Ancient water tanks of Sri Lanka to adapt to a changing climate

Director: Marta Baraibar
2D and 3D Animations: Alex Petrovsky

Over 2400 years ago, in Sri Lanka, a tiny country near the southern tip of India, flourished into one of the finest hydraulic civilizations of the world. This country, at the core of the south east monsoon, has 80% of its territory covered by a dry zone prone to water scarcity. Its ancient kings built a sophisticated network of small tanks connected by canals to large reservoirs to collect and redistribute every single drop of rain the land received. The tanks were built in cascading systems, using the natural inclination and topography of the land, full of small watersheds. They kept the natural cycle of water through soil, vegetation and atmosphere. The main goal of the system was to save and re-use water, allowing cultivation of rice in the dry zone. Tanks, paddy fields, watersheds, canals and natural ecosystems were perfectly interlaced.

The cascade system was perfectly adapted to cope with Sri Lanka’s climate, characterized by recurrent droughts and floods. The tanks were equipped with features to prevent floods, preserve water and control evaporation.

Today, Climate Change is exposing Sri Lanka to higher temperatures, heavier and more irregular rains and longer droughts, and most of the cascade systems are in disrepair.

The ancient tank's design and construction sophistication was poorly understood by modern engineers and some key features were dropped. During the colonial era tank cascade systems were neglected and abandoned. Many farmers accumulate debts and hope for the rains to come on time. Kidney disease has become a national problem due to drinking of water, contaminated by agro-chemicals from the fields and compounded by rainfall shortages, adding serious health expenses to already strained rural budgets.

The Ministry of Disaster Management of the Government of Sri Lanka with the support of UNDP is working to adapt to the new climatic conditions.

Ancient kings were visionaries. Their sophisticated system of tanks, canals and reservoirs kept a perfect ecological balance and was able to mitigate droughts, cool down temperature and save water. For this reason, the Government of Sri Lanka and UNDP are rehabilitating 33 tanks that were in disrepair and need upgrading given the new climate change realities that are unfolding in this part of the world. In doing so, the Government and UNDP will also reintroducing ancient elements that have been forgotten over the centuries.

Rehabilitating tanks will make communities more self-sufficient, allowing them to produce a surplus of crops from home gardens and rice, which Sri Lanka’s farmers associate to their very own cultural identity.

UNDP is also supporting Sri Lanka to use geospatial data on disasters, climate change and socioeconomic conditions to identify the most needed interventions. UNDP and USAID are also supporting the publication of a study on the economic cost of climate change.

UNDP’s holistic approach to support Sri Lanka to adapt to a changing climate and its work to revive millenary ecological wisdom has brought back hope to people like Ganga.

Learn more: http://adaptation-undp.org/projects/s...