Radiocarbon dating of Jerusalem’s Siloam Dam links climate data and major waterworks

Using well-established microarchaeological sampling methods, we reached a precise radiocarbon date of 800 BC for the Siloam Pool’s monumental water dam in Jerusalem. This date is a critical link connecting several imposing waterworks constructed at that time. Climate data pointing to droughts and flash floods during the last decades of the 9th century BC provide a logical framework for the reasons behind such endeavors. These included the fortification of the city’s primary water source, the Gihon Spring, and the redirection of the water into the city through a channel to an artificial reservoir created by building the Siloam Dam at the end of the Tyropoeon Valley, which blocked the drainage of rain and redirected spring waters.