Archaeological finds show how past societies adapted to variable environmental conditions and which techniques succeeded or failed. The water-management techniques of ancient peoples often worked on a local level. Unlike many modern-day water-management projects that include large dams and the rerouting of river water, these local methods are cheaper, more sustainable and don’t need as much oversight from distant authorities.

Complications arise from the many aspects of human societies that do not leave traces in the archaeological record, for example religion or social organization. Such aspects can have a large impact on human behaviour and don’t always lead to rational responses to external threats. So to implement ancient techniques successfully today, it’s important to understand ancient methods in their sociocultural context.

With that in mind, Kaptjin cites the example of the Mexican province of Tabasco, where the government tried to reinstate an old agricultural technique that used raised fields in swamps and lakes. These Chinampas were favoured by Aztec and Mayan societies across the region. The first modern attempt saw Chinampas built using bulldozers and without the involvement of archaeologists and local farmers. This led to failed harvests and a mismatch between the crops produced and market demands. After strict regulations were dropped, local indigenous peoples were able to build and farm the Chinampas more successfully.

A second example are the Cochas in Peru – natural depressions used by Inca societies to store rain and run-off. A modern-day implementation recruited local people as community messengers to advocate for the practice. These messengers informed local communities about the necessity of adaptation to climate change and functioned as contacts locals could turn to when problems arose.

The main lessons learned from this study, which appeared in Wiley Interdisciplinary Reviews: Water, are that modern-day planners need a detailed understanding of the ancient techniques. This includes the geological and geomorphological environment and details of the technical execution, as well as the socio-cultural context in which the method was developed and whether it’s translatable to the modern situation. And the involvement of local communities and inclusion of their environmental knowledge from an early stage is fundamental to success today. But if these lessons are accounted for, the past has great potential for the future.