The millennium-old hydrogeology textbook <i>The Extraction of Hidden Waters</i> by the Persian mathematician and engineer Abubakr Mohammad Karaji (953&thinsp;CE–1029&thinsp;CE)

Abstract

We revisit and shed light on the millennium-old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Karaji. Despite the nature of the understanding and conceptualization of the world by the people of that time, ground-breaking ideas and descriptions of hydrological and hydrogeological perceptions such as components of hydrological cycle, groundwater quality and even driving factors for groundwater flow were presented in the book. Although some of these ideas may have been presented elsewhere, to the best of our knowledge, this is the first time that a whole book was focused on different aspects of hydrology and hydrogeology. More importantly, we are impressed that the book is composed in a way that covered all aspects that are related to an engineering project, including technical and construction issues, guidelines for maintenance, and final delivery of the project when the development and construction were over. We speculate that Karaji's book is the first of its kind to provide a construction and maintenance manual for an engineering project.