While virtual reconstruction commonly aims to visualise the past, this article argues that its knowledge production can also contribute to heritage future-making. We explore this in the ruins of the Capuchos Convent in Alferrara, Portugal, a largely forgotten site founded by Franciscan friars in the sixteenth century. After nearly two centuries of abandonment, and midway through a 25-year recovery plan, the site’s identity is being reconsidered through new trajectories and heritage programmes that echo past uses while responding to increasing drought and water scarcity in southern Portugal. These include selective recovery, curated decay, and agricultural learning rather than total restoration. Key to this is the convent’s sophisticated gravity-fed hydraulic system. Currently inactive, its network of mines, channels, conduits, and storage tanks allowed the former community to inhabit and cultivate the landscape across centuries. Combining non-invasive digital surveying with comparative analysis and local testimony, we clarify the remaining fragments of this system while showing how this knowledge identifies pathways for further interpretation and reactivation. The research contributes to underdeveloped discussions on virtual reconstruction as heritage practice by showing how knowledge generated from derelict and forgotten sites can inform future-oriented decisions about interpretation, selective intervention, and possible reuse in the Anthropocene.