[i] FAO. (2024). The Cascaded Tank-Village System in the Dry Zone of Sri Lanka, Sri Lanka. GIAHS. Retrieved November 6, 2024, from https://www.fao.org/giahs/giahsaroundtheworld/sri-lanka-cascaded-tank-village-system/en.

[ii] Ratnayake, S. S., Khan, A., Reid, M., Dharmasena, P. B., Hunter, D., Kumar, L., et al. (2022). Land Use-Based Participatory Assessment of Ecosystem Services for Ecological Restoration in Village Tank Cascade Systems of Sri Lanka. Sustainability, 14(16), 10180.

[iii] The World Bank. (2022). Sri Lanka Development Update. Protecting the Poor and Vulnerable in a Time of Crisis. Retrieved from https://documents1.worldbank.org/curated/en/099052823154036369/pdf/P179559078517c0bd0bcc20748bed66c540.pdf.

[iv] Ministry of Environment, Sri Lanka. (2021). Updated Nationally Determined Contribution. Retrieved from https://unfccc.int/sites/default/files/NDC/2022-06/Amendmend%20to%20the%20Updated%20Nationally%20Determined%20Contributions%20of%20Sri%20Lanka.pdf.

[v] Ministry of Environment, Sri Lanka. (2016). National Adaptation Plan for Climate Change Impacts in Sri Lanka, 2016-2025. Retrieved from https://www4.unfccc.int/sites/NAPC/Documents%20NAP/National%20Reports/National%20Adaptation%20Plan%20of%20Sri%20Lanka.pdf.

[vi] Alliance Bioversity & CIAR & CGIAR. (n.d.). Tank Cascade System (TCS): A Nature-based Solution for Achieving Climate Resilience in Sri Lanka’s Dry Zone. Retrieved from https://cgspace.cgiar.org/server/api/core/bitstreams/6d6d9005-c3e2-4db5-b229-24db22075061/content.

[vii] FAO. (2018). Country Gender Assessment of Agriculture and the Rural Sector in Sri Lanka.

[viii] Mendonce, S., Borelli, T., Hunter, D., Silva, A., Bandara, T., & Ratnayake, S. S. (2022). Healthy landscapes: Managing agricultural landscapes in socio-ecologically sensitive areas to promote food security, well-being and ecosystem health. Retrieved November 6, 2024, from https://hdl.handle.net/10568/127661.