Built towards the end of the 1st century BC, the hydrological system at Petra is vital for the protection of both visitors and monuments, notably the Khazne (Treasury) and its courtyard, from the potentially devastating impact of seasonal flash floods. Part of a multi-year effort to restore the ancient Nabataean hydrological system of retention and diversion dams and canals at Petra to active use, this AFCP project involved the restoration of the dam on the Wadi al-Jarra to function as designed.