The irrigation systems of the Malwathu Oya river are a legacy of the Sri Lankan ancient hydraulic revolution. Even today, the basin has hundreds of small inter-connected rainwater storage tank cascade systems, and larger reservoirs. Some of the large irrigation tanks provide multiple services such as water for irrigation and livestock, water for municipalities, households, industries and aquaculture and fulfil the water requirement of the natural ecosystems and sanctuaries. New water resources development projects are being implemented including a construction of a new dam at the Lowar Malwatu Oya area and the rehabilitation of abandoned and degraded tanks.

In recent times, due to the impacts of climate change, the Malwathu basin is prone to water scarcity and floods which affects the country’s economy, people’s health and livelihoods, dairy, fisheries, industry, ecosystems and wildlife. At different times of the year, people in the project area suffer from severe scarcity of water and devastation of properties due to floods. No adequate data and information are available for proper planning and management of water resources. The success of newly planned water sector development investments will depend on sound planning and up-to-date, reliable information