But integrating new techniques like precision agriculture could also help increase land productivity, Geekiyange adds. “Sri Lanka should test these out for the benefit of our agriculture, so it will reduce the pressure on traditional systems,” he says. “That would help promote the sustainability of our agriculture in the dry zone.”
And while Dharmasena says that the cascade systems can only be replicated in regions with the requisite geological conditions, Geekiyanage explains that some of the accompanying ancient water-management technologies, such as conservation of the surrounding forest, could be applied in modern irrigation projects in Sri Lanka and beyond.
For instance, soil ridges can be used to control sediment flow and prevent blockages, Geekiyanage says. Unlike tank cascades, modern irrigation projects in Sri Lanka, such as the Mahaveli Development Project, have little concern for the environment, Geekiyangae says, “Every year, soil is washed out from vegetable farms in the upland and ends up in the reservoirs.”
Ancient knowledge, new uses
Back in Maeliya, Siriwardene remembers his childhood years; swimming with friends to pluck water lilies and white lotus to offer to the Buddha image in the temple. And still today, the tank is integral to the community.
Sri Lanka’s recent economic crisis has doubled the country’s poverty rates, but villagers in Maeliya are thankful for the tank that enables them to survive.
“We live because of this tank,” Siriwardene says. Every morning, fishers from the village hop on small wooden boats to catch freshwater fish like tilapia and snakeheads. They sell them fresh and dried on small makeshift stalls along the main road. People grow rice because we get water from the tank. We get fish from the tank. Everything has become very expensive in the country, but in our village people can sustain themselves thanks to this water.”
Traditional farming practices tied to tank cascade systems also have modern relevance, Geekyange says. During drought years, farmers with land close to the tank grew rice in a smaller area and shared the remaining land with others. When there was extreme drought, farmers grew rice in the tank bed itself, so they can preserve seed paddy for the next season. “It allows people to share available water resources for farming. It’s helped civilisations to survive.”