I'll be dammed: Efficiency and cost-analysis of a rehabilitated prehispanic dam in the Andes

Abstract

Within archaeology there is a growing shift away from the purely aesthetic towards making the past relevant to present and future needs and demands. The Past Water Futures project charts the impact of ancient dam rehabilitation on climate change‐induced water scarcity in the North Central Andes. The rehabilitation of late period (AD 750–1532) Prehispanic dams is a novel approach to assuage increasing water shortage among the rural communities of the Andean highlands. Nevertheless, until now, we lacked data on the real‐time impact of these modern conservation and rehabilitation projects. Here we present preliminary results, including volume capacity, potential demand, hydrological and hydraulic analysis and a reservoir filling log of the Prehispanic Weetacocha ‘Lake of Flowers’ Dam, which was rehabilitated in late 2024. Weetacocha belongs to the rural community of Racratumanka, District of Pamparomás, Province of Huaylas, Ancash Region, Peru. Importantly, we analyse the cost per m3 unit of water recovered through the rehabilitation of the Weetacocha Dam, proving that the restoration of water dams can provide a viable, cost‐effective, community‐led, sustainable alternative to modern micro‐dam construction in the Central Andes and potentially further afield.