Abstract
Qanats are traditional irrigation systems, the construction and maintenance of which required collective action. Exploring their role as a venue for cooperation, we find a significant positive relationship between location of qanats and cooperative economic activities today by employing unique geo-coded data on ancient qanats in Iran together with information collected and digitized on cooperatives at the sub-province level. We build an IV using grid-level geological preconditions necessary for the construction and functioning of qanats: intermediate clay content and gentle terrain slope. The cooperation culture nurtured at qanat sites persists particularly close to historical trade routes and in areas with stable climatic conditions.